THE IMPORTANCE OF EARLY WEIGHT-GAIN IN THE INTRAUTERINE GROWTH AND BIRTH-WEIGHT OF TWINS

OBJECTIVE: It was our objective to evaluate the association between ea rly maternal weight gain (before 20 weeks), midpregnancy weight gain ( 20-28 weeks), and late pregnancy weight gain (28 weeks to birth) with fetal growth and birth weight in twins. STUDY DESIGN: This historic co hort study was based on 1564 births of live twins greater than or equa l to 28 weeks' gestation from Baltimore, Maryland, Miami, Florida, Cha rleston, South Carolina, and Ann Arbor, Michigan. RESULTS: Early fetal growth was affected only by smoking and chorionicity. Factors in mode ls of both mid and late fetal growth included maternal age, pregravid weight, parity, rates of early pregnancy and midpregnancy maternal wei ght gain, smoking, and pre-eclampsia. Increased midpregnancy fetal gro wth was associated with early maternal weight gain (10.91 g/wk per pou nd per week) and midpregnancy maternal weight gain (15.89 g/wk per pou nd per week). Increased late fetal growth was associated with early ma ternal weight gain (16.86 g/wk per pound per week) and midpregnancy ma ternal weight gain (23.88 g/wk per pound per week). Increased birth we ight was associated with early (283.02 g per pound per week), mid (163 .58 g per pound per week), and late (69.76 g per pound per week) mater nal weight gains. CONCLUSIONS: These findings confirm the importance o f early maternal weight gain in twin fetal growth end birth weight.