Fetal growth in women with homozygous sickle cell disease: an observational study.

Objectives: To assess fetal growth and whether lower birthweight to mothers with homozygous sickle cell (SS) disease is related to maternal body composition or to clinical events in pregnancy.

Study Design: A prospective study of 41 pregnant women with SS disease and 41 women with a normal (AA) phenotype attending the antenatal clinic, University Hospital of the West Indies, Kingston, Jamaica. Maternal anthropometry, body composition and fetal sonographic measurements were assessed at 15, 25, and 35 weeks' gestation from December 2005 to April 2008. Birth measurements were performed within 24h of delivery. Differences between maternal genotypes and between their offspring were assessed using 2-sample t-tests. Multiple linear regression was used to control for baby's gender and gestational age at delivery. Fetal growth was compared in SS mothers with and without admission for sickle-related complications including bone pain crisis, acute chest syndrome, pregnancy-induced hypertension and urinary tract infection.

Results: Mothers with SS disease had lower weight, body fat, fat mass and lean body mass throughout pregnancy but correlation with birth size did not reach statistical significance. Sonographically, babies of SS mothers had smaller abdominal circumference, femoral length and a lower estimated fetal weight at 35 weeks. Birth measurements confirm lower birthweight, crown-heel length and head circumference but the differences were no longer significant after adjustment for baby gender and gestational age at delivery. Bone pain crisis in pregnancy was associated with a significantly reduced crown-heel length at birth.

Conclusion: Lower birthweight in babies of mothers with SS disease is largely the result of the lower gestational age. Fetal sonography showed no growth differences by maternal genotype until 35 weeks' gestation and a reduced crown-heel length in offspring of SS mothers was associated with bone pain crises in pregnancy.