Pregnancy in the underweight woman. Course, outcome, and growth patterns of the infant.

The obstetric performance and pregnancy outcome of 354 underweight patients were compared with matched control subjects of normal weight. The growth patterns of their infants were also compared. The underweight women had significantly higher rates of cardiac/respiratory problems, anemia, PROM, and endometritis but were less prone to develop pre-eclampsia. Prematurity and low Apgar scores were significantly more frequent in the infants of underweight women. There was no difference in the frequency of IUGR and in perinatal mortality rates. The mean birth weight of the infants of underweight women was 231 grams less than that of infants of control subjects. Underweight women, particularly if they were anemic, had a higher incidence of low-birth-weight infants despite adequate weight gain. AGA infants of underweight women were more likely to be below the twenty-fifth percentile for weight correlated with length by 12 months of age.