Sage Journals: Discover world-class research

Abstract

Luteinizing hormone is now available as the recombinant product, lutropin alfa for the treatment of female infertility. It is necessary in the natural process of follicular growth and maturation. It is not yet clear which patients really benefit from the addition of this medication to conventional gonadotropin stimulation procedures in infertility treatment. Certainly, it has a proven benefit in patients suffering from hypogonadotropic hypogonadism (WHO I). Others may be older patients, patients with a profound gonadotropin suppression stimulated in long gonadotropin-releasing hormone agonist protocols, or patients with poor ovarian response to conventional stimulation strategies. The available data are reviewed herein.

Keywords

gonadotropin hypogonadism hypogonadotrophic lutropin alfa ovarian stimulation poor response recombinant technology

Luteinizing hormone & oocyte maturation

It is well documented that in women with regular cycles, a basal luteinizing hormone (LH) concentration is secreted throughout the early to mid-follicular phases of the cycle, followed by a midcycle LH surge that triggers final oocyte maturation [1]. Gougeon reported that oocyte maturation is not a process that occurs in one menstrual cycle, but the end point of an almost 1-year period in the face of repeated cycles of changing gonadotropin levels [2]. The first months of oocyte development up to the late secondary follicle are follicle-stimulating hormone (FSH) independent [3], but the influence of FSH increases during later stages. However, the recruitment of follicles, selection of a leading follicle and ovulation are the result of the combined effects of FSH and LH. The so-called two-cell-two-gonadotropin theory means that LH stimulates the theca cell layer to secrete androgens, which diffuse to the granulosa cells and are aromatized to estrogens under the influence of FSH [4]. Therefore, a balance between these two gonadotropins is necessary to achieve a regular ovulatory cycle.

This theory was recently revisited as it has been demonstrated that LH receptors are expressed by granulosa cells during the intermediate follicular phase [5 –7]. This means that LH directly contributes to optimizing growth and steroidogenesis of the leading follicle and favors atresia of small follicles. Therefore, using these receptors, LH has an influence not only on the theca cells but also on the granulosa cell layer [8].

Detrimental effects of high LH levels have been described in women with polycystic ovary syndrome (PCOS) who showed disrupted follicular maturation and often multiple small follicles on ultrasound [9]. Actual data regarding the relationship between PCOS and insulin resistance have demonstrated that the high LH level in these cases is an epiphenomenon of insulin resistance and that the latter could be the reason for the higher abortion rates in PCOS patients. Using insulin-sensitizing agents may therefore be an alternative to increase treatment efficacy [10]. However, the problem of LH and disturbed folliculogenesis in PCOS is not directly comparable due to additional variables (i.e., insulin resistance and hyperandrogenemia) influencing ovarian function.

Howles and MacNamee suggested an ‘LH window’ for normal follicle growth and concluded that follicle atresia and premature oocyte maturation would occur if LH levels exceeded this window [11].

Starting from this knowledge, later in vitro studies established the so-called ‘ceiling’ level of LH and the ‘LH therapeutic window’ [12 –14]. It postulates that there is not only a threshold requirement for LH but also a ceiling level beyond which LH might be deleterious to ovarian stimulation [15,16]. Tesarik and Mendoza obtained the same findings in an oocyte-donation model [17]. In their study, donors with a deeply suppressed pituitary LH (<1 IU/l) had significantly more mature oocytes, good-quality embryos and a higher implantation rate after supplementation of exogenous LH. This was in contrast to supplemented donors with a prestimulation serum LH level of 1 IU/l or greater.

The LH ceiling concept

It has been demonstrated in an LH dose-finding study in WHO class I infertile women (hypogonadotrophic, hypogonadal patients) that ovarian stimulation with 225 IU recombinant human (r-h)LH in combination with r-hFSH 150 IU/day led to fewer follicles in comparison with r-hLH 75 IU [18]. The negative influence of high LH levels on follicular maturation was confirmed in two randomized, placebo-controlled studies [19].

A recent study further supported the LH ceiling theory and confirmed that, considering a fine balance between FSH and LH, both gonadotropins are necessary during follicular development [20]. Hugues and colleagues concluded from their study that in patients over-responding to FSH during ovarian stimulation, doses of up to r-hLH 660 IU/day appear to increase the proportion of patients developing a single dominant follicle (≥16 mm) [20]. The proportion of patients with a single dominant follicle was increased from 13.3% in the placebo group to 32.1% in the r-hLH 660 IU group (p = 0.048), demonstrating the ability of LH to influence the development of the follicular cohort.

It is especially interesting when taking into account the data published by Filicori and colleagues [21,22]. They postulated that human chorionic gonadotropin (hCG) 400 IU/day in the late stimulation phase of a long gonadotropin-releasing hormone (GnRH) agonist/r-hFSH protocol may result in a lower oocyte yield and premature luteinization. In contrast, hCG 100 or 200 IU/day lowered the r-hFSH consumption and increased the number of mature follicles and oocytes retrieved. Stokman and colleagues compared the bioactivity of LH and hCG and found hCG 6 IU was equivalent to approximately 50 IU of LH (ratio approximately 1:8) [23]. Transferred to the data by Filicori and colleagues, hCG 400 IU is equivalent to approximately 3200 IU of LH [21]. In conclusion, the cited studies described different LH ceiling levels (225–660 to 3200 IU/day). These differences are a matter of debate and must be the focus of further studies.

LH & ovarian stimulation

From experiences with ovarian stimulation in hypogonadotrophic, hypogonadal patients, the importance of an LH threshold that must be exceeded to mature normal ovarian follicles is known. One possible stimulating agent is urinary human menopausal gonadotropin (hMG), but during the last few years, all necessary components (FSH, LH and hCG) have become available as recombinant agents. A trial to stimulate WHO I patients with r-hFSH alone resulted in a normal follicular growth but low estradiol levels (hCG 228 pg/ml/day, seven oocytes retrieved, endometrial thickness 5 mm) and a low fertilization rate of 28% (2/7). The fertilization rate increased to 93% (13/14) using only hMG (estradiol hCG 5073 pg/ml/day, 14 oocytes retrieved, endometrial thickness 10 mm), which proves the necessity of LH for ovarian stimulation in WHO I patients [24]. The efficacy of an exogenous recombinant LH preparation was first described some years ago [25].

