Birth weight and polycystic ovary syndrome in adult life: a register-based study on 523,757 Danish women born 1973–1991

Comorbidities in women with polycystic ovary syndrome: a sibling study

BACKGROUND

Polycystic ovary syndrome (PCOS) has previously been associated with several comorbidities that may have shared genetic, epigenetic, developmental or environmental origins. PCOS may be influenced by prenatal androgen excess, poor intrauterine or childhood environmental factors, childhood obesity and learned health risk behaviors. We analyzed the association between PCOS and several relevant comorbidities while adjusting for early-life biological and socioeconomic conditions, also investigating the extent to which the association is affected by familial risk factors.

METHODS

This total-population register-based cohort study included 333,999 full sisters, born between 1962 and 1980. PCOS and comorbidity diagnoses were measured at age 17-45 years through national hospital register data from 1997 to 2011, and complemented with information on the study subjects´ early-life and social characteristics. In the main analysis, sister fixed effects (FE) models were used to control for all time-invariant factors that are shared among sisters, thereby testing whether the association between PCOS and examined comorbidities is influenced by unobserved familial environmental, social or genetic factors.

RESULTS

Three thousand five hundred seventy women in the Sister sample were diagnosed with PCOS, of whom 14% had obesity, 8% had depression, 7% had anxiety and 4% experienced sleeping, sexual and eating disorders (SSE). Having PCOS increased the odds of obesity nearly 6-fold (adjusted OR (aOR): 5.9 [95% CI:5.4-6.5]). This association was attenuated in models accounting for unobserved characteristics shared between full sisters, but remained considerable in size (Sister FE: aOR: 4.5 [95% CI: 3.6-5.6]). For depression (Sister FE: aOR: 1.4 [95% CI: 1.2-1.8]) and anxiety (Sister FE: aOR: 1.5 [95% CI: 1.2-1.8), there was a small decrease in the aORs when controlling for factors shared between sisters. Being diagnosed with SSE disorders yielded a 2.4 aOR (95% CI:2.0-2.6) when controlling for a comprehensive set of individual-level confounders, which only decreased slightly when controlling for factors at the family level such as shared genes or parenting style. Accounting for differences between sisters in observed early-life circumstances influenced the estimated associations marginally.

CONCLUSION

Having been diagnosed with PCOS is associated with a markedly increased risk of obesity and sleeping, sexual and eating disorders, also after accounting for factors shared between sisters and early-life conditions.

Early Life Factors and Polycystic Ovary Syndrome in a Swedish Birth Cohort

Polycystic ovary syndrome (PCOS) is a medical condition with important consequences for women's well-being and reproductive outcomes. Although the etiology of PCOS is not fully understood, there is increasing evidence of both genetic and environmental determinants, including development in early life. We studied a population of 977,637 singleton women born in in Sweden between 1973 and 1995, followed sometime between the age 15 and 40. The incidence of PCOS was measured using hospital register data during 2001-2012, complemented with information about the women's, parents' and sisters' health and social characteristics from population and health care registers. Cox regression was used to study how PCOS is associated with intergenerational factors, and a range of early life characteristics. 11,594 women in the study sample were diagnosed with PCOS during the follow-up period. The hazard rate for PCOS was increased 3-fold (HR 2.98, 95% CI 2.43-3.64) if the index woman's mother had been diagnosed with PCOS, and with 1.5-fold (HR 1.51, 95% CI 1.39-1.63) if their mother had diabetes mellitus. We found associations of PCOS with lower (<7) one-minute Apgar score (HR 1.19, 95% CI 1.09-1.29) and with post-term birth (HR 1.19, 95% CI 1.13-1.26). Furthermore, heavy (10+ cigarettes/day) maternal smoking (HR 1.30, 95% CI 1.18-1.44) and maternal obesity (HR 1.90, 95% CI 1.62-2.36) were strongly associated with PCOS. This study finds support for the heritability and fetal origins of PCOS. Risk of PCOS could be reduced by further emphasizing the importance of maternal and early life health.

