Pregnancies after IVF are considered high risk, as they increase the chances of pathological conditions such as gestational diabetes or hypertension.
Causes are older women and the presence of other aggravating factors. There is a 41% higher chance of preeclampsia or hypertension compared to other groups of pregnant women. This may be due to age of the mothers or poor placental development later on in pregnancy.
After IVF, there is a greater chance of multiple pregnancies, which are high-risk, with a higher rate of preterm birth and miscarriage in the first trimester.
This can be explained in many ways:
- In IVF, the pregnancy test is performed on specific days after the embryo transfer, without waiting for delay of the period.Consequently, in IVF cycles, biochemical pregnancies are more prevalent. Biochemical pregnancies are when the β-HCG initially rises, and after a few days, decreases. Menstruation begins but the endometrial pregnancy sac does not appear on the ultrasound. In natural conceptions, women do not have a pregnancy test the day they are expecting their menstrual cycle, therefore a biochemical pregnancy is nothing but a delayed menstrual cycle
- Miscarriages in IVF may also be associated with the original cause of infertility (ex: women with unexplained infertility have higher rate of thrombophilia)
- Many women have a history of miscarriage or endometrial death in previous pregnancies, which increases the chance of miscarriage in the following pregnancy
