Use of Inhaled Corticosteroids During Pregnancy Does Not Reduce Foetal Growth

By Paula Moyer

DENVER, CO -- March 12, 2003 -- Pregnant women who use inhaled corticosteroids to manage their asthma are no more likely than other women to have babies with low birth weights, according to research presented here March 10^th at the 60^th Annual Meeting of the American Academy of Allergy, Asthma, and Immunology (AAAAI).

Data from the Registry for Allergic and Asthmatic Pregnant Patients (RAAPP) were presented by Jennifer A. Namazy, MD, a clinical fellow at the Scripps Clinic in La Jolla, California, United States.

The finding lays to rest a concern that has long troubled physicians who care for women with asthma during their pregnancies, as well as the women themselves.

Prior research had shown an association between the use of oral corticosteroids in pregnancy and low birth weight. Therefore, conventional medical advice had been to cautiously encourage women with asthma to continue their inhaled corticosteroids, because the risks of the inhaled formulations were unknown, but probably less than the risks of uncontrolled asthma -- primarily maternal and foetal hypoxia.

"Our findings show that inhaled corticosteroids are safe for women to use during pregnancy and do not pose the risks to foetal growth that oral corticosteroids do," said Dr. Namazy. "If a woman needs to take inhaled corticosteroids to control her asthma, she should continue to do so during pregnancy."

She noted that physicians often face pressure from pregnant women with asthma, who express a desire to discontinue their medications during pregnancy, and that the health care providers managing such women's pregnancies also express concern about their medications. "We can now say that appropriate maternal use of inhaled corticosteroids for asthma during pregnancy does not impair foetal growth," she said.

The American College of Allergy, Asthma, and Immunology (ACAAI) and the AAAAI established RAAPP to evaluate the effects of inhaled corticosteroids on foetal growth in infants of pregnant women with asthma who are managed by allergists. Dr. Namazy and colleagues wanted to establish the rate at which these women gave birth to infants that were small for gestational age -- defined as less than 2500 gm -- in comparison to the general population in the United States.

Among the 475 women in the registry, 15 had spontaneous abortions; eight had twins; 46 were lost to follow-up; and the outcomes were pending for 10. The investigators based their analysis on the remaining 396 singleton births.

Among these women, 51.2%used the inhaled corticosteroid beclomethasone. The next most commonly used medication in this class was fluticasone, used by 33.8%, followed by triamcinolone, 20.2%; budesonide, 10.2%; and flunisolide, 6.4%. Another 19.6% of the registrants used more than one specific inhaled corticosteroid.

One woman died, not due to her asthma, and one foetus died.

Incidence of low birth weight was 3.3% and of preterm birth it was 6.1%. The incidence of infants who were small for gestational age was 6.9% (95% confidence interval) compared with 10.0% in the general population.

The investigators found no significant relationships among the infants' mean birth weight -- more than 3,000 gm -- the incidence of infants being born small for gestational age, and the mothers' total dose of inhaled corticosteroid. Nor was a correlation found between these parameters and the type of inhaled corticosteroid that the mother used.

The investigators did note that 30.9% of the women required oral corticosteroids during pregnancy. Among these women, 10.7% had infants who were small for gestational age, compared to 4.9% of the women who did not require such medications (p<0.031).

The study was funded by Aventis Pharmaceuticals.


[Study title: Use of Inhaled Corticosteroids (CS) During Pregnancy Does Not Reduce Fetal Growth. Abstract 800]