Fluctuations of plasma lipoprotein-A concentrations during pregnancy and post partum.

The changes in plasma lipoprotein-a Lp-a concentrations during pregnancy were investigated. Out of 42 women with normal pregnancy, 22 reached Lp-a values greater than 10 mg/dL. Plasma levels of Lp-a in addition to total cholesterol, and apolipoprotein B were measured at 4 to 6-week intervals during pregnancy and post partum. The hormones hCG, human placenta lactogen, progesterone, estradiol, and insulin were measured concomitantly. The results can be summarized as follows: Plasma Lp-a concentrations rose steadily during the first trimester of pregnancy and reached a maximum in the middle of the second trimester. Maximal Lp-a values in the 19th week on average were 2.8 times higher as compared to the values of the eight week of pregnancy. Plasma Lp-a fell from the 19th week of pregnancy, reaching a basal value at the time of birth. This value remained virtually unchanged until 6 months post partum. Despite the fact that apolipoprotein-B and total cholesterol rose significantly, exhibiting pronounced maxima during the course of pregnancy, there was no overlap in the shape of their concentration curve with Lp-a. The rise in plasma Lp-a concentration did not correlate with any of the measured hormones at a given time interval. Time shifted analysis of the concentration curve revealed a correlation with hCG, however, with a lag phase of approximately 11 weeks. This study substantiates the independent metabolic control of Lp-a, as compared to plasma apolipoprotein-B and total cholesterol.