In another study, different r-hLH dosages were added to r-hFSH for ovarian stimulation in WHO I patients [18]. A total of 38 patients (28 with primary and 10 with secondary hypogonadotrophic hypogonadism) were prospectively randomized for ovarian stimulation with either r-hFSH in a fixed dose of 150 IU/day alone or with the addition of different doses of r-hLH (25, 75 or 225 IU). Ovarian stimulation was continued for up to 20 days. Ovulation was induced with urine (u)-hCG 10,000 IU when a follicle reached at least 17 mm in diameter. Treatment with higher doses of LH (75 and 225 IU) resulted in a higher number of follicles compared with the group without LH or with a low LH dose (25 IU). Furthermore, estradiol level increased with the LH dose and a positive influence on the endometrium was documented. The authors concluded from their data that a dose of r-hFSH 150 IU and r-hLH 75 IU led to an optimal ovarian reaction.

Patients stimulated in a long GnRH-agonist protocol are said to be in a comparable situation to women with hypogonadotrophic hypogonadism (WHO I). In this protocol, downregulation of the hypophysis with a GnRH agonist starts in the late luteal phase, followed by ovarian stimulation after achieving hypogonadal status. The LH level in these patients is often below the lower detection level of the LH assay. In contrast to the hypogonadotrophic patient, ovaries of patients treated in a long protocol are free from the influence of LH for days, whereas hypogonadotrophic hypogonadal patients may be without the influence of LH for many years. Therefore, it is not appropriate to extrapolate data directly from one group to the other and separate studies are necessary to come to final conclusions.

Low LH levels in long GnRH-agonist cycles

Studies analyzing the reproductive outcome in patients treated with highly purified urinary FSH (u-FSH-HP) or r-hFSH have demonstrated different results with different LH thresholds [26]. This is in contrast to the data from the LH dose-finding study [18] as well as the observation that the results using r-hFSH are better than those obtained using u-FSH-HP and at least as good as those with hMG [27,28]. Different observational studies, including patients stimulated with FSH in long GnRH-agonist protocols, examined the influence of serum LH level on reproductive outcome (Table 1) [26,29 –34].

Table 1.

Studies dealing with the influence of LH levels on reproductive outcome in patients stimulated with FSH in a long GnRH-agonist protocol.

Study design	Protocol	LH measurements	LH level (IU/I)	n		Effects	Ref.

				LH↑	LH↓
Retrospective	Long luteal protocol (buserelin 4 × 200 μg intranasal/day) + u-FSH-HP	Day 7	<0.7	125 160	271 536	Rate of low response ↑ Duration of gonadotropin stimulation ↑ Estradiol (hCG day) ↓ Number of oocytes ↓ Estradiol (hCG day) ↓	[26]
Prospective	Long luteal protocol (buserelin 4 × 200 μg intranasal/day) + u-FSH-HP	Day 7, 8 or 9	<0.5	20	41	Number of oocytes (trend) ↓ Fertilization rate ↓ Supernumerary embryos ↓ Normal blastocyst rate	[29]
Retrospective	Long luteal protocol (leuprolide acetate 0.5 mg/day s.c.) + r-hFSH	Day 8	<0.5	98	102	Estradiol (hCG day) ↓ Similar clinical pregnancy rate Abortion rate ↑	[30]
Retrospective	Long luteal protocol (leuprolide acetate 0.5/0.25 mg/day s.c.) + r-h FSH	Day 5 (4–5 values averaged starting on day 5)	<3.0	116	50	Fertilization rate ↓ Biochemical abortions (trend) ↑	[31]
Prospective	Long luteal protocol (leuprolide acetate 0.5 mg/day s.c.) + r-hFSH	Day 6 and 9	<2.0	95	77	Duration of gonadotropin stimulation ↓ Estradiol (hCG day) ↓ Number of oocytes ↓ Pregnancy rates ↓	[32]
Retrospective, controlled	Long luteal protocol (leuprolide acetate 1.0/0.5 mg/day s.c.) + r-hFSH	Day 7	<0.5 <0.7 <1.0	10 21 44	134 123 100	No effects	[33]
Retrospective	Long luteal protocol (leuprolide acetate 0.8/0.4 mg/day s.c.) + r-hFSH	Day 8	<0.5 0.51–1.0 1.01–1.5 >1.5	24 108 38 37	183 75 37 –	Number of fertilized oocytes ↓ Fertilization rate ↓*	[34]

Negative effects with LH levels > 1.5 IU/I were more severe than those corresponding to low LH levels: significantly lower implantation rate than in patients with LH < 0.5 IU/I and significantly lower clinical pregnancy rate compared with LH 0.5–1.0 IU/I.

FSH: Follicle-stimulating hormone; GnRH: gonadotropin-releasing hormone; hCG: Human chorionic gonadotropin; LH: Luteinizing hormone; r-h: Recombinant human; s.c.: Subcutaneous; u-FSH-HP: Highly purified urinary FSH.

The conflicting results can be caused by the use of different types and amounts of GnRH agonists, modes of administration and the detection limit of the LH assay used, making it difficult to compare studies performed in individual centers. However, there may be a threshold below which LH needs to be replaced to guarantee optimal ovarian stimulation. The main question is: how low is this threshold and how often does it occur?

One can assume that it is a problem of a small subgroup of patients in long GnRH-agonist protocols. Furthermore, it has been established that less than 1% of LH receptors must be occupied to achieve an optimal ovarian response [35].

