Are Egg Donation Pregnancies at Higher Risk of Pre-eclampsia?
There is an increase year on year in the number of patients attending fertility clinics. There have been social factors such as delayed age for having the first child. In some, it will mean that they may have to seek fertility treatment not to start, but to complete their family. In fact, there has been an increase in the number of IVF cycles worldwide using egg donors.
The European Society of Human reproduction and Embryology or ESHRE reports that the number of egg donation IVF cycles have almost doubled in Europe between 2007 and 2011. Specialists discover that women using donor eggs for IVF treatment are at higher risk of pre-eclampsia. Many believed that this increase is due to the later age of pregnancy rather than having treatment using donor eggs. But, a recently French team conducted and reported an interesting study.
In this study, they collected data from over five hundred women. They divided them into two groups. One had IVF treatment using donor eggs and the control group had IVF treatment using their own eggs. They also ensured that women in both the groups were of similar average age. By doing so, they removed the age-related effect on the occurrence of blood pressure disorders in pregnancy.
It was observed that women having IVF treatment using donor eggs are subjected to a higher risk. In fact, pre-eclampsia or blood pressure problems in pregnancy occurred three times more often. Pre-eclampsia was more common and also of more severe variety compared to women having IVF treatment with their own eggs.
Scientists had noted that the risk of pre-eclampsia was higher in a woman’s first pregnancy. This risk dropped in further pregnancies with the same partner. Otherwise, if women had further pregnancies with a new partner, the chances of having pre-eclampsia are higher.
So, this led to the thinking that this risk is because of the woman’s exposure to her male partner’s proteins (antigens). Repeated exposure to his proteins meant that the woman develops immunity to his proteins. It is well known that pre-eclampsia results from a poorly developed placenta. Development of a healthy placenta requires mother’s tolerance to the partner’s proteins.
There is no direct contact between the mother’s and fetus’s blood circulation. A well developed healthy placenta could be responsible for helping fetus to evade the immune system.
A woman’s ability to develop immune tolerance is the most intriguing and unresolved question. A successful implantation of the embryo results from its ability to evade the mother’s immune system. But, it is still not understood how an embryo can evade the mother’s immune system. There are also doubts about how pregnant woman develop immune tolerance.
If pregnancy occurs after an IVF treatment using egg donor, the mother’s immune system is exposed to many different proteins. This triggers some form of an immune intolerance that affects the development of placenta or afterbirth. This then results in pre-eclampsia.
So, if women are having IVF treatment using donated eggs at a later age, then they may be at even higher risk of pre-eclampsia and related disorders. Whilst it is unlikely that women would decide against having treatment. But at least informing them of the risk will help in detecting early signs of pre-eclampsia.