The Clinical Application of Growth Hormone and Its Biological and Molecular Mechanisms in Assisted Reproduction

Growth hormone (GH) has been used as a co-gonadotrophin in assisted reproduction, particularly in poor ovarian responders. The application of GH has been alleged to activate primordial follicles and improve oocyte quality, embryo quality, and steroidogenesis. However, the effects of GH on the live birth rate among women is controversial. Additionally, although the basic biological mechanisms that lead to the above clinical differences have been investigated, they are not yet well understood. The actions of GH are mediated by GH receptors (GHRs) or insulin-like growth factors (IGFs). GH regulates the vital signal transduction pathways that are involved in primordial follicular activation, steroidogenesis, and oocyte maturation. However, the therapeutic windows and duration of GH administration during assisted reproductive technology require further investigation. The review aimed to clarify the role of GH in human fertility from a molecular and biological point of view to provide evidence for proper GH administration.

Early-life factors and adult anti-Müllerian hormone levels

AIM

This study aims to examine whether early-life factors are associated with adult ovarian reserve, measured by anti-Müllerian hormone (AMH) levels.

METHODS

The work is based on the Jerusalem Perinatal Study (JPS), an extensive birth cohort with detailed information on all pregnancies and deliveries in Jerusalem between 1974 and 1976. A subset of individuals participated in a follow-up study that took place between 2007 and 2009 in which they completed questionnaires and were physically examined at mean age of 32. A blood sample was additionally drawn from each participant, and AMH was measured in a sample of 239 women. The associations between each early-life factors, including birth weight, maternal pre-pregnancy weight, gestational weight gain (GWG), socioeconomic position at birth, and parental smoking during pregnancy, were assessed with AMH levels at the age of 32.Multivariable regression models were used to examine the associations with AMH, adjusting for potential confounders at birth and at the age of 32.

RESULTS

Low birth weight was significantly associated with lower ovarian reserve reflected by lower levels of AMH at age 32 (range 30-36), independent of other early-life factors and after adjusting for confounders (β = 0.180, p = 0.03).

CONCLUSIONS

This prospective study demonstrates the association of birth weight and adult ovarian reserve. Underlying mechanisms are yet to be fully understood.

What is the evidence for beneficial effects of growth hormone treatment beyond height in short children born small for gestational age? A review of published literature

Background An increasing body of evidence supports the view that both an adverse intrauterine milieu and rapid postnatal weight gain in children born small for gestational age (SGA) contribute towards the risk for the development of chronic diseases in adult life. Content The aim of this review was to identify and summarize the published evidence on metabolic and cardiovascular risk, as well as risk of impaired cardiac function, intellectual capacity, quality of life, pubertal development and bone strength among children born SGA. The review will then address whether growth hormone (GH) therapy, commonly prescribed to reduce the height deficit in children born SGA who do not catch up in height, increases or decreases these risks over time. Summary Overall, there are limited data in support of a modest beneficial effect of GH therapy on the adverse metabolic and cardiovascular risk observed in short children born SGA. Evidence to support a positive effect of GH on bone strength and psychosocial outcomes is less convincing. Outlook Further evaluation into the clinical relevance of any potential long-term benefits of GH therapy on metabolic and cardiovascular endpoints is warranted.

Biomarkers of ovarian reserve in childhood and adolescence: A systematic review

INTRODUCTION

Certain medical disorders as well as their management may affect gonadal function. Recent advances in the management of these conditions accompanied by the availability and success of methods of fertility preservation has highlighted the need for assessment of ovarian reserve in childhood and adolescence. Serum anti-Mullerian hormone (AMH) and antral follicle count are well established markers of ovarian reserve and serum inhibin has also been used. However, literature on reference ranges for ovarian reserve markers in this age-group is relatively scarce. Thus, our aim was to evaluate published data to estimate reference values of ovarian reserve makers in childhood and adolescence.

MATERIAL AND METHODS

We performed a systematic review of the literature reporting ovarian reserve markers in childhood and adolescence. We included only those studies examining markers of ovarian reserve in the normal healthy population between the ages of 0 and 19 years. PROSPERO registration: CRD42018119064.

