RESUMO
OBJECTIVE: To study whether osteopenia occurs following pregnancy and to evaluate its severity in young primiparas. STUDY DESIGN: A prospective case control study. Sixty-one young primigravidae early after birth and 59 nulligravidae matched for age and BMI participated in the study. Bone status was examined using ultrasonic bone transmission velocity over the tibia; Z-score and T-score for bone density were calculated. Serum bone alkaline phosphatase, osteocalcin and urinary N-telopeptide crosslinks were evaluated as bone remodeling biochemical markers. RESULTS: Ultrasonic parameters of bone status following delivery were significantly lower in the puerperal group as compared to the nulligravida group. Serum mean bone alkaline phosphatase levels and urinary N-telopeptide crosslinks secretion were higher by 50% in the puerperal group, while serum osteocalcin levels were significantly lower (by 25%) than in the nulligravida controls. A positive correlation between ultrasonic measurements and biochemical markers was demonstrated in the postpartum group, whereas the control group showed a negative correlation. CONCLUSION: Women at their early puerperium demonstrate a significant cortical bone mass reduction as measured by ultrasonograph and markers of bone turnover. It appears that pregnancy is a state of unbalanced accelerated bone turnover that may be associated with reduced osteoblastic activity.