Undergoing in vitro fertilization using frozen embryos is linked to a greater risk of hypertensive disorders, including preeclampsia, during pregnancy, according to research published Monday in the journal Hypertension.
Overall, the risk of hypertensive disorders was low: about 7.4% in women who used frozen embryos, compared with 5.6% in women who used fresh embryos and 4.3% for women who conceived naturally.
In addition, they found, there was no significant difference in risk between the women who conceived naturally and those who did IVF using fresh embryos.
The group included 4.4 million naturally conceived pregnancies and compared them to just over 78,000 IVF pregnancies conceived using a fresh embryo and about 18,000 using a frozen embryo.
Petersen emphasized that the overall risk for preeclampsia was still low and that the results of the new study should not scare women away from using frozen embryos.