Hormonal evaluation of early pregnancy

Human Chorionic Gonadotropin-A Review of the Literature

Importance

The measurement of human chorionic gonadotropin (hCG) levels in different body fluids is a commonly utilized tool in obstetrics and gynecology, as well as other fields. It is often one of the first steps in the medical workup of female patients, and the results and interpretation of this test can have significant downstream ramifications. It is essential to understand the uses and limitations of hCG as a testing and therapeutic measure to appropriately evaluate, counsel, and treat patients.

Objective

The purpose of this article is to review the current literature on hCG, including its origins, structure, pharmacokinetics, metabolism, and utility in testing and medical treatment.

Evidence Acquisition

Original research articles, review articles, and guidelines on hCG use were reviewed.

Conclusions and Relevance

While the primary function of hCG is to maintain early pregnancy, testing for hCG demonstrates that this molecule is implicated in a multitude of different processes where results of testing may lead to incorrect conclusions regarding pregnancy status. This could affect patients in a myriad of settings and have profound emotional and financial consequences. In addition, hCG testing may be revealing of alternative pathology, such as malignancy. It is imperative to understand the nuances of the physiology of hCG and testing methods to effectively use and interpret this test for appropriate patient management.

Serum β-human chorionic gonadotropin profile and its correlations with ultrasound parameters in low-lying-implantation ectopic pregnancy in the first trimester

AIM

Cervical pregnancy (CP) and cesarean scar pregnancy (CSP), defined as low-lying-implantation ectopic pregnancy (LLIEP), are rare conditions of aberrant implantation around the lowest portion of the uterus. This study aimed to illustrate the serum β-human chorionic gonadotropin (β-hCG) profile of LLIEP and to explore its implications with the clinical characteristics.

METHODS

Women with LLIEP during the first trimester were retrospectively evaluated at a tertiary referral center from August 1999 to July 2016. Demographic and clinical data were recorded, including maternal age, gestational age (GA), serum β-hCG level, maximal diameter of the gestational mass/sac (MDM/MDS) by ultrasonography and CSP implantation types. The serum β-hCG level was measured on the day of ultrasound imaging. The significance of pretreatment the serum β-hCG level and its correlations with the clinical characteristics were analyzed.

RESULTS

A total of 88 LLIEP with 64 CSP and 24 CP was included. The mean GA at the time of diagnosis was 7 weeks (range, 5-12 weeks). The β-hCG concentrations rapidly increased from GA 5 to 9 weeks and fluctuated thereafter. The β-hCG levels correlated positively with GA and ultrasound MDM/MDS. In the CSP group, there was no difference in the β-hCG level between superficial and deep implantation types. β-hCG levels demonstrated no significant differences among simple and complicated LLIEP.

CONCLUSION

This study established the serum β-hCG profile in LLIEP in the first trimester. The exponential increase of β-hCG levels was similar to that of normal intrauterine pregnancies. The β-hCG levels were not associated with placentation complexity of CSP. Higher β-hCG levels did not implicate less success in conservative surgical management.

Comparative expression patterns of selected membrane transporters in differentiated BeWo and human primary trophoblast cells

Although placental membrane transporters have an important impact on materno-fetal nutrient transfer, placental cell models are poorly characterized regarding transporter expression. We assessed the mRNA expression of 26 physiologically important solute carriers and ABC transporters in BeWo (b30 clone) and primary human trophoblast cells (PHT) before and after syncytialization. 77% of the transporters showed similar mRNA expression changes between BeWo and PHT after syncytialization. Selected transporters, however, were either lacking in BeWo or showed different trends after syncytialization. In conclusion, BeWo cells generally represent an apt model for transporter studies, but their suitability should be confirmed for each transporter by comparison with PHT.

Novel Insights into Concepts and Directionality of Maternal⁻Fetal Cholesterol Transfer across the Human Placenta

Cholesterol is indispensable for cellular membrane composition and function. It is also a precursor for the synthesis of steroid hormones, which promote, among others, the maturation of fetal organs. A role of the ATP-binding-cassette-transporter-A1 (ABCA1) in the transport of maternal cholesterol to the fetus was suggested by transferring cholesterol to apolipoprotein-A-1 (apo-A1), but the directionality of the apoA-1/ABCA1-dependent cholesterol transport remains unclear. We isolated primary trophoblasts from term placentae to test the hypotheses that (1) apoA-1/ABCA1 dispatches cholesterol mainly towards the fetus to support fetal developmental maturation at term, and (2) differentiated syncytiotrophoblasts (STB) exert higher cholesterol transport activity than undifferentiated cytotrophoblasts (CTB). As experimental models, we used (1) trophoblast monolayers grown on Transwell^® system consisting of apical (maternal-like) and basal (fetal-like) compartments, and (2) trophoblasts grown on conventional culture plates at CTB and STB stages. Surprisingly, apoA-1-mediated cholesterol efflux operated almost exclusively at the apical-maternal side, where ABCA1 was also localized by immunofluorescence. We found greater cholesterol efflux capacity in STB, which was increased by liver-X-receptor agonist treatment and decreased by ABCA1 inhibition. We conclude that at term the apoA-1/ABCA1 pathway is rather involved in cholesterol transport to the mother than in transfer to the fully developed fetus.

