Radioimmunoassay of serum chorionic gonadotropin activity in normal pregnancy

Disappearance of human chorionic gonadotropin after cesarean section with regard to fetal sex

BACKGROUND

To evaluate the influence of gender on the disappearance of human chorionic gonadotropin by cesarean section after fullterm pregnancies.

MATERIALS AND METHODS

Forty-nine uncomplicated pregnancies: 26 had male (male group) and 23 had female (female group) fetuses.

RESULTS

Before the cesarean section the serum human chorionic gonadotropin levels were higher in the female than in the male bearing pregnancies. After cesarean section the human chorionic gonadotropin levels fell rapidly. The decrease in the human chorionic gonadotropin values was significantly faster in the male than in the female group during the first hours after delivery (2P < 0.02), while no significant difference was seen after 24 and 72 h.

CONCLUSION

This study shows a significantly faster human chorionic gonadotropin disappearance rate in pregnancies with male compared with female fetuses during the first hours after a cesarean section. This indicates a gender difference, which could be related to different human chorionic gonadotropin molecular structures or to more specific metabolic events.

Emergency department pregnancy testing

The rapid and accurate diagnosis of pregnancy is a necessity for emergency physicians. Physicians of the 1990s are fortunate to have available inexpensive, rapid pregnancy tests with virtually no false positives or negatives. The current basis of endocrine pregnancy tests is detection of Human Chorionic Gonadotrophin (HCG) in the serum or urine. The single HCG tests in combination with ultrasound, as well as serial HCGs, are also useful in the diagnosis of ectopic pregnancy. Serum progesterone, although at present not widely used in the emergency department, shows great promise as a test useful in the often difficult task of distinguishing ectopic and abnormal pregnancies from viable intrauterine pregnancies.

Further observations on the doubling time of human chorionic gonadotropin in early asymptomatic pregnancies

The doubling time (DT) of human chorionic gonadotropin (hCG) in serum was investigated retrospectively using serial serum hCG values that had been obtained from asymptomatic pregnant women with a prior history of infertility. The DT of hCG did not increase significantly as pregnancy advanced during the period in gestation when the serum hCG concentration was less than 10,000 mIU/mL (International Reference Preparation). Serum hCG concentrations increased subnormally in 2 of 60 women with normal intrauterine pregnancies, 5 of 8 women with asymptomatic ectopic pregnancies (EPs), and in 2 of 8 asymptomatic women who subsequently aborted their pregnancies. Neither the sensitivity nor the specificity of serial hCG testing for EP was enhanced by adopting different test criteria at different serum hCG concentrations.

Observations on the log human chorionic gonadotropin-time relationship in early pregnancy and its practical implications

In this study, we examined whether the doubling time of human chorionic gonadotropin is different at different stages of early pregnancy and whether the use of multiple nomograms for doubling time of human chorionic gonadotropin rather than a single critical value can improve the diagnosis of ectopic pregnancy. Forty-four women with intrauterine pregnancies who had abdominal pain and/or vaginal bleeding but who did not abort their pregnancies and 44 women with surgically proved ectopic pregnancies were studied. No difference was found in the doubling time of human chorionic gonadotropin when women were classified according to recently published criteria (Pittaway DE, Reish RL, Wentz AC. Doubling times of human chorionic gonadotropin increase in early viable intrauterine pregnancies. Am J Obstet gynecol 1985;152:299-302), and estimates of the doubling time of human chorionic gonadotropin were not influenced by the initial human chorionic gonadotropin values or the sampling interval used. In the human chorionic gonadotropin range of practical interest, multiple nomograms identified 26 of 33 (79%) women with ectopic pregnancy who had rising levels of human chorionic gonadotropin, whereas our previously reported criteria identified 28 of 37 (76%) cases. The false positive rate for each method was 9.7%. Seventeen (19%) of 88 patients could not be allotted to the human chorionic gonadotropin categories for which nomograms of the doubling time of human chorionic gonadotropin have been derived. We conclude that our previous recommendations for determining the rate of increase of human chorionic gonadotropin in serum from paired samples do not require revision at this time.

