With the expansion of routine antenatal HIV testing, women are increasingly discovering they are HIV-positive during pregnancy. While several studies have examined the impact of HIV on childbearing in Africa, few have focused on the antenatal/postpartum period. Addressing this research gap will help tailor contraceptive counseling to HIV-positive women’s needs. Our study measures how antenatal HIV diagnosis affects postpartum childbearing desires, adjusting for effects of HIV before diagnosis. A baseline survey on reproductive behavior was administered to 5,284 antenatal clients before they underwent routine HIV testing. Fifteen months later, a follow-up survey collected information on postpartum reproductive behavior from 2,162 women, and in-depth interviews with 25 women investigated attitudes toward HIV and childbearing. HIV diagnosis was associated with a long-term downward adjustment in childbearing desires, but not with changes in short-term postpartum desires. The qualitative interviews identified health concerns and nurses’ dissuasion as major factors discouraging childbearing post-diagnosis. At the same time, pronatalist social norms appeared to pressure women to continue childbearing. Given the potential for fertility desires to change following antenatal HIV diagnosis, contraceptive counseling should be provided on a continuum from antenatal through postpartum care, taking into account the conflicting pressures faced by HIV-positive women in relation to childbearing.