Differential diagnosis and management of placental polyp and uterine arteriovenous malformation: Case reports and review of the literature

Postpartum uterine bleeding is not uncommon and is caused by a variety of obstetrical and gynecological disorders, such as retained placenta, dysfunctional bleeding, and endometrial polyps. Placental polyps and uterine arteriovenous malformation are disorders often encountered in cases of abnormal uterine bleeding in the late puerperal period. These patients may experience life-threatening bleeding and require prompt intervention based on the correct differential diagnosis. The optimal treatments for both diseases differ as follows: intrauterine curettage or transcervical resection are chosen for placental polyps, while total abdominal hysterectomy or uterine artery embolization is preferred for uterine arteriovenous malformation since intrauterine curettage or transcervical resection has the risk of massive bleeding. However, since placental polyp and uterine arteriovenous malformation have similar clinical characteristics, it is important to accurately identify and differentiate between them to ensure optimal therapy. We report here cases that were suggestive of placental polyp or uterine arteriovenous malformation. We discuss the differential diagnoses and treatments for both diseases based on a literature review and propose a novel algorithm for managing such patients.

Testicular choriocarcinoma: a rare variant that requires a unique treatment approach

Testicular germ cell tumors represent the most common malignancy among young men. While 5-year overall survival and cure for this population is greater than 95%, choriocarcinoma is an aggressive subtype of this disease with far worse prognosis--5-year survival for choriocarcinoma is less than 80%. In order to be able to treat these patients appropriately, a provider must recognize characteristic features of choriocarcinoma including elevated human chorionic gonadotropin in a young man with testicular mass; the astute clinician should also know the signs and symptoms of choriocarcinoma syndrome, characterized by bleeding from metastatic sites, which represents a medical emergency and is associated with high morbidity and mortality. Treatment should be directed towards a goal of tumor marker normalization, and patients with refractory disease should be considered for advanced therapies and clinical trials. Choriocarcinoma is a unique and aggressive germ cell malignancy, and these patients require early aggressive treatment to improve their chance of survival.

New discoveries on the biology and detection of human chorionic gonadotropin

Human chorionic gonadotropin (hCG) is a glycoprotein hormone comprising 2 subunits, alpha and beta joined non covalently. While similar in structure to luteinizing hormone (LH), hCG exists in multiple hormonal and non-endocrine agents, rather than as a single molecule like LH and the other glycoprotein hormones. These are regular hCG, hyperglycosylated hCG and the free beta-subunit of hyperglycosylated hCG. For 88 years regular hCG has been known as a promoter of corpus luteal progesterone production, even though this function only explains 3 weeks of a full gestations production of regular hCG. Research in recent years has explained the full gestational production by demonstration of critical functions in trophoblast differentiation and in fetal nutrition through myometrial spiral artery angiogenesis. While regular hCG is made by fused villous syncytiotrophoblast cells, extravillous invasive cytotrophoblast cells make the variant hyperglycosylated hCG. This variant is an autocrine factor, acting on extravillous invasive cytotrophoblast cells to initiate and control invasion as occurs at implantation of pregnancy and the establishment of hemochorial placentation, and malignancy as occurs in invasive hydatidiform mole and choriocarcinoma. Hyperglycosylated hCG inhibits apoptosis in extravillous invasive cytotrophoblast cells promoting cell invasion, growth and malignancy. Other non-trophoblastic malignancies retro-differentiate and produce a hyperglycosylated free beta-subunit of hCG (hCG free beta). This has been shown to be an autocrine factor antagonizing apoptosis furthering cancer cell growth and malignancy. New applications have been demonstrated for total hCG measurements and detection of the 3 hCG variants in pregnancy detection, monitoring pregnancy outcome, determining risk for Down syndrome fetus, predicting preeclampsia, detecting pituitary hCG, detecting and managing gestational trophoblastic diseases, diagnosing quiescent gestational trophoblastic disease, diagnosing placental site trophoblastic tumor, managing testicular germ cell malignancies, and monitoring other human malignancies. There are very few molecules with such wide and varying functions as regular hCG and its variants, and very few tests with such a wide spectrum of clinical applications as total hCG.