Balasch and colleagues analyzed different LH threshold levels (0.5, 0.7 and 1.0 U/I) in relation to the abortion and pregnancy rates in an in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) program [33]. They found no significant difference between the groups regarding these two parameters.

The problem seems to be an empirical addition of exogenous LH, which may negatively influence the therapeutic outcome. This conclusion was supported by another study comparing a GnRH-agonist long protocol, either with r-hFSH alone or in combination with r-hLH [36]. The duration of ovarian stimulation and estradiol levels on the day of hCG were not statistically different in both groups. But there was a higher rate of metaphase II oocytes in the r-hFSH group, with a higher fertilization rate and a lower rate of fertilization failure.

The data were confirmed, for example, by Humaidan and colleagues [34]. They too described, in a long protocol, that optimal results were achieved in patients whose LH levels were in the range 0.51–1.5 IU/I on cycle day 8. If the LH levels increased above this point, the patients had a lower pregnancy rate. The outcome was less favorable than that found in patients with LH levels of 0.5 IU/I or lower. Obviously, a functional deficit of LH, more than an LH excess, could lead to a suboptimal result. They suggest that a discrepancy between circulating LH levels and LH bioactivity may exist in vivo. Women displaying high LH levels may have a less active form, requiring exogenous LH. These conflicting results further indicate that a certain threshold level of LH might be required in endo-crinologically healthy patients during ovarian stimulation in GnRH-agonist protocols. If LH falls below this cut-off, poor results are the consequence. However, the discrepancies among the studies do not allow the definition of a clinically useful cut-off level that identifies women who require LH supplementation.

Ho and colleagues described that a higher FSH:LH ratio (≥3) on the first day of stimulation following administration of a GnRH agonist in a long-luteal protocol is associated with a poor response [37]. In a retrospective study of 240 short GnRH-agonist cycles, the implantation rates were lower if the LH level on stimulation day 8 was 5 IU/I or lower [38]. Explanations for this phenomenon could be a resulting excess of androgens, which may subsequently disrupt follicular and oocyte maturation [33,39].

Importance of flexible LH administration during ovarian stimulation in long GnRH agonist protocols

After the introduction of r-hLH, many studies have been performed dealing with the key question: is LH supplementation in GnRH-agonist protocols useful? In contrast to urinary preparations of hMG containing LH with a high batch-to-batch variability in hCG and LH content, the r-hLH filled by mass allows a precise titration of the individual amount of LH necessary during ovarian stimulation with r-hFSH. Two interesting subgroups of patients initially studied were poor responders [40] and patients who respond inadequately to FSH stimulation [41,42]. In addition, Marrs and colleagues [43] and Humaidan and colleagues [44] postulated from their results that patients aged 35 years or older benefited from LH supplementation in terms of increasing the number of mature oocytes retrieved.

LH supplementation in potentially normal responders

Three different studies clearly indicated that LH supplementation is not required in all women [43 –45]. Sills and colleagues compared the IVF outcome in two age-matched groups receiving either FSH-HP alone (n = 17) or FSH-HP plus r-hLH (n = 14) in a long GnRH-agonist protocol (leuprolide acetate 1 or 0.5 mg/day subcutaneously) prospectively [45]. They found a trend toward better pregnancy outcomes in patients stimulated with FSH-HP alone (mean implantation rate 26.9 vs 11.9%; clinicial pregnancy rate/initiated cycle: 64.7 vs 35.7%). Due to the small study groups, these differences did not reach statistical significance. In another prospective, randomized study, 231 normogonadotrophic patients were stimulated with either r-hFSH alone (n = 115) or r-hFSH plus r-hLH in a ratio of 2:1 (n = 116) in a long GnRH-agonist protocol [44]. These groups did not differ with respect to pregnancy rate. This result was confirmed by Marrs and colleagues, who also compared women stimulated with r-hFSH alone (n = 219) versus r-hFSH plus r-hLH (n = 212) [43].

Tarlatzis and colleagues performed a double-blind, randomized, prospective study in young normogonadotrophic women and compared ovarian stimulation with r-hFSH alone versus r-hFSH with additional r-hLH for the last few days of FSH stimulation in a long GnRH-agonist protocol [46]. They found no significant difference between the groups in all end points evaluated. These results confirm that only subgroups (as mentioned above) may benefit from r-hLH supplementation.

One difference between the studies was that LH was given at doses of 75–150 IU/day starting on different stimulation days. Nevertheless, all these studies were unable to demonstrate a clinical benefit of LH supplementation in normal responders. In contrast, in another prospective, randomized study (stimulation with r-hFSH vs r-hFSH plus hMG), LH supplementation increased the number of mature oocytes, fertilized oocytes and transferable embryos [47].

LH supplementation in patients aged 35 years or older

Humaidan and colleagues described significantly increased implantation rates in a subgroup of women aged 35 years or older supplemented with r-hLH in a long GnRH-agonist protocol [44]. The total FSH consumption necessary was significantly lower in comparison with nonsupplemented controls. An additional subgroup of women with LH levels higher than 1.99 IU/I on stimulation day 8 had a benefit with regard to the treatment outcome.

Patients in the older age group may need LH supplementation to achieve good ovarian response and follicular maturation. Endogenous LH, as well as FSH, levels increase with age and the onset of menopause [48]. This may be caused by a decreased number of functional LH receptors [49] and a different biological activity of endogenous LH [50 –53], resulting in an increased resistance to LH-mediated processes [54].

Fabregues and colleagues could not confirm the benefit of r-hLH supplementation in this subgroup. In a prospective, randomized study, stimulation with r-hFSH alone or r-hFSH plus r-hLH in a long GnRH-agonist protocol (60 vs 60 patients) was compared [55]. Administration of r-hLH did not increase ovarian response and implantation rates in infertile women aged 35 years or older.

