OP21.05: The cerebroplacental ratio as a prognostic factor of fetal outcome in pregnancies complicated by maternal sickle cell disease

Abstract

Sickle cell disease (SCD) in pregnancy can have adverse effects on both maternal and fetal circulations. These circulations can be assessed using Doppler ultrasound of the middle cerebral and umbilical arteries. The cerebroplacental ratio (CPR), a ratio of the middle cerebral and umbilical artery indices, is emerging as an important predictor of adverse pregnancy outcomes. This has implications for assessing well-being in fetuses diagnosed as small for gestational age, a common finding in SCD patients. The aim of this study was to assess the role of CPR in predicting adverse fetal outcomes in patients with sickle cell disease. A prospective cohort study was conducted at Korle Bu Teaching Hospital, Ghana over a six-month period. SCD patients at 34 weeks gestation or more were recruited to undergo weekly Doppler assessment until delivery. The CPR was calculated and participants were categorised into two study arms based on a CPR<1.1 or >1.1. Adverse perinatal outcomes including IUGR, stillbirth, low birth weight and NICU admissions were compared between the two groups. There were five fetuses with CPR<1.1 and 25 adverse perinatal events: 2 stillbirths, 10 low birth weight neonates, 12 NICU admissions and 1 APGAR score below 7 at 5 minutes. A CPR<1.1 had positive and negative predictive values of 100% and 72% respectively for predicting composite adverse perinatal outcomes. The sensitivity and specificity for predicting stillbirths were 100% and 93% respectively and 40% and 97% respectively for low birth weight. There was no significant difference in perinatal outcomes between the two major sickle cell genotypes (SS and SC). Mothers in the CPR< 1.1 group were also more likely to have severe anemia, blood transfusions and acute malaria during their pregnancy. A CPR <1.1 was shown to be significantly associated with adverse perinatal outcome especially low birthweight (<2.5kg) and antenatal stillbirths in fetuses of women with sickle cell disease.