CHICAGO – Women with inflammatory bowel disease can safely continue monotherapy with azathioprine/6-mercaptopurine or antitumor necrosis–alpha agents during pregnancy to maintain remission, according to an analysis of 1,289 women and 1,039 live births.
Infants exposed to azathioprine/6 MP and anti-TNF-alpha agents achieve developmental milestone scores at rates similar to unexposed infants and do not have higher rates of congenital anomalies, lead author Dr. Uma Mahadevan said at the annual Digestive Disease Week.
Overall, there were 55 congenital anomalies, with 21 diagnosed at birth. Events were similar among infants with in utero exposure to azathioprine, anti-TNF agents, combination therapy, and those with no drug exposure (12 vs. 17 vs. 7 vs. 19 events).
Exposure was defined as any use of azathioprine/6 MP or the anti-TNF-alpha agents infliximab (Remicade), adalimumab (Humira), or certolizumab pegol (Cimzia) at any time from 3 months prior to conception to the end of the pregnancy. Nine women had exposure to the recombinant monoclonal antibody natalizumab (Tysabri) and were included in the anti-TNF agents group.
The analysis was based on the PIANO registry, a prospective cohort of pregnant women with IBD who were followed by telephone or in-person questionnaire at every trimester, at delivery, at 4, 9, and 12 months after delivery, and annually for the first 4 years of their child’s life. Seven women received their diagnosis of IBD during pregnancy, 59.4% had Crohn’s disease, 38.3% ulcerative colitis, and 2.3% were indeterminate.
Two-thirds of women reported breastfeeding, with unexposed women significantly more likely to breastfeed than women with exposure to azathioprine, anti-TNF agents, or combination therapy (85% vs. 65% vs. 71% vs. 61%; P less than .0001).
After controlling for drug exposure, breastfeeding was not associated with an increased risk of infant infection or reduced height or weight, reported Dr. Mahadevan, with the University of California San Francisco.
Infants exposed to combination therapy, however, had higher rates of preterm birth, after adjustment for none/mild vs. moderate/severe IBD activity (odds ratio, 2.6; P less than .05).
Infants exposed to combination therapy who were born to mothers with ulcerative colitis also had increased rates of preterm birth (odds ratio, 4.9), low birth weight (OR, 6.1), and NICU stay (OR, 3.9).
One possible reason for this signal is that women with ulcerative colitis in the PIANO registry, as well as two other studies, have more disease activity during pregnancy, Dr. Mahadevan suggested. Another possibility is that mothers with ulcerative colitis may have low levels of untreated inflammation.
With just 161 women available for analysis, the PIANO investigators previously reported a significant increase in infant infections at 12 months of age in those exposed to combination infliximab or adalimumab plus azathioprine. Most anti-TNF agents cross the placenta in the second and third trimester, which has raised concerns about immune system development and risk of subsequent infections.
In the current analysis, there was no increase in infant infections when the investigators looked at all anti-TNF drugs. "But when we removed certolizumab from the analysis, it was significant just as it was 2 years ago," Dr. Mahadevan said in an interview. "Certolizumab is not actively transported across the placenta. Fortunately, the majority of the infections were minor, including otitis media and upper respiratory infections."
Developmental milestones
Overall, infants exposed to azathioprine or anti-TNF agents were found to achieve developmental milestones at rates similar to unexposed infants of mothers with IBD based on Denver Childhood Developmental Test and Ages and Stages Questionnaire scores, she said.
After controlling for preterm birth, the mean developmental milestone score at 4 months was 0.92 for infants with no drug exposure, with a nonsignificant mean delta difference of 0.01, 0.01, 0.00 points for infants exposed to azathioprine, anti-TNF agents, and combination therapy, respectively.
In a surprising twist, infants exposed to anti-TNF agents alone actually had significantly better scores at 12 months than unexposed infants, bettering the average score of 0.81 in the unexposed group by a mean delta of 0.02 points (P = .01), Dr. Mahadevan said.
"I wouldn’t interpret this data [as indicating] that biologics make your baby smarter. I think the key thing is that it doesn’t make it worse," she remarked. "When you see the deltas, they are pretty small."
On the Ages and Stages Questionnaire, the biologic group had significantly better mean scores than the unexposed group for gross motor skills at 36 months (55.94 vs. 47.53; P = .01), gross motor skills at 48 months (60 vs. 51.20; P = .02), fine motor skills at 48 months (53.50 vs. 42.11; P = .01), and personal/social interaction at 48 months (58 vs. 51.93; P = .04).