Serum lipid concentrations change with serum alkaline phosphatase activity during pregnancy

To investigate the relationship between serum lipids and alkaline phosphatase during normal pregnancy, we measured triglyceride, total cholesterol, HDL-cholesterol, and LDL-cholesterol concentrations and alkaline phosphatase activity in serum samples from 546 apparently healthy pregnant, postpartum, and nonpregnant women. Serum HDL-cholesterol levels did not change significantly during pregnancy, but serum triglyceride, total cholesterol, LDL-cholesterol, and alkaline phosphatase levels increased gradually as pregnancy proceeded, reached maximum values in the third trimester, and returned to nonpregnant levels by 20-24 wk postpartum. The serum alkaline phosphatase activity averaged 2.1-fold higher in the late third trimester than in the first trimester; the serum triglyceride concentration averaged 2.3-fold higher in the late third trimester than in the first trimester. Compared to the peak values during pregnancy, serum alkaline phosphatase activity averaged 45% lower and serum triglyceride level averaged 47% lower at 12-16 wk postpartum. The serum alkaline phosphatase activity was correlated with the serum concentrations of total cholesterol (r = 0.68, p < 0.01) and triglyceride (r = 0.71, p < 0.01). In short, this study shows that serum triglyceride and total cholesterol levels change in parallel with serum alkaline phosphatase activity during and after normal pregnancy.