The International Lipid-Based Nutrient Supplements Project has developed a small-quantity (20 g/d) lipid-based nutrient supplement (LNS) for pregnant and lactating women. This study evaluated the effects of prenatal LNS supplementation on fetal growth. In a community-based, partially double-blind, individually randomized controlled trial, 1320 pregnant women received iron-folic acid (IFA), or 1–2 Recommended Dietary Allowances of 18 micronutrients, including iron (MMN), or LNS with the same micronutrients as the MMN group, plus 4 minerals and macronutrients contributing 118 kcal (LNS) daily until delivery. Fetal growth was compared across groups by using intention-to-treat analysis. Among primiparous women the LNS group had greater mean birth length than did the IFA group; similar differences were found when comparing the LNS and MMN groups. Prenatal LNS supplementation can improve fetal growth among vulnerable women in Ghana, particularly primiparous women.