LH supplementation in women who abnormally respond to FSH

A further subgroup in whom LH supplementation could be beneficial is patients suffering from hypogonadotrophic hypogonadism (natural or induced). The latter group includes patients with GnRH-agonist depot preparations, especially in ultralong protocols of several months. It is well known that the degree of LH suppression in GnRH-agonist protocols varies between different preparations [56]. One can further speculate that patients with profound LH suppression may benefit from LH supplementation. In this context, the potential detrimental effect of excessive LH levels if a patient is oversupplemented must be carefully considered.

De Placido and colleagues performed three prospective, randomized studies on normogonadotrophic IVF patients stimulated with FSH in a long GnRH-agonist depot protocol [41,57,58]. In a subgroup of low responders to stimulation (estradiol < 180 pg/ml and no follicle > 10 mm on day 8 of FSH stimulation), they found a significant increase in the number of retrieved oocytes with increasing doses of LH. The number of oocytes was comparable to a control group after using 150 IU r-hLH [57]. In another study, they tested whether using 150 IU r-hLH from day 8 in a similar population of patients was associated with an improvement in outcomes compared with increasing the doses of r-hFSH [58]. Surprisingly, adding r-hLH, but not increasing r-hFSH, led to an improved clinical pregnancy outcome. Lisi and colleagues added r-hLH to r-FSH stimulation in IVF cycles (n = 12) of patients who needed more than 3000 IU r-hFSH in further stimulations without LH (n = 17) [40]. The result was significantly higher fertilization (60.9 vs 86%) and clinical pregnancy rates (5.9 vs 50%). De Placido and colleagues also suggested from their study that LH supplementation improves the ovarian outcome in patients characterized by an inadequate initial response to r-hFSH therapy in a long GnRH-ago-nist depot protocol [41]. In a subgroup of patients without follicles larger than 10 mm and an estradiol concentration of 0.6 pmol/ml or lower on stimulation day 8, the investigators added hMG 150 IU/day. The consequences were significantly higher estradiol concentrations on the day of hCG treatment and significantly more oocytes retrieved in comparison with controls, which were further stimulated with r-hFSH alone. Intriguingly, the addition of a small amount of r-hLH (75–150 IU/day), but not hMG, was able to rescue oocyte competence to produce viable embryos (inclusion criteria: plateau on follicular growth between cycle day 7 and 10) [42].

In this context, it has to be underlined that in almost all of these trials, women who benefited from LH supplementation had circulating LH levels comparable with those who normally responded to r-hFSH. This evidence is consistent with the previously mentioned data by Humaidan and colleagues [44], and reinforces the idea of possible discrepancies between immunoreactive and bioactive LH. Interestingly, some authors have recently suggested an association between ovarian resistance to r-hFSH monotherapy and the presence of an LH polymorphism (V-β LH) in normogonadotrophic women undergoing a GnRH-agonist long protocol [59]. This evidence suggests that women carrying a less effective form of LH, despite normogonadotrophism and regular ovulatory cycles, require higher FSH doses and/or LH supplementation during ovarian stimulation.

How can LH supplementation result in a positive effect? Foong and colleagues demonstrated that in low or poor responders during r-hFSH stimulation, intrafollicular estradiol was significantly lower and progesterone significantly higher in low and poor responders despite comparable peak estradiol levels to normal responders [60]. Concluding from these results, it seems that LH may have a beneficial effect through a mechanism that improves oocyte cytoplasmic maturation, either through estradiol or some other intraovarian factor. An additional effect on the endometrium itself cannot be excluded [61].

Importance of flexible LH administration during ovarian stimulation in GnRH antagonist protocols

Another controversial issue is the use of LH supplementation in patients receiving GnRH antagonists. This idea is related to the evidence that a rapid decline in both LH and estradiol concentration usually follows the administration of a GnRH antagonist. As a consequence, the oocyte/follicle unit may undergo dramatic and potentially detrimental changes due to the hormonal environment. On the other hand, a significantly higher pregnancy rate was described in patients with profound LH suppression (≤0.5 IU/l) on day 8 of stimulation (prospective, n = 116, r-hFSH 200 IU fixed from cycle day 2 and daily 0.25 mg GnRH antagonist from day 6 of stimulation) [62]. Some clinical trials have been designed in order to investigate the efficacy of LH supplementation in different subsets of patients treated with GnRH antagonists (Table 2) [63 –65].

Table 2.

Studies dealing with the influence of LH supplementation on reproductive outcome in patients stimulated with FSH in a GnRH-antagonist protocol.

Study design	Protocol	n		Effects	Ref.

		With r-hLH	Without r-hLH
Prospective	Single-dose GnRH antagonist (cetrorelix 3.0 mg when the leading follicle reached 14–16 mm) + r-hFSH	114	104	Higher estradiol level in the group with LH supplementation (p < 0.001) Similar number of oocytes/embryos Similar delivery and implantation rate	[63]
Prospective	Single-dose GnRH antagonist (cetrorelix 3.0 mg on stimulation day 7) + r-hFSH	21	21	Higher concentration of estradiol per follicle level in the group with LH supplementation (p = 0.022) Similar duration of stimulation Similar total dose of r-hFSH Similar number of oocytes/embryos Similar clinical pregnancy and implantation rate	[64]
Prospective	Multiple dose GnRH antagonist (cetrorelix 0.25 mg/day from stimulation day 6 up to and including the day of hCG) + r-hFSH	62	65	Higher estradiol level in the group with LH supplementation (p < 0.03) Higher LH level in the group with LH supplementation (p < 0.01) Similar duration of stimulation Similar number of oocytes/embryos Similar clinical pregnancy and implantation rate	[65]

FSH: Follicle-stimulating hormone; GnRH: Gonadotropin-releasing hormone; hCG: Human chorionic gonadotropin; LH: Luteinizing hormone; r-h: Recombinant human.

