Elsevier

Annals of Epidemiology

Volume 18, Issue 12, December 2008, Pages 873-879
Annals of Epidemiology

Parity and Cardiovascular Disease Risk among Older Women: How Do Pregnancy Complications Mediate the Association?

https://doi.org/10.1016/j.annepidem.2008.09.009Get rights and content

Purpose

To determine whether parity is associated with increased risk of cardiovascular disease (CVD) after accounting for perinatal complications.

Methods

CVD prevalence, number of births, and a history of preeclampsia, term low birth weight, preterm or stillbirth were evaluated among 540 women (mean age, 80 years; 47% black) enrolled in the Pittsburgh, PA site of the Health, Aging and Body Composition Study. Biomarkers were measured and CVD status was determined by self-report and hospital records.

Results

Nulliparous women (n = 89) had lower CVD prevalence compared with parous women (18.0% vs. 30.2%). Parous women without perinatal complications of interest (n = 321) had higher statin use compared with nulliparas, a trend accompanied by lower high-density lipoprotein (HDL) and higher triglycerides among women with perinatal complications (n = 130). After adjustment, parous women with no complicated births had a 1.95-fold (95% confidence interval [CI], 1.03–3.7) higher CVD prevalence compared to nulliparas. Among women with one or more pregnancy complications, CVD prevalence was 2.67 times (CI, 1.34–5.33) higher. Women with five or more births had the highest CVD prevalence (odds ratio [OR], 2.60; CI, 1.17–5.76) that was attenuated to 2.27 (1.00–5.15) after adjustment for complications of interest.

Conclusions

History of pregnancy complications and higher statin use accounted for some but not all of the excess CVD prevalence among older parous women.

Introduction

Parity evaluated cross-sectionally has been associated with increased risk of cardiovascular disease (CVD) in women in many, but not all, studies. Some studies indicate that each live birth confers additional, albeit modest, risk for prevalent maternal CVD (1) or atherosclerosis (2). Alternatively, other studies have found a threshold effect such that women with more than five or six children have excess CVD risk 3, 4. Risks associated with nulliparity are contradictory. Some studies indicate that nulliparous women are at lower risk compared with parous women 2, 3, 4, 5; others have found nulliparous women to be at higher risk for CVD compared with parous women with one or two births 1, 6, 7.

Separate studies have also found that certain pregnancy complications, including preeclampsia 8, 9, 10, 11, preterm delivery 12, 13 and low birth weight 14, 15 have been associated with excess maternal cardiovascular risk. Only one study to date has attempted to disaggregate the effects of parity and pregnancy complications on women's long-term cardiovascular risk. Hannaford et al. (6) found that nulliparous women at an average age of 56 had an increased risk for developing hypertension or stroke compared with parous women whose births had been without complications from hypertension.

We set out to assess the effect of parity on CVD prevalence and to determine whether this effect was mediated by pregnancy complications. In particular, we sought to determine whether parity was associated with higher prevalence of CVD among older women after excluding those who had experienced at least one pregnancy complicated by preeclampsia, low birth weight, or preterm delivery. A secondary aim was to investigate how cardiovascular risk factors, including body composition as well as vascular, metabolic or inflammatory markers were related to parity, pregnancy complications, and maternal CVD risk.

Section snippets

Participants

This was a cross-sectional study nested within the Health, Aging and Body Composition (Health ABC) Study. The Health ABC study is a large ongoing epidemiologic study of how changes in body composition affect morbidity, disability, and mortality. A total of 3,075 community dwelling participants (50% female) were enrolled in Pittsburgh, Pennsylvania and Memphis, Tennessee in the period 1997–1998. Recruitment procedures have been described elsewhere in detail (16). All participants signed an

Results

Of the 540 women studied, 89 (16.5%) reported no births, and 321 parous women (59.4%) reported no history of pregnancy complications of interest in this study. A total of 130 parous women (24.1%) reported at least one pregnancy complicated by preeclampsia or hypertension (n = 32), term low birth weight (n = 68), preterm birth (n= 64), or stillbirth (n = 9). There were 35 women who reported two or more affected births.

Parous women with no perinatal complications were younger and, as expected,

Discussion

Our results indicate that almost one fourth of the older women in our study reported a previous experience of at least one pregnancy complicated by the conditions of interest. Parous women with no pregnancy complications were twice as likely to have CVD compared with nulliparous women, and those with at least one complicated pregnancy had rates of CVD almost three times higher. High rates of statin use, lower HDL, and pregnancy complications accounted for some, but not all, of this excess CVD

References (35)

  • R. Ness et al.

    Number of pregnancies and the subsequent risk of cardiovascular disease

    N Engl J Med

    (1993)
  • V. Beral

    Long-term effects of childbearing on health

    J Epidemiol Community Health

    (1985)
  • P. Hannaford et al.

    Cardiovascular sequelae of toxaemia of pregnancy

    Heart

    (1997)
  • G. Colditz et al.

    A prospective study of age at menarche, parity, age at first birth, and coronary heart disease in women

    Am J Epidemiol

    (1987)
  • J. Chambers et al.

    Association of maternal endothelial dysfunction with preeclampsia

    JAMA

    (2001)
  • C. Hubel et al.

    Dyslipoproteinaemia in postmenopausal women with a history of eclampsia

    Br J Obstet Gynaecol

    (2000)
  • G. Davey Smith et al.

    Birth dimensions of offspring, premature birth, and the mortality of mothers

    Lancet

    (2000)
  • Cited by (59)

    • Parity History and Later Life Sex Hormone Levels in the Multi-Ethnic Study of Atherosclerosis (MESA)

      2022, Canadian Journal of Cardiology
      Citation Excerpt :

      Parity and gravidity were assessed via self-report using a standardized questionnaire completed at the baseline examination. Parity and gravidity were categorized as 0 (reference), 1-2, 3-4, or ≥ 5 for our primary analyses, as has been done in previous studies.15,16,23,24 In a supplemental model, we also examined these exposures more linearly as 0, 1, 2, 3, 4, and ≥ 5.

    • Multiparity is associated with poorer cardiovascular health among women from the Multi-Ethnic Study of Atherosclerosis

      2019, American Journal of Obstetrics and Gynecology
      Citation Excerpt :

      According to prior studies,23 the validity of self-report for parity vs chart review is very high (kappa 0.93–0.98). As per prior studies,24,25 we categorized parity as 0, 1–2, 3–4, and ≥5, and 0 (nulliparity) was the reference category. Age, race/ethnicity, education, income, health insurance, marital status, MESA field site, menopause status, and current use of hormone therapy were the covariates included in this study.

    View all citing articles on Scopus
    View full text