Preservation of human chorionic gonadotropin and placental lactogen secretion and normal morphology following long-term culture of normal human placental cells

In order to study the regulation of hCG and hPL secretion during gestation, a system for the preservation of the functional integrity of normal placental cells in long-term culture was established. Normal term placental cells were dispersed with 0.25% trypsin-500 units DNAse I and cultured in a monolayer in Dulbecco's modified Eagle medium with 10% fetal bovine serum. Normal cell morphology, basal hCG and hPL production and hCG responses to dibutyryl cAMP were preserved till 54 days of culture. This model may be useful for the study of long-term regulation of normal placental hCG and hPL synthesis and secretion.

Serum concentrations of human chorionic gonadotrophin and its alpha and beta subunits. 1. During normal singleton and twin pregnancies

Homologous radioimmunoassays have been developed for native hCG and its alpha and beta subunits. Their specificities were assessed by analysis of the inhibition ca and beta subunits. 1. During normal singleton and twin pregnancies.

Chorionic gonadotropin prevents LRF-agonist-induced luteolysis in the human

The effects of exogenous and endogenous hCG on the luteolytic action of LRF-agonist, [D-Trp6, Pro9NEt]-LRF (LRF-Ag), were evaluated. In sequential studies, 4 normal cycling women treated with LRF-Ag (50 microgram S.C.) on two consecutive days had premature decline of circulating levels of progesterone (P) and estradiol (E2) with a shortened (p < 0.05) luteal phase (11.5 +/- 1.2 days) when compared to the control cycle (15 +/- 0.7 days). When intramuscular hCG was added to the LRF-Ag treatment in doses of 100 IU or 5000 IU daily for 7 days, the luteal function was prolonged (19 +/- 1.2 days, p < 0.05) with significant (p < 0.001) elevation of P and E2 levels compared with the control cycle. Four women with early pregnancy, requesting therapeutic abortion, were given LRF-Ag (50 microgram or 500 microgram S.C.) on 2 consecutive days. None of the 4 women aborted and there was no change in the levels of beta hCG, P or E2 over the course of a week. These results indicate that both exogenous or endogenous hCG can overcome the luteolytic effect of LRF-Ag within the dose and duration used. The possibility that a more prolonged administration of a larger dose of LRF-Ag may negate the luteotropic effect of hCG remains to be explored.

Comparative study of high-dose chorionic gonadotropin on the human and rat corpus luteum and effect of gonadotropin-releasing hormone on human luteal function

Human chorionic gonadotropin (hCG) was administered to pseudopregnant rats with 4-day-old corpora lutea and to normal women on days 16 to 18 following onset of menses. In the rat serum progesterone levels fell by 90% within 8 hours as did unoccupied luteal luteinizing hormone (LH) receptors following treatment with hCG (100 IU). Total receptor number for LH, however, remained unchanged until after 12 hours. In the woman 20,000 or 40,000 IU of hCG given on day 16 and day 18 of the cycle did not reduce serum progesterone or serum estradiol levels although the serum hCG level was similar to that achieved in the rat. In fact, serum progesterone levels rose and the cycle length was extended by hCG treatment in the human. Conversely, treatment of the woman with gonadotropin-releasing hormone (GnRH, 500 microgram on day 16 and on day 18) caused an initial rapid rise, then a fall in serum progesterone levels and the cycle length was shortened. It was concluded that the human corpus luteum may be resistant to densensitization by hCG but possibly not to LH. However, the possibility cannot be excluded that GnRH may compromise luteal function through mechanisms independent of effects on pituitary gonadotropin secretion or action.

Estrogens delay the postpartum recovery of the LH-RH-induced gonadotropin release

In 27 healthy postpartum women, who were neither lactating nor receiving any therapy, LH-RH stimulation tests (50 micrograms i.v.) were performed on days 7, 14, 21 and 28 of the puerperium. In a second group of 9 postpartum women an i.m. injection of 10 mg estradiol valerianate was administered within the 3rd postpartum day, and an LH-RH stimulation test was performed on days 14 and 21 of the puerperium. Blood was withdrawn at standard intervals and LH and FSH measured by radioimmunoassay. No significant FSH and LH response was found on day 7. On day 14 there was a significant release of FSH but no LH was released. On days 21 and 28 there was a significant release of FSH and LH but the magnitude of the FSH response was greater than that of the LH release. The administration of estrogens did inhibit the recovery of the pituitary from its refractoriness: on day 14 no release of LH and FSH was observed; on day 21, only a significant release of FSH could be detected in the second group of postpartum women. This emphasizes the major role played by steroids in the regulation of the hypothalamo-pituitary-gonadal function.