Fetal genome predicted birth weight and polycystic ovary syndrome in later life: a Mendelian randomization study

Associations between lower birth weight and higher polycystic ovary syndrome (PCOS) risk have been reported in previous observational studies, however, the causal relationship is still unknown. Based on decomposed fetal and maternal genetic effects on birth weight (n  =  406,063), we conducted a two-sample Mendelian randomization (MR) analysis to assess potential causal relationships between fetal genome predicted birth weight and PCOS risk using a large-scale genome-wide association study (GWAS) including 4,138 PCOS cases and 20,129 controls. To further eliminate the maternally transmitted or non-transmitted effects on fetal growth, we performed a secondary MR analysis by utilizing genetic instruments after excluding maternally transmitted or non-transmitted variants, which were identified in another birth weight GWAS (n = 63,365 parent-offspring trios from Icelandic birth register). Linkage disequilibrium score regression (LDSR) analysis was conducted to estimate the genetic correlation. We found little evidence to support a causal effect of fetal genome determined birth weight on the risk of developing PCOS (primary MR analysis, OR: 0.86, 95% CI: 0.52 to 1.43; secondary MR analysis, OR: 0.86, 95% CI: 0.54 to 1.39). In addition, a marginally significant genetic correlation (rg = -0.14, se = 0.07) between birth weight and PCOS was revealed via LDSR analysis. Our findings indicated that observed associations between birth weight and future PCOS risk are more likely to be attributable to genetic pleiotropy driven by the fetal genome rather than a causal mechanism.

Polyphenols: Natural compounds with promising potential in treating polycystic ovary syndrome

Polyphenols are natural compounds used by plants as a defense system against various stresses. In recent years, the importance of these polyhydroxyphenols has extensively increased due to their potent cardioprotection, anti-carcinogenic, anti-oxidant, anti-apoptotic, and anti-inflammatory properties. Therefore, various studies have reported promising results from the studies investigating their efficacy as a therapeutic strategy in various disorders such as human malignancies, cardiovascular diseases, nervous system impairments, diabetes, metabolic syndrome, aging, and inflammation-associated disorders, as well as a polycystic ovarian syndrome (PCOS). Since oxidative stress, hormonal, metabolic, and endocrine disturbances have been shown to play a crucial role in the initiation/progression of PCOS, polyphenols are suggested to be an effective treatment for this disorder. Therefore, this study aimed to discuss the therapeutic potential of multiple polyphenols in PCOS.

High DHEAS Level in Girls Is Associated with Earlier Pubertal Maturation and Mild Increase in Androgens throughout Puberty without Affecting Postmenarche Ovarian Morphology

OBJECTIVE

To assess whether the presence of high DHEAS (HD) at 7 years determines different timing, sequence, and rate of pubertal events, and whether it is associated with adrenal and/or ovarian hyperandrogenism and changes in ovarian morphology throughout puberty.

METHODS

In a longitudinal study of 504 girls, clinical evaluation was performed every 6 months after 7 years of age to detect Tanner stages; hormonal and anthropometric measurements were conducted at thelarche (B2), breast Tanner 4 (B4), and 1 year after menarche; ultrasonographic evaluation was also performed after menarche. The girls were classified as HD if their DHEAS level was >42.1 µg/dL (>75th percentile) around 7 years.

RESULTS

HD around 7 years is associated with a younger age at thelarche, pubarche, and menarche. Girls with HD had higher androstenedione and total testosterone levels, and a higher free androgen index (FAI), and lower levels of antimüllerian hormone (AMH) at B2, and higher levels of androstenedione and FAI at B4 and after menarche. All these results were significant even after adjusting for body mass index, age at first DHEAS determination, and birth weight. One year after menarche, polycystic ovarian morphology was detected in 7.6 and 7.3% of the HD and the normal DHEAS group, respectively. Ovarian volume was correlated with AMH, testosterone, androstenedione, and LH but not with DHEAS around 7 years.

CONCLUSION

Prepubertal HD in normal girls was associated with earlier thelarche, pubarche, and menarche, and a mild androgen increase throughout puberty. We believe continuous follow-up of this cohort is important to prospectively address the interrelationships between biochemical adrenarche and early growth as determinants of ovarian function.

