Association between interpregnancy interval and future risk of maternal cardiovascular disease-a population-based record linkage study.
OBJECTIVE
To examine the associations between interpregnancy interval and later maternal cardiovascular disease (CVD) risk.


METHODS
Population-based record linkage study.


METHODS
New South Wales, Australia, 1994-2011.


METHODS
216 467 women having first and second liveborn singleton infants, excluding those with an existing or pregnancy-related CVD risk factor.


METHODS
We linked birth records of mothers to the mothers' subsequent CVD (coronary heart disease, cerebrovascular events, and chronic heart failure) hospitalisation or death. Multivariable Cox proportional hazard regression was used to estimate adjusted hazard ratios (AHR) [95% confidence interval (CI)], accounting for maternal age, parity, socioeconomic status, and smoking during pregnancy.


METHODS
The first occurrence of a CVD hospitalisation or death after the second birth.


RESULTS
In comparison with mothers with an interpregnancy interval of 18-23 months (reference category), the AHR among mothers with interpregnancy interval of <12 months was 1.56 (95% CI 1.18-2.07) and of 12-17 months was 1.13 (95% CI 0.84-1.51). The AHRs were 1.40 (95% CI 1.07-1.82), 1.87 (95% CI 1.21-2.89), and 3.41 (95% CI 1.07-10.91), corresponding to interpregnancy intervals of 24-59, 60-119, and ≥120 months, respectively. AHRs of specific CVD categories showed a similar pattern.


CONCLUSIONS
Interpregnancy interval is associated with the risk of subsequent maternal CVD in a J-shaped fashion. The association is independent of the existing and pregnancy-related CVD risk factors analysed. Both short and long interpregnancy intervals can be used as risk markers to identify women with an elevated CVD risk later in life.


CONCLUSIONS
Interpregnancy interval is associated with the risk of subsequent maternal cardiovascular disease in a J-shaped fashion.
Clinical and Population Perinatal Health Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, Australia.|Sydney Medical School Northern, University of Sydney, Sydney, NSW, Australia.
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Clinical and Population Perinatal Health Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, Australia.|Sydney Medical School Northern, University of Sydney, Sydney, NSW, Australia.
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Sydney Medical School Northern, University of Sydney, Sydney, NSW, Australia.|Department of Cardiology, Royal North Shore Hospital, St Leonards, NSW, Australia.
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D000293:Adolescent; D000328:Adult; D001721:Birth Intervals / Q000706:statistics & numerical data*; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000401:mortality; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D016247:Information Storage and Retrieval; D008423:Maternal Age; D015999:Multivariate Analysis; D009517:New South Wales / Q000453:epidemiology; D010298:Parity; D011247:Pregnancy; D016016:Proportional Hazards Models; D012907:Smoking / Q000453:epidemiology; D012923:Social Class; D055815:Young Adult
Birth spacing; cardiovascular disease; hospitalisation; interpregnancy interval; record linkage; survival analysis