The Journal of Practical Medicine ›› 2025, Vol. 41 ›› Issue (10): 1555-1562.doi: 10.3969/j.issn.1006-5725.2025.10.018

• Clinical Research • Previous Articles    

The relationship between normal high blood pressure and grade 1 hypertension in early pregnancy and maternal preeclampsia and adverse pregnancy outcomes

Jun LIU,Fulin TIAN,Lin CHEN,Jian. LI   

  1. Department of Obstetrics,Shiyan Maternal and Child Health Hospital,Shiyan 442000,Hubei,China
  • Received:2024-12-25 Online:2025-05-25 Published:2025-05-21

Abstract:

Objective To investigate the effects of normal-high blood pressure and Grade 1 hypertension during early pregnancy on preeclampsia (PE) and adverse pregnancy outcomes in pregnant women. Methods A retrospective cohort study was conducted, enrolling 2,562 postpartum women who delivered at the Shiyan Maternal and Child Health Hospital from March 2020 to November 2023 as study participants. Prenatal examination data and delivery medical records were collected for analysis. Women were categorized into three groups based on blood pressure measurements taken before 20 weeks of gestation: normal blood pressure (n = 2 029): systolic blood pressure < 120 mmHg and diastolic blood pressure < 80 mmHg; normal high blood pressure (n = 375): systolic blood pressure 120 ~ 139 mmHg or diastolic blood pressure 80 ~ 89 mmHg; and Level 1 hypertension (n = 158): systolic blood pressure 140 ~ 159 mmHg or diastolic blood pressure 90 ~ 99 mmHg. The incidence rates of PE and adverse pregnancy outcomes (including cesarean section, placental abruption, spontaneous preterm delivery [before 37 weeks], postpartum hemorrhage, stillbirth after 20 weeks of gestation, Apgar score < 7, neonatal admission to the NICU, small for gestational age, macrosomia, and neonatal death within 28 days of birth) were compared and analyzed across the three groups. Cox regression analysis was performed to investigate the impact of early pregnancy blood pressure levels on the risk of PE and adverse pregnancy outcomes. Results (1) Women with normal high blood pressure had a 2.163-fold increased risk of PE compared to women with normal blood pressure (95%CI: 1.228 ~ 3.809, P = 0.007). However, there were no statistically significant differences in the rates of cesarean section (OR = 1.341, 95%CI: 0.528 ~ 3.405, P = 0.537), placental abruption (OR = 1.016, 95%CI: 0.925 ~ 1.115, P = 0.740), Apgar score <7 (OR = 1.422, 95%CI: 0.976 ~ 2.071, P = 0.066), spontaneous preterm birth (OR = 1.027, 95%CI: 0.925 ~ 1.140, P = 0.617), postpartum bleeding (OR = 1.141, 95%CI: 0.873 ~ 1.491, P = 0.334), stillbirth after 20 weeks of gestation (OR = 1.276, 95%CI: 0.980 ~ 1.661, P = 0.070), neonatal admission to NICU (OR = 1.301, 95%CI: 0.674 ~ 2.511, P = 0.432), small for gestational age (OR = 1.089, 95%CI: 0.927 ~ 1.279, P = 0.299), macrosomia (OR = 1.336, 95%CI: 0.824 ~ 2.166, P = 0.240), or neonatal death within 28 days of birth (OR = 1.275, 95%CI: 0.918 ~ 1.770, P = 0.147). (2) Compared to women with normal blood pressure, women with grade 1 hypertension had a significantly higher risk of preeclampsia (OR = 3.829, 95%CI: 1.749 ~ 8.385, P < 0.001), cesarean section (OR = 2.414, 95%CI: 1.298 ~ 4.489, P = 0.005), and placental abruption (OR = 2.537, 95%CI: 1.196 ~ 5.384, P = 0.015). Additionally, they had a higher rate of Apgar score < 7 (OR = 1.829, 95%CI: 1.069 ~ 3.130, P = 0.027). No statistically significant differences were observed for spontaneous preterm birth (OR = 1.404, 95%CI: 0.713 ~ 2.764, P = 0.326), postpartum bleeding (OR = 1.236, 95%CI: 0.845 ~ 1.807, P = 0.274), stillbirth after 20 weeks of gestation (OR = 1.076, 95%CI: 0.902 ~ 1.283, P = 0.415), neonatal admission to NICU (OR = 1.346, 95%CI: 0.873 ~ 2.075, P = 0.178), small for gestational age (OR = 1.417, 95%CI: 0.926 ~ 2.168, P = 0.108), macrosomia (OR = 1.235, 95%CI: 0.629 ~ 2.424, P = 0.539), or neonatal death within 28 days of birth (OR = 1.275, 95%CI: 0.918 ~ 1.770, P = 0.147). (3)ROC analysis shows that when the sample combination was normal high blood pressure(n = 375), the predictive/evaluative efficacy AUC of early pregnancy blood pressure values (threshold 139/89) for PE was 0.757. When the sample combination was level 1 hypertension(n = 158), the predictive/evaluative efficacy AUC of early pregnancy blood pressure values (threshold 159/99) for four adverse outcomes, including PE, cesarean section, placental abruption, and Asperger's score < 7, were 0.789, 0.717, 0.709, and 0.742, respectively. Conclusion Compared with pregnant and parturient women with normal blood pressure, having a normal high blood pressure or grade 1 hypertension before 20 weeks of pregnancy will significantly increase the risk of PE; in addition, grade 1 hypertension is also associated with a higher incidence of adverse pregnancy outcomes, including cesarean section, placental abruption, and low Apgar score of the newborn.

Key words: early pregnancy, preeclampsia, blood pressure, adverse pregnancy outcomes

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