Adverse Pregnancy Outcomes Among Women with Human Immunodeficiency Virus Taking Isoniazid Preventive Therapy During the First Trimester.

Background: Isoniazid preventive therapy (IPT) is recommended for tuberculosis prevention yet data on the safety of first-trimester pregnancy exposure are limited.
Methods: Planned secondary analysis in a TB prevention trial of adverse pregnancy outcomes among participants assigned to 9-month IPT who became pregnant during (IPT-exposed) or after (unexposed) IPT. Regression models compared binary outcomes of a composite adverse outcome (any non-live birth, excluding induced abortion); preterm delivery <37 weeks; and low birth weight <2500 g) among exposure groups. Models were adjusted for latent TB infection, maternal age, CD4 count, and antiretroviral therapy (ART).
Results: In total, 128 participants had a known pregnancy outcome; 39 IPT-exposed and 89 unexposed. At pregnancy outcome, ART use was lower in IPT-exposed (79%) than unexposed women (98%). Overall, 29 pregnancies ended in a composite adverse outcome (25 spontaneous abortions, 2 stillbirths and 2 ectopic pregnancies), 15 preterm deliveries, and 10 infants with low birth weight. IPT was associated with the composite adverse outcome adjusting for covariates at enrollment (adjusted relative risk [aRR] 1.98; 95% confidence interval [CI] 1.15, 3.41), but the effect was attenuated when adjusted for covariates at pregnancy outcome (aRR 1.47; 95% CI .84, 2.55); IPT was not associated with preterm delivery (relative risk [RR] 0.87; 95% CI .32-2.42) or low birth weight (RR 1.01; 95% CI .29, 3.56).
Conclusions: First-trimester IPT exposure was associated with nearly two-fold increased risk of fetal demise, mostly spontaneous abortion, though the association was attenuated when adjusted for covariates proximal to pregnancy outcome including ART use. Further study is needed to inform TB prevention guidelines.
Competing Interests: Potential conflicts of interest. A. G. reports Advisory Board roles from NIAID and Indo-US Science and Technology Forum (IUSSTF). M. H. reports institutional research and training grants related to infectious diseases from US NIH; board membership of Botswana-Harvard Partnership through employer; spouse's research grants from NIH related to infectious diseases research. C. A. B. reports institutional grant support for clinical trials from Gilead and DNAe; consulting fees (paid to author) from National Data and Analytics Platform (NDAP), Inc.; honoraria for medical education lectures and travel support (paid to author) from International Antiviral Society–United States (IAS-USA), a non-profit medical education entity; and unpaid positions as Present of the non-profit Conference on Retroviruses and Opportunistic Infections (CROI) Foundation Board, and Secretary/Treasurer of the IAS-USA Board of Directors. R. E. C. reports spouse's stock in Merck. S. S. reports institutional research support from ViiV Healthcare and participation on a Data Safety Monitoring or Advisory board for now completed NIH coronavirus disease (COVID)-related trials. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.
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