Maternal weight and weight gain in pregnancy and obstetric outcome

Abstract

We studied 3002 antenatal patients to assess the relationship between maternal weight at booking in the first trimester and the total weight gain during the pregnancy and the birth weight of infants, pregnancy complications and mode of delivery. We found if the weight of the mother in the first trimester was lower or higher by 20% as compared with the standard weight, and the weight gain was more than 16 kg and less than 2.5 kg, there was higher incidences of maternal and fetal morbidity (P less than 0.01).

PIP: A total of 3002 antenatal patients at St. George's Hospital Medical School (Cranmer Terrace, London) were studied over the 1978 to 1980 period to assess the relationship between maternal weight at booking in the 1st trimester and the total weight gain during pregnancy and the birth weight of infants, pregnancy complications, and mode of delivery. The patients were seen every 4 weeks during the 1st 28 weeks of pregnancy, every 2 weeks from 28-26 weeks, and weekly thereafter until delivery. If patients had preexisting hypertension or developed pregnancy related hypertension they were admitted into hospitals for rest and assessment of fetoplacental function or seen weekly as outpatients in the antenatal clinic provided there was no threat to the safety of either the mother or the fetus. Maternal weight was recorded under standardized conditions taking into account patient's dress, same weight machine, and by the same team of nurses. The incidence of infants with low birth weight was significantly higher if the maternal weight was 50 kg or less. 75% in this group had a weight which was less than 20% below the standard weight for their height and build. As the maternal booking weight increased to 81 kg or more, the weights of the babies were more than 2.5 kg. The percentage of infants born with a birth weight of 3.5 kg or more was significantly less if the mother's weight was 50 kg or less as compared with the rest of the maternal weight group. If the maternal booking weight was more than 51 kg or more, there was no consistent pattern of birth weight of infants. The incidence of low birth weight infants was significantly higher if the maternal weight gain was less than 6 kg. There was a significant increase in the number of babies born with a birth weight of 3.0 kg or more if the maternal weight gain was 6 kg or more. The incedence of preexisting hypertension and preeclampsia of pregnancy was higher as the maternal booking weight was higher. There was a significant reduction in the incidence of intrauterine growth retardation as the maternal booking weight increased. The incidence of premature labor was significantly higher in the low maternal booking weight group. There was a significant increase in the incidence of fetal distress in labor, cesarean section, and forceps deliveries in the higher maternal weight group. There was a higher incidence of preeclampsia and preexisting hypertension as the maternal weight gain showed a significant increase. Premature labor, intrauterine growth retardation, and fetal distress in labor showed a higher incidence in the low weight gain group, but the incidence of forceps delivery and cesarean section was significantly higher in the higher weight gain group.