Distinct maternal and fetal pregnancy outcomes in women with sickle cell disease can be predicted using routine clinical and laboratory data

Abstract

We aimed to identify risk factors for adverse outcomes in pregnancies of women with sickle cell disease (SCD) and develop risk prediction models. Models were derived from a retrospective cohort of pregnant women with SCD and constructed using generalised estimating equation logistic regression, with clustering by woman. Maternal event(s) consisted of acute anaemia; cardiac, pulmonary, hepatobiliary, musculoskeletal, skin, splenic, neurological or renal complications, multi-organ failure, venous thromboembolism, admission-requiring vaso-occlusive events (VOE), red cell transfusion, mortality or hypertensive disorder of pregnancy. Fetal events included preterm birth, small-for-gestational-age or perinatal mortality. Of 199 pregnancies, 71% and 45% resulted in adverse maternal and fetal outcomes respectively. Low first-trimester haemoglobin, admission-requiring VOE in the year before pregnancy, multiple transfusions before pregnancy, SCD genotype and previous cardiac complications predicted maternal risk. Younger age and SCD genotype allowed early prediction of fetal risk (model-F1). Adding maternal event(s) and high lactate dehydrogenase enabled re-assessment of fetal risk with advancing gestation (model-F2). Models were well calibrated and moderately discriminative for maternal outcome (c-statistic 0·81, cross-validated value 0·79) and fetal outcome (model-F1 c-statistic 0·68, cross-validated value 0·65; model-F2 c-statistic 0·72, cross-validated value 0·68). The models will allow early identification of women with SCD at high risk of adverse events, permitting early targeted interventions and ongoing fetal risk re-assessment enabling intensification of surveillance and optimisation of delivery timing.

Keywords: adverse outcomes; pregnancy; risk factors; sickle cell disease.