Fetal exposure to biologics, thiopurine not linked to worse pregnancy outcomes

Last Updated: 2020-12-04

By Anne Harding

NEW YORK (Reuters Health) - Women with inflammatory bowel disease (IBD) who take biologics with or without thiopurine during pregnancy are not at increased risk of adverse outcomes, according to a new prospective study.

"The data from PIANO in 1,490 pregnancies of which 869 were exposed to a biologic (alone or in combination with thiopurine) showed no evidence of harm with biologic exposure - no increase in birth defects, pregnancy loss or complications, infant infections or infant development," Dr. Uma Mahadevan of the University of California, San Francisco, told Reuters Health by email.

IBD itself, especially active disease, confers a greater risk of preterm birth, miscarriage and other adverse outcomes, she and her colleagues note in Gastroenterology. The American Gastroenterological Association's clinical care pathway recommends that women with IBD continue medical treatment during pregnancy and breastfeeding, but guidelines from Europe and elsewhere advise stopping biologic therapy at 22 weeks to reduce fetal exposure.

"However, this practice has clearly been associated with an increase in flares which can then lead to increased adverse outcomes for the baby," Dr. Mahadevan said.

She and her colleagues looked at outcomes for 1,490 completed pregnancies and 1,431 live births for women with IBD enrolled from 30 centers between 2007 and 2019. Data on infant outcomes at one year were available for 1,010 children.

There were 379 completed pregnancies in women not exposed to biologics or thiopurines, and 242 in women exposed to thiopurines, 642 in women exposed to biologics, and 227 in women exposed to both drug types.

Congenital malformations occurred in 133 infants (9%), while there were 42 spontaneous abortions (3%), 91 (7%) low birth weights, and 132 (10%) preterm births. There were also 58 (4%) children who were small for gestational age, 30 (2%) with intrauterine growth restriction and five (0.30%) stillbirths.

There was no association between drug exposure and congenital malformations, spontaneous abortions, preterm birth or low birth weight or infant infections, Dr. Mahadevan and her colleagues found.

However, women with higher disease activity were significantly more likely to miscarry (hazard ratio, 3.41), and infants delivered preterm were at increased risk of infection during their first year (odds ratio, 1.73).

"Providers and patients should be reassured by this data," the researcher said. "As always, 'more studies are needed' but this study of 1,490 patients with outcomes out to 4 years is very reassuring. Continue biologics during pregnancy, make sure the mother is in remission and all IBD pregnancies should be followed as high risk, as even in remission they can have increased complications compared to others their age."

She and her colleagues are continuing the PIANO registry to investigate the safety of newer IBD drugs. Clinicians treating pregnant patients with IBD who are interested in participating should contact the study team at PIANO@ucsf.edu.

The study had no commercial funding. Dr. Mahadevan reports financial ties to companies selling biologics.

SOURCE: https://bit.ly/3g8C9eo Gastroenterology, online November 20, 2020.