Effect of parity on pituitary prolactin response to metoclopramide and domperidone: implications for the enhancement of lactation.

OBJECTIVE: The gastrointestinal motility agents metoclopramide and domperidone are known to increase pituitary prolactin (PRL) secretion and breast milk production. This study compared the effect of single doses of two strengths of metoclopramide and a single dose of domperidone on PRL secretion. METHODS: Ten nonpregnant women had baseline evaluation of serum PRL concentrations. The PRL concentrations were then determined after random oral administration of metoclopramide 10 mg, metoclopramide 5 mg, and domperidone 10 mg. Blood samples were drawn in the first 7 days of the menstrual cycle, at 13 time points over a 6-hour period (0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300, and 360 minutes), with the zero time point beginning at 0800 hours. Variables such as weight, height, age, gravidity, parity, and oral contraceptive use were recorded. RESULTS: Baseline PRL concentrations showed the natural circadian rhythm. Metoclopramide and domperidone both caused a significant increase in PRL. However, PRL secretion was most influenced by parity. Nulliparous women had the quickest and highest PRL secretion with metoclopramide 10 mg, compared with the PRL response with metoclopramide 5 mg and domperidone 10 mg. Conversely, multiparous women had PRL secretion patterns that were equivalent between the medications. CONCLUSIONS: The PRL response to the medications was most influenced by parity. Therefore, we suggest that the medication therapy of choice for enhancing lactation may not be the same in all women, but may instead be determined by parity.

The acute release of maternal prolactin by instrumental cervical dilatation simulates the second stage of labor.

OBJECTIVE: 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. METHODS: 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 1/2 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. RESULTS: 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 1/2 hour postevacuation. After 1 hour, PRL had declined to 173% +/- 10%. Serum levels of estradiol and hCG changed only after evacuation. CONCLUSION: 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.

Maternal prolactin secretion is phasic during induced term and post-term labor.

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.

Phasic maternal prolactin secretion during spontaneous labor is associated with cervical dilatation and second-stage uterine activity.

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 dilatation 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.

Prostaglandin F2 alpha output by amnion-chorion-decidua: relationship with labor and prostaglandin E2 concentration at the amniotic surface.

OBJECTIVE: Our purpose was to evaluate prostaglandin F2 alpha output at fetal membrane surfaces relative to labor and to assess amniotic prostaglandin E2 concentration changes on prostaglandin F2 alpha output. STUDY DESIGN: Intact and separated fetal membranes from 10 elective cesarean sections and nine vaginal deliveries were incubated in double-sided perfusion chambers. Prostaglandin F2 alpha and 13,14-dihydro-15-keto-prostaglandin F2 alpha output was measured by radioimmunoassay. Alterations of prostaglandin F2 alpha and 13,14-dihydro-15-keto-prostaglandin F2 alpha output were assessed after exogenous prostaglandin E2 addition at amniotic surfaces of intact membranes. RESULTS: Prostaglandin F2 alpha concentration was higher at maternal surfaces of intact but not separated membranes after labor (p = 0.0001). Amniotic 13,14-dihydro-15-keto-prostaglandin F2 alpha was increased in association with preceding labor (p = 0.038). Addition of prostaglandin E2 at the amniotic surface did not alter prostaglandin F2 alpha or 13,14-dihydro-15-keto-prostaglandin F2 alpha production. CONCLUSION: Prostaglandin F2 alpha concentration at the maternal surface of fetal membranes likely plays a critical role in induction or maintenance of myometrial contractions associated with term labor independent of amniotic fluid prostaglandin E2 concentrations.

Y body association with morphologic heterogeneity of human sperm.

