Weight gain patterns during twin gestation.

Few data are available about desirable weight gain during twin gestation. The present study addresses this issue through retrospective evaluation of 217 women pregnant with twins who delivered at Swedish Hospital Medical Center, Seattle, between 1982 and 1986. The purpose of the study was to identify an optimum total weight gain and an optimum weight gain pattern for normal twin gestation. A mean prenatal weight gain of 20 kg (44 lb) was associated with "optimum" outcome; optimum outcome was defined as a pregnancy lasting at least 37 weeks with the delivery of two living infants weighing greater than or equal to 2,500 gm each with 5-minute Apgar scores greater than or equal to 7. A weight gain curve for twin gestation was generated and compared with the standard curve for singleton pregnancy. While the weight gain curve during twin gestation was similar to the standard curve during the first half of pregnancy, increased weight gain began in the second trimester and continued to term. The weight gain pattern of twin gestations with less-than-optimum outcome paralleled that of the optimum outcome group until about 30 weeks' gestation, at which time weight gain slowed in women in the former group, whose mean total weight gain was 16.8 kg (37 lb).