Relationship between lipid and lipoprotein metabolism in trimesters of pregnancy in Nigerian women: Is pregnancy a risk factor?

BACKGROUND: Changes in lipid metabolism have been shown to occur during pregnancy, to ensure a continuous supply of nutrients to the growing fetus, despite intermittent maternal food intake. Abnormal lipid metabolism has also been linked to atherosclerosis. OBJECTIVE: To investigate the effect of pregnancy on the lipid profile and possible predisposition of pregnant Nigerian women to atherosclerosis. SETTINGS AND DESIGN: Serum lipid and lipoprotein levels of 60 apparently healthy pregnant women aged between 25 and 45 years, attending the antenatal clinic of the U.N.T.H, Enugu and 60 apparently healthy non-pregnant, age-matched females (controls) were estimated. The test samples were collected from each subject at each of the trimesters. MATERIALS AND METHODS: Total cholesterol (TC), high-density lipoprotein (HDL) and triglyceride (TG) were analyzed using enzymatic/spectrophotometric methods while low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) were calculated using Friedewald's formula. STATISTICAL ANALYSIS USED: The data obtained were analyzed with Students’ t-test and Pearson's Product Moment Correlation, using graph pad prism software program and results expressed as mean ± SD. The level of significance was determined at 95% confidence level. RESULTS AND CONCLUSION: The serum lipid levels were significantly higher (P<0.05) in all the trimesters of the pregnant women than in the controls. There was a steady increase in the serum lipid levels with increasing gestational age. A significant positive correlation (P<0.05) was observed between the lipid fractions and the different trimesters of pregnancy. TC/HDL was decreased significantly (P<0.05) in pregnant women, with increasing gestational age. Cardiac risk factor, however, decreased with gestational age, signifying possible protection from atherosclerosis. A comparison of two age groups of pregnant women (25-34 years and 35-45 years) showed no significant differences (P>0.05) in all the lipid fractions studied, suggesting no possible age-related effect on lipid metabolism in the women in their first trimester. Even with significant increase in plasma lipid during pregnancy, normal pregnancy in Nigerian women does not appear to increase the risk.