OBJECTIVE: The purpose of this study was to determine a possible association between the Y body and sperm head shape, since sperm head shape may be a factor that influences the rate of migration of X- and Y-bearing sperm cells. MATERIALS: Sperm cell (n = 1,065) preparations from seven donors were fluorochrome stained for the Y body, and area and shape of Y body-positive and -negative cells were measured from digitized images. The distributions of the segregated cell population measurements were statistically analyzed nonparametrically. RESULTS: Of the total cells, 528 were Y body-positive and 537 were not, and the ratio (0.983) of the two cell categories, both within and between donors, was equivalent to the theoretical ratio of 1.0 expected for the X:Y sperm cell population. Sperm head area distributions were equal between the two populations. However, the length-width ratios of Y-bearing cells were significantly higher (P < .0001) and calculated roundness was significantly (P = .006) less than non Y body-bearing cells. CONCLUSIONS: The Y body may represent the Y chromosome. Furthermore, the Y body may impart a more ellipsoidal shape to sperm cells. Sperm shape may influence the migration rate of cells through cervical mucus such that differences in the male-to-female sex ratio of conceptuses, and at birth, may reflect a shape-imparted advantage in the migration rate of Y-bearing sperm in reaching the oocyte.

Human embryo associated immunosuppressor factor and serum estradiol synergism in ovarian follicle development.

PROBLEM: The purpose of this study was to test whether the level of serum immunosuppressor factor (EASF) correlates with ovarian follicle development and with serum hormones during the ovarian cycle. METHOD: One hundred seventy-three serum samples were collected starting at the time of ovulation and 1 wk after insemination from 29 women attempting pregnancy by ovarian hyperstimulation and intrauterine insemination. After ovarian stimulation, the patients were given human chorionic gonadotropin (hCG) 38 h before insemination. Number and size of follicles were measured by ultrasound. Serum samples were tested for hCG, estradiol (E2), luteinizing hormone, follicle-stimulating hormone (FSH), and progesterone levels. The level of EASF in patients' sera was assayed using a two-site sandwich enzyme-linked immunosorbent assay system. The levels of different hormones and EASF were then correlated among themselves and with the number of ovarian follicles. RESULTS: Eleven out of 29 patients had detectable levels of serum EASF-Patients positive for EASF had a significantly higher number ovarian follicles > or = 13 mm and E2 levels after hCG treatment as compared to patients with no detectable EASF. The levels of EASF correlated with number of follicles (P = .001), blood E2 (P < .02) and FSH levels (P < .02). Number of follicles > or = 13 mm correlated with E2 (P = .01) and FSH levels (P < .01) only in patients positive for EASF. CONCLUSIONS: The levels of EASF, E2; and FSH may act synergistically in the development of ovarian follicles.

Adverse effects of the salazopyrine metabolite sulphapyridine on female fertility in the rat.

Salazopyrine, a common therapy for inflammatory bowel disease, is known to have a reversible antifertility effect in men and male rats via its metabolite, sulphapyridine. To determine if there is an adverse effect in females, 20 mature Sprague-Dawley rats were assigned to a treatment (400 mg/kg sulphapyridine daily), or a control group. After three estrous cycles of treatment, the rats were bred to males of proven fertility. When killed at 10 days gestation, there was a significant reduction in the proportion of fertilized oocytes between control (112/174) and treatment (81/212) groups (chi-square = 26.16, d.f. = 1, P less than .00001). These findings suggest an adverse effect of sulphapyridine on female fertility.

The role of fetal membranes in regulating production, transport, and metabolism of prostaglandin E2 during labor.

