Independent associations of women's age at marriage and first pregnancy with their height in rural lowland Nepal.

OBJECTIVES: In many South Asian communities, the majority of women are married during adolescence and reproduce before 20 years. Early reproduction may adversely affect maternal nutrition and linear growth, however whether early marriage has similar effects is unknown. Shorter women might also be preferentially chosen for earlier marriage. We hypothesized that early marriage and early pregnancy may each be associated with women's shorter height, independent of any selection effects. MATERIALS AND METHODS: We analyzed cross-sectional data on 7,146 women aged 20-30 years from rural lowland Nepal. Linear regression models tested associations of early marriage and early reproduction with height, adjusting for women's education and husbands' characteristics (education and wealth) that might index preferential selection of short young women for marriage. RESULTS: Median ages at marriage and first pregnancy were 15 and 18 years, respectively, with 20% pregnant <16 years. Both early marriage and early pregnancy were independently associated with shorter stature, accounting for a decrement of 1.4 cm, which decreased to 1 cm after adjusting for women's education. Effects of early marriage and reproduction persisted after adjusting for the tendency of poorer and less educated men to marry young and short women, indicating a role for social selection. DISCUSSION: The decrements in height associated with early marriage and reproduction are indicative of broader adverse effects on maternal metabolism during a "critical period" of growth and maturation in the life-course of women. Although the magnitudes of effect are relatively small, they affect large numbers of women in this population.