SummaryWe describe the findings from a national study of maternal and fetal outcomes of pregnancy in women with sickle cell disease (SCD). Data were collected via the United Kingdom Obstetric Surveillance System between 1 February 2010 and 31 January 2011 from 109 women, of whom 51 (46Á8%) had HbSS and 44 (40Á4%) had HbSC. Data included antenatal, maternal and fetal outcomes. Comparisons were made between women with HbSS and HbSC. Incidence of complications were acute pain (57%), blood transfusion (26%), urinary tract infection (UTI; 12%) and critical care unit admission (23%) and these were all more common in women with HbSS than HbSC. There was no difference in the incidence of acute chest syndrome, hypertension and venous thromboembolism between HbSS and HbSC. Women with HbSS were more likely to deliver at <37 weeks gestation (P = 0Á01) and their babies were more likely to have reduced birth weight. Delivery at <34 weeks was increased in both HbSS and HbSC women (5Á9% vs. 4Á6%) compared to national data. This study confirms a high rate of maternal and fetal complications in mothers with SCD, even in women with HbSC, which has previously been considered to have a more benign phenotype in pregnancy.