Objective: To investigate the incidence of hypertension disorders complicating pregnancy (HDCP) and vitamin E (VE) nutritional status among pregnant women in Beijing, and to determine the relationship between serum VE concentration in the first trimester of pregnancy and the risk of developing HDCP.
Methods: A retrospective cohort study was performed including 22 283 cases of pregnant women who underwent singleton deliveries in Tongzhou Maternal & Child Health Hospital of Beijing from January 2016 through December 2018 and received tests of serum VE concentrations in the first trimester of pregnancy. Nonconditional Logistic regression model was used to analyze the association between serum VE concentration levels and the risk of developing HDCP.
Results: The total incidence of HDCP was 5.4%, with the incidence of gestational hypertension around 2.1% and the incidence of preeclampsia-eclampsia around 3.3%. The median concentration of serum VE in early pregnancy was 10.1 (8.8-11.6) mg/L, and 99.7% of the participants had normal serum VE concentrations. The incidence of gestational hypertension and that of preeclampsia-eclampsia had been annually increasing in three years; a linear-by-linear association had also been observed between the serum VE concentrations and the years of delivery. According to the results of the univariable and the multivariable Logistic regression analyses, higher risks of developing HDCP had been observed among women with higher serum VE concentrations. Compared to those with serum VE concentrations in interquartile range (P25–P75) of all the participants, the women whose serum VE concentrations above P75 were at higher risks to be attacked by HDCP (OR = 1.34, P < 0.001), gestational hypertension (OR = 1.39, P = 0.002), or preeclampsia-eclampsia (OR = 1.34, P = 0.001), as suggested by the results of the multivariable Logistic regression model analyses. In addition, the women with serum VE concentrations of 11.2 mg/L or above had a significantly higher risk of developing HDCP than those whose serum VE concentrations of P40–P60 of all the participants, and this risk grew higher as serum VE concentrations in the first trimester of pregnancy increased.
Conclusion: Women in Beijing are at good nutritional status. From January 2016 to December 2018, the incidence of HDCP increased with serum VE concentration level, and serum VE concentration of 11.2 mg/L is an indicator of an increased risk of developing HDCP, suggesting that pregnant women should take nutritional supplements containing VE carefully.