There are 2 different types of hyperstimulation. One is the hyperstimulation that happens early on, after the oocyte retrieval, which is usually limited to a couple of days. And when you are monitoring the cycle closely, and you are aware of the risk, and you sort of introduce the maturation with the GnRH agonist, then those patients will just have some discomfort for a couple of days, and that’s going to be all.
The late hyperstimulation syndrome happens during pregnancy, so if you do have patients entering the hyperstimulation, and you do transfer the embryos and those patients get pregnant, this is something that you cannot control. And those are the patients that end up in hospital.
Generally, I would say that we see fewer and fewer patients because nowadays, in the lab — I think that all the IVF labs are quite familiar with freezing — so this is something that has changed over the years, especially with the introduction of vitrification of the embryos. If you have similar rates of fresh or frozen embryo transfers, you don’t want to put your patients at risk of overstimulation. We are more cautious, and we are taking preventive measures.
