Research Horizons


Moms with Sickle Cell Anemia Can Take Life-Saving Med and Breastfeed Baby

HELPS clinical trial shows no harm from taking hydroxyurea

Breastfeeding mothers with sickle cell anemia are instructed to not take oral hydroxyurea for their disease because of potential harm to their baby. But a new clinical trial shows that lactating women who take a daily oral dose of hydroxyurea don’t accumulate enough of the drug in their breastmilk to be dangerous for their infants.

Data from the prospective HELPS pharmacokinetics clinical trial are published in The Journal of Pediatrics by researchers at the Cincinnati Children’s Hospital Medical Center’s Divisions of Hematology, Clinical Pharmacology, and Center for Breastfeeding Medicine. Pharmacokinetics is a term that describes how drugs move through and are metabolized in the body.

“Hydroxyurea is the most effective treatment for sickle cell anemia, a life-threatening inherited disorder characterized by misshapen red blood cells that cause a number of clinical complications,” said lead study investigator Russell Ware MD, PhD, director of the Division of Hematology at Cincinnati Children’s.

“Breastfeeding mothers who have sickle cell anemia are currently told to stop using hydroxyurea, but until our study the safety of hydroxyurea had not been addressed for women during lactation,” he added. “Our results demonstrate that hydroxyurea enters the bloodstream and moves into the breastmilk, although the amount in milk is very low, amounting to only about 3.4 percent of the mother’s dose. That is below the recommended safety threshold of 5 to 10 percent proposed by the World Health Organization.”

Improved Health for Moms and Babies

 Study authors recommend that women taking hydroxyurea for sickle cell anemia be encouraged to continue breastfeeding their newborn infants without stopping treatment. This will improve the health of the mothers by allowing them to continue their medication, and also the babies who get the many benefits of breastfeeding, they write.

Co-author Julie Ware MD, MPH, points to the fact that breastfeeding is now considered a public health imperative due to the many beneficial health outcomes for both mothers and infants. The American Academy of Pediatrics and other major health organizations recommend exclusive breastfeeding for about 6 months, followed by continued breastfeeding for at least one year. Ware is in the Center for Breastfeeding Medicine at Cincinnati Children’s.

The HELPS study involved 14 healthy mothers without sickle cell anemia, and two with sickle cell anemia, who were lactating at the time they volunteered for the study. The women were administered one oral dose of hydroxyurea with careful monitoring of the drug into their blood, breastmilk, and urine. Researchers then removed breastmilk for laboratory analysis.

Co-author Alexander Vinks PhD, PharmD, notes that hydroxyurea was detected in breastmilk within 30 minutes of oral administration and remained at 80-90 percent of corresponding plasma concentrations for one to three hours. Vinks said that a small amount of hydroxyurea was detected in the breastmilk 12 hours after the dose, but none was detected at 24 hours. Vinks is director of the Division of Clinical Pharmacology at Cincinnati Children’s.

Potential Global Impact

Women with sickle cell anemia have a high risk of morbidity and mortality during pregnancy and post-partum, the authors write in their manuscript. Withholding effective disease-modifying treatment could harm both mothers and their babies. Extensive clinical studies in the United States, the Caribbean, and sub-Saharan Africa led by Ware prove that people who take one oral dose of hydroxyurea each day have healthier blood cells that do not assume a sickle shape. Instead their blood cells retain a healthy soft, round shape that moves easily through the circulatory system.

Although hydroxyurea use is not yet common in places like Africa, breastfeeding is a common practice there. Ware and his colleagues – including physicians in Africa – are working to spread the use of hydroxyurea. The fact that it can be administered via one pill a day makes it a useful tool for battling sickle cell in remote regions where medical care is less than optimal.

“Although there isn’t much hydroxyurea use in low-resource settings at present, this is changing because of our clinical trials in the Caribbean and Africa,” Ware said. “And knowledge from the current HELPS study will help inform treatment choices for women of child-bearing years in those regions and other parts of the globe.”

Funding support for the study came in part from the Cincinnati Children’s Research Foundation.

Publication Information
Original title: Hydroxyurea Exposure in Lactation: a Pharmacokinetics Study (HELPS)
Published in: Journal of Pediatrics
Publish date: March 11, 2020
Read the Study

Research By

Russell Ware, MD, PhD
Director, Division of Hematology
The Ware Lab team focuses on translational hematology research to improve our overall understanding of sickle cell disease with the long-term goal of improving the lives of affected children.