Longitudinal study of babies born to mothers enrolled in a preconception prospective pregnancy study: study design and methodology, New York State Angler cohort study.

Persistent environmental chemicals such as organochlorine pesticides and polychlorinated biphenyls (PCBs) have been associated with alterations in fetal development and child health including subtle differences in developmental status. Previous prospective studies have ascertained prenatal or postnatal exposures but none have been designed to assess exposures at critical windows including preconception. To address this gap, we followed infants born to mothers recruited prior to conception in the New York State Prospective Pregnancy Study to assess feasibility issues including acceptability of a relatively invasive study protocol during the child's first 2 years of life. Longitudinal measurements on health, development, and growth were obtained from 53 live-born infants; 49 families consented to standardized in-home neurodevelopmental and psychosocial evaluations at 12 and 24 months of age. Nineteen participating parents consented to the collection of blood from infants for lead thyroid and PCB levels. Despite the intensive data collection protocol over 2 years coupled with the mothers having completed an intensive prospective pregnancy protocol, we found parents readily open to continued participation in a longitudinal study involving their children. Suggestions for conducting in-home assessments include use of a consistent contact nurse, comprehensive parent-friendly developmental assessment tools with some interim assessment by parent report, and periodic team visits.