RESULTS

Serum AMH emerged as the most common biomarker assessed. Serum AMH was detectable at birth and, after a transient increase in infancy, increased steadily in childhood. Following a slight decrease at puberty, levels were constant throughout adolescence with a peak in adolescence or early adulthood. The mean serum AMH values during infancy, childhood and adolescence were 10.55, 22.32 and 31.84 pmol/L, respectively. The corresponding median values were 9.85, 24.49 and 26.32 pmol/L. It was not possible to construct age-specific reference intervals because of methodological heterogeneity, variations in the assay used to measure AMH and differing interval width for age used in included studies. Serum inhibin showed an increase from childhood to adolescence, with median serum inhibin values of 53.86 pg/mL in adolescence. Antral follicle count showed a significant positive correlation with serum AMH and a median value of 30.52 in adolescence.

CONCLUSIONS

We summarize the trends and levels of biomarkers of ovarian reserve from birth until young adulthood. Peak levels of serum AMH are reported in adolescence or early adulthood. We have reported median/mean values for serum AMH in different age-groups based on data pooled from several studies, which may be used as a reference when evaluating ovarian reserve in childhood and adolescence especially when considering fertility preservation.

The 'Developmental Origins' Hypothesis: relevance to the obstetrician and gynecologist

The recognition of 'fetal origins of adult disease' has placed new responsibilities on the obstetrician, as antenatal care is no longer simply about ensuring good perinatal outcomes, but also needs to plan for optimal long-term health for mother and baby. Recently, it has become clear that the intrauterine environment has a broad and long-lasting impact, influencing fetal and childhood growth and development as well as future cardiovascular health, non-communicable disease risk and fertility. This article looks specifically at the importance of the developmental origins of ovarian reserve and ageing, the role of the placenta and maternal nutrition before and during pregnancy. It also reviews recent insights in developmental medicine of relevance to the obstetrician, and outlines emerging evidence supporting a proactive clinical approach to optimizing periconceptional as well as antenatal care aimed to protect newborns against long-term disease susceptibility.

Sexual dichotomy of gonadal function in Prader-Willi syndrome from early infancy through the fourth decade

STUDY QUESTION

At what age does the type of hypogonadism, namely hypothalamic or primary gonadal defect, become established in men and women with Prader-Willi syndrome (PWS)?

SUMMARY ANSWER

The type of hypogonadism becomes established only in late adolescence and early adulthood.

WHAT IS KNOWN ALREADY

The etiology of hypogonadism in PWS is heterogeneous and the clinical expression is variable. Primary testicular failure is common in PWS men, while combinations of ovarian dysfunction and gonadotrophin deficiency are seen in women.

STUDY DESIGN, SIZE, DURATION

This is a prospective study of a cohort of 106 PWS patients followed for a mean duration of 4.5 years. Serial blood samples were obtained and assayed for gonadotrophins, inhibin B, anti-Mullerian hormone (AMH), dehydroepiandrosterone sulfate (DHEAS), testosterone (males), and estradiol (females). Results were compared with normal reference values obtained from the literature. For the purpose of this study, we defined the following age groups: infants <1 year; children 1-10 years; adolescents 11-20 years and adults >20 years.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Study participants were 49 males (aged 2 months to 36 years) and 57 females (aged 1 month to 37 years) with genetically confirmed diagnoses of PWS (deletions 60, uniparental disomy 54, imprinting center defect 2) followed in the Israel national multidisciplinary PWS clinic.

MAIN RESULTS AND THE ROLE OF CHANCE

Serum LH levels were in the normal range (1.0-6.0 mIU/ml) for 7/10 adult men, and high in 3, while FSH (normal range 1.0-6.1 mIU/ml) was elevated (34.4 ± 11.5 mIU/ml) in 6 and normal (3.5 ± 1.6 mIU/ml) in 4 men. Testosterone was low (5.7 ± 3.4 nmol/l) compared with the normal range of 12.0-34.5 nmol/l in the reference population in all men >20 years. AMH showed a normal decrease with age, despite low testosterone levels. Inhibin B was normal (241 ± 105 pg/ml) in infant boys, but low or undetectable in most adult men. Hormonal profiles were more heterogeneous in women than in men. Estradiol was consistently detectable in only 7/13 adult women. Inhibin B was low or undetectable in all PWS females although occasional samples showed levels within the normal range of 15-95 pg/ml. Vaginal bleeding was reported to occur for the first time in eight women at a median age of 20 years (13-34 years), but only one had regular monthly menses. The type of hypogonadism (primary or secondary) in PWS can be determined only after age 20 years.

LIMITATIONS, REASONS FOR CAUTION

The study cohort was heterogeneous, showing variability in BMI, cognitive disability and medical treatment.

