Endometrial changes after methotrexate treatment: Relation with multiple nabothian cysts and future pregnancies

Abstract

A clinical study was conducted in order to validate the effect of methotrexate on 30 patients with ectopic pregnancy (EP). A typical ultrasound appearance of multiple cysts of Naboth in the cervix was observed on six cases that are studied below. Endometrial sample with endogyn was retrieved from the six cases after the treatment with methotrexate was complete. The cytological results were studied and there were many changes found in the endometrial cells, in their cores, and some inflammatory cells as well. Two out of the six cases studied show more profound evidence. The cellular appearance of the endometrium after the treatment is discussed, in relation to the presence of multiple Nabothian cysts, as a result of inflammatory reaction, and the possibility of any influence in the capacity for a future pregnancy.

Introduction

The presence of multiple Nabothian cysts can be related to some pathological conditions, mostly as a consequence of an inflammatory reaction. The pathological conditions are: (1) the chronic cervicitis due to microbial causes, such as Chlamydia, Streptococcus, and Staphylococcus; (2) the granulomatous diseases such as pulmonary tuberculosis, syphilis, and inguinal granuloma; (3) endometriotic cysts; (4) ectopic cervical pregnancy; and (5) rarely, cervical cancer, most likely adenoid cystic carcinoma and Botryoide type of sarcoma, without excluding any other type of cancer of the lower genital system. ¹

Nabothian cysts are an asymptomatic condition and a random finding, which did not raise any suspicion of any other pathological issue or malignancy until now.^2,3

Methotrexate has become a standard treatment for ectopic pregnancy (EP). Methotrexate is a folic acid antagonist that inhibits dihydrofolate reductase, resulting in a block in the synthesis of thymidine and in the inhibition of DNA synthesis. Folic acid is an essential vitamin, needed to help rapidly dividing cells in pregnancy. The drug stops the pregnancy from developing any further and the pregnancy is gradually reabsorbed by the body, leaving the fallopian tube intact.

Methotrexate has been used for the treatment of malignancy, rheumatic disorders, psoriasis, and termination of intrauterine pregnancy.

Methotrexate is most effective in the earlier stages of pregnancy, usually when the pregnancy hormone ‘beta-human Chorionic Gonadotropin’ (β-hCG) levels are below 5000 mIU/mL. The risk of rupture is higher in pregnancies with levels greater than this. However, in cornual EP it is not unusual to try and treat the EP with the drug, even in cases with higher levels of β-hCG. With EP, it is not really the stage of pregnancy (as in the number of gestational weeks), but the size of the gestational sac, which can vary over the first few weeks depending on the rate of growth, that is important. This study aims to assess the unusual finding of multiple Nabothian cysts in women with EPs after the treatment with methotrexate, to identify any significant changes or abnormalities in the endometrium in such patients, and to investigate any correlation between them. This study also investigates whether the endometrial changes can affect future pregnancies.

Material and methods

This prospective study included a cohort of 6 out of 30 patients with sonographically confirmed EP. Serum β-hCG findings were positive in all patients.

The age of patients was in the range of 29–37 years (mean age, 33 years). The last menstrual period was in the range of 4–12 weeks (mean, 8 weeks). All patients underwent transvaginal ultrasound (TVS) with an empty bladder, under the consent of the patient and with the presence of a chaperone. Abdominal examination was performed. The TVS criterion for a diagnosis of EP was the presence of a solid extra-ovarian adnexal mass with or without a cystic component, in association with high β-hCG levels and lack of intrauterine pregnancy.

A serial measurement of β-hCG, together with blood tests, was done before and after the treatment on days 0, 4, and 7. A single, second, and, if needed, a third dose of methotrexate was administered, depending on the values of the β-hCG and the physical status of the patient. The patients were under supervision for any abnormal blood tests results or any clinical consequence or side effect of methotrexate. The dose of methotrexate was determined based on the height and weight of the woman. All the risks were explained to the patients and all of them gave a written consent.

A series of TVS examinations were performed after the treatment. This was done to follow-up the size of the gestational sac, ovary, endometrial thickness, and for any significant complication. All of them had a songraphic appearance of multiple cysts of Naboth in the cervix.

An endometrial sample was taken with Endogyn 3 weeks after the first dose of the methotrexate, and it was sent in cytology department for analysis. Results of the biopsy were taken 2 days later.

Results

As mentioned above, the age of the patients was in the range of 29–37 years. Four out of six had just one dose of 50 mgs/m² of methotrexate, one had two doses of the same quantity, and one had three doses.

Quantitative serum β-hCG levels were available in those patients. All of them had a serum level of more than 1000 IU/L in the beginning; one of them started with a level of 3600 IU/L and another one of 13,827 IU/L. The five of them had a decrease of β-hCG 2 weeks after the first dose of methotrexate. The ectopic of 13827 IU/L reached a value of 17,827 2 weeks after the first dose of methotrexate and the β-hCG started to drop 20 days later on. It reached normal values 2 months after the completion of the therapy.

