- Five adverse pregnancy outcomes were independently associated with increased peripheral artery disease (PAD) risk later on.
- These associations remained in co-sibling analyses, suggesting that familial factors are not to blame.
- Women with adverse pregnancy outcomes should have lifelong clinical follow up.
Five major pregnancy complications were independently associated with heightened long-term risk of peripheral artery disease (PAD), a Swedish cohort study of more than 2 million deliveries found.
At 30 to 46 years after delivery, relative rates of PAD were elevated 3.8-fold among women with gestational diabetes, 1.7-fold among those with small for gestational age, 1.6-fold among those with preterm delivery, 1.6-fold among those with other hypertensive disorders of pregnancy, and 1.3-fold among those with preeclampsia, reported Casey Crump, MD, PhD, MPH, of the University of Texas Health Science Center in Houston, and colleagues.
Within 10 years of delivery, the relative rate of PAD was only elevated among women with preterm delivery (2.0-fold), gestational diabetes (1.8-fold), or small for gestational age (1.5-fold), they reported in PLOS Medicine.
Women with multiple adverse pregnancy outcomes had more increased risk.
“Despite being clinically distinct outcomes, each was independently linked with higher long-term risk of PAD, suggesting shared underlying vascular pathways,” Crump told MedPage Today. “The fact that this risk was detectable up to 46 years after delivery is also important — it suggests that pregnancy complications can serve as an early marker of vascular risk decades before PAD would often be considered or screened for.”
Co-sibling analyses indicated that these findings were largely unexplained by genetic or environmental factors that may be shared determinants of adverse pregnancy outcomes and PAD within families. Across the entire follow-up, the adjusted HRs for PAD (95% CI for all) were:
- Preterm delivery: 1.73 in the primary analysis vs 1.62 in the co-sibling analysis
- Small for gestational age: 1.72 vs 1.56
- Preeclampsia: 1.39 vs 1.32
- Other hypertensive disorders of pregnancy: 1.31 vs 1.06
- Gestational diabetes: 2.87 vs 2.97
“All major adverse pregnancy outcomes should now be recognized as long-term risk factors for PAD,” the authors concluded.
“Women with a history of adverse pregnancy outcomes need lifelong clinical follow-up for continued prevention, timely detection, and treatment of PAD and other cardiovascular diseases,” Crump added.
It’s already known that women with pregnancy complications have higher risk of subsequent heart disease; however, the long-term impacts on PAD risk remain less understood. For instance, some studies have suggested that preeclampsia and hypertensive disorders of pregnancy increase risk of PAD in mid-adulthood while others haven’t found that association.
So researchers set out to determine the long-term risks of PAD in women who had pregnancy complications, with the ultimate goal of identifying “high-risk women early, so we can intervene sooner to protect their long-term health,” Crump said.
They used data from the Swedish Medical Birth Register to identify 2,201,446 women who had a singleton delivery from 1973 to 2015. Women with a prior PAD diagnosis were excluded. PAD was identified with ICD codes in the Swedish Hospital Register and primary care records. Over 54 million person-years of follow-up, 13,211 (0.6%) women were diagnosed with PAD.
They looked at five major adverse pregnancy outcomes: preterm delivery (gestational age <37 weeks); small for gestational weight (infant birth weight <10th percentile); preeclampsia with or without further complications like eclampsia; other hypertensive disorders of pregnancy; and gestational diabetes. All were identified with diagnostic codes.
Women were followed up to 46 years and median follow-up time among those who survived was 27 years. In all, 30.4% of women experienced at least one adverse pregnancy outcome. Median age at first delivery was 27 and median age at PAD diagnosis was 62. Authors noted that this cohort was relatively young and that it’s possible the “risks of PAD following adverse pregnancy outcomes may be even higher as women reach older ages when PAD is more likely to manifest.”
Crump and team noted some limitations, including not being able to validate PAD diagnoses with detailed clinical records, that data on some covariates were only available during prenatal care, and that outpatient diagnoses weren’t available until 2001, meaning that PAD may have been underreported in years prior. Lastly, the cohort was Swedish and findings may not apply to other more diverse settings.
