Birthweight and PCOS: systematic review and meta-analysis

Abstract

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.

Birthweight, Childhood Body Mass Index, Height and Growth, and Risk of Polycystic Ovary Syndrome

“…Despite speculations of such an association, findings from previous studies are inconsistent. A recent meta-analysis of 14 studies found that a low birthweight might increase the risk of PCOS [9], but a subsequent, largescale, registry-based study from Sweden did not find an association [24]. Thus, based on the current evidence, the role of birthweight in the etiology of PCOS is still uncertain.…”

“…As clinical manifestations of PCOS often emerge during the teenage years, the preceding years from birth and throughout childhood may be a critical period for this condition to develop. Birthweight, as an indicator of the intrauterine environment, may be inversely associated with PCOS risk but there is uncertainty about this, as the association is not significant in largescale studies, suggesting a publication bias [9]. Six studies have investigated links between body size in childhood and a subsequent risk of developing PCOS, and generally found positive associations [10][11][12][13][14][15].…”

Assisted reproductive technology or infertility: What underlies adverse outcomes? Lessons from the Massachusetts Outcome Study of Assisted Reproductive Technology

“…However, Kobayashi et al (50) suggested that the literature varied on this subject. In another example, PCOS was found in some, but not all, studies to be associated with increased PTB and LBW (51,52).…”

Polycystic ovary syndrome and type 2 diabetes mellitus: A state-of-the-art review

“…Based on the well-known developmental origins of health and disease, an inverse association between birth weight and T2D risk seems highly likely. Indeed, low birth weight has been associated with PCOS diagnosis later in life, with a birth weight < 2.5 kg conferring a 76% higher likelihood of developing PCOS[ 84 ]. In a similar manner, age of menarche has been related to dysglycemia in PCOS.…”