In a randomized, placebo-controlled, double-blind effectiveness trial among antenatal care attendees in Harare, Zimbabwe, pregnant women were randomly allocated to receive a multimicronutrient or placebo supplement daily until delivery. Supplementation with iron and folic acid (IFA) was part of antenatal care (ANC). Multimicronutrient supplementation (MMS) was associated with tendencies for increased gestational length, birth weight, and head circumference but was not associated with low birth weight (LBW). The effect of MMS on birth weight was not significantly different between HIV-uninfected and HIV-infected women.