The level of prostaglandin E2, a potent stimulator of myometrial contractions, increases in amniotic fluid during labor. We tested whether amniotic prostaglandin E2 crosses the reflected fetal membranes to the myometrium during labor. Disks of amnion, chorion-decidua, and amnion chorion-decidua from 10 term pregnancies before labor and nine vaginal deliveries after normal spontaneous labor were incubated in two-sided perfusion chambers in the absence or presence of 1 mumol/L indomethacin, or in the presence of a bolus of prostaglandin E2 and radiolabeled prostaglandin E2 added to the fetal chamber. Net amniotic prostaglandin E2 increased significantly (p = 0.003) after labor. However, there was no significant difference in prostaglandin E2 concentrations on the maternal side of amnion chorion-decidua between labor conditions. High-pressure liquid chromatography identified the transport of intact tritiated prostaglandin E2 across amnion but not across chorion-decidua or amnion chorion-decidua in which prostaglandin E2 was completely metabolized. Because of 15-hydroxyprostaglandin dehydrogenase activity in chorion, we suggest that amniotic prostaglandin E2 transport to the myometrium is impaired. Thus the increase in prostaglandin E2 production that occurs in amnion tissue after labor commences does not result in an increase in prostaglandin E2 concentration on the myometrial side of the fetal membranes in the in vitro preparation.

Quantitative analysis of the effect of freezing on donor sperm motion kinetics.

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%.

Umbilical cord is the major source of prostaglandin E2 in the gestational sac during term labor.

The umbilical cord is an amniotic structure histologically resembling amnion lining the basal plate and reflected chorion. Prostaglandin E2 is secreted by amnion and is present in amniotic fluid. This study measured prostaglandin E2 production by amnion from all three locations to determine the relative contributions of prostaglandin E2 to amniotic fluid at term. Total surface areas and weights of umbilical cord, basal placental plate, and reflected chorionic amnion were measured in afterbirths from 20 normal patients delivered at term by elective repeat cesarean section before the onset of labor or vaginally after spontaneous onset of labor. Subsequently, 2 cm lengths of umbilical cord and 8 cm2 disks of basal placental plate and reflected chorionic amnion were incubated in perfusion chambers, and prostaglandin E2 production was measured by radioimmunoassay. Umbilical cord accounted for the least surface area (16% to 17%) but greatest tissue mass (75% to 76%). Both basal placental plate and reflected chorionic amnion increased prostaglandin E2 production 2.3-fold and 4.1-fold, respectively, after labor versus before labor, whereas umbilical cord prostaglandin E2 output was unchanged. However, umbilical cord accounted for 66% and 44% of the total prostaglandin E2 output before labor (697 +/- 169 ng/hr) versus (1201 +/- 380 ng/hr) after labor. Thus, of the three amniotic locations, umbilical cord represents the principal site of prostaglandin E2 production within the gestational sac.

Fetal control of maternal prolactin production and bioactivity in utero.

Amniotic fluid prolactin is a product of maternal decidualized endometrium that is derived by translocation of the hormone across the reflected fetal membranes. Amniotic fluids from 26 second-trimester (14 to 23 weeks) and 75 third-trimester (29 to 40 weeks) normal singleton pregnancies were evaluated for prolactin content by radioimmunoassay and bioassay with the Nb2 rat lymphoma cell line. The relative bioactivity was calculated as the ratio of bioassay to radioimmunoassay for each fluid. Data segregated by gestational age and fetal genetic sex identified a highly significant difference (p = 0.0004) in amniotic fluid prolactin radioimmunoassay concentrations (mean +/- SEM) that surround male (682 +/- 49, n = 42) versus female (440 +/- 39, n = 33) fetuses of third-trimester age. Paired bioassay values were significantly lower (p = 0.002) than radioimmunoassay values among males (626 +/- 52) but equivalent (p = 0.1066) among females (464 +/- 44). The bioassay/radioimmunoassay ratios of third-trimester fetal female-associated amniotic fluid prolactin were significantly higher (p = 0.0004) than those of third-trimester males and second-trimester males and females. The results suggest a fetal gender-related factor is associated with both the production and the biologic activity of the maternally derived hormone. Thus the fetus appears to have some control over the dynamics of uterine prolactin production.

Prostaglandin E2 release on the fetal and maternal sides of the amnion and chorion-decidua before and after term labor.

