Parity and risk of maternal cardiovascular disease: A dose–response meta-analysis of cohort studies

Abstract

Background Parity has been reported to play an important role in the development of cardiovascular disease; however, the results are still controversial. We aimed to conduct a meta-analysis of cohort studies to assess quantitatively the association between parity and cardiovascular disease risk. Methods PubMed and Web of Science databases were searched to 1 June 2018, supplemented by manual searches of the bibliographies of retrieved articles. And multivariate-adjusted relative risks were pooled by using random-effects models. Restricted cubic spline analysis with four knots was used to explore the relationship of parity and the risk of cardiovascular disease. Results Ten cohort studies involving 150,512 incident cases of cardiovascular disease among 3,089,929 participants were included in the meta-analysis. A significant association between parity and cardiovascular disease risk was observed while comparing parity with nulliparity, with a summarised relative risk of 1.14 (95% confidence interval (CI) 1.09–1.18; I2 = 62.0%, P = 0.002). In the dose–response analysis, we observed a potential non-linear J-shaped dose–response relationship between the number of parity and cardiovascular disease risk, the summary risk estimates for an increase of one live birth was 1.04 (95% CI 1.02–1.05), with significant heterogeneity ( I2 = 89.6%). In addition, the similar J-shaped associations between parturition number and cardiovascular disease, ischaemic heart disease or stroke risk were also observed. Conclusions Our findings suggest that ever parity is related to cardiovascular disease risk and there is an association between the number of pregnancies and the risk of cardiovascular disease. Since the number of included studies was limited, further studies are warranted to confirm our findings.

Number of parity/live birth(s) and cardiovascular disease among Iranian women and men: Results of over 15 years of follow-up.

“…The ndings of the current study about the association of parity number with incident CVD among women are consistent with a meta-analysis study on this issue by Li et al [9]. in which they found a non-linear Jshaped dose-response relationship between the number of parity and CVD among women.…”

“…They also found that each live birth was associated with a 1% non-signi cant increased risk for CVD mortality (I 2 = 86.4%). It should be noted that the signi cant heterogeneity in these two meta-analyses [9,21] could be related to different study populations, sample sizes and other epidemiologic aspects of studies. Marginally signi cant increased CVD risk for women with ≥ 4 parity in our results agrees with the ndings of other studies [22,23].…”

“…A possible explanation for the association between parity and incident CVD in women is the biologic pathway. During pregnancy, some physiologic changes can have adverse effects for incident CVD which remained even after delivery, including weight gain, dyslipidemia, increased plasma glucose and insulin resistance as well as endothelial dysfunction and in ammatory and hemostatic processes [7][8][9]. In the light of multiple pregnancies, exposure time to these changes increased [9,31].…”

“…Additional stressors such as endothelial dysfunction, in ammation and hemostasis process during pregnancy may exacerbate this situation [7][8][9]. Results of previous studies on the association of parity (i.e., number of pregnancies reaching viable gestational age) and gravidity (i.e., number of times a woman is or has been pregnant, regardless of the pregnancy outcome) with the risk of CVD are inconclusive [9,10]. Peters et al showed that among 10 European countries, parous women had a 19% higher risk of CHD than nulliparous women; with this risk reaching up to 95% among women who had ≥5 children [10].…”

More children, more happiness? Fewer and better births, a happy life: The relationship of parity and maternal cardiovascular disease risk

“…Recently, a dose-response meta-analysis to assess quantitatively the association between parity and maternal CVD risk was conducted in the paper by Li et al 10 It consisted of 10 prospective cohort studies performed from 1987 to 2018. The investigators reported a potential non-linear J-shaped dose-response relationship between them and concluded the risk of CVD increased by 14% among parous women compared with nulliparous women, and an increasing number of parity was associated with a non-linearly increased CVD risk.…”