WIDER IMPLICATIONS OF THE FINDINGS

Demonstration of the natural history of reproductive hormone development in PWS suggests that androgen replacement may be indicated for most PWS boys in mid-adolescence. Recommendations for hormone replacement in PWS women need to be individually tailored, serial measurements of inhibin B should be performed, and contraception should be considered in those women who may have the potential for fertility.

Prenatal exposures and anti-Mullerian hormone in female adolescents: the Avon Longitudinal Study of Parents and Children

Given that the primordial ovarian follicular pool is established in utero, it may be influenced by parental characteristics and the intrauterine environment. Anti-Müllerian hormone (AMH) levels are increasingly recognized as a biomarker of ovarian reserve in females in adulthood and adolescence. We examined and compared associations of maternal and paternal prenatal exposures with AMH levels in adolescent (mean age, 15.4 years) female offspring (n = 1,399) using data from the Avon Longitudinal Study of Parents and Children, a United Kingdom birth cohort study that originated in 1991 and is still ongoing (data are from 1991–2008). The median AMH level was 3.67 ng/mL (interquartile range: 2.46–5.57). Paternal but not maternal smoking prior to and during pregnancy were inversely associated with AMH levels. No or irregular maternal menstrual cycles before pregnancy were associated with higher AMH levels in daughter during adolescence. High maternal gestational weight gain (top fifth versus the rest of the distribution) was associated with lower AMH levels in daughters. Parental age, body mass index, and alcohol intake during pregnancy, child's birth weight, and maternal parity and time to conception were not associated with daughters' AMH levels. Our results suggest that some parental preconceptual characteristics and environmental exposures while the child is in utero may influence the long-term ovarian development and function in female offspring.

Ontogeny of polycystic ovary syndrome and insulin resistance in utero and early childhood

Polycystic ovary syndrome (PCOS) is a prevalent hyperandrogenic infertility and cardiometabolic disorder that increases a woman's lifetime risk of type 2 diabetes mellitus. It is heritable and intensely familial. Progress toward a cure has been delayed by absence of an etiology. Evidence is mounting, however, for in utero T excess, together with gestational hyperglycemia, contributing to either early differentiation of PCOS or phenotypic amplification of its genotypes. Abnormal endocrine, ovarian, and hyperinsulinemic traits are detectable as early as 2 months of age in daughters of women with PCOS, with adiposity enhancement of hyperinsulinemia during childhood potentially contributing to hyperandrogenism and LH excess by adolescence. These findings encourage increasing clinical focus on early childhood markers for adiposity and hyperinsulinemia accompanying ovarian and adrenal endocrine abnormalities that precede a diagnosable PCOS phenotype. They raise the possibility for lifestyle or therapeutic intervention before and during pregnancy or during childhood and adolescence alleviating the manifestations of a familial genetic predisposition to PCOS.

Peripubertal changes in circulating antimüllerian hormone levels in girls

Objective

To identify correlates and longitudinal changes in circulating antimüllerian hormone (AMH) levels as a marker of ovarian primordial follicle recruitment in normal peripubertal girls.

Design

Observational study using mixed longitudinal and cross-sectional analyses.

Setting

Not applicable.

Patient(s)

Unselected girls assessed at ages 7–11 years.

Intervention(s)

None.

Main Outcome Measure(s)

AMH, inhibin B, and FSH levels were analyzed in blood samples collected at ages 7, 9, and 11 years for longitudinal analyses and at age 8 years for cross-sectional analyses.

Result(s)

In the cross-sectional analysis, AMH levels at age 8 years were lower in pubertal girls (median 25.0 pmol/L, interquartile range [IQR] 16.0–33.9; n = 39) than in prepubertal girls (33.5 pmol/L, IQR 22.3–49.1; n = 342). In prepubertal girls, higher AMH levels were associated with higher inhibin B levels, lower FSH levels, and larger body mass index at age 8 years and subsequently with later age at menarche. AMH levels were unrelated to birth weight or birth length. In the longitudinal analysis, AMH levels increased between ages 7 (median 27.0 pmol/L, IQR 19.2–34) and 9 years (32.0 pmol/L, IQR 26.5–42.7), then declined between 9 and 11 years (26.5 pmol/L, IQR 19–42.25) with high intraindividual correlation in AMH levels between ages 7 and 9 years and 7 and 11 years.

Conclusion(s)

Measurement of circulating AMH and inhibin B levels suggests that the rate of ovarian primordial follicle recruitment increases in the prepubertal years then declines again following the onset of puberty as follicular activity pattern changes.