Study finds new evidence of adverse pregnancy outcomes when taking hydroxyurea for sickle cell

Pregnant Black woman experiences episode of pain while sitting on a couch.

Researchers are reporting new evidence that pregnant women who are taking hydroxyurea for sickle cell disease (SCD) may face more adverse pregnancy outcomes than those who are not taking the drug.  In an observational study, they showed that the overall rate of pregnancy loss due to miscarriage and stillbirth was almost twice as high as those women who did not take the drug during pregnancy. The results support advising women to discontinue use of the medication during pregnancy, the researchers say. 
Hydroxyurea, which helps boost oxygen supplies in the body, is used by people with SCD to reduce pain crises, acute chest syndrome, and blood transfusions. It remains a vital disease-modifying therapy. Researchers have suspected for some time, based on animal studies, that the drug has potential for detrimental effects on fertility and birth outcomes and have previously cautioned against its use during pregnancy.  But few studies have evaluated the safety of hydroxyurea during pregnancy among those with SCD. 

In the current study, researchers collected self-reported pregnancy history, hydroxyurea use, and pregnancy outcomes in women with SCD in the clinical setting.  The study included 1,285 women 18-45 years of age. The study analyzed 1,788 pregnancies, which included 1,079 live births, 394 miscarriages, and 40 stillbirths.  

The researchers found that use of hydroxyurea during conception and pregnancy, but not during conception only, was associated with an increase of miscarriage or stillbirth among those with SCD. It also carries an increased risk of low birth weight. However, the drug was not associated with premature births or serious medical problems at birth. The findings suggest that hydroxyurea may be safe up to the time of conception, but that doctors should continue to advise caution regarding its use during pregnancy. 

The study, funded in part by the NHLBI, appeared in the American Journal of Hematology