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We hypothesize that artificial stimulation of the cervix causes an acute secretion of maternal prolactin (PRL) that mimics PRL secretion during the second stage of human labor. Eighteen women scheduled for first-trimester therapeutic abortion had a blood sample drawn at the following times: before and after laminaria tent (LT) insertion for cervical ripening, 18–24 hours later upon entry in the procedure room, after LT removal, during instrumental cervical dilatation and uterine evacuation by suction curretage, soon after evacuation, and ½ hour and 1 hour after evacuation. Local cervical anesthesia, intravenous analgesics, and sedation were administered before the procedure. Blood serum was assayed for PRL, human chorionic gonadotropin (hCG), and estradiol. The initial PRL levels were 34 ng/mL ± 4.2 standard error of the mean (SEM) and did not change after 18–24 hours of LT placement nor after LT removal. However, PRL increased significantly (t = 5.8; P = .00001) over basal levels by 204% ± 15 at the time of instrumental dilatation and rose to 378% ± 33 at ½ hour postevacuation. After 1 hour, PRL had declined to 173% ± 10%o. Serum levels of estradiol and hCG changed only after evacuation. Artificial stimulation of the cervix causes an immediate surge in PRL levels. We suggest that the acute increase in pituitary PRL secretion that occurs during the second stage of labor results from a neural signal from the cervix and not from endocrine changes associated with labor. (J Soc Gynecol Invest 1999;6:22–6)

OBJECTIVE We hypothesized that regimens of labor induction do not alter the biphasic secretion of maternal prolactin (PRL) seen during spontaneous labor. METHODS Serial blood samples drawn from 12 women before, during, and after induced labor were assayed for PRL and hCG and compared with cervical dilatation and uterine contraction frequency (UCF). Induction methods were cervical ripening with dinoprostone gel (Prepidil) followed by oxytocin infusion (n = 1), amniotomy followed by oxytocin (n = 4), oxytocin followed by amniotomy (n = 3), amniotomy only (n = 2), and oxytocin only (n = 2). RESULTS Regardless of the induction method, PRL decreased with advancing cervical dilatation during the first stage of labor and reached a nadir at full dilatation. Prolactin levels then increased rapidly during the second stage, correlating significantly with the increase in UCF, and peaked at 1 hour postpartum before decreasing. Levels of hCG increased during labor and peaked just before or at delivery before rapidly decreasing. CONCLUSIONS The biphasic secretion of maternal PRL is a fundamental characteristic of active term labor and occurs regardless of the method used to induce labor.

Circulating prolactin (PRL) levels and parity are directly related to the risk for breast cancer in both premenopausal and post-menopausal women. In non-gravid women, basal secretion of PRL declines inversely with parity. We have identified changes in maternal sera during pregnancy that could explain the long term effect of pregnancy on circulating PRL. Significant differences exist in pregnant PRL levels according to parity and fetal sex from as early as the first trimester. Comparison of PRL to the placental hormone human chorionic gonadotrophin (hCG) failed to identify hCG as the controlling element. We suggest that the fetus determines maternal PRL secretion both during pregnancy and in subsequent years, and that the effect is cumulative and fetal sex-related with each pregnancy. Therefore, we propose that a fetal product promotes the reduction in a woman's risk for breast cancer by conditioning her physiology towards a reduction in basal PRL secretion following each pregnancy.

Current global infant and maternal mortality rates are estimated at 66/1,000 and 338/100,000 births per annum respectively. The ranges by country are dramatic and are directly linked to living standards. Historically, mortality rates due to extrinsic factors have been reduced by improving public health policies and social conditions. However, modern medical practice further reduces mortality rates below the thresholds achieved by public health measures by treating intrinsic pathologic factors. Thus, by viewing reproductive mortality from a global perspective, the greatest reductions in infant and maternal deaths can be achieved through public health policies, education, and improved social conditions. On the other hand, developed countries can afford to place greater emphasis on the individual's needs and on personalized obstetrical care. This requires research into the basic mechanisms of pregnancy and parturition, and the development of new therapies to treat a variety of pregnancy related pathologies, particularly that of preterm birth. Moreover, with the current cost effective health care measures being implemented in developed countries, research into the causes of preterm birth and development of truly effective and safe tocolytic treatments will yield substantial savings in this most costly of obstetrical conditions.

One hundred ninety-two semen specimens from 14 donors were analyzed on a CellSoft Semen Analyzer (CRYO Resources, New York, NY) before and after freezing. Mean post-thaw motility decreased by 52%. Correlation of the percent decrease in post-thaw versus prefreeze motility was significant but of poor predictive value. Comparisons of the percent change in post-thaw motility and sperm motion kinetics between four discrete ranges of prefreeze motility (32% to 66%, 67% to 76%, 77% to 84%, 85% to 94%) revealed that the effect of freezing on sperm cell survival was equivalent between all ranges. However, significant differences occurred between these ranges for curvilinear velocity, straight line velocity, and mean amplitude of lateral head displacement but not for linearity nor beat cross frequency. All correlations between prefreeze and post-thaw motion variables were significant but closest for curvilinear velocity and straight line velocity. Furthermore, correlations of prefreeze versus post-thaw velocity measurements were strongest for those cells within the 65% to 85% range of prefreeze motility. We suggest that sperm survival is independent of prefreeze motility. However, velocity kinetics appear stable after freezing for those specimens that had an initial motility of 65% to 85%.