Release of prostaglandin E2 on each of the fetal and maternal sides of the fetal membranes (8 cm2) from term cesarean (no labor) and spontaneous vaginal (labor) deliveries was studied with the use of dual-compartment perfusion chambers. Postlabor amnion released significantly (p less than 0.05) more total prostaglandin E2 (5.66 +/- 1.02 ng, mean +/- SEM) than prelabor tissue (3.34 +/- 1.76 ng) with equivalent prostaglandin E2 levels being released on both sides. A net decrease (p less than 0.001) in prostaglandin E2 release by chorion-decidua was identified after labor (fetal = 0.12 +/- 0.05 ng; maternal = 0.17 +/- 0.09 ng) when compared with that before labor (fetal = 1.28 +/- 0.69 ng; maternal = 2.31 +/- 0.56 ng). Amnion-chorion-decidua released more prostaglandin E2 on the fetal side after labor (2.37 +/- 1.43 ng) than prior to labor (1.49 +/- 0.60 ng); however, prostaglandin E2 on the maternal side was significantly less (p less than 0.05) after labor (0.24 +/- 0.12 ng) when compared with that of the prelabor membrane (2.03 +/- 1.08 ng). Elution of prostaglandin E2 from preincubated membranes and endogenous membrane prostaglandin E2 content showed similar results. Thus concentrations of prostaglandin E2 on the maternal side of the fetal membranes appear diminished after spontaneous labor despite an increased release from the fetal surface.

Intrauterine insemination for infertility due to cystic fibrosis.

Mild CF is not associated with increased obstetric risk to patients or offspring. These patients can be identified on the basis of Shwachman-Kulczycki scores, nutritional status, normal chest x-ray and pulmonary function tests, normal lung volumes, and mild to moderate airway obstruction. Spontaneous pregnancy has been achieved in women with CF, but they appear to have a decreased fertility. One possible cause in mild disease is a cervical factor due to abnormal viscous mucus. This mucus has been shown to fail to hydrate, and at midcycle contains less than 80% water, whereas 93% to 96% hydration appears to be necessary for sperm migration. Cyclic electrolyte changes in cervical mucus are not noted in CF patients, and sodium concentration in dry residue at midcycle is 10% of normal. Intrauterine insemination with a washed sperm fraction offers a theoretically safe method of bypassing this barrier. Preliminary data have revealed that this may be a useful therapy in other cases of infertility in which the abnormality is an unexplained, negative postcoital test. CF patients should be carefully evaluated and advised of risks before becoming pregnant. In cases of mild CF in which no factor for infertility exists other than consistently abnormal cervical mucus, intrauterine insemination with washed motile sperm may be beneficial. We believe this to be the first case of a CF patient successfully treated in this manner.

Epithelial regulation of prolactin effect on amnionic permeability.

The permeability of human amnion to tritiated water is reduced in the presence of both human and ovine prolactin. The cellular composition of amnion is such that the action of prolactin on this membrane probably occurs by way of the epithelium lining the fetal surface. The present study sought to confirm an epithelial site of action of prolactin on the permeability of amnionic membrane to tritiated water. In addition, radioautography and competition experiments were conducted to determine a possible receptor-mediated mechanism for prolactin action. Membrane permeability to tritiated water was found to be equivalent for both intact membranes and membranes enzymatically stripped of the lining epithelial cells. However, when ovine prolactin was presented to the fetal surface of amnion, only intact membrane displayed decreased permeability to tritiated water. Although localization of iodine 125-labeled prolactin to the light cell population of amniotic epithelium was observed, positive evidence of a receptor-mediated mechanism could not be established. The results indicate that the permeability of human amnion to water is influenced principally by cells of the epithelium in response to prolactin.

Variances in mucus architecture as a cause of cervical factor infertility.

