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. 2025 Jan 7;25(1):8.
doi: 10.1186/s12884-024-07117-3.

Gestational - age - specific reference intervals for blood pressure in normal pregnancy in a Southern Chinese population

Yuguo Deng  1   2 , Lanfang Liang  1   2 , Ying Gao  1   2 , Guilian Liao  1   2 , Qiaozhu Chen  3 , Zijian Huang  3 , Jinying Yang  4   5
Affiliations

Gestational - age - specific reference intervals for blood pressure in normal pregnancy in a Southern Chinese population

Yuguo Deng et al. BMC Pregnancy Childbirth. .

Abstract

Objective: Physiological blood pressure changes in pregnancy are insufficiently defined. This paper describes the blood pressure changes across healthy pregnancies in a Southern Chinese population to present gestational - age - specific blood pressure ranges with smoothed centiles (3rd, 10th, 50th, 90th, and 97th).

Methods: Antenatal blood pressure measurements [median (interquartile range) 9 (8 - 10) per woman] were repeated in 17, 776 women from a Southern China population. Multilevel cubic splines models were used to derive longitudinal reference ranges for systolic blood pressure (SBP) and diastolic blood pressure (DBP) from 6 to 42 weeks of gestation for the normal pregnancies (excluding chronic hypertension, preeclampsia, diabetic ones, and preterm birth et al.).

Results: Systolic and diastolic BP increased from 6 weeks of gestation: 50th centile (3rd - 97th centile) 106 (87 - 125); 61 (47 - 77) mm Hg to 12 weeks of gestation: 50th centile (3rd - 97th centile) 108 (88 - 129); 64 (49 - 81) mm Hg. Then, the lowest value of 107 (87 - 129); 62 (47 - 78) mm Hg was reached at 16 weeks and 20 weeks of gestation, respectively. Systolic and diastolic BP then rose to a maximum median (3rd - 97th centile) of 115 (96 - 135); 68 (53 - 85) mm Hg at 42 weeks of gestation. Additionally, the ascending tendency of SBP after 16 weeks of gestation was interrupted by two fluctuations that occurred at 24 weeks and 30 weeks of gestation.

Conclusions: In summary, our study provides blood pressure reference values for Southern Chinese women with normal pregnancies. To identify gestational hypertension and hypotension, centiles for gestational - age - specific BP should be defined in healthy pregnancies. Understanding these changes in low risk pregnancies is essential to optimize maternal blood pressure management.

Keywords: Blood pressure trajectory; Normal pregnancy; Reference intervals.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: This study has ethical approval from the Longgang District Maternal & Child Healthcare Hospital Research Ethics Committee (No. LGFYYXLLL-2022-016). All participants have signed the written informed consent. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Flowchart illustrating women enrolled in the study. Abbreviations: GDM, gestational diabetes mellitus; PGDM, pregestational diabetes mellitus
Fig. 2
Fig. 2
Reference ranges for systolic blood pressure (upper line and centiles, mm Hg) and diastolic blood pressure (lower line and centiles, mm Hg) between 6 weeks and 42 weeks of gestation in normal pregnancies. Centiles are labelled. A normal pregnancy was defined as a woman did not have chronic hypertension, preeclampsia, nondiabetic pregnancies and delivered at term
See this image and copyright information in PMC

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