Little is known about nutrition and well-being indicators of pregnant adolescents and the availability and use of nutrition interventions delivered through maternal, newborn, and child health (MNCH) programs. This study compared the differences between pregnant adolescents and adult pregnant women in services received, and in maternal and child nutrition and health conditions. A survey of 2,000 recently delivered women with infants <6 months of age was carried out in 20 sub-districts in Bangladesh where MNCH program is being implemented. Differences in service use and outcomes between pregnant adolescents and adult women were tested using multivariate regression models. The coverage of antenatal care and nutrition services was similar for adolescent and adult mothers. Compared to adult mothers, adolescent mothers had significantly fewer ownership of assets and lower decision making power. Adolescent mothers weighed significantly less than adult women (45.8 vs 47.1 kg, p = 0.001), and their body mass index was significantly lower (19.7 vs 21.3, p = 0.001). Adolescents recovered later and with greater difficulty after childbirth. Infants of adolescent mothers had significant lower height-for-age z-score (-0.89 vs -0.74, p = 0.04), lower weight-for age z-score (-1.21 vs -1.08, p = 0.02) and higher underweight prevalence (22.4% vs 17.9%, p = 0.04) compared to infants of adult women. In conclusion, this study confirms that adolescent pregnancy poses substantial risks for maternal and infant outcomes, and emphasizes that these risks are significant even where services during pregnancy are available and accessed. A focus on preventing adolescent pregnancy is imperative, while also strengthening health and nutrition services for all pregnant women, whether adult or adolescent.