Characteristics of obesity in polycystic ovary syndrome: Etiology, treatment, and genetics

Polycystic ovary syndrome (PCOS) has multiple etiologies including ovarian and adrenal hyperandrogenism, neuro-endocrine and hypothalamic-pituitary dysfunction, and disorders of peripheral insulin resistance. Obesity is neither necessary nor sufficient for the PCOS phenotype, and the association of PCOS with obesity is not universal, with national, cultural, and ethnic differences. Obesity, particularly visceral adiposity which is common in obese and non-obese women with PCOS, amplifies and worsens all metabolic and reproductive outcomes in PCOS. Obesity increases insulin resistance and compensatory hyperinsulinemia, which in turn increases adipogenesis and decreases lipolysis. Obesity sensitizes thecal cells to LH stimulation and amplifies functional ovarian hyperandrogenism by upregulating ovarian androgen production. Obesity increases inflammatory adipokines which, in turn, increase insulin resistance and adipogenesis. Lifestyle interventions focused on diet-weight loss and concurrent exercise are central to therapy which also commonly subsequently needs to include pharmacologic therapy. PCOS symptoms commonly improve with 5% to 10% weight loss, but 25% to 50% weight loss, usually achievable only through bariatric surgery, may be required for morbid obesity unresponsive to lifestyle-medical treatment. Bariatric surgery is a valuable approach to weight loss in PCOS where BMI is ≥40 kg/m² when non-surgical treatment and/or induction of pregnancy have failed, and can be an initial treatment when BMI is ≥50 kg/m². Further research in PCOS is needed to better understand the fundamental basis of the disorder, to ameliorate obesity, to correct hyperandrogenism, ovulation, hyperinsulinemia, and to optimize metabolic homeostasis.

Age at adiposity rebound in childhood is associated with PCOS diagnosis and obesity in adulthood-longitudinal analysis of BMI data from birth to age 46 in cases of PCOS

Background:

Adiposity rebound (AR), the second BMI rise in childhood at around the age of 6 years, is associated with obesity and metabolic alteration in later life. Given that polycystic ovary syndrome (PCOS) has a strong metabolic component, early life growth patterns could reveal a risk of PCOS. Thus, we aimed to investigate the associations between age at AR and PCOS diagnosis and BMI later in life.

Materials and methods:

This study is part of a prospective, population-based longitudinal study, where women with PCOS diagnosis by age 46 (n = 280) were compared with asymptomatic women (CTRLs, n = 1573). Weight and height data from birth to age 13 years, at age at menarche, and at ages 31 and 46 years were analyzed

Results:

Women with PCOS had lower birth weight (3357 ± 477 vs. 3 445 ± 505 g, p < 0.001), earlier age at AR (5.2 ± 1.0 vs. 5.6 ± 0.90 years, p < 0.001) and higher BMI from AR onwards compared with controls. Early timing of AR was associated with PCOS diagnosis independently of BMI (OR 1.62, 95% Cl 1.37–1.92). Women with PCOS and early AR had higher BMI at 31 and 46 years when compared to controls with early AR. The age at AR did not associate with T levels at ages 31 or 46 years.

Conclusions:

Early AR was associated with PCOS diagnosis and high BMI in adulthood. Adolescent girls with early AR and persisting obesity should be screened for PCOS symptoms, such as persistent irregular cycles and hirsutism.

Ovarian and Extra-Ovarian Mediators in the Development of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder affecting women of reproductive age. The origin of PCOS is still not clear and appears to be a function of gene x environment interactions. This review addresses the current knowledge of the genetic and developmental contributions to the etiology of PCOS, the ovarian and extra-ovarian mediators of PCOS and the gaps and key challenges that need to be addressed in the diagnosis, treatment and prevention of PCOS.

Prenatal exposures and birth indices, and subsequent risk of polycystic ovary syndrome: a national registry-based cohort study

OBJECTIVE

To study the associations between prenatal exposures and risk of developing polycystic ovary syndrome (PCOS).

DESIGN

National registry-based cohort study.