In spite of higher estradiol and LH levels on the day of hCG administration, no benefit of r-hLH supplementation in an unselected group of patients stimulated in a GnRH-antagonist protocol was found [63,65]. The only difference in patients stimulated with r-hFSH alone was a significantly lower concentration of estradiol per follicle [64].

In a prospective, randomized study De Placido and colleagues, patients at risk for a poor response (age ≥ 37 years or basal FSH on cycle day 2 ≥ 9 IU/l) were compared [66]. Patients were stimulated either in a short GnRH-agonist protocol (r-hFSH 300 IU/day plus triptorelin 0.1 mg/day starting on cycle day 2, 150 IU r-hLH starting when the leading follicle reached 14 mm; n = 62) or a GnRH-antagonist protocol (r-hFSH 300 IU starting on cycle day 2, GnRH antagonist 0.125 mg/day for 2 days starting when the leading follicle reached 14 mm, thereafter GnRH antagonist 0.25 mg/day, r-hLH 150 IU/day starting on the first day of GnRH antagonist; n = 62). The mean number of metaphase II oocytes was significantly higher in the antagonist group (5.73 ± 3.57 vs 4.64 ± 2.23; p < 0.05). It is not possible to conclude from the study if this benefit was a result of the antagonist protocol itself or of the additional r-hLH. Implantation rate and ongoing pregnancy rate demonstrated no significant differences between the groups.

Conclusion

As very low levels of LH are necessary for sufficient follicular development, lutropin alfa allows precisely controlled LH supplementation in patients who need additional LH. This subgroup of patients are women with a profound LH suppression in long GnRH agonist cycles, older patients and patients with low ovarian response to gonadotropin stimulation.

Future perspective

Ovarian stimulation has not really changed since its beginning in the 1950s. There are two main steps: gonadotropin stimulation and subsequent hCG administration. What has changed is the variety of stimulation protocols that are now available, with the introduction of the GnRH agonist in the early 1980s and the GnRH antagonists in the late 1990s. Furthermore, the gonadotropins have become more pure, more consistent and optimally defined by modern manufacturing techniques. Future studies should address the question of which patients really benefit from certain amounts and types of gonadotropins. It may be possible to modify the gonadotropin molecules to achieve an optimal response in individual patients. The first steps in this direction have been completed with modification of the C-terminal peptide in FSH molecules to increase their half-life [67]. However, other modifications may substitute certain genomic individualities in patients, such as LH-or FSH-receptor anomalies. Recent studies have demonstrated that this approach may really result in an improved outcome for the patients [68,69].

It is possible that, in the future, we will be able to screen a patient on a basis of certain gonadotropin and receptor anomalies and initiate an individualized scheme of gonadotropin stimulation with not only individualized amounts of gonadotropins, but also with an individualized mixture of different gonadotropin isoforms.

Executive summary

In the menstrual cycle, luteinizing hormone (LH) is important for follicle development and maturation.

According to the two-cell-two-gonadotropin concept, LH has its major impact on the theca cells for the production of androgen precursors.

A lower beneficial level of LH (threshold level) and a higher detrimental level of LH (ceiling level) has been suggested in the literature; however, these levels cannot yet be precisely defined.

There are some groups of patients (hypogonadotrophic hypogonadism, WHO I) who benefit from LH supplementation, since they do not have any endogenous LH activity.

Other groups, such as patients with severely suppressed levels of gonadotropins, especially LH, by the use of long-term gonadotropin-releasing hormone (GnRH)-agonist depot preparations, older patients, or patients with low response to conventional gonadotropin stimulation, may also benefit from LH supplementation.

Overall, the data from prospective, randomized studies are not yet able to ideally define these subgroups.

References

Papers of special note have been highlighted as either of interest (•) or of considerable interest (••) to readers.

Howles

: Role of LH and FSH in ovarian function. Mol. Cell. Endocrinol. 161, 25–30 (2000).

Gougeon

: Dynamics of follicular growth in the human: a model from preliminary results. Hum. Reprod. 1, 81–87 (1986).

Oktay

Newton

Mullan

Gosden

: Development of human primordial follicles to antral stages in SCID/hpg mice stimulated with follicle stimulating hormone. Hum. Reprod. 13, 1133–1138 (1998).

Ryan

Petro

: Steroid biosynthesis by human ovarian granulosa and theca cells. J. Clin. Endocrinol. Metab. 26, 46–52 (1966).

Erickson

Wang

Hsueh

: FSH induction of functional LH receptors in granulosa cells cultured in a chemically defined medium. Nature 279, 336–338 (1979).

Shima

Kitayama

Nakano

: Gonadotropin binding sites in human ovarian follicles and corpora lutea during the menstrual cycle. Obstet. Gynecol. 69, 800–806 (1987).

Hillier

Whitelaw

Smyth

: Follicular oestrogen synthesis: the ‘two-cell, two-gonadotrophin’ model revisited. Mol. Cell. Endocrinol. 100, 51–54 (1994).

Original ‘two-cell mechanism’ explained the endocrine regulation of follicular estrogen synthesis and implied paracrine signaling in the follicle wall. Different additional knowledge (influence of inhibin, luteinizing hormone [LH] receptor expression by granulosa cells) is added in this revised model

10.

Filicori

Cognigni

Pocognoli

Ciampaglia

Bernardi

: Current concepts and novel applications of LH activity in ovarian stimulation. Trends Endocrinol. Metab. 14, 267–273 (2003).

11.

Demonstrates that LH has an influence not only on the theca cells but also on the granulosa cell layer

12.

Adams

Polson

Abdulwahid

: Multifollicular ovaries: clinical and endocrine features and response to pulsatile gonadotropin releasing hormone. Lancet 2, 1375–1379 (1985).

13.

Glueck

Phillips

Cameron

Sieve-Smith

Wang

: Continuing metformin throughout pregnancy in women with polycystic ovary syndrome appears to safely reduce first-trimester spontaneous abortion: a pilot study. Fertil. Steril. 75, 46–52 (2001).

