Importance: Maternal antiretroviral treatment (ART) started before conception may increase the risk for adverse birth outcomes among women with human immunodeficiency virus (HIV) infection, but whether the risk differs by ART regimen is unknown.

Objective: To compare the risk for selected birth outcomes by maternal ART regimen.

Design, setting, and participants: This observational birth outcomes surveillance study compared all live births and stillbirths with a gestational age of at least 24 weeks in 8 geographically dispersed government hospitals throughout Botswana (approximately 45% of births nationwide). Data were collected from August 15, 2014, through August 15, 2016.

Exposures: Births among HIV-infected women who started 3-drug ART regimens before their last menstrual period and did not switch or stop ART in pregnancy were considered to be ART exposed from conception.

Main outcomes and measures: The primary outcomes were any adverse birth outcome, including stillbirth, preterm birth (<37 weeks), small size for gestational age (SGA; <10th percentile of weight for gestational age) or neonatal death (<28 days from delivery), and any severe adverse outcome, including very preterm birth (<32 weeks), very SGA (<3rd percentile of weight for gestational age), stillbirth, and neonatal death.

Results: Information was available for 47 027 of 47 124 births (99.8%) at surveillance maternity hospitals (mean [SD] age of mothers, 26.86 [6.45] years). Among 11 932 HIV-exposed infants, 5780 (48.4%) were ART exposed from conception. Adverse birth outcomes were more common among HIV-exposed infants than HIV-unexposed infants (39.6% vs 28.9%; adjusted relative risk [ARR], 1.40; 95% CI, 1.36-1.44). The risk for any adverse birth outcome was lower among infants exposed from conception to tenofovir disoproxil fumarate, emtricitabine, and efavirenz (TDF-FTC-EFV) (901 of 2472 [36.4%]) compared with TDF-FTC and nevirapine (NVP) (317 of 760 [41.7%]; ARR, 1.15; 95% CI, 1.04-1.27); TDF-FTC and lopinavir-ritonavir (TDF-FTC-LPV-R) (112 of 231 [48.5%]; ARR, 1.31; 95% CI, 1.13-1.52); zidovudine, lamivudine, and NPV (ZDV-3TC-NVP) (647 of 1365 [47.4%]; ARR, 1.30; 95% CI, 1.20-1.41); or ZDV-3TC-LPV-R (75 of 167 [44.9%]; ARR, 1.21; 95% CI, 1.01-1.45). The risk for any severe adverse outcome was also lower among infants exposed from conception to TDF-FTC-EFV (303 of 2472 [12.3%]) compared with TDF-FTC-NVP (136 of 760 [17.9%]; ARR, 1.44; 95% CI, 1.19-1.74), TDF-FTC-LPV-R (45 of 231 [19.5%]; ARR, 1.58; 95% CI, 1.19-2.11), ZDV-3TC-NVP (283 of 1365 [20.7%]; ARR, 1.68; 95% CI, 1.44-1.96), or ZDV-3TC-LPV-R (39 of 167 [23.4%]; ARR, 1.93; 95% CI, 1.43-2.60) from conception. Compared with TDF-FTC-EFV, all other regimens were associated with higher risk for SGA; ZDV-3TC-NVP was associated with higher risk of stillbirth, very preterm birth, and neonatal death; and ZDV-3TC-LPV-R was associated with higher risk for preterm birth, very preterm birth, and neonatal death.

Conclusions and relevance: Among infants exposed to ART from conception, TDF-FTC-EFV was associated with a lower risk for adverse birth outcomes than other ART regimens.