Sickle-cell trait and small-for-gestational age babies: Is there a link?

Sickle cell disease is the most common haemoglobinopathy in pregnancy that can result in small babies. Sickle cell trait's (SCT) influence is unclear with a few conflicting published studies which did not relate birth weight to gestation and maternal or fetal factors. To assess the incidence of small-for-gestation age (SGA) babies in SCT pregnancies we conducted a retrospective analysis of all SCT deliveries at St Thomas' Hospital, London between 2000 and 2005. The Gardosi bulk centile calculator was used to determine the customised birth weight centile accounting for maternal height, weight, parity, ethnicity, infant's birth weight, sex and gestational age. A total of 16.8% (79/471) SCT pregnancies analysed had SGA babies. When cases with identified pregnancy complications were excluded, the SGA rate remained higher than the anticipated 10%, at 14.8% (p <or= 0.05). Further study comparing the incidence of customised SGA in pregnancies with SCT and without haemoglobinopathy is warranted to confirm this risk.