SETTING

Sweden.

POPULATION

Girls born in Sweden during the years 1982-1995 (n = 681 123).

METHODS

The girls were followed until the year 2010 for a diagnosis of PCOS. We estimated the associations between maternal body mass index (BMI), smoking, and size at birth with the risk of developing a PCOS diagnosis. Risks were calculated by adjusted hazard ratio (aHR) and 95% confidence intervals (95% CIs).

MAIN OUTCOME MEASURES

A diagnosis of PCOS at 15 years of age or later.

RESULTS

During the follow-up period 3738 girls were diagnosed with PCOS (0.54%). Girls with mothers who were overweight or obese had 1.5-2.0 times higher risk of PCOS (aHR 1.52, 95% CI 1.36-1.70; aHR 1.97, 95% CI 1.61-2.41, respectively), compared with girls born to mothers of normal weight. The risk of PCOS was increased if the mother smoked during pregnancy (1-9 cigarettes/day, aHR 1.31, 95% CI 1.18-1.47; ≥10 cigarettes/day, aHR 1.44, 95% CI 1.27-1.64). Being born small for gestational age (SGA) was associated with a later diagnosis of PCOS in crude estimates, but the association was not significant after adjusting for maternal factors.

CONCLUSIONS

Maternal smoking and increased BMI appear to increase the risk of PCOS in offspring. The association between SGA and the development of PCOS appears to be mediated by maternal factors.

TWEETABLE ABSTRACT

Smoking during pregnancy and high maternal BMI are associated with PCOS diagnosis in the offspring.

Birthweight and PCOS: systematic review and meta-analysis

STUDY QUESTION

Are intrauterine conditions, reflected in birthweight, associated with the development of polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

Our study indicates that a low birthweight as a summary measure of intrauterine environment may be associated with PCOS when diagnosed according to the Rotterdam criteria.

WHAT IS ALREADY KNOWN

The etiology of PCOS is still largely unknown. Besides subfertility, women diagnosed with PCOS have an increased risk of chronic health issues. PCOS has been linked to adverse prenatal conditions, including a low birthweight.

STUDY DESIGN SIZE DURATION

A systematic search of the literature and meta-analysis of pooled data was undertaken, according to the preferred reporting items for systematic reviews and meta-analysis (PRISMA) and meta-analysis of observational studies in epidemiology (MOOSE) guidelines.

PARTICIPANTS/MATERIALS SETTING METHOD

The following online databases were systematically searched: PubMed, EMBASE, CINAHL (via EBSCO) and Cochrane library up to 10 June 2017, with no language or date restrictions.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 1484 studies were identified of which 16 met the inclusion criteria and 14 provided data for meta-analysis. The exposure variable birthweight was either analyzed as a categorical variable using the birthweight categories <2.5, 2.5-4 and >4 kg, or as a continuous variable. We composed a birthweight category consisting of birthweights <2.5 kg plus birthweights >4 kg, reflecting extreme birthweights. In a subset analysis, we investigated the association between a low birthweight and PCOS while differentiating between Rotterdam and NIH criteria. When diagnosed according to the Rotterdam criteria, women born with birthweights lower than 2.5 kg had an odds ratio [95% CI] of 1.76 [1.14,2.70] for PCOS compared to women born with birthweights higher than 2.5 kg. For the latter analysis, we were able include 1252 women (I ² = 16%). There was no significant effect of birthweight on PCOS when diagnosed according to NIH criteria.

LIMITATIONS REASONS FOR CAUTION

The funnel plot of the studies providing data for the meta-analysis and the subset analysis indicates a publication bias.

WIDER IMPLICATIONS OF THE FINDINGS

A low birthweight could be a risk factor for PCOS when diagnosed according to the Rotterdam criteria.

STUDY FUNDING/COMPETING INTERESTS

None.

TRIAL REGISTRATION NUMBER

The protocol of this study was registered at PROSPERO under registration number CRD42016048972.