Structural changes of IgG induced by heat treatment and by adsorption onto a hydrophobic Teflon surface studied by circular dichroism spectroscopy

Thermal denaturation of mouse monoclonal immunoglobulin G (isotype 1), as well as structural rearrangements resulting from adsorption on a hydrophobic Teflon surface, are studied by circular dichroism spectroscopy. Both heat-induced and adsorption-induced denaturation do not lead to complete unfolding into an extended polypeptide chain, but leave a significant part of the IgG molecule in a globular or corpuscular form. Heating dissolved IgG causes a decrease of the fractions of beta-sheet and beta-turn conformations, whereas those of random coil and, to a lesser extent, alpha-helix increase. Adsorption enhances the formation of alpha-helices and random coils, but the beta-sheet content is strongly reduced. Heating adsorbed IgG results in a gradual break-down of the alpha-helix and beta-turn contents, and a concomitant formation of beta-sheet structures. Thus, the structural changes in IgG caused by heating and by adsorption, respectively, are very different. However, after heating, the structure of adsorbed IgG approaches the structure of thermally denatured IgG in solution.

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.

Hormonal profiles of early gestations with abnormal karyotype

OBJECTIVE

To describe the hormonal profiles of chromosomally abnormal pregnancies during the first trimester.

DESIGN

A prospective study from 1984 through 1990 in which infertility patients who conceived were monitored weekly with serum E2, P, and beta-hCG levels.

SETTING

The infertility practice at Rush-Presbyterian-St. Luke's Medical Center in Chicago, Illinois.

PATIENTS

Study included 15 women who had dilatation and curettage for first trimester fetal losses with confirmed abnormal karyotype, 6 women with chromosomally normal male abortuses, and 60 consecutive women whose pregnancies yielded normal term infants.

RESULTS

After natural conception, E2 demonstrated a moderate rise in both normal and chromosomally abnormal pregnancies to approximately 300 pg/mL by day 29 (6 weeks of gestation). In normal gestations, E2 continued a steady increase to exceed the level of 1,000 pg/mL by day 64 (11 weeks of gestation). In chromosomally abnormal pregnancies, the mean E2 plateaued and remained at approximately 200 pg/mL until fetal demise was noted. In stimulated conceptions, the rise of E2 was sharp and early (1,200 pg/mL by day 29); in normal pregnancies, E2 steadily increased to an average of 1,400 pg/mL by the end of the first trimester, whereas in karyotypically abnormal gestations, E2 declined to approximately 200 pg/mL by day 64. In pregnancies yielding a male abortus, a sharp decline and plateau at 800 pg/mL by day 56 (10 weeks of gestation) was observed. In both natural and stimulated normal pregnancies, hCG levels first demonstrated a linear rise, followed by a curvilinear increase from day 29 until day 56, with a peak of approximately 110,000 mIU/mL. The beta-hCG in chromosomally abnormal pregnancies, as well as in pregnancies yielding a male abortus, was characterized by a slow and gradual rise to a maximum of 40,000 mIU/mL, which remained relatively linear until day 64 when fetal demise was detected in all cases. Progesterone level data were excluded from analysis because of frequent P supplementation.

CONCLUSIONS

There were significant differences in the hormonal profiles of chromosomally normal and abnormal pregnancies. Serial measurements of serum E2 and beta-hCG from the 6th week of gestation may be useful in predicting an abnormal karyotype sooner than other current diagnostic tests.

Comparison of maternal serum estradiol and progesterone levels in pregnancies after induced and spontaneous ovulation

Maternal serum estradiol and progesterone levels during the early 6th to 15th weeks of gestation, were measured by radioimmunoassay in 140 pregnancies following induction of ovulation with gonadotropins or clomiphene citrate. The levels were compared with those observed in 79 spontaneous pregnancies. Significantly higher levels were observed in gonadotropin and clomiphene citrate induced pregnancies (both P values less than 0.001) between the 6th to 9th week of gestation as compared to spontaneous pregnancies. Steroid levels were similar in the two groups from the 9th week onwards. No statistically significant differences in steroid hormone values were observed in aborted and successful pregnancies within each group studied. We conclude that ovulation induction is associated with higher estradiol and progesterone levels until placental steroidogenesis starts.

