Relationship between recurrent miscarriage and early preterm delivery and recurrent events in patients with manifest vascular disease: The SMART study

Background Women with a complication of pregnancy are at increased risk of cardiovascular morbidity and mortality later in life. Yet, information on risk of recurrent events in women with a previous cardiovascular event is lacking. We aimed to assess the relationship between early preterm delivery, (recurrent) miscarriage and the risk for recurrent cardiovascular events in women with manifest vascular disease. Methods We included 1014 women with a mean age of 60 years from the SMART study, a prospective ongoing cohort study among subjects with clinically manifest vascular disease. The included women had a history of 1 pregnancy and were followed for the occurrence of subsequent vascular events. The relationship between the pregnancy complications ((miscarriage (gestational age <14 weeks), recurrent miscarriage (3 miscarriages) and early preterm delivery (gestational age 14-32 weeks)) and cardiovascular morbidity and mortality were estimated using multivariable adjusted hazard ratios. Results During a mean follow-up of 5.0 years, 80 women had a recurrent cardiovascular event, of which 28 were fatal. A history of recurrent miscarriage was associated with an increased risk for a recurrent cardiovascular event (hazard ratio 4.3 95% confidence interval 1.7--10.9). In addition, early preterm delivery was related to a 4.1 (95% confidence interval 1.5-11.3) fold increased risk of cardiovascular death in women with previous cardiovascular disease. No statistically significant relationships were found for less than three miscarriages. Conclusions In women with previous cardiovascular disease, an obstetric history of recurrent miscarriage is associated with an increased risk of recurrent cardiovascular morbidity and early preterm delivery with cardiovascular mortality.