Adolescent Caucasian mothers have reduced adult hip bone density.

Objective: To determine the long-term effect of full term teen pregnancy on peak hip bone mineral density.

Design: Longitudinal observational study.

Setting: Academic clinical research center.

Patient(s): Sixteen non-Hispanic white females: 4 cases and 12 matched controls who are part of The Penn State Young Women's Health Study and have been studied from ages 12 to 21.

Main Outcome Measures: Four of the subjects had uncomplicated full-term pregnancies between ages 16.5 and 19.5 years.

Intervention(s): The cases and controls were matched for body mass index at age 12 years, total body bone mineral content at age 12 years, age of menarche, and sports-exercise score during ages 12-18 years. They were then compared with respect to bone measures, cardiovascular disease risk factors, and endocrine profiles at ages 19-21 years.

Result(s): The four teen mothers had significantly lower adult hip bone mineral density than did the controls (0.89 g/cm(2) vs. 0.99 g/cm(2); P=.03). The reproductive hormone patterns of the cases were not statistically significantly different from those of the controls, yet the cases showed a postmenopausal blood lipid pattern.

Conclusion(s): The persistent reduction in hip bone mineral density of the cases is consistent with significantly increased risk of future hip fracture.