Bone turnover in preeclampsia-complicated pregnancy in North Indian women

This prospective study aims to investigate the levels of bone turnover markers in pregnancy and correlate it with the assessment of preeclampsia.

A total of 140 women were followed up during their pregnancy. The women who developed preeclampsia (n=22), were compared with age-matched women (controls) who did not develop preeclampsia and had an uncomplicated pregnancy (n=22). Maternal serum levels of serum bone-specific alkaline phosphatase (sBAP), a marker of bone formation, and N-telopeptide of type 1 collagen (NTx), a marker of bone resorption, were estimated at recruitment (in the second trimester) and at delivery. sBAP and NTx levels were measured by enzyme immunoassay (EIA) and enzyme linked immunosorbent assay (ELISA), respectively. Serum and urinary calcium titers were compared by using a commercially-available calcium assay kit.

Serum NTx levels increased significantly during pregnancy (P<0.02) and were significantly higher at delivery (P<0.01) in women with preeclampsia compared with controls. The levels of sBAP and serum calcium did not change significantly in both groups during pregnancy. There was no significant correlation between sBAP and NTx with maternal factors. A negative correlation was observed between sBAP and NTx levels in the preeclamptic group.

Biochemical markers of bone turnover are greater in preeclampsia compared with normal pregnancy only when the disease is clinically evident (at delivery).