Dual Metabolic Burden of Polyendocrine Metabolic Ovarian Syndrome (PMOS) and Gestational Diabetes in Pregnancy: Impact on Neonatal Anthropometry: Insights From the Born in Bradford Cohort

Background Polyendocrine metabolic ovarian syndrome (PMOS) and gestational diabetes mellitus (GDM) independently influence foetal growth, but their combined impact remains poorly characterised. This study examined the individual and joint associations of PMOS and GDM with neonatal anthropometry in a large, multi‐ethnic population. Methods We performed a secondary analysis of 9454 singleton pregnancies from the Born in Bradford (BiB) cohort (UK, 2007–2011). Women were classified into four groups: (1) normoglycemic non‐PMOS controls, (2) PMOS only, (3) GDM only and (4) PMOS + GDM. GDM was defined using NICE criteria. The primary outcome was birth weight; secondary outcomes included head circumference, mid‐arm circumference and subscapular skinfold thickness. Multivariable linear regression models were used to assess associations, adjusting for maternal age, pre‐pregnancy BMI and ethnicity. Results Women with PMOS were younger (25.5 ± 4.6 vs. 27.3 ± 5.6 years, p < 0.001) and had higher BMI (27.9 vs. 25.9 kg/m 2 , p < 0.0001) than controls. Offspring of women with PMOS or GDM had lower mean birth weights than controls (3171 and 3162 g vs. 3242 g, p = 0.0005), with the greatest reduction among PMOS + GDM pregnancies (3118 g). In adjusted models, maternal BMI was strongly associated with birth weight ( β = 19.3 g/kg/m 2 , p < 1 × 10 −62 ), whereas PMOS ( β = −123.9 g, p = 0.007), GDM ( β = −136.5 g, p = 1.8 × 10 −9 ) and PMOS + GDM ( β = −241.8 g, p = 0.046) were associated with lower birth weights. Infants of mothers with combined PMOS + GDM also had the lowest mid‐arm circumference and subscapular skinfold thickness. Conclusions Both PMOS and GDM are independently and additively associated with lower foetal birth weight, with coexisting PMOS + GDM conferring the greatest reduction in neonatal size and adiposity. These findings highlight the compounded intrauterine metabolic stress in pregnancies in women with coexisting PMOS and GDM and underscore the importance of targeted antenatal care to mitigate intergenerational metabolic risk.