ABSTRACT
Objective:To analyze the lipid levels, adverse perinatal outcome and their correlation in Tibetan pregnant women in high altitudes in late pregnancy.Methods:Retrospective analysis was performed on clinical and laboratory data of 523 Tibetan singleton pregnant women who delivered after 28 weeks at the Department of Obstetrics and Gynecology, Chaya People's Hospital, Changdu City. The subjects were divided into three groups according to the altitude of their long-term residence, including altitude<3 500 m (Group A, n=161), altitude ≥3 500 m and <4 000 m (Group B, n=203) and altitude≥4 000 m (Group C, n=159). In addition, the subjects were also grouped into high TG group (TG≥3.23 mmol/L, n=80) and control group (TG<3.23 mmol/L, n=443). The baseline information, levels of lipid and perinatal outcome were compared among Group A,B and C, and also between the high TG and control group, respectively, using Mann-whitney U test, Kruskal-Wallis H test, LSD- t, Chi-square test, or Fisher exact test. Multivariate logistic regression analysis was also applied to analyze the correlation between hypertriglyceridemia and adverse perinatal outcome. Results:The maternal age, gravidity and parity, body mess index, blood pressure on admission and total cholesterol (TC), TG, high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), TG/HDL-C ratio and LDL-C/HDL-C ratio in late pregnancy and the occurrence of adverse perinatal outcome did not show any significant differences among Group A, B and C (all P>0.05). However, the hemoglobin (Hb) level increased with the elevation of altitude as expected, and that in Group C was higher than that in Group A and B [121.0 g/L (108.0-132.0 g/L) vs 115.0 g/L (103.5-128.0 g/L) and 117.0 g/L (101.0-127.0 g/L), H=2.37 and 1.97, both P<0.05]. The proportion of women with hypertriglyceridemia, the high TG group, in late pregnancy was 15.3% (80/523), and no significant difference was found in HDL-C or Hb levels between the high TG and control group [1.7 mmol/L (1.5-2.0 mmol/L) vs 1.8 mmol/L (1.5-2.1 mmol/L), Z=－1.51;123.5 g/L (110.0-131.8 g/L) vs 117.0 g/L (104.0-128.0 g/L), Z=1.69; both P>0.05]. Higher rates of cesarean section [13.8% (11/80) vs 6.6% (29/443), χ2＝4.98], hypertensive disorders of pregnancy (HDP) [16.3% (13/80) vs 7.5% (33/443), χ2＝6.54], preeclampsia (PE) [8.8% (7/80) vs 1.6% (7/443), χ2＝13.37], hyperglycemia during pregnancy [11.3%( 9/80) vs 3.6% (16/443), χ2＝8.69], preterm birth (PB) [7.5% (6/80) vs 2.0% (9/443), χ2＝7.27], microsomia [5.0% (4/80) vs 0.9% (4/443), Fisher exact test] and neonatal asphyxia [8.8%(7/80) vs 2.5% (11/443), χ2＝8.01] were observed in the high TG group than in the control group (all P<0.05). Regarding the pregnant women at different altitude, TG was negatively correlated with Hb ( r=－0.17, P=0.037) only in Group C .Multivariate logistic regression analysis revealed higher risk of HDP ( OR=2.42,95% CI:1.17-5.00), PE ( OR=5.25, 95% CI:1.73-16.00), hyperglycemia during pregnancy ( OR=3.77, 95% CI:1.56-9.09), PB ( OR=4.33, 95% CI:1.42-13.22), microsomia ( OR=4.33, 95% CI:1.42-13.22), neonatal asphyxia ( OR=3.45, 95% CI:1.27-9.35) and fetal demise ( OR=4.94, 95% CI:1.01-24.21) in women with high TG level in late pregnancy (all P<0.05). Conclusions:There were no differences in adverse perinatal outcomes or serum lipid levels in late pregnancy among women living at different high altitudes. However, hypertriglyceridemia at the third trimester is closely associated with the incidence of HDP, PE, hyperglycemia during pregnancy, PB, microsomia, neonatal asphyxia and fetal demise in this group of women.