Ovarian reserve and anti-Mullerian hormone (AMH) in mothers of dizygotic twins

Association of adverse pregnancy outcomes and multiple gestation with natural menopause: A population-based cohort study

OBJECTIVE

Adverse pregnancy outcomes (APOs) and early menopause are each associated with increased risk of cardiovascular disease (CVD); whether APOs are associated with age at menopause is unclear. We examined the association of gestational diabetes (GDM), hypertensive disorders of pregnancy (HDP), preterm birth, and multiple gestation with age at natural menopause.

STUDY DESIGN

Observational, prospective study within the Nurses' Health Study II cohort (1989-2019).

MAIN OUTCOMES MEASURES

Risk of early natural menopause, defined as occurring before the age of 45 years, and age at onset of natural menopause (hazard ratio (HR) >1 indicates younger age at menopause).

RESULTS

The mean [SD] baseline age of 69,880 parous participants was 34.5 [4.7] years. Compared with participants who had a term singleton first birth, those with a term multiple-gestation first birth had higher risk of early menopause (HR: 1.65, 95% CI: 1.05, 2.60) and younger age at natural menopause (HR: 1.46, 95% CI: 1.31, 1.63). Estimates for preterm multiple gestation were of similar magnitude. Menopause occurred at a younger age for those with a preterm birth with spontaneous labor (HR: 1.08, 95% CI: 1.03, 1.14) compared to those with a term birth with spontaneous labor. Conversely, estimates for GDM (HR: 0.95, 95% CI: 0.89, 1.02) and HDP (preeclampsia, HR: 0.93, 95% CI: 0.89, 0.97) suggested an association with older age at menopause.

CONCLUSIONS

In this large cohort study, several statistically significant associations between APOs and age at natural menopause were observed. A deeper understanding of the relationships among APOs, menopause, and CVD is needed to help identify people at higher risk for early menopause and later CVD.

A Narrative Review of Current Understanding of the Pathophysiology of Polycystic Ovary Syndrome: Focus on Plausible Relevance of Vitamin D

Polycystic ovarian syndrome (PCOS) is the most prevalent endocrinopathy of reproductive years. Salient features in presentation of patients PCOS include menstrual dysfunction, hyperandrogenism and/or polycystic appearance of ovaries on ultrasound. While the diagnosis of PCOS depends on presence of specified criteria, misdiagnoses are common. Despite years of extensive research, the exact aetiology of PCOS remains largely unknown. In the past decade, apart from insulin resistance and hyperandrogenemia, anti-mullerian hormone (AMH), an important marker of ovarian reserve, and vascular endothelial growth factor (VEGF), a crucial factor in angiogenesis, have been examined as plausible players of causative relevance for PCOS. Vitamin D, a sex-steroid hormone that is universally known for its relevance for skeletal health, has received increasing attention due to growing evidence supporting its pivotal in reproductive physiology and in PCOS. In this review we summarize our current understanding of the mechanisms relevant to the pathophysiology of PCOS and examine the role of vitamin D signalling in this context.

In-utero cigarette smoke exposure and the risk of earlier menopause

OBJECTIVE

Cigarette smoking is a risk factor for earlier menopause. Animal studies show that in-utero smoke exposure is toxic to developing ovaries. Our aim was to evaluate whether in-utero smoke exposed women reach menopause earlier compared with nonexposed women.

METHODS

This is a cohort study within the Avon Longitudinal Study of Parents and Children. Participants included in this study were followed from 1991/1992 until 2010. Participant characteristics for the current analysis were obtained from obstetric records and from annual follow-up questionnaires. When not available, age at natural menopause was estimated by age at filling in the questionnaire minus 1 year. Cox proportional hazards modeling was used to estimate hazard ratios of menopause for in-utero exposed and nonexposed women.

RESULTS

There were 695/2,852 postmenopausal women, of whom 466 had natural menopause, 117 had hormonal therapy, and 112 had surgical menopause. Age at natural menopause was 50.6 ± 3.7 years. Of all participants, 20.2% (577/2,852) were exposed to smoke in-utero. Participants who were in-utero exposed but were not smokers did not have higher hazards of menopause (adjusted hazard ratio [HR] 0.92, 95% CI 0.72-1.18), whereas participants who were ever smokers (current or previous) and were in-utero exposed (adjusted HR 1.41, 95% CI 1.01-1.95) or were ever smokers but not exposed (adjusted HR 1.24, 95% CI 1.00-1.53) did have higher hazards of earlier menopause.

CONCLUSIONS

In-utero smoke exposure was not associated with earlier menopause, but the effect of in-utero smoke exposure was modified by the smoking habits of the participants themselves increasing the risk for smokers who were in-utero exposed.

Fragile x-associated premature ovarian failure in a large Turkish cohort: Findings of Hacettepe Fragile X Registry

OBJECTIVE

To determine frequency of fragile X associated premature ovarian insufficiency (FXPOI) among Turkish premutation carriers.

