Maternal diet and placental outcomes: Evidence of sexual dimorphism among mothers with overweight and obesity.

INTRODUCTION

Maternal diet may influence placental development and efficiency, reflected by placental weight (PW) and the birthweight-to-placental weight ratio (BW:PW). Mothers with overweight or obesity (OWOB) are at increased risk of adverse placental outcomes, yet evidence on maternal dietary influences on placental outcomes in OWOB remains limited.

METHODS

We conducted secondary analysis of data on 423 mother-child pairs with maternal BMI ≥25 kg/m2 from two Irish cohorts (Lifeways Cross-Generation Cohort (n = 66) and the Pregnancy Exercise and Nutrition Research Study (PEARS) randomized controlled trial (n = 357)). Maternal diet in early pregnancy was assessed using food frequency questionnaires (Lifeways) and 3-day food diaries (PEARS). Dietary scores representing diet quality (HEI-2015, DASH, AHEI-P), inflammatory and antioxidant potential (E-DII, DII, DAQ), and glycemic and insulinemic characteristics (GI, GL, II, IL) were calculated. PW and birthweight were obtained from hospital records and BW:PW ratios were derived. Cohort-specific linear regression assessed dietary score associations with placental outcomes, including sex-stratified analyses.

RESULTS

In Lifeways, higher general and pregnancy-specific DAQ scores were inversely associated with PW in fully adjusted models overall (B = -32.06 g and -29.73 g; p = 0.01) and among male (B = -39.77 g, p = 0.04 (DAQ)), but not female placentas. In sensitivity analyses of uncomplicated pregnancies in PEARS, II was positively associated with BW:PW ratio in females (B = 0.04, p = 0.04), while the DII was positively associated with male PW (B = 29.75 g, p = 0.02).

CONCLUSIONS

Results suggest that maternal dietary patterns may be associated with placental growth in OWOB pregnancies, with potential sex-specific effects.