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Gestational-age-specific reference ranges for blood pressure in pregnancy: findings from a prospective cohort.

Macdonald-Wallis C, Silverwood RJ, Fraser A, Nelson SM, Tilling K, Lawlor DA, de Stavola BL - J. Hypertens. (2015)

Bottom Line: Stratified reference ranges were higher for women in higher prepregnancy BMI categories, and lower for smokers than for nonsmokers throughout pregnancy.Normal ranges for blood pressure vary with gestation age and by maternal subgroups.Whole population and stratified normograms could be used as a reference to identify abnormal trajectories.

View Article: PubMed Central - PubMed

Affiliation: aMRC Integrative Epidemiology Unit at the University of Bristol bSchool of Social and Community Medicine, University of Bristol, Bristol cCentre for Statistical Methodology dDepartment of Medical Statistics, London School of Hygiene and Tropical Medicine, London eSchool of Medicine, University of Glasgow, Glasgow, UK.

ABSTRACT

Objective: Pregnancy is a period of considerable change in blood pressure, with an early pregnancy decrease followed by a late pregnancy rise. High blood pressure in pregnancy is associated with adverse perinatal outcomes for the mother and offspring. We aimed to define normal ranges of blood pressure across gestation.

Methods: We used repeated antenatal blood pressure measurements [median (interquartile range) 10 (9-11) per woman] for 10,327 women. Multilevel models were used to derive longitudinal reference ranges for SBP and DBP from 12 to 40 weeks gestation for the whole cohort, for women with normal pregnancies (without essential hypertension or preeclampsia who delivered an appropriate-size-for-gestational age infant at term) and for subgroups of normal pregnancies defined by different levels of maternal prepregnancy BMI, smoking and parity.

Results: In normal pregnancies, the mean (95% reference range) SBP and DBP for iparous women at 12 weeks gestation were 112.1 (88.6-135.5) and 65.4 (48.9-81.9) mmHg, and at 37 weeks were 116.0 (92.3-139.7) and 70.0 (52.2-87.9) mmHg, respectively. For every additional 10  mm Hg of blood pressure at 12 weeks, normal ranges were 2-3 mm Hg higher across gestation. Reference ranges for multiparous women were 1-2  mm Hg lower throughout pregnancy. Stratified reference ranges were higher for women in higher prepregnancy BMI categories, and lower for smokers than for nonsmokers throughout pregnancy.

Conclusion: Normal ranges for blood pressure vary with gestation age and by maternal subgroups. Whole population and stratified normograms could be used as a reference to identify abnormal trajectories.

No MeSH data available.


Related in: MedlinePlus

Reference ranges for SBP and DBP by maternal prepregnancy BMI category for iparous nonsmokers with normal pregnancies (N = 2270). Centiles are labelled.
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Figure 3: Reference ranges for SBP and DBP by maternal prepregnancy BMI category for iparous nonsmokers with normal pregnancies (N = 2270). Centiles are labelled.

Mentions: Reference ranges stratified by maternal prepregnancy BMI are shown for iparous nonsmoking women in Fig. 3 and for multiparous women in Supplementary Figure 1. For both iparous and multiparous women, there was an increasing trend in the limits of the reference ranges with increasing prepregnancy BMI category at each gestational age. For example, for iparous women, upper and lower reference range limits of SBP were approximately 10 mmHg higher throughout pregnancy for obese than for normal weight women, and for DBP were approximately 7.5–8 mmHg higher (Supplementary Table 2). The shape of the blood pressure trajectory also differed by prepregnancy BMI category (Supplementary Figures 2 and 3), with obese women having a more distinct nadir in SBP and DBP than normal weight women in the iparous group.


Gestational-age-specific reference ranges for blood pressure in pregnancy: findings from a prospective cohort.

Macdonald-Wallis C, Silverwood RJ, Fraser A, Nelson SM, Tilling K, Lawlor DA, de Stavola BL - J. Hypertens. (2015)

Reference ranges for SBP and DBP by maternal prepregnancy BMI category for iparous nonsmokers with normal pregnancies (N = 2270). Centiles are labelled.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4255761&req=5

Figure 3: Reference ranges for SBP and DBP by maternal prepregnancy BMI category for iparous nonsmokers with normal pregnancies (N = 2270). Centiles are labelled.
Mentions: Reference ranges stratified by maternal prepregnancy BMI are shown for iparous nonsmoking women in Fig. 3 and for multiparous women in Supplementary Figure 1. For both iparous and multiparous women, there was an increasing trend in the limits of the reference ranges with increasing prepregnancy BMI category at each gestational age. For example, for iparous women, upper and lower reference range limits of SBP were approximately 10 mmHg higher throughout pregnancy for obese than for normal weight women, and for DBP were approximately 7.5–8 mmHg higher (Supplementary Table 2). The shape of the blood pressure trajectory also differed by prepregnancy BMI category (Supplementary Figures 2 and 3), with obese women having a more distinct nadir in SBP and DBP than normal weight women in the iparous group.

Bottom Line: Stratified reference ranges were higher for women in higher prepregnancy BMI categories, and lower for smokers than for nonsmokers throughout pregnancy.Normal ranges for blood pressure vary with gestation age and by maternal subgroups.Whole population and stratified normograms could be used as a reference to identify abnormal trajectories.

View Article: PubMed Central - PubMed

Affiliation: aMRC Integrative Epidemiology Unit at the University of Bristol bSchool of Social and Community Medicine, University of Bristol, Bristol cCentre for Statistical Methodology dDepartment of Medical Statistics, London School of Hygiene and Tropical Medicine, London eSchool of Medicine, University of Glasgow, Glasgow, UK.

ABSTRACT

Objective: Pregnancy is a period of considerable change in blood pressure, with an early pregnancy decrease followed by a late pregnancy rise. High blood pressure in pregnancy is associated with adverse perinatal outcomes for the mother and offspring. We aimed to define normal ranges of blood pressure across gestation.

Methods: We used repeated antenatal blood pressure measurements [median (interquartile range) 10 (9-11) per woman] for 10,327 women. Multilevel models were used to derive longitudinal reference ranges for SBP and DBP from 12 to 40 weeks gestation for the whole cohort, for women with normal pregnancies (without essential hypertension or preeclampsia who delivered an appropriate-size-for-gestational age infant at term) and for subgroups of normal pregnancies defined by different levels of maternal prepregnancy BMI, smoking and parity.

Results: In normal pregnancies, the mean (95% reference range) SBP and DBP for iparous women at 12 weeks gestation were 112.1 (88.6-135.5) and 65.4 (48.9-81.9) mmHg, and at 37 weeks were 116.0 (92.3-139.7) and 70.0 (52.2-87.9) mmHg, respectively. For every additional 10  mm Hg of blood pressure at 12 weeks, normal ranges were 2-3 mm Hg higher across gestation. Reference ranges for multiparous women were 1-2  mm Hg lower throughout pregnancy. Stratified reference ranges were higher for women in higher prepregnancy BMI categories, and lower for smokers than for nonsmokers throughout pregnancy.

Conclusion: Normal ranges for blood pressure vary with gestation age and by maternal subgroups. Whole population and stratified normograms could be used as a reference to identify abnormal trajectories.

No MeSH data available.


Related in: MedlinePlus