STUDY DESIGN

FMR1 premutation is the single most common genetic cause of POI (FXPOI). Fragile X Registry at Hacettepe University has been reviewed for the frequency of FXPOI among female premutation carriers. Since 1991 when FMR1 testing was available, 760 individuals from 243 families have been registered. Actual data on menstrual status of female premutation carriers were gathered and analysed.

RESULTS

Among 314 premutation-bearing females in the cohort, 268 could be reached for an update of their menstrual history; 107 adults were 40 or younger and 156 were older than 40 years of age, whereas the remaining 5 patients were prepubertal. Among 263 postpubertal females with premutations, 90 women stopped menstruating before or at 40 years of age (premature ovarian failure - POF), constituting 34.2% of our cohort. Additionally, one carrier of a gray zone allele experienced FXPOI. History of twinning was present once in 18 women (5.7%) and twice in two women (0.6%), one of the latter interestingly bearing a full-mutation.

CONCLUSIONS

FXPOI rates in the present cohort are higher than those reported in other populations. Higher FXPOI rates in Turkish premutation carriers might be a reflection of younger mean menopause age and higher POI rates in otherwise healthy Turkish women. Since POI is much more frequent among premutation carriers than in general population, testing for CGG repeat expansions in FMR1 should be included in the work-up.

Smoking, alcohol and caffeine in relation to two hormonal indicators of ovarian age during the reproductive years

OBJECTIVE

To examine whether or not cigarette smoking, alcohol and caffeine intake are related to two indicators of ovarian age-anti-Müllerian hormone (AMH) and follicle stimulating hormone (FSH).

STUDY DESIGN

Cross-sectional study of 477 women with a recent index spontaneous abortion (SA) (105 trisomic, 93 non-trisomic) or livebirth (LB) (279) with hormones measured on days 2-4 of an apparently normal menstrual cycle after the index pregnancy.

RESULTS

Current smoking is associated with about a 15% increase in median FSH (β for ln(FSH)=0.14, 95% CI 0.03,0.25). It is not significantly related to AMH (β for ln(AMH)=-0.25, 95% CI -0.56,0.06). Neither alcohol 2-7days per week nor caffeine 122-<553mg per day is independently related to AMH or FSH.

CONCLUSIONS

The observation that current smoking is associated with FSH, but not with AMH, suggests that current smoking either impairs the development of antral follicles or dysregulates the hypothalamic-pituitary-ovarian axis. The absence of an association with AMH argues against mechanisms related to accelerated follicle atresia.

Identification of Common Genetic Variants Influencing Spontaneous Dizygotic Twinning and Female Fertility

Spontaneous dizygotic (DZ) twinning occurs in 1%-4% of women, with familial clustering and unknown physiological pathways and genetic origin. DZ twinning might index increased fertility and has distinct health implications for mother and child. We performed a GWAS in 1,980 mothers of spontaneous DZ twins and 12,953 control subjects. Findings were replicated in a large Icelandic cohort and tested for association across a broad range of fertility traits in women. Two SNPs were identified (rs11031006 near FSHB, p = 1.54 × 10(-9), and rs17293443 in SMAD3, p = 1.57 × 10(-8)) and replicated (p = 3 × 10(-3) and p = 1.44 × 10(-4), respectively). Based on ∼90,000 births in Iceland, the risk of a mother delivering twins increased by 18% for each copy of allele rs11031006-G and 9% for rs17293443-C. A higher polygenic risk score (PRS) for DZ twinning, calculated based on the results of the DZ twinning GWAS, was significantly associated with DZ twinning in Iceland (p = 0.001). A higher PRS was also associated with having children (p = 0.01), greater lifetime parity (p = 0.03), and earlier age at first child (p = 0.02). Allele rs11031006-G was associated with higher serum FSH levels, earlier age at menarche, earlier age at first child, higher lifetime parity, lower PCOS risk, and earlier age at menopause. Conversely, rs17293443-C was associated with later age at last child. We identified robust genetic risk variants for DZ twinning: one near FSHB and a second within SMAD3, the product of which plays an important role in gonadal responsiveness to FSH. These loci contribute to crucial aspects of reproductive capacity and health.

Molecular insights into the aetiology of female reproductive ageing

As age at pubertal onset declines and age at first pregnancy increases, the mechanisms that regulate female reproductive lifespan become increasingly relevant to population health. The timing of menarche and menopause can have profound effects not only on fertility but also on the risk of diseases such as type 2 diabetes mellitus, cardiovascular disease and breast cancer. Genetic studies have identified dozens of highly penetrant rare mutations associated with reproductive disorders, and also ∼175 common genetic variants associated with the timing of puberty or menopause. These findings, alongside other functional studies, have highlighted a diverse range of mechanisms involved in reproductive ageing, implicating core biological processes such as cell cycle regulation and energy homeostasis. The aim of this article is to review the contribution of such genetic findings to our understanding of the molecular regulation of reproductive timing, as well as the biological basis of the epidemiological links between reproductive ageing and disease risk.