Young maternal age and the risk of neonatal mortality in rural Nepal.

OBJECTIVES

To investigate the relationship between adolescent pregnancy and neonatal mortality in a nutritionally deprived population in rural Nepal, and to determine mechanisms through which low maternal age may affect neonatal mortality.

DESIGN

Nested cohort study using data from a population-based, cluster-randomized, placebo-controlled trial of newborn skin and umbilical cord cleansing with chlorhexidine.

SETTING

Sarlahi District of Nepal.

PARTICIPANTS

Live-born singleton infants of mothers younger than 25 years who were either parity 0 or 1 (n = 10,745).

MAIN EXPOSURE

Maternal age at birth of offspring.

OUTCOME MEASURE

Crude and adjusted odds ratios of neonatal mortality by maternal age category.

RESULTS

Infants born to mothers aged 12 to 15 years were at a higher risk of neonatal mortality than those born to women aged 20 to 24 years (odds ratio, 2.24; 95% confidence interval, 1.40-3.59). After adjustment for confounders, there was a 53% excess risk of neonatal mortality among infants born to mothers in the youngest vs oldest age category (1.53; 0.90-2.60). This association was attenuated on further adjustment for low birth weight, preterm birth, or small-for-gestational-age births.

CONCLUSIONS

The higher risk of neonatal mortality among younger mothers in this setting is partially explained by differences in socioeconomic factors in younger vs older mothers; risk is mediated primarily through preterm delivery, low birth weight, newborns being small for gestational age, and/or some interaction of these variables.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00109616.