14.

Howles

MacNamee

: The endocrinology of stimulated cycles and influence on outcome. In: Advances in Assisted Reproductive Technologies. Mashiach

(Ed). Plenum Press, NY, USA, 311–325 (1990).

15.

Hillier

: Current concepts of the roles of follicle stimulating hormone and luteinizing hormone in folliculogenesis. Hum. Reprod. 9, 188–191 (1994).

16.

Shoham

: Treatment of female infertility with recombinant human luteinizing hormone: is there a benefit over other available drugs? Expert Opin. Pharmacother. 4, 1985–1994 (2003).

17.

Balasch

Fabregues

: Is luteinizing hormone needed for optimal ovulation induction? Curr. Opin. Obstet. Gynecol. 14, 265–274 (2002).

18.

Stanger

Yovich

: Reduced in-vitro fertilization of human oocytes from patients with raised basal luteinizing hormone levels during the follicular phase. Br. J. Obstet. Gynaecol. 92, 385–393 (1985).

19.

Howles

Macnamee

Edwards

Goswamy

Steptoe

: Effect of high tonic levels of luteinising hormone on outcome of in-vitro fertilisation. Lancet 30, 521–522 (1986).

20.

Tesarik

Mendoza

: Effects of exogenous LH administration during ovarian stimulation of pituitary down-regulated young oocyte donors on oocyte yield and developmental competence. Hum. Reprod. 17, 3129–3137 (2002).

21.

The European Recombinant Human LH Study Group: Recombinant human luteinizing hormone (LH) to support recombinant human follicle-stimulating hormone (FSH)-induced follicular development in LH- and FSH-deficient anovulatory women: a dose-finding study. J. Clin. Endcrinol. Metab. 83, 1507–1514 (1998).

22.

Loumaye

Engrand

Shoham

Hillier

Baird

: Clinical evidence for an LH “ceiling” effect induced by administration of recombinant human LH during the late follicular phase of stimulated cycles in World Health Organization type I and type II anovulation. Hum. Reprod. 18, 314–322 (2003).

23.

Two double-blind pilot studies in WHO I and WHO II anovulatory patients demonstrated that recombinant human (r-h)LH alone can trigger follicular growth arrest in a significant number of patients, suggesting the existence of an ‘LH ceiling’ during late follicular maturation

24.

Hugues

Soussis

Calderon

Balasch

Anderson

Romeu

, Recombinant LH Study Group: Does the addition of recombinant LH on WHO group II anovulatory women over-responding to FSH treatment reduce the number of developing follicles? A dose-finding study. Hum. Reprod. 20, 629–635 (2005).

25.

Filicori

Cognigni

Ferlini

: Prospective, randomized, dose finding study of human chorionic gonadotropin (hCG) administration in controlled ovarian stimulation (COS). Hum. Reprod. 20(Suppl. 1), S64–S65 (2005).

26.

Filicori

Cognigni

Gamberini

Parmigiani

Trailo

Roset

: Efficacy of low-dose human chorionic gonadotropin alone to complete controlled ovarian stimulation. Fertil. Steril. 84, 394–401 (2005).

27.

Stokman

de Leeuw

van den Wijngaard

Kloosterboer

Vemer

Sanders

: Human chorionic gonadotropin in commercial human menopausal gonadotropin preparations. Fertil. Steril. 60, 175–178 (1993).

28.

Balasch

Miro

Burzaco

: The role of luteinizing hormone in human follicle development and oocyte fertility: evidence from in-vitro fertilization in a woman with long-standing hypogonadotrophic hypogonadism and using recombinant human follicle-stimulating hormone. Hum. Reprod. 10, 1678–1683 (1995).

29.

Hull

Corrigan

Piazzi

Loumaye

: Recombinant human luteinising hormone: an effective new gonadotropin preparation. Lancet 344, 334–335 (1994).

30.

Fleming

Rehka

Deshpande

Jamieson

Yates

Lyall

: Suppression of LH during ovarian stimulation: effects differ in cycles stimulated with purified urinary FSH and recombinant FSH. Hum. Reprod. 15, 1440–1445 (2000).

31.

Daya

Gunby

: Recombinant versus urinary follicle stimulating hormone for ovarian stimulation in assisted reproduction. Hum. Reprod. 14, 2207–2215 (1999).

32.

Daya

: Gonadotropin releasing hormone agonist protocols for pituitary desensitization in in vitro ferilization and gamete intrafallopian transfer cycles. Cochrane Database Syst. Rev. 2, CD001299 (2000).

33.

Fleming

Lloyd

Herbert

Fenwick

Griffiths

Murdoch

: Effects of profound suppression of luteinizing hormone during ovarian stimulation on follicular activitiy, oocyte and embryo function in cycles stimulated with with purified follicle stimulating hormone. Hum. Reprod. 13, 1788–1792 (1998).

34.

Westergaard

Laursen

Andersen

: Increased risk of early pregnancy loss by profound suppression of luteinizing hormone during ovarian stimulation in normogonadotrophic women undergoing assisted reproduction. Hum. Reprod. 15, 1003–1008 (2000).

35.

Esposito

Barnhart

Coutifaris

Patrizio

: Role of periovulatory luteinizing hormone concentrations during assisted reproductive technology cycles stimulated exclusively with recombinant follicle-stimulating hormone. Fertil. Steril. 75, 519–524 (2001).

36.

Fanchin

Schönauer

Righini

Olivennes

Taieb

Frydman

: Beneficial effects of residual LH levels after GnRH agonist on ovarian response to r-FSH, embryo quality, and IVF-ET outcome. Fertil. Steril. 76(Suppl. 1), S91 (2001).

37.

