Study on the regularity of blood pressure changes in pregnant women and its influencing factors.

Objective: To explore the patterns and influencing factors of blood pressure changes in pregnant women at different stages of pregnancy.

Method: A retrospective analysis of 445 pregnant women who underwent prenatal examination and delivered at the First Hospital of Hebei Medical University between December 2016 and November 2017. A questionnaire survey was conducted on pre-pregnancy information, and data was collected from pre-pregnancy blood routines, blood lipids, cortisol levels, and other biochemical indicators, as well as blood pressure measurements taken before pregnancy, in early pregnancy, mid-pregnancy, and late pregnancy. High-normal blood pressure (HNBP) during pregnancy and abnormal blood pressure variability (ABPV) were examined. Logistic regression and chi-square tests were used to identify risk factors and analyze the impact of ABPV on delivery outcomes.

Results: Blood pressure was significantly higher before pregnancy, decreased after conception, and gradually increased during mid- and late pregnancy (P < 0.001). Logistic regression identified pre-pregnancy systolic blood pressure (SBP), body mass index (BMI), and cortisol levels as high-risk factors for high systolic blood pressure during pregnancy (P < 0.05). Pre-pregnancy diastolic blood pressure (DBP) and occupation type were high-risk factors for high diastolic blood pressure (P < 0.05). SBP before pregnancy, family annual income, and total cholesterol levels were associated with abnormal blood pressure variability (ABPV) during pregnancy (P < 0.01). However, neither HNBP nor ABPV had a significant impact on gestational age, delivery method, delivery complications, or neonatal outcomes (all P > 0.05).

Conclusion: Blood pressure in pregnant women typically decreases in early pregnancy, then gradually rises during mid- and late pregnancy. The duration of HNBP is generally short, with most cases resolving on their own. Pre-pregnancy hypertension, BMI, cortisol levels, and occupational type are risk factors for gestational hypertension. However, normal blood pressure variability during pregnancy has little effect on maternal and neonatal outcomes.