The neonatal implications of a high placental ratio in small-for-gestational age infants

An increased placental ratio has been associated with small-for-gestational age (SGA) infants. A retrospective study on 252 singleton SGA infants without major anomalies born within a 1-year period was performed to determine the relationship between placental ratio and maternal/infant characteristics, and perinatal complications. The cases were categorized into three groups according to the placental ratio (<1 sd below the mean, within 1 sd of the mean, >1 sd above the mean) based on our previous data. There were more infants with a high ratio (32.9 per cent) than with a low ratio (15.5 per cent). While there was no difference in the maternal characteristics or antenatal complications, there was a significant trend in decreasing birthweight and an increasing placental weight in relation to an increasing placental ratio. The infants with a high ratio had increased incidence of meconium stained liquor, hypocalcaemia, hypomagnesaemia and phototherapy, a trend that was consistent even after exclusion of the preterm infants. Our data indicated that a high placental ratio in SGA infants was due to both increased placental size and decreased birthweight, and this was associated with increased neonatal morbidity.