Objective:In this study, we attempted to determine the physiologic roles of prolactin (PRL) and hCG during labor.
Methods:Serial blood samples were collected from 19 women (15 multiparous and four nulliparous) before, during, and after labor; assayed for PRL and hCG; and compared with cervical dilatation and uterine contraction frequency.
Results:Prolactin levels decreased in association with progressive cervical dilation during the first stage of labor and reached a nadir at full dilatation. Thereafter, PRL increased rapidly during the second stage of labor and peaked within 1 hour postpartum. Uterine contraction frequency also increased during the second stage and correlated significantly (r2 = 0.60; P = .0006) with levels of PRL. Levels of hCG increased during labor and peaked at about the time of delivery.
Conclusion:These data suggest that phasic PRL secretion is associated with cervical dilatation and that after transition to the second stage of labor, uterine contraction frequency may be associated with the increase in PRL levels.
1. Russell KP, Biswas MK. The course and conduct of normal labor & delivery. In: Pernoll ML, ed. Current obstetric & gynecologic diagnosis & treatment. Norwalk, Connecticut: Appleton & Lange, 1991:198-224.
2.
2. Cunningham FG, MacDonald PC, Gant NF, Levono KJ, Gilstrap LC. Parturition: Biomolecular and physiological processes. In: Licht J, ed. Williams obstetrics. 19th ed.Norwalk, Connecticut: Appleton & Lange, 1993:297-361.
3.
3. Rigg LA, Yen SSC. Multiphasic prolactin section during parturition in human subjects. Am J Obstet Gynecol1977; 128:215-218.
4.
4. McCoshen JA, Bose R, Embree JE. Uterine prolactin and labor: Modulation by human chorionic gonadotropin affects prostaglandin (PG) E2 and PGF2α production. Semin Reprod Endocrinol1992;10:294-298.
5.
5. Fernandes PA, Embree JE, Bose R, Chudasama S, McCoshen JA. Regulation of fetal membrane prostaglandin production by hCG/PRL synergism in premature and term labor. 25th Annual Meeting of the Canadian Fertility and Andrology Society, Kananaskis, Alberta, 1992; Abstract FP49.
6.
6. MacDonald PC, Casey ML. The accumulation of prostaglandins (PG) in amniotic fluid is an aftereffect of labor and not indicative of a role of PGE2 or PGF2α in the initiation of human parturition. J Clin Endocrinol Metab1993;76:1332-1339.
7.
7. Yamamoto K, Kitao M. Interrelation among endogenous catecholamines, prostaglandin F2a and prolactin in last trimester and during parturition. Acta Obstet Gynaecol Jpn1989;41:1479-1486.
8.
8. Nagata I, Sunaga H, Furuya K, Makimura N, Kato K. Changes in plasma prostaglandin F2α metabolite before and during spontaneous labor and labor induced by amniotomy, oxytocin and prostaglandin E2. Endocrinol Jpn1988;34:153-159.
9.
9. Fuchs AR, Goeschen K, Husslein P, Rasmussen AB, Fuchs F. Oxytocin and the initiation of human parturition. III. Plasma concentrations of oxytocin and 13,14-dihydro-15-keto prostaglandin F2α in spontaneous and oxytocin-induced labor at term. Am J Obstet Gynecol1983;147:497-502.
10.
10. McCoshen JA. Fetal control of maternal prolactin production and bioactivity in utero. Am J Obstet Gynecol1989;160:322-327.
12. Wynn RM. Obstetric procedures. In: Cooke DB, Martin JH, eds. Obstetrics and gynecology the clinical core. 5th ed.Philadelphia: Lea & Febiger, 1992:159-164.
13.
13. Bigazzi M, Nardi E. Prolactin and relaxin: Antagonism on the spontaneous motility of the uterus. J Clin Endocrinol Metab1981;53:665-667.
14.
14. Bigazzi M. Specific endocrine function of human decidua. Semin Reprod Endocrinol1983;1:343-356.
15.
15. Ho Yuen B, Cannon W, Lewis J, Sy L, Woolley S. A possible role for prolactin in the control of human chorionic gonadotropin and estrogen secretion by the fetoplacental unit. Am J Obstet Gynecol1980;136:286-291.
16.
16. Tyson JE, McCoshen JA, Dubin NH. Inhibition of fetal membrane prostaglandin production by prolactin: Relative importance in the initiation of labor. Am J Obstet Gynecol1985;151:1032-1038.
17.
17. Bremme K, Eneroth P, Kindahl H. 15-keto 13,14-dihydro prostaglandin F2α and prolactin in maternal and cord blood during prostaglandin E2 or oxytocin therapy for labor induction. J Perinat Med1987;15:143-151.
18.
18. Rajabi MR, Dean DD, Beydoun SN, Woessner JF Jr. Elevated tissue levels of collagenase during dilation of uterine cervix in human parturition. Am J Obstet Gynecol1988;159:971-976.
19.
19. Osmers R, Rath W, Pflanz MA, Kuhn W, Stuhlsatz HW, Szeverenyi M. Glycosaminoglycans in cervical connective tissue during pregnancy and parturition. Obstet Gynecol1993;81:88-92.
