BackgroundIn India, due to the high prevalence of child marriage, most adolescent pregnancies occur within marriage. Pregnancy and childbirth complications are among the leading causes of death in girls aged 15 to 19 years. Hence, adolescent pregnancy is a serious health threat to young women in India.MethodsThe study focuses on the level and trends of adolescent pregnancy rate (per thousand currently married adolescent women) in India in the last two decades, based on cross-sectional data from three different periods, DLHS-1 (1998–99), DLHS-2 (2002–04) and DLHS-3 (2007–08). Further, the determinants of adolescent pregnancy and its effects are analyzed using the DLHS-3 data, which used a multi-stage stratified systematic sampling design. The sample size of this study was 18,709 pregnancies that occurred to 14,006 currently married adolescent (15–19 years) women. Chi-square tests and logistic regression were used to examine the association between pregnancy outcomes (live birth vs. abortion/stillbirth) and health complications with socioeconomic variables and maternal-child health (MCH) service utilization.ResultsDuring the periods of 1998–99, 2002–04 and 2007–08, the rate of adolescent pregnancy was 427, 467 and 438 respectively. In 2007–08, the proportion of live births (vs. stillbirth or abortion) was significantly higher among older adolescents aged 18–19 years (OR = 1.25, 95 % CI (1.08–1.44), p < 0.001) than among younger adolescent women of 15–17 years. The proportion of live births was also higher among women having 10 years or more education (OR = 1.26, 95 % CI (1.01–1.56), p < 0.01). The prevalence of live birth was significantly higher among women who had received some delivery advices (OR = 1.38, 95 % CI (0.96–1.95), p < 0.01), had consumed iron/folic acid tablets, (OR = 1.37, 95 % CI (0.89–2.11), p < 0.05), had received Tetanus Toxoid injection (OR = 2.29, 95 % CI (1.25–4.19), p < 0.001), while those with assisted vaginal delivery were significantly less likely to have a live birth (OR = 0.38,95 % CI (0.21–0.68), p < 0.001). Adolescent women had 66.6 % delivery complications (i.e. any one problem) vs. 62.5 % among adult women (20–24 years), (p < 0.001).ConclusionStillbirth and abortion are more prevalent among younger adolescents than among older adolescents, and among all adolescents than among adult women. Delaying the first birth until age 20 appears to benefit both mothers and babies. Access to reproductive health services; timely and quality family planning services and safe abortion and delivery advice; tetanus toxoid and iron/folic acid for those married adolescents who do become pregnant could improve health outcomes.