Leptin and maternal growth during adolescent pregnancy

Background: Maternal growth on the basis of knee height occurs in nearly 50 % of pregnant teenagers and is associated with greater gestational weight g ain and accrual of subcutaneous fat in the mother but lower fetal growth co mpared with nongrowing teenagers and mature pregnant women. Objective: The objective of this study was to determine whether leptin is a biomarker for continued maternal growth. Design: Leptin concentrations were measured in 162 growing and nongrowing t eenage gravidas (aged less than or equal to 18 y) and in mature gravidas (a ged 19-29 y) from the Camden Study at 2 time points during pregnancy and 1 time point postpartum. Results: Growing teenagers had leptin concentrations that increased with ge station and were higher at 28 wk gestation and postpartum than in nongrowin g teenagers and mature gravidas. The differences were related to a leptin s urge between entry into the study (16.9 wk) and week 28, primarily in still -growing gravidas. Leptin-surge quartiles were associated with higher knee- height velocity and weight gain, increased skinfold thicknesses in late pre gnancy (28 wk) and early postpartum (4-6 wk), and changes in postpartum wei ght and body mass index. For the highest quartile, low birth weight increas ed > 5-fold, fetal growth restriction increased > 6-fold, and infant birth weight decreased by approximate to 200 g. Gravidas who developed pregnancy- induced hypertension showed a different pattern-higher leptin concentration s at entry and week 28, no difference in the leptin surge, and no postpartu m difference in leptin concentration. Conclusion: A leptin surge by week 28 appears to mark reduced mobilization of maternal fat stores that is associated with maternal growth on the basis of knee height during adolescent pregnancy.