Statistical analysis
REGRESSION
The sample size of 500 provided 90% power to detect an increase in HIV testing from 30% in the SOC arm to 55% in the intervention arm, with a 1:2 randomization ratio and two‐sided alpha = 0.05. The intention‐to‐treat analysis included all women enrolled and randomized. Kaplan−Meier methods and log‐rank tests were used to compare time from the women's enrolment until her male partner was tested in the clinic, by randomization arm (as women had different study duration, depending on the trimester of enrolment). Pointwise confidence intervals for the proportion tested 12 months after the women's enrolment were computed assuming the normal approximation, using the standard error of the estimate from the Kaplan−Meier curve. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% CI. Since the intervention could affect male partner enrolment differentially by HIV status, we assessed the probability of PrEP initiation for all HIV‐negative men, both unconditional and conditional on enrolment. We assessed the difference in PrEP initiation between arms among the (unobserved) true number of HIV‐negative male partners of enrolled pregnant women using a likelihood ratio test. The likelihood of difference in PrEP initiation between arms was computed assuming the probability of an HIV‐negative partner was the same in both arms. Factors associated with maternal VS were assessed using Poisson regression with robust standard errors. Statistical analyses were performed using SAS version 9.4 (SAS Institute). Study data were reviewed every 6 months by an independent data monitoring committee.