A cervical factor accounts for 5% to 10% of infertility among women. In the absence of an immunologic or endocrine-related basis for incompetent sperm/mucus interaction, an idiopathic cause is usually ascribed. This study describes quantitative analyses of the microstructure of mucin strands, observed under scanning electron microscopy, from infertile women displaying incompetent sperm/mucus interaction unrelated to any apparent immunologic or endocrine-associated cause. The results revealed a highly significant reduction in the spacing of mucin fibers incompatible to sperm penetrability and migration. Additional quantitative measurements of mucin strand diameter and number and geometry of strand crosslinks suggest inadequate hydration of the mucin gel as a causative basis for the structural inadequacies observed in some cases of cervical-factor infertility.

Prolactin bioactivity following decidual synthesis and transport by amniochorion.

Current evidence suggests that high concentrations of prolactin in human amniotic fluid result from the transport of human decidual prolactin across reflected amniochorion. In this study, tritiated leucine placed on the isolated maternal side of amniochorion with adherent decidua was incorporated into newly synthesized tritiated human decidual prolactin. Identification of tritiated decidual prolactin on the fetal side of suspended membranes was confirmed within 4 hours of incubation. A heterologous species of human decidual prolactin identified on the maternal side of membranes was also detectable on the fetal side, and its bioactivity was found to be equivalent in both fetal and maternal chambers separated by amniochorion. These results confirm the de novo synthesis of human decidual prolactin and transport by amniochorion to the fetal side. Subsequent to transport, the biologic activity of human decidual prolactin is retained. Thus concentrations and biologic activity of amniotic-fluid prolactin can be accounted for by the transport of newly synthesized human decidual prolactin by the reflected amniochorion.

Inhibition of fetal membrane prostaglandin production by prolactin: relative importance in the initiation of labor.

Production of a biologically active prolactin by human decidual tissue and its influence on the permeability of amniochorion to water suggests a functional relationship between the polypeptide and fetal membrane metabolism. Under in vitro circumstances, we used ovine prolactin and the Ussing chamber technique to determine the role of prolactin in prostaglandin E2 production by human fetal membrane. Fresh reflected membranes obtained from elective cesarean sections were exposed to ovine prolactin (10 micrograms/ml). Aliquots of incubation media were sampled at 0, 30, 60, 120, and 240 minutes, quick-frozen, and later assayed for prostaglandin E2. Multifactorial analysis of variance revealed that ovine prolactin significantly reduced prostaglandin E2 production (f = 13.42, p less than 0.005). Prostaglandin E2 output was greatest by amnion (3581 +/- 596 pg/ml/gm declining to 1819 +/- 452 pg/ml/gm during 4 hours). Other combinations of fetal membranes including amnion-chorion-decidua produced only 12% to 15% prostaglandin E2 per gram compared with that produced by amnion alone. Those membranes similarly responded to prolactin with a reduction in prostaglandin E2 output of 34% to 59%. Correlation analysis identified a significant relationship between prostaglandin E2 production and time (r = 0.298; p less than 0.001), which was abolished by ovine prolactin (r = 0.115, p greater than 0.10). This model illustrates that ovine prolactin modifies the production of prostaglandin by fetal membranes in vitro. By analogy, endogenous prolactin by human decidual tissue might also inhibit the elaboration of prostaglandin E2 from its precursors residing within the fetal membranes.

Altered prolactin bioactivity in amniotic fluid of hypertensive pregnancy.

The high concentrations of prolactin (hPRL) in human amniotic fluid appear to be derived principally from maternal decidua. The present study evaluated both the biologic and immunologic activity of amniotic fluid hPRL obtained from normal and selected complicated pregnancies. Biologic and immunologic activities of amniotic fluid hPRL were also compared with lecithin:sphingomyelin ratios and phosphatidylglycerol content. No significant correlation existed between amniotic fluid hPRL activities and fetal lung maturation. However, a significant increase in amniotic fluid hPRL concentration as well as specific biologic activity of the hormone was found in pregnancies complicated by hypertension. These findings suggest alterations in the synthesis of decidual hPRL and/or its transport to the amniotic fluid that may influence pregnancy-induced hypertension.