Particle counting immunoassay of choriogonadotropin using monoclonal antibodies

A latex particle immunoassay has been developed for the quantification of choriogonadotropin in human serum using two monoclonal antibodies specific for the beta-chain of the hormone. The assay, based on optical counting of monomeric particles, was achieved in 40 min and the calibration curve was linear between 10 and 200 IU/l. Intra- and interassay precisions at three different levels of the curve varied between 3.3 and 10.9%. The method was validated by comparison with two different radioimmunoassays and correlation coefficients of 0.97-0.99 were obtained.

Early chorionic activity in women bearing inert IUD, copper IUD and levonorgestrel-releasing IUD

Early chorionic activity was assessed in the premenstrual days by means of serum HCG beta-fraction. As control, a group of women with no contraceptive use was studied; early chorionic activity was detected in 31.8% of the cycles. In the group bearing an inert IUD the incidence was 20%, which did not differ from the control; while in the medicated IUD groups (Cu-IUD and LNG-IUD) the incidences were 4.8% and nil, respectively. Both medicated IUD groups showed a significant difference when compared with the control, as well as the inert IUD groups. The meaning of these findings, pointing out differences in the main mechanism of action between inert and medicated IUDs, is discussed.

What's new in pregnancy tests

Immunologically based pregnancy tests that will diagnose pregnancy even before the menstrual period is missed are now available. Nurses who deal with female patients in the reproductive years must be aware of these newer pregnancy tests now in use. Appropriate interpretation of pregnancy tests will aid women in early pregnancy to avoid potentially harmful radiation, drugs, or treatments.

Hormonal monitoring of early pregnancy by a direct radioimmunoassay of steroid glucuronides in first morning urine

The usefulness of the direct 4-hour radioimmunoassay of estriol-16-glucuronide (E3G) and pregnanediol-3-glucuronide (P2G) in first morning urine (FMU) for establishing a prognosis of the early pregnancy outcome was evaluated in 106 patients that became pregnant. Microaliquots of FMU were serially assayed from day 3 of the conception cycle until day 80 of pregnancy. The E3G and P2G profiles of 19 pregnancies which terminated in spontaneous abortion with either a diagnosis of the blighted ovum syndrome (n = 11) or presumption of a corpus luteum/trophoblast failure (n = 8) have been compared with those of clinically normal pregnancies (n = 87). Normal pregnancies displayed typical patterns of E3G and P2G development, while variations were observed in abortive events that reflected changes of the fetoplacental unit.

Norethisterone acetate and ethinylestradiol in early human pregnancy

In a double-blind randomized trial, 25 women (8-9 weeks pregnant) received 20 mg norethisterone acetate (NET-AC) and 0.04 mg ethinylestradiol (EE2), 25 women receiving placebo. The patients were followed by ultrasound and the products at curettage studied macroscopically and microscopically. In an open trial, ten patients (5-9 weeks pregnant) received NET-AC + EE2, 11 serving as controls. The concentrations of plasma progesterone, estradiol-17 beta, 17 alpha-hydroxyprogesterone, norethisterone, and FSH were followed. The frequency of intrauterine hemorrhage in early pregnancy was not affected by NET-AC + EE2. Ultrasound was not reliable when studying the occurrence of decidual hemorrhages during early pregnancy. The pharmacokinetics and bioavailability of NET remain unchanged during early pregnancy. The treatment with NET-AC + EE2 had no effect on the heights and the time courses of the mean plasma values of progesterone, estradiol-17 beta, 17 alpha-hydroxyprogesterone, and FSH. No differences were found between treated and nontreated patients in the pathology of the placenta or decidua as determined by both macroscopic and microscopic examinations. The hypothesis of Papp and Gardo, that decidual hemorrhages may be induced in early pregnancy as a consequence of a "withdrawal effect" of hormonal pregnancy tests, is not supported by the results of this investigation.

Induced corpus luteum dysfunction after aspiration of the preovulatory follicle in monkeys

In order to obtain a mature ovum for in vitro fertilization or alternative procedures, the technique must be reliable both for collection of the fertilizable egg and preservation of a receptive maternal milieu, supported principally by normal corpus luteum function. During aspiration of the dominant follicle in the immediate preovulatory interval, some of the granulosa cells and follicular fluid unavoidably are removed from the antrum, along with the ovum. We used laboratory primates to assess the consequences of this granulosa cell and follicular fluid loss on subsequent corpus luteum function. Two types of luteal dysfunction were observed in approximately one-third of the monkeys: (1) transient subnormal progesterone secretion in the 1st postovulatory week and (2) very low progesterone secretion throughout the luteal phase. Only the former group demonstrated responsiveness to human chorionic gonadotropin.