Safety of biologic immunosuppressants in pregnant women with immune-mediated inflammatory diseases.

Background: Immune-mediated inflammatory diseases (IMIDs) typically affect women of childbearing age. One of the challenges in treating these women during pregnancy is to manage the disease while minimizing or avoiding the use of disease-modifying antirheumatic drugs (DMARDs) that may increase the risk to the mother or fetus. Biologic therapy has transformed the management of these patients. This study aimed to evaluate the maternal-fetal safety and perinatal outcomes in pregnant women with IMID exposed to biologic DMARDs either preconceptionally or during pregnancy and compare them with women using conventional DMARDs and a group of healthy pregnant women.

Methods: We conducted a retrospective study with prospective follow-up of pregnant women with IMID at a single center. We analyzed baseline maternal demographic characteristics, diseases, DMARDs, and maternal-fetal outcomes.

Results: A cohort of 244 pregnancies was studied. One hundred twenty-eight patients met classificatory criteria for rheumatic and musculoskeletal diseases (RMD) or inflammatory bowel disease (IBD), and 116 pregnancies of healthy women were evaluated from the same study period. One hundred and one pregnancies in IMID patients (89.84 %) occurred under immunosuppressive treatment, 78.91 % of IMID pregnancies were under cDMARD (33.59 % exclusive cDMARD), 56.25 % under bDMARD, and 27.34 % under oral glucocorticoids. Anti-TNF was the most frequent (88.88 %) bDMARD and was used in 50.78 % of the IMIDs. There was at least one flare in 37.10 % of the IMID pregnancies, and 9.38 % experienced more than one. Among flares, 43.48 % happened in the first trimester, 34.78 % in the second trimester, and 19.57 % in the third. Flares were more frequent in the RMD patients compared with IBD (p = 0.041; OR 2.15, 95%CI: 1.03-4.52). Flare was associated with discontinuation of bDMARD before the eighth week of gestation (p = 0.016), but especially in the second (p = 0.042) and third trimester (p = 0.012). Maternal infections were an infrequent complication overall (7.66 %), although more frequent in patients with IMIDs (p = 0.004) but were not associated with cDMARD or bDMARD. IMID patients needed assisted reproductive techniques (ART) more often (p = 0.001, OR 2.83, 95%CI: 1.02-7.90). More cesarean sections were performed in gestations under treatment with bDMARD (p = 0.020) and especially in those under treatment with anti-TNF. Aneuploidies calculation risk and fetal malformations were not correlated with DMARDs (cDMARDs, bDMARDs, or its combination) nor with any of the DMARDs individually preconcepcionally or during gestation. Small for gestational age (SGA) newborns were higher in patients with IMIDs however, it was not associated with DMARD use.

Discussion: In general, patients with IMIDs who require treatment with bDMARDs have a more severe or refractory disease prior to gestation. In our cohort, we found a higher risk of flare among patients with bDMARDs, especially when those were suspended early. Among maternal outcomes, we found that IMID patients needed ART more often. This is probably, first of all, because of maternal age. Among fetal outcomes, there are no differences in congenital malformations in the IMIDs and healthy patients and were not correlated with DMARDs.

Conclusion: The use of bDMARDs was effective in disease control and safe from a maternal-fetal point of view, with no increase in prematurity, SGA, malformations, or infections.