Lipid variations of first and third trimester in pregnant women with different pre-pregnancy body mass index / 中华围产医学杂志

ABSTRACT

ObjectiveTo investigate the influence of pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) on lipid variations of first and third trimester.MethodsA retrospective analysis was conducted on 2 593 singleton pregnant women without diabetes from 15 hospitals in Beijing from June 20 to November 30 in 2013. Serum lipid levels were determined in all of these women at the first trimester (<14 weeks) and the third trimester (≥28 weeks). Demographic data and medical information were collected individually through questionnaires. The recruited gravidas were divided into normal pre-pregnant BMI group (BMI<25) and pre-pregnant overweight and obese group (BMI≥25) according to recommendations of the Institute of Medicine (IOM). Based on the same recommendations on normal GWG, the pregnant women in the two groups were further assigned to two subgroups including normal GWG and over GWG group. The serum lipid levels in both first and third trimester and the increases from first to third trimester were compared between the normal and abnormal BMI groups with two independent samplet-test.Results(1) The levels of total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C) and low density lipoprotein-cholesterol (LDL-C) in the third trimester were all significantly higher than those in the first trimester in the normal BMI group [(6.47±1.17) vs (4.63±0.80), (3.14±1.19) vs (1.22±0.70), (1.94±0.44) vs (1.85±0.49) and (3.56±1.00) vs (2.29±0.67) mmol/L,t=-61.250,-65.909,-6.448 and-49.952, allP<0.01]. And the same results were shown in the abnormal BMI group [(6.20±1.14) vs (4.75±0.88), (3.31±1.20) vs (1.44±0.70), (1.86±0.44) vs (1.65±0.37) and (3.30±0.89) vs (2.51±0.82) mmol/L, t=-18.756,-25.165,-6.905 and-12.191,allP<0.01]. Significant differences were identified between the normal and abnormal pre-pregnant BMI groups both in first and third trimester (allP<0.05). (2) The increases of TC from early to late pregnancy in the abnormal BMI group was lower than that in the normal BMI group [(1.45±1.01) vs (1.84±1.02) mmol/L,t=6.664,P<0.01], but the increase of HDL-C was higher [(0.21±0.39) vs (0.09±0.51) mmol/L,t=-4.301,P<0.01]. (3) In the normal BMI group, the increase of TC and HDL-C between the third and the first trimester was lower in the over GWG subgroups than in the normal GWG subgroups [(1.77±0.96) vs (1.89±1.05) mmo/L,t=-2.802,P=0.005; (0.06±0.41) vs (0.12±0.58) mmo/L,t=-2.588,P=0.010], but the increase of TG was higher [(2.00±1.07) vs (1.86± 1.18) mmo/L,t=3.015,P=0.003]. While in the abnormal BMI group, smaller increase of HDL-C was found in the over GWG subgroup than in the normal GWG subgroup [(0.17±0.35) vs (0.29±0.44) mmo/L,t=-2.664, P=0.008].ConclusionsThe lipid levels during pregnancy are significantly higher in late pregnancy than in early pregnancy. Pre-pregnancy BMI has much more effect on lipid variations during pregnancy than GWG, which primarily affect the lipid levels of women with normal pre-pregnancy BMI.