The minimum size of the EP in the tube was 0.5 cm and the maximum 2.1 cm (reaching up to 5.1 in the last patient). There was no presence of a fetus in any of them, but in one, in the patient with 13,827 IU/L, there was a yolk sac present. The size of the endometrium was in the range of 0.7–4 cm before the treatment and it reached 0.3–0.5 cm after the methotrexate. We should mention that the two of them had a thick endometrium, similar with that of the second half of the menstrual cycle.

An endometrial sample was taken 3 weeks after the treatment to evaluate the changes in the endometrium, as the level of β-HCG started to decrease 2 weeks after the administration of methotrexate in most cases. All of them had negative results for any form of neoplasia. Four of them had a normal cell size of the columnar epithelium of endometrium without any significant change, but there were some inflammatory cells present. The cell core was of normal size and good cellular cohesion was observed. However, in two of them there were some substantial cellular alterations, which merit further discussion. There were cells of the columnar epithelium that were bigger and hyperplastic without atypia, whereas their cores were larger and unequal in size. The density of chromatin was more easily visible and concentrated. Finally, there were many inflammatory cells among them, more than in the rest of the cases.

Discussion

The existence of an extra-ovarian adnexal mass is the most usual feature of EP. This feature has been indicated to have a high specificity for detecting EP in a patient with a positive serum pregnancy test result. With the introduction of high-resolution TVS, in conjunction with serum assays for the β-hCG, rapid and precise diagnosis of this entity is now regularly achievable. In fact, these two factors have changed the course and management of ectopic pregnancy. ⁴ Once considered to be a surgical emergency, earlier and more expeditious diagnosis with TVS has changed the management approach to EP in such a way that maintaining fertility with medical and expectant management is now possible. Correlation with serum ß-hCG levels and physical findings allows the medical team to formulate a quick and accurate diagnosis and recommend the appropriate follow-up and treatment. The values of β-hCG are studied during the following days and at the same time measurements of the size of EP, its blood supply, and the size of the endometrium are taken.^5,6

The hypothesis of any correlation between the presence of multiple Naboth cysts with other pathological issues is still under study. Most frequently, it could be related with various inflammatory changes, such as cervicitis or granulomatous disease or due to endometriosis and rarely with cervical cancer. ⁷

Therefore, it was interesting for these six cases, treated with methotrexate, to investigate if there is any relationship between the presence of Nabothian cysts and methotrexate treatment. The result in the endometrial structure and the influence in the woman’s fertility should also be examined. It is also of interest that these six patients had the highest value of β-hCG compared to the rest of the cases.

Two of the six cases had shown more inflammatory changes between the cells of the columnar epithelium and in the appearance of the cells themselves. There were changes in the cellular core and in the density of the chromatin as well. These two cases had the highest values of β-hCG from all six cases under consideration and the time needed for β-hCG to decrease was much longer. The size of the gestational sac was bigger in those two, and in one of the two (with the highest value of β-hCG and the most significant changes in ovary and endometrium), there was a yolk sac.

As we mentioned, methotrexate is a folic antagonist, which disrupts synthesis of DNA, RNA, and protein, and leads to cell death. Methotrexate is further metabolized to methotrexate polyglutamates, which are long-living metabolites, inhibiting other folate-dependent enzymes. Although the half-life of methotrexate is 8–15 h, its presence in the liver has been reported to last up to 116 days after exposure. Due to the concerns about methotrexate and its metabolites remaining in some organs and possibly affecting a future pregnancy or fetal development, several sources have arbitrarily recommended that women should wait 3–6 months to get pregnant after finishing therapy.^8–10 In previous studies,^11,12 the incidence of abnormal outcome (e.g. miscarriages, stillbirth, possible mole pregnancy) was found to be significantly higher in women who conceived within 6 months than in those who conceived 12 months after the treatment with methotrexate. In this study, we investigated if the environment of the endometrium after methotrexate becomes inflammatory, toxic, or hinders a future pregnancy, and the period in which these changes in the columnar epithelium will exist so as to influence and lead to an abnormal pregnancy. A possible correlation between the changes of endometrium, Nabothian cysts, and the treatment of methotrexate was found. Nabothian cysts are a possible consequence of inflammatory reaction.^1,3

Therefore, the existence of these cysts, the presence of many inflammatory cells in endometrium, the significant changes in the cellular appearance of the columnar epithelium, and at the same time, the abnormal outcome of pregnancy during the first 6 months after methotrexate, show that that there might be a correlation between all of them. Adverse pregnancy outcomes may be explained by increased inflammatory cells in the endometrium. However, increased Nabothian cysts and their relation with the endometrial inflammatory process and pregnancy outcome need to be investigated in future work.