Low birth-weight is a PCOS risk factor for Southern-Italian women

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine and metabolic disorder, characterized by chronic anovulation/oligomenorrhea, hyperandrogenism and insulin-resistance. Initial studies on the genetic basis of this disorder suggested both a maternal and paternal pattern of inheritance. Birth weight has become a main factor to consider when investigating the etiology of an adult-onset disease, since it is a simple indicator of intrauterine adverse conditions. The aim of our study is to validate the "low birth-weight" as risk factor for the development of PCOS. We performed a retrospective study on 188 PCOS patients and 185 controls, showing that Southern-Italian PCOS population have a significant lower birth-weight comparing to the control population; interestingly, PCOS women with low and normal low weight at birth show higher levels of androgens. Taken together, our result highlights the importance of the "birth-weight" factor for PCOS anamnesis.

Effect of maternal PCOS and PCOS-like phenotype on the offspring's health

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder with both reproductive and metabolic abnormalities affecting women of reproductive age. While the exact origin of PCOS is unknown, observations from clinical and animal studies suggest that maternal hyperandrogenism may be a contributing factor. Because women with PCOS manifest hyperandrogenism during pregnancy, changes in the gestational endocrine milieu may play a role in the vertical transmission of this syndrome. This review discusses the potential developmental origins of PCOS, the impact of maternal PCOS on the offspring's health and contributions of the postnatal environment, capitalizing on findings from animal models that exhibit a PCOS-like phenotype. In addition, this review highlights the scarcity of data at early gestational stages in humans and the importance of animal experimentation to better understand the cellular and molecular mechanisms involved in the programming of adult diseases, therefore, helping identify therapeutic targets for preventive and treatment strategies.

Developmental origins of polycystic ovary syndrome (PCOS), a case control study comparing birth weight in women with PCOS and control group

Evidence from various epidemiological studies and experimental animal studies has linked adverse intrauterine circumstances with health problems in adult life. This field of investigation is known as Developmental Origins of Health and Disease (DOHaD). Studies investigating the relation between developing polycystic ovary syndrome (PCOS) in adulthood and birth weight have yielded inconsistent results: PCOS is described more often in women with low birth weight and high birth weight, while other studies have failed to establish any relation. In this retrospective case-control study, we evaluated whether women diagnosed with PCOS had lower birth weight compared to women with a regular menstrual cycle (controls). Binary logistic regression models were used to analyze the data and correct for known confounders. About 65 women with PCOS and 96 controls were recruited for this purpose. The average birth weight of PCOS women (3357 g) did not differ from the average birth weight of controls (3409 g). Mean age at menarche differed significantly between groups, 13.7  years and 12.8  years (p = 0.006), respectively, for PCOS women and controls. In conclusion, we could not confirm the effect of adverse intrauterine conditions, reflected in birth weight, on developing PCOS.

Developmental programming: exposure to testosterone excess disrupts steroidal and metabolic environment in pregnant sheep

Gestational exposure to excess T leads to intrauterine growth restriction, low birth weight, and adult metabolic/reproductive disorders in female sheep. We hypothesized that as early mediators of such disruptions, gestational T disrupts steroidal and metabolic homeostasis in both the mother and fetus by both androgenic and metabolic pathways. Maternal blood samples were measured weekly for levels of insulin, glucose, and progesterone from four groups of animals: control; gestational T (twice weekly im injections of 100 mg of T propionate from d 30 to d 90 of gestation); T plus an androgen antagonist, flutamide (15 mg/kg·d oral; T-Flutamide); and T plus the insulin sensitizer, rosiglitazone (0.11 mg/kg·d oral; T-Rosi) (n = 10-12/group). On day 90 of gestation, maternal and umbilical cord samples were collected after a 48-hour fast from a subset (n = 6/group) for the measurement of steroids, free fatty acids, amino acids, and acylcarnitines. Gestational T decreased maternal progesterone levels by 36.5% (P < .05), which was prevented by flutamide showing direct androgenic mediation. Gestational T also augmented maternal insulin levels and decreased medium chained acylcarnitines, suggesting increased mitochondrial fatty acid oxidation. These changes were prevented by rosiglitazone, suggesting alterations in maternal fuel use. Gestational T-induced increases in fetal estradiol were not prevented by either cotreatment. Gestational T disrupted associations of steroids with metabolites and progesterone with acylcarnitines, which was prevented either by androgen antagonist or insulin sensitizer cotreatment. These findings suggest a future combination of these treatments might be required to prevent alteration in maternal/fetal steroidal and metabolic milieu(s).

