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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 in pregnancy conditional on the level of blood pressure at 12 weeks gestation for iparous normal-weight nonsmoking women with normal pregnancies (N = 1832). Centiles are labelled. Note that in each of the plots, there is a star that corresponds to the value of SBP/DBP at 12 weeks.
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Figure 5: Reference ranges for SBP and DBP in pregnancy conditional on the level of blood pressure at 12 weeks gestation for iparous normal-weight nonsmoking women with normal pregnancies (N = 1832). Centiles are labelled. Note that in each of the plots, there is a star that corresponds to the value of SBP/DBP at 12 weeks.

Mentions: Figure 5 shows the predicted reference ranges of SBP and DBP across pregnancy, conditional on different possible levels of blood pressure at 12 weeks gestation for iparous women. The equivalent reference ranges for multiparous women are shown in Supplementary Figure 7. For each additional 10 mmHg in SBP at 12 weeks, the reference ranges for SBP were predicted to be approximately 4 mmHg higher at 20 weeks and around 3 mmHg higher at 37 weeks gestation in both iparous and multiparous women (Supplementary Table 3). For each additional 10 mmHg in DBP at 12 weeks, the reference ranges for DBP were predicted to be around 3 mmHg higher at 20 weeks and around 2.5 mmHg higher at 37 weeks (Supplementary Table 3).


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 in pregnancy conditional on the level of blood pressure at 12 weeks gestation for iparous normal-weight nonsmoking women with normal pregnancies (N = 1832). Centiles are labelled. Note that in each of the plots, there is a star that corresponds to the value of SBP/DBP at 12 weeks.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: Reference ranges for SBP and DBP in pregnancy conditional on the level of blood pressure at 12 weeks gestation for iparous normal-weight nonsmoking women with normal pregnancies (N = 1832). Centiles are labelled. Note that in each of the plots, there is a star that corresponds to the value of SBP/DBP at 12 weeks.
Mentions: Figure 5 shows the predicted reference ranges of SBP and DBP across pregnancy, conditional on different possible levels of blood pressure at 12 weeks gestation for iparous women. The equivalent reference ranges for multiparous women are shown in Supplementary Figure 7. For each additional 10 mmHg in SBP at 12 weeks, the reference ranges for SBP were predicted to be approximately 4 mmHg higher at 20 weeks and around 3 mmHg higher at 37 weeks gestation in both iparous and multiparous women (Supplementary Table 3). For each additional 10 mmHg in DBP at 12 weeks, the reference ranges for DBP were predicted to be around 3 mmHg higher at 20 weeks and around 2.5 mmHg higher at 37 weeks (Supplementary Table 3).

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