Women who suffer any of the major pregnancy complications—including preterm birth or pre-eclampsia, have an elevated chance of developing ischemic heart disease, even after 46 years of giving birth, a Sweden study has found.
The study published in The British Medical Journal (BMJ) was to investigate the links between a mother’s long-term risk of developing ischemic heart disease and five significant unfavourable pregnancy outcomes.
Ischemic heart disease is a serious condition where the blood vessels supplying the heart are narrowed or blocked and is the leading cause of death among women worldwide.
The researchers located 2,195,266 Swedish women who gave birth to a single live child between 1973 and 2015, with an average age of 27 and no history of heart disease. Then, from the moment of delivery until December 2018, they followed ischemic heart disease patients using national medical records (average follow-up time 25 years, up to a maximum of 46 years).
Preterm delivery (less than 37 weeks gestation), small for gestational age at birth, pre-eclampsia, other perinatal blood pressure abnormalities, and gestational diabetes were the five main unfavorable pregnancy outcomes of interest.
Overall, 83,881 (3.8%) women with an average age of 58 years were diagnosed with ischemic heart disease. The findings indicate a higher chance of developing ischemic heart disease in women who suffered any of five significant negative pregnancy outcomes.
Women who had many unfavourable pregnancy outcomes had higher risks overall. In the ten years following delivery, rates of ischemic heart disease with one, two, or three negative pregnancy outcomes increased by 1.3, 1.8, and 2.3 times, respectively (20, 34, and 58 instances per 100,000 person years).
Even 30-46 years after delivery, the majority of relative rates continued to be considerably elevated (1.1- to 1.5-fold) and were only partially explained by shared genetic or environmental variables within families.
The researchers cannot rule out the possibility that ischemic heart disease was underreported or that unreported maternal smoking, obesity, or other risk factors during pregnancy may have had an impact on their findings because this is an observational study, which makes it impossible to determine cause.
However, the large sample size based on highly complete nationwide birth and medical registry data and long-term follow up prompt the researchers to say that all major adverse pregnancy outcomes should be recognized as lifelong risk factors for ischemic heart disease.
“Women with adverse pregnancy outcomes should be considered for early preventive evaluation and long term risk reduction to help prevent the development of ischemic heart disease,” they concluded.