High Density Lipoprotein (HDL) Cholesterol levels in young pregnant Women

A woman's reproductive history may affect her risk for coronary heart disease. Parity has been associated with increased coronary disease risk in some studies, while other studies have shown that nulliparous women are at increased risk (1-3). Pregnancy fre­quency (including frequency of spontaneous abortion (4, 5)) and age at first pregnancy (6) have also been associated with increased coronary disease risk. Although reports of associations of coronary disease risk with parity, age at menarche, or incidence of miscar­riage are not all consistent (7, 8), the majority of cohort studies have shown an increased risk of coro­nary disease among women with high gravidity or parity (9). Long-term effects of pregnancy on coronary disease risk factors, such as lipoproteins (10, 11), are potential mechanisms for an association between par­ity and coronary artery disease risk. Marked increases in lipoprotein concentrations oc­cur during pregnancy (12) and have been correlated with pregnancy-related increases in insulin, 17-beta estradiol, progesterone, and human placental lactogen (13). Total and low density lipoprotein (LDL) choles­terol and triglyceride levels progressively increase during gestation (10, 14). Although triglycerides have been reported to decrease rapidly during the postpar­tum period, total and LDL cholesterol levels may require several months to return to baseline (10, 14). High density lipoprotein (HDL) cholesterol, which has been shown to be inversely associated with coronary disease risk among women (15, 16), peaks at mid- gestation and then falls to levels approximately 15 percent above baseline at term (12). Few data are available on the long-term effects of pregnancy on lipoproteins; however, there are reports of inverse associations between parity and postpartum HDL cho­lesterol levels (17-20). In order to examine further relations of parity with lipid risk factors, we assessed plasma lipids at baseline and at the year 1 and year 2 follow-up examinations among young adult women in an ongoing epidemiologic study.