Pathogenesis of polycystic ovary syndrome: multifactorial assessment from the foetal stage to menopause

Polycystic ovary syndrome (PCOS) is a multifactorial disorder that arises from interactions between genetic, environmental and intra-uterine factors. Small-for-gestational-age (SGA) babies and the daughters of mothers with PCOS represent possible postnatal clinical targets for developmental programming by steroid excess. The presence of excess glucocorticoids and/or androgens during foetal organogenesis and growth might promote changes in gene expression, and these changes might be related to an increase in the risk of PCOS-like reproductive and metabolic disorders in postnatal life, such as rapid growth and weight gain during the first 2 years of life (only in SGA babies), hyperinsulinaemia, adipocyte dysfunction and childhood visceral obesity, premature pubarche and adrenarche (only in SGA babies) and PCOS. In the fourth decade of life, women who have PCOS may be at higher risk for type 2 diabetes mellitus, dyslipidaemia and systemic arterial hypertension, which suggests that these women are also at higher risk for cardiovascular disease during menopause. However, PCOS can also occur in women who were born at appropriate weight for GA or in newborns of women without PCOS, which suggests that genetic variation and environmental factors play important roles in the development and maintenance of PCOS in a population. Genome-wide association studies based on adequate population samples have shown a higher frequency of genetic polymorphisms of the LHCGR, THADA and DENND1A genes in women with PCOS. Genetic studies of PCOS have also included analyses of structural changes in the chromosome based on an assessment of telomere length in single, cross-sectional evaluations, and these studies have produced controversial results. The present narrative review assesses the multifactorial origins of PCOS (including environmental, genetic and intra-uterine factors) and the development of conditions associated with this disorder. It is concluded that although PCOS might originate in the intra-uterine environment through developmental programming by steroid excess, the interaction between genetic and environmental factors is crucial for its appearance. Follow-up studies should be conducted to assess the same populations over their entire lifespans while taking into account different aspects of the pathogenesis of PCOS.

Birth weight and polycystic ovary syndrome in adult life: is there a causal link?

Objectives

Several studies have demonstrated associations of birth weight with metabolic and reproductive abnormalities in adults. The aim of this study was to investigate the birth weight in women with PCOS and its correlation with clinical and biochemical characteristics of the syndrome.

Materials and Methods

We studied 288 women with PCOS according to the NIH criteria and 166 women with normal cycle and without clinical hyperandrogenism. Birth weight and anthropometric characteristics were recorded, and levels of serum androgens, SHBG, insulin and fasting glucose were measured.

Results

Birth weight data were available for 243/288 women with PCOS and age- and BMI-matched 101/166 controls. No differences were found (p> 0.05) in birth weight among women with PCOS and normal controls. Birth weight of PCOS women was negatively correlated with DHEAS levels (p = 0.031, r = -0.143) and positively correlated with waist circumference (p <0.001, r = 0.297) and body mass index (BMI) (p = 0.040, r = 0.132). Birth weight of controls was negatively correlated with SHBG levels (p = 0.021, r = -0.234). Women from both groups were further divided in 6 categories according to birth weight (A. <2.500 gr, B. 2.501-3.000 gr, C. 3.001-3.500 gr, D. 3.501-4.000 gr, E. 4.001-4.500 gr, F. > 4.500 gr). No statistically significant differences were observed in the distribution percentages between PCOS women and controls. (A. 7% vs 7.9%, B. 26.8% vs 20.8%, C. 39.1% vs 48.5%, D. 21.4% vs 20.8%, E. 4.9% vs 2%, F. 0.8% vs 0%), (in all comparisons, p> 0.05).

Conclusions

Women with PCOS do not differ from controls in birth weight distribution. However, birth weight may contribute to subtypes of the syndrome that are characterized by adrenal hyperandrogenism and central obesity.