Balasch

Vidal

Penarrubia

: Suppression of LH during ovarian stimulation: analysing threshold values and effects on ovarian response and the outcome of assisted reproduction in down-regulated women stimulated with recombinant FSH. Hum. Reprod. 16, 1636–1643 (2001).

38.

Humaidan

Bungum

Andersen

: Ovarian response and pregnancy outcome related to mid-follicular LH levels in women undergoing assisted reproduction with GnRH agonist down-regulation and recombinant FSH stimulation. Hum. Reprod. 17, 2016–2021 (2002).

39.

Chappel

Howles

: Reevaluation of the roles of luteinizing hormone and follicle-stimulating hormone in the ovulatory process. Hum. Reprod. 6, 1206–1212 (1991).

40.

Balasch

Creus

Fabregues

: The effect of exogenous luteinizing hormone (LH) on oocyte viability: evidence from a comparative study using recombinant human follicle-stimulating hormone (FSH) alone or in combination with recombinant LH for ovarian stimulation in pituitary-suppressed women undergoing assisted reproduction. J. Assist. Reprod. Genet. 18, 250–256 (2001).

41.

JYP

Guu

Chen

ESC

: The serum follicle-stimulating hormone-to-luteinizing hormone ratio at the start of stimulation with gonadotropins after pituitary down-regulation is inversely correlated with a mature oocyte yield and can predict “low responders”. Fertil. Steril. 83, 883–888 (2005).

42.

Liu

Han

Peng

Dong

Yan

: Effect of midfollicular luteinizing hormone levels on ovarian response and pregnancy outcome in patients undergoing in vitro fertilization in a short-term protocol. Fertil. Steril. 83, 1043–1046 (2005).

43.

Erickson

Magoffin

Dyer

Hofeditz

: The ovarian androgen producing cells: a review of structure/function relationships. Endocr. Rev. 6, 371–399 (1985).

44.

Lisi

Rinaldi

Fishel

Lisi

Pepe

Picconeri

: Use of recombinant FSH and recombinant LH in multiple follicular stimulation for IVF: a preliminary study. Reprod. Biomed. Online 3, 190–194 (2001).

45.

De Placido

Mollo

Alviggi

: Rescue of IVF cycles by HMG in pituitary down-regulated normogonadotrophic young women characterized by a poor initial response to recombinant FSH. Hum. Reprod. 16, 1875–1879 (2001).

46.

Prospective, randomized study demonstrating that LH supplementation improves the ovarian outcome in patients characterized by an inadequate initial response to recombinant follicle-stimulating hormone (rFSH) therapy in a long protocol

47.

Ferraretti

Gianaroli

Magli

D'angelo

Farfalli

Montanaro

: Exogenous luteinizing hormone in controlled ovarian hyperstimulation for assisted reproduction techniques. Fertil. Steril. 82, 1521–1526 (2004).

48.

Marrs

Meldrum

Muasher

Schollcraft

Werlin

Kelly

: Randomized trial to compare the effect of recombinant human FSH (follitropin alfa) with or without recombinant human LH in women undergoing assisted reproduction treatment. Reprod. Biomed. Online 8, 175–182 (2004).

49.

Prospective, randomized study demonstrating that younger patients do not seem to benefit from an LH-supplemented ovarian stimulation protocol, but women aged 35 years or older undergoing assisted reproduction may benefit from using r-hLH in addition to r-hFSH

50.

Humaidan

Bungum

Andersen

Yding C

: Effects of recombinant LH supplementation in women undergoing assisted reproduction with GnRH agonist down-regulation and stimulation with recombinant FSH: an opening study. Reprod. Biomed. Online 8, 635–643 (2004).

51.

Prospective, randomized study demonstrating that supplementation with r-hLH seems to benefit treatment outcome for women over 35 years of age and for the subgroup of women exhibiting LH concentrations above 1.99 IU/l on stimulation day 8

52.

Sills

Levy

Moomjy

McGee

Rosenwaks

: A prospective, randomized comparison of ovulation induction using highly purified follicle-stimulating hormone alone and with recombinant human luteinizing hormone in in-vitro fertilization. Hum. Reprod. 14, 2230–2235 (1999).

53.

Tarlatzis

Tavmergen

Szamatowicz

: The use of recombinant human LH (lutropin alfa) in the late stimulation phase of assisted reproduction cycles: a double-blind, randomized, prospective study. Hum. Reprod. 21, 90–94 (2006).

54.

In normo-ovulatory women (aged 18–37 years), the addition of r-hLH during the late follicular phase of a long gonadotropin-releasing hormone (GnRH)-agonist and r-hFSH stimulation cycle (prospective, randomized study) provides no further benefit in terms of oocyte maturation or other end points, suggesting that only subgroups may benefit from r-hLH supplementation

55.

Drakakis

Loutradis

Kallianidis

: Small doses of LH activity are needed early in ovarian stimulation for better quality oocytes in IVF-ET. Eur. J. Obstet. Gynecol. Reprod. Biol. 121, 77–80 (2005).

56.

Robertson

Burger

: Reproductive hormones: ageing and the perimenopause. Acta Obstet. Gynecol. Scand. 81, 612–616 (2002).

57.

Vihko

Kujansuu

Morsky

Huhtaniemi

Punnonen

: Gonadotropins and gonadotropin receptors during the perimenopause. Eur. J. Endocrinol. 134, 357–361 (1996).

58.

Mitchell

Hollis

Rothwell

Robertson

: Age related changes in the pituitary-testicular axis in normal men; lower serum testosterone results from decreased bioactive LH drive. Clin. Endcrinol. (Oxf.) 42, 501–507 (1995).

59.

Huhtaniemi

Pettersson

: Alterations in gonadal steroidogenesis in individuals expressing a common genetic variant of luteinizing hormone. J. Steroid Biochem. Mol. Biol. 69, 281–285 (1999).

60.

Jiang

Pakarinen

Zhang

: A common polymorphic allele of the human luteinizing hormone beta-subunit gene: additional mutations and differential function of the promoter sequence. Hum. Mol. Genet. 8, 2037–2046 (1999).

