Previous small studies have been reassuring regarding the pregnancy safety of hydroxychloroquine. One recent report found an increase in major birth defects at doses ≥400 mg/day. This study was undertaken to examine pregnancy outcomes following use of hydroxychloroquine.
Pregnant women prospectively enrolled in MotherToBaby/OTIS Pregnancy Studies exposed to hydroxychloroquine were selected. Disease-matched and healthy comparison groups without hydroxychloroquine exposure were randomly selected from the same source using a 1:1 ratio. Data were collected through interviews, medical records, and dysmorphology examinations. Outcomes were major and minor birth defects, spontaneous abortion, preterm delivery and infant growth.
Between 2004 and 2018, 837 pregnancies met criteria for inclusion, 279 exposed to hydroxychloroquine and 279 in each comparison group. Sixty pregnancies (7.2%) were lost-to-follow-up. Among live births, 20/232 (8.6%) with first-trimester hydroxychloroquine exposure had a major birth defect compared to 19/256 (7.4%) in the disease-matched group (Odds Ratio (OR) 1.18, 95% Confidence Interval (CI) 0.61, 2.26), and 13/239 (5.4%) in the healthy group (adjusted OR 0.76, 95% CI 0.28, 2.05). Risks did not differ at doses ≥400 mg/day. No pattern of birth defects was identified. There were no differences in rates of spontaneous abortion or preterm delivery. Growth deficiency measures did not differ in the hydroxychloroquine-exposed vs. disease-matched group, except birth head circumference (adjusted OR 1.85, 95% CI 1.07, 3.20).
We found no evidence of an increased risk for structural defects or other outcomes with hydroxychloroquine, with the exception of birth head circumference. For women treated with hydroxychloroquine, these findings are reassuring.