Poor weight gain in late third trimester: a predictor of poor perinatal outcome for term deliveries?

In many parts of the world weighing women in antenatal clinics is no longer thought to be important. At Port Moresby General Hospital we noticed that failure to gain weight in the third trimester (or weight loss) was associated with poor perinatal outcomes. To investigate this issue we designed a prospective case-control study to determine whether poor weight gain in the third trimester is a useful clinical indicator of poor placental function by being associated with intrauterine growth restriction (IUGR) or inadequate placental function in labour by being significantly associated with suspected intrapartum fetal compromise, birth asphyxia, meconium aspiration syndrome and neonatal intensive care unit admission. We found that a failure to gain weight for more than three weeks preceding the onset of labour was significantly associated with intrapartum fetal compromise (OR 2.24), IUGR (OR 2.88), meconium aspiration syndrome (OR 4.19), the presence of thick meconium or the passage of meconium during labour (OR 2.26) and the need for admission to the neonatal intensive care unit for more than 24 hours (OR 2.22). Weighing women in the antenatal clinic setting is a useful way of screening for deteriorating or inadequate placental function, and is particularly relevant in settings where more sophisticated modalities of screening and diagnosis of placental function are not available.