The effect of bearing and rearing a child on blood pressure: a nationally representative instrumental variable analysis of 444 611 mothers in India

Felix Teufel; Pascal Geldsetzer; Nikkil Sudharsanan; Malavika Subramanyam; H Manisha Yapa; Jan-Walter De Neve; Sebastian Vollmer; Till Bärnighausen

doi:10.1093/ije/dyab058

The effect of bearing and rearing a child on blood pressure: a nationally representative instrumental variable analysis of 444 611 mothers in India

Int J Epidemiol. 2021 Nov 10;50(5):1671-1683. doi: 10.1093/ije/dyab058.

Authors

Felix Teufel¹, Pascal Geldsetzer^{1

2}, Nikkil Sudharsanan¹, Malavika Subramanyam³, H Manisha Yapa⁴, Jan-Walter De Neve¹, Sebastian Vollmer^{5

6}, Till Bärnighausen^{1

7

8}

Affiliations

¹ Heidelberg Institute of Global Health (HIGH), Faculty of Medicine and University Hospital, Heidelberg University, Heidelberg, Germany.
² Division of Primary Care and Population Health, Department of Medicine, Stanford University, Stanford, CA, USA.
³ Indian Institute of Technology, Gandhinagar, Gujarat, India.
⁴ Kirby Institute, University of New South Wales, Sydney, Australia.
⁵ Department of Economics, University of Goettingen, Goettingen, Germany.
⁶ Centre for Modern Indian Studies, University of Goettingen, Goettingen, Germany.
⁷ Africa Health Research Institute (AHRI), Somkhele and Durban, South Africa.
⁸ Harvard Center for Population and Development Studies, Harvard University, Cambridge, MA, USA.

Abstract

Background: At the individual level, it is well known that pregnancies have a short-term effect on a woman's cardiovascular system and blood pressure. The long-term effect of having children on maternal blood pressure, however, is unknown. We thus estimated the causal effect of having children on blood pressure among mothers in India, a country with a history of high fertility rates.

Methods: We used nationally representative cross-sectional data from the 2015-16 India National Family and Health Survey (NFHS-4). The study population comprised 444 611 mothers aged 15-49 years. We used the sex of the first-born child as an instrumental variable (IV) for the total number of a woman's children. We estimated the effect of an additional child on systolic and diastolic blood pressure in IV (two-stage least squares) regressions. In additional analyses, we stratified the IV regressions by time since a mother last gave birth. Furthermore, we repeated our analyses using mothers' husbands and partners as the regression sample.

Results: On average, mothers had 2.7 children [standard deviation (SD): 1.5], a systolic blood pressure of 116.4 mmHg (SD: 14.4) and diastolic blood pressure of 78.5 mmHg (SD: 9.4). One in seven mothers was hypertensive. In conventional ordinary least squares regression, each child was associated with 0.42 mmHg lower systolic [95% confidence interval (CI): -0.46 to -0.39, P < 0.001] and 0.13 mmHg lower diastolic (95% CI: -0.15 to -0.11, P < 0.001) blood pressure. In the IV regressions, each child decreased a mother's systolic blood pressure by an average of 1.00 mmHg (95% CI: -1.26 to -0.74, P < 0.001) and diastolic blood pressure by an average of 0.35 mmHg (95% CI: -0.52 to -0.17, P < 0.001). These decreases were sustained over more than a decade after childbirth, with effect sizes slightly declining as the time since last birth increased. Having children did not influence blood pressure in men.

Conclusions: Bearing and rearing a child decreases blood pressure among mothers in India.

Keywords: Blood pressure; child-rearing; global health; instrumental variable analysis; pregnancy; women’s health.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Blood Pressure
Cross-Sectional Studies
Female
Humans
Hypertension* / epidemiology
India / epidemiology
Male
Mothers*
Pregnancy

Abstract

Publication types

MeSH terms

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