Antiphospholipid antibodies in chronic hypertension: The value of screening during pregnancy

To determine if screening for antiphospholipid antibodies in gravid chronic hypertension patients is warranted, we performed a retrospective cohort st udy to test the association between antiphospholipid antibodies and perinat al outcome in this group of women. The primary outcome we compared was adve rse perinatal outcome, defined as delivery <37 weeks' gestation secondary t o maternal or fetal indications, intrauterine or neonatal death, birth weig ht <10th percentile for gestational age, early-onset severe preeclampsia, o r placental abruption. Our sample size allowed for the detection of a 60% r eduction in the relative risk of adverse perinatal outcome in patients who were antiphospholipid antibody screen negative (80% power, P= 0.05). No inc reased risk of adverse perinatal outcome was demonstrated among patients wi th positive serum antiphospholipid antibodies (33.3%, 5/15) versus patients with negative screening (40.0%, 22/55) in our cohort (RR 0.88, 95% Cl 0.38 -1.83). Furthermore, antiphospholipid antibody status was not associated wi th adverse perinatal outcome after controlling for classic indications for antibody screening (RRMH 0.63, 95% CI 0.30-1.33). In conclusion, chronic hy pertension patients with positive antiphospholipid antibody screening are n ot at increased risk for adverse perinatal outcome compared to those with n egative screening. Therefore, screening for antiphospholipid antibodies in chronic hypertension patients without classic indications for screening is not warranted.