61.

Ropelato

Garcia-Rudaz

Castro-Fernandez

: A preponderance of basic luteinizing hormone (LH) isoforms accompanies inappropriate hypersecretion of both basal and pulsatile LH in adolescents with polycystic ovarian syndrome. J. Clin. Endocrinol. Metab. 84, 4629–4636 (1999).

62.

Piltonen

Koivunen

Ruokonen

Tapanainen

: Ovarian age-related responsiveness to human chorionic gonadotropin. J. Clin. Endocrinol. Metab. 88, 3327–3332 (2003).

63.

Fabregues

Creus

Penarrubia

Manau

Vanrell

Balasch

: Effects of recombinant human luteinizing hormone supplementation on ovarian stimulation and the implantation rate in down-regulated women of advanced reproductive age. Fertil. Steril. 85(4), 925–931 (2006).

64.

Westergaard

Erb

Laursen

Rex

Rasmussen

: Human menopausal gonadotropin versus recombinant follicle-stimulating hormone in normogonadotropic women down-regulated with a gonadotropin-releasing hormone who were undergoing in vitro fertilization and intracytoplasmic sperm injection: a prospective randomized study. Fertil. Steril. 76, 543–549 (2001).

65.

De Placido

Alviggi

Mollo

: Effects of recombinant LH (rLH) supplementation during controlled ovarian hyperstimulation (COH) in normogonadotrophic women with an initial inadequate response to recombinant FSH (rFSH) after pituitary downregulation. Clin. Endocrinol. (Oxf.) 60, 637–643 (2004).

66.

De Placido

Alviggi

Perino

: Recombinant human LH supplementation versus recombinant human FSH (rFSH) step-up protocol during controlled ovarian stimulation in normogonadotropic women with initial inadequate response to rFSH. A multicentre, prospective, randomized controlled trial. Hum. Reprod. 20, 390–396 (2005).

67.

Alviggi

Pettersson

Mollo

: Impaired multiple follicular development in carriers of Trp8Arg and Ile15Thr LH-beta variant undergoing controlled ovarian stimulation. Hum. Reprod. 20(Suppl. 1), S139–S140 (2005).

68.

Foong

Abbott

Lesnick

Session

Walker

Dumesic

: Diminished intrafollicular estradiol levels in in vitro fertilization cycles from women with reduced ovarian response to recombinant human follicle-stimulating hormone. Fertil. Steril. 83, 1377–1383 (2005).

69.

Tesarik

Hazout

Mendoza

: Luteinizing hormone affects uterine receptivity independently of ovarian function. Reprod. Biomed. Online 7, 59–64 (2003).

70.

Kolibianakis

Zikopoulos

Schiettecatte

: Profound LH suppression after GnRH antagonist administration is associated with a significantly higher ongoing pregnancy rate in IVF. Hum. Reprod. 19, 2490–2496 (2004).

71.

Cedrin-Durnerin

Grange-Dujardin

Laffy

: Recombinant human LH supplementation during GnRH antagonist administration in IVF/ICSI cycles: a prospective randomized study. Hum. Reprod. 19, 1979–1984 (2004).

72.

First prospective, randomized study demonstrating that in an unselected group of patients, there is no evident benefit to supplementing GnRH antagonist-treated cycles with r-hLH

73.

Sauer

Thornton

II Schoolcraft

Frishman

: Comparative efficacy and safety of cetrorelix with or without mid-cycle recombinant LH and leuprolide acetate for inhibition of premature LH surges in assisted reproduction. Reprod. Biomed. Online 9, 487–493 (2004).

74.

Griesinger

Schultze-Mosgau

Dafopoulos

: Recombinant luteinizing hormone supplementation to recombinant follicle-stimulating hormone induced ovarian hyperstimulation in the GnRH-antagonist multiple-dose protocol. Hum. Reprod. 20, 1200–1206 (2005).

75.

De Placido

Mollo

Clarizia

Strina

Conforti

Alviggi

: Gonadotropin-releasing hormone (GnRH) antagonist plus recombinant luteinzing hormone vs. a standard GnRH agonist short protocol in patients at risk for poor ovarian response. Fertil. Steril. 85, 247–250 (2006).

76.

Balen

Mulders

Fauser

: Pharmacodynamics of a single low dose of long-acting recombinant follicle-stimulating hormone (FSH-carboxy terminal peptide, corifollitropin alfa) in women with World Health Organization group II anovulatory infertility. J. Clin. Endocrinol. Metab. 89, 6297–6304 (2004).

77.

Behre

Greb

Mempel

: Significance of a common single nucleotide polymorphism in exon 10 of the follicle-stimulating hormone (FSH) receptor gene for the ovarian response to FSH: a pharmacogenetic approach to controlled ovarian hyperstimulation. Pharmacogenet. Genomics 15, 451–456 (2005).

78.

Greb

Grieshaber

Gromoll

: A common single nucleotide polymorphism in exon 10 of the human follicle stimulating hormone receptor is a major determinant of length and hormonal dynamics of the menstrual cycle. J. Clin. Endocrinol. Metab. 90, 4866–4872 (2005).

Is there a Need for Recombinant Human Luteinizing Hormone (Lutropin Alfa) Supplementation in Ovarian Stimulation for Assisted Reproduction?

Abstract

Keywords

Luteinizing hormone & oocyte maturation

The LH ceiling concept

LH & ovarian stimulation

Low LH levels in long GnRH-agonist cycles

Importance of flexible LH administration during ovarian stimulation in long GnRH agonist protocols

LH supplementation in potentially normal responders

LH supplementation in patients aged 35 years or older

LH supplementation in women who abnormally respond to FSH

Importance of flexible LH administration during ovarian stimulation in GnRH antagonist protocols

Conclusion

Future perspective

References