Early-life nutritional effects on the female reproductive system

There is now considerable epidemiological and experimental evidence indicating that early-life environmental conditions, including nutrition, affect subsequent development in later life. These conditions induce highly integrated responses in endocrine-related homeostasis, resulting in persistent changes in the developmental trajectory producing an altered adult phenotype. Early-life events trigger processes that prepare the individual for particular circumstances that are anticipated in the postnatal environment. However, where the intrauterine and postnatal environments differ markedly, such modifications to the developmental trajectory may prove maladaptive in later life. Reproductive maturation and function are similarly influenced by early-life events. This should not be surprising, because the primordial follicle pool is established early in life and is thus vulnerable to early-life events. Results of clinical and experimental studies have indicated that early-life adversity is associated with a decline in ovarian follicular reserve, changes in ovulation rates, and altered age at onset of puberty. However, the underlying mechanisms regulating the relationship between the early-life developmental environment and postnatal reproductive development and function are unclear. This review examines the evidence linking early-life nutrition and effects on the female reproductive system, bringing together clinical observations in humans and experimental data from targeted animal models.

Premature adrenarche: etiology, clinical findings, and consequences

Adrenarche means the morphological and functional change of the adrenal cortex leading to increasing production of adrenal androgen precursors (AAPs) in mid childhood, typically at around 5-8 years of age in humans. The AAPs dehydroepiandrosterone (DHEA) and its sulfate conjugate (DHEAS) are the best serum markers of adrenal androgen (AA) secretion and adrenarche. Normal ACTH secretion and action are needed for adrenarche, but additional inherent and exogenous factors regulate AA secretion. Inter-individual variation in the timing of adrenarche and serum concentrations of DHEA(S) in adolescence and adulthood are remarkable. Premature adrenarche (PA) is defined as the appearance of clinical signs of androgen action (pubic/axillary hair, adult type body odor, oily skin or hair, comedones, acne, accelerated statural growth) before the age of 8 years in girls or 9 years in boys associated with AAP concentrations high for the prepubertal chronological age. To accept the diagnosis of PA, central puberty, adrenocortical and gonadal sex hormone secreting tumors, congenital adrenal hyperplasia, and exogenous source of androgens need to be excluded. The individually variable peripheral conversion of circulating AAPs to biologically more active androgens (testosterone, dihydrotestosterone) and the androgen receptor activity in the target tissues are as important as the circulating AAP concentrations as determinants of androgen action. PA has gained much attention during the last decades, as it has been associated with small birth size, the metabolic and polycystic ovarian syndrome (PCOS), and thus with an increased risk for type 2 diabetes and cardiovascular diseases in later life. The aim of this review is to describe the known hormonal changes and their possible regulators in on-time and premature adrenarche, and the clinical features and possible later health problems associating with PA.

Intrauterine environment and polycystic ovary syndrome

The maternal-fetal environment plays an important role in developmental programming of adult disease. Metabolic and hormonal dysfunction during human fetal development accompanies gestational diabetes as a common occurrence in mothers with polycystic ovary syndrome (PCOS), while human fetal androgen excess from congenital adrenal hyperplasia or virilizing tumors precedes PCOS-like symptoms after birth. To date, clinical studies of infant blood levels at term have yet to confirm that human fetal androgen excess promotes PCOS development after birth. Earlier in development, however, circulating androgen levels in the second trimester female human fetus can normally rise into the male range. Furthermore, midgestational amniotic testosterone levels are elevated in female fetuses of PCOS compared with normal mothers and might influence fetal development because experimentally induced fetal androgen excess in animals produces a PCOS-like phenotype with reproductive and metabolic dysfunction. Such alterations in the maternal-fetal environment likely program adult PCOS by epigenetic modifications of genetic susceptibility of the fetus to PCOS after birth. Understanding this phenomenon requires advanced fetal surveillance technologies and postnatal assessment of midgestational androgen exposure for new clinical strategies to improve reproduction in PCOS women, optimize long-term health of their offspring, and minimize susceptibility to acquiring PCOS in future generations.