Safety of Ustekinumab and Vedolizumab During Pregnancy-Pregnancy, Neonatal, and Infant Outcome: A Prospective Multicentre Study.

Background and Aims: Evidence on the safety of newer biologics during pregnancy is limited. We aimed to assess the safety of ustekinumab and vedolizumab treatment during gestation on pregnancy and infant outcome. Furthermore, we evaluated the placental transfer of these agents.
Methods: We performed a prospective, multicentre, observational study in consecutive women with inflammatory bowel disease exposed to ustekinumab or vedolizumab 2 months prior to conception or during pregnancy. Pregnancy, neonatal, and infant outcomes were evaluated and compared with the anti-tumour necrosis factor [TNF]-exposed control group. Drug levels were assessed in maternal and cord blood at delivery.
Results: We included 54 and 39 pregnancies exposed to ustekinumab and vedolizumab, respectively. In the ustekinumab group, 43 [79.9%] resulted in live births, and 11 [20.4%] led to spontaneous abortion. Thirty-five [89.7%] pregnancies on vedolizumab ended in a live birth, two [5.1%] in spontaneous, and two [5.1%] in therapeutic abortion. No significant difference in pregnancy outcome between either the vedolizumab or the ustekinumab group and controls was observed [p >0.05]. Similarly, there was no negative safety signal in the postnatal outcome of exposed children regarding growth, psychomotor development, and risk of allergy/atopy or infectious complications. The median infant-to-maternal ratio of ustekinumab levels was 1.67 and it was 0.59 in vedolizumab.
Conclusions: Use of ustekinumab and vedolizumab in pregnancy seems to be safe, with favuorable pregnancy and postnatal infant outcomes. Placental transfer differed between these two drugs, with ustekinumab having similar and vedolizumab having inverse infant-to-maternal ratio of drug levels compared with anti-TNF preparations.
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