Pregnancy increases risk of aortic dissection
There are several reports mentioning that pregnancy increases risk of aortic dissection, especially in those predisposed due to aortic disease. A recent study published in Circulation  by Kamel H and associates noted 5.5 cases of aortic complications per million patients during pregnancy and post partum period. The corresponding rate 1 year later was 1.4 per million. They had analysed the data from three US regions covering over six and a half million pregnancies in about 5 million women during the period from 2005 to 2013. The pregnancy related risk period was considered as 6 months before delivery to 3 months after delivery. An equivalent 270 day period 1 year later was used for comparison in this cohort-crossover study using data on emergency department visits and acute care hospitalizations. The study included women 12 years or older with labour, delivery or abortion.
Even though the study documents an almost four fold increased risk of aortic complications in pregnancy, the absolute numbers are comfortingly not very high. The rate of aortic complications during pregnancy and post partum was only 5.5 per million compared to 1.4 million during a period one year later. The increased risk in pregnancy is thought to be due to effects of hormones like relaxin on the connective tissue and the increased central aortic pressure during the strain of parturition.
- Kamel H, Roman MJ, Pitcher A, Devereux RB. Pregnancy and the Risk of Aortic Dissection or Rupture: A Cohort-Crossover Analysis. Circulation. 2016 Aug 16;134(7):527-533.