BACKGROUND: Prenatal exposure to bisphenol A (BPA) and phthalates may affect fetal growth; however, previous findings are inconsistent and based on few studies. OBJECTIVES: We assessed whether prenatal exposure to BPA and phthalates was associated with fetal growth in a Spanish birth cohort of 488 mother-child pairs. METHODS: We measured BPA and eight phthalates [four di(2-ethylhexyl) phthalate metabolites (DEHPm), mono-benzyl phthalate (MBzP), and three low-molecular-weight phthalate metabolites (LMWPm)] in two spot-urine samples collected during the first and third trimester of pregnancy. We estimated growth curves for femur length (FL), head circumference (HC), abdominal circumference (AC), biparietal diameter (BPD), and estimated fetal weight (EFW) during pregnancy (weeks 12-20 and 20-34), and for birth weight, birth length, head circumference at birth, and placental weight. RESULTS: Overall, results did not support associations of exposure to BPA or DEHPm during pregnancy with fetal growth parameters. Prenatal MBzP exposure was positively associated with FL at 20-34 weeks, resulting in an increase of 3.70% of the average FL (95% CI: 0.75, 6.63%) per doubling of MBzP concentration. MBzP was positively associated with birth weight among boys (48 g; 95% CI: 6, 90) but not in girls (-27 g; 95% CI: -79, 25) (interaction p-value = 0.04). The LMWPm mono-n-butyl phthalate (MnBP) was negatively associated with HC at 12-20 pregnancy weeks [-4.88% of HC average (95% CI: -8.36, -1.36%)]. CONCLUSIONS: This study, one of the first to combine repeat exposure biomarker measurements and multiple growth measures during pregnancy, finds little evidence of associations of BPA or phthalate exposures with fetal growth. Phthalate metabolites MBzP and MnBP were associated with some fetal growth parameters, but these findings require replication.

This study was funded by grants from RecerCaixa (2010ACUP 00349), Instituto de Salud Carlos III (Red INMA G03/176, CB06/02/0041, postdoctoral grant CD12/00563), Spanish Ministry of Health (FIS-PI041436, FIS-PI081151), Generalitat de Catalunya-CIRIT (Comissió Interdepartamental de Recerca i Innovació Tecnològica) (1999SGR00241), and Fundación Roger Torné.