In vitro fertilization using frozen embryos may be associated with a 74 percent higher risk of hypertensive disorders in pregnancy, the American Heart Association reported Sept. 26.
Frozen embryo transfers were associated with twice as high risk of hypertensive disorders compared to natural conception. Pregnancies from fresh embryo transfer did not have higher risks compared to natural conception.
UK researchers followed nearly 2.4 million women between 1988 through 2015. The sibling study compared IVF pregnancy and naturally conceived pregnancy and is the largest sibling comparison study to date.