Recently, we showed that following pregnancy and 6 months of lactation, adolescents cease linear growth and have reduced fat and lean mass in rural Bangladesh. Here, we examined whether these changes varied by pregnancy outcomes such as fetal loss, low birthweight (LBW) and neonatal mortality. Anthropometric measurements were taken among 12–19-year-old primigravidae (n = 229) in early pregnancy and at 6 months post-partum. Never-pregnant adolescents (n = 456) matched on age and time since menarche were also measured at the same time. Change in anthropometry among pregnant vs. never-pregnant adolescents was compared by pregnancy outcome adjusting for confounders using mixed effects regression models. Pregnant girls, irrespective of birth outcome, did not gain in stature, while never-pregnant girls increased in height by 0.36 ± 0.04 cm year−1 (P < 0.05). Body mass index, mid-upper arm circumference (MUAC) and % body fat among pregnant adolescents whose infants survived the neonatal period had decreased at 6 months post-partum, whereas those who experienced a fetal loss or neonatal death did not change in any of the measurements. Consequently, the difference in change in ponderal size and body composition measures between pregnant and never-pregnant girls was higher among those whose neonates survived vs. those who experienced a fetal loss/neonatal death (BMI: −0.64 ± 0.11 vs. 0.01 ± 0.16 kg m−2 year−1; MUAC: −0.96 ± 0.12 vs. −0.35 ± 0.17 cm year−1, both P < 0.05). LBW and preterm birth did not have a similar effect modification. Linear growth ceased among pregnant girls regardless of birth outcome. Maternal weight loss and depletion of fat and lean mass at 6 months post-partum were more pronounced when the infants survived through the neonatal period.