[Study on the dynamic variations and influencing factors of serum lipid levels during pregnancy and postpartum].

Objective: To study the variations and influencing factors of serum triglycerides and cholesterol levels during pregnancy and postpartum. Methods: A retrospective study was performed among 5 020 healthy singleton (95.10%, 4 774/5 020) and twin (4.90%, 246/5 020) women who had delivery in Women's Hospital, Zhejiang University School of Medicine from January 2011 to December 2016. Serum triglycerides and cholesterol levels during pregnancy and postpartum of all the cases were collected. Both singleton and twin pregnant women were divided into advanced age and appropriate age groups, and then data of serum sample were assigned to 3 groups according to the gestation weeks, which were second trimester pregnancy (24-28 gestation weeks) , third trimester pregnancy (32-41 gestation weeks) and postpartum (within 72 hours after delivery) . The serum triglycerides and cholesterol levels in each groups were compared. Results: (1) Serum triglycerides and cholesterol levels during the second trimester pregnancy, third trimester pregnancy and postpartum were higher than levels of non-pregnancy in both singleton and twin groups (all P< 0.05) . (2) Serum triglycerides and cholesterol levels in the third trimester pregnancy group were higher than those of second trimester pregnancy group in both advanced age and appropriate aged women regardless singleton or twin pregnancy (all P< 0.05) . The 95% CI of serum lipid levels in each group during second and third trimester pregnancy were as follows: in appropriate aged singleton group, the triglycerides levels were 1.07-4.13 and 1.52-7.21 mmol/L, and the cholesterol levels were 2.77-12.11 and 4.44-9.36 mmol/L. In advanced aged singleton group, the triglycerides levels were 1.28-4.61 and 1.70-7.80 mmol/L, and the cholesterol levels were 4.35-8.40 and 4.46-9.35 mmol/L; in appropriate aged twin group, the triglycerides levels were 1.39-7.16 and 1.90-9.29 mmol/L, and the cholesterol levels were 4.99-12.16 and 4.52-10.07 mmol/L; in advanced aged twin group, the triglycerides levels were 1.61-5.32 and 1.94-9.29 mmol/L, and the cholesterol levels were 5.24-8.10 and 4.53-8.86 mmol/L. (3) Serum lipids levels rapidly decreased during postpartum compared to the third trimester pregnancy. The 95% CI of blood lipid levels in each group were as follows: in appropriate aged singleton group, the triglycerides level was 0.90-5.64 mmol/L and the cholesterol level was 4.70-8.52 mmol/L; in advanced aged singleton group, the triglycerides level was 0.87-5.43 mmol/L and the cholesterol level was 4.68-9.04 mmol/L; in appropriate aged twin group, the triglycerides level was 1.20-8.21 mmol/L and the cholesterol level was 4.66-8.45 mmol/L; in advanced aged twin group, the triglycerides level was 1.32-6.61 mmol/L, and the cholesterol level was 5.01-7.94 mmol/L. (4) Serum triglycerides and cholesterol levels in twin pregnant women were significantly higher than in singleton during the second trimester and third trimester pregnancy both in advanced age and appropriate age groups (all P< 0.05) . During postpartum, there was no difference in serum lipid levels between the singleton and twin pregnant women in appropriate age group (triglycerides: P= 0.982; cholesterol: P= 0.759, respectively) . While the serum lipid levels in twin pregnant women were significantly higher than those of singleton women in advanced age group (triglycerides: P= 0.000; cholesterol: P= 0.000, respectively) . Conclusions: The standard of serum lipid levels of non-pregnant adults is not suitable for assessing that in pregnant women. Regardless of singleton or twin pregnancy, serum triglyceride and cholesterol levels during pregnancy elevate with the increasing gestational week and then rapidly decrease during postpartum. Age and twins are the influencing factors of the elevated physiological lipid levels during pregnancy.