There are probably very few protocols that have changed more over the years than the instructions we give our patients following embryo transfer. When IVF was first introduced, patients were actually hospitalized for a week with bedpan privileges only! This was supposed to give the embryos a chance to implant so they wouldn’t fall out! Some programs did embryo transfers in the knee-chest position for patients with anteverted uteri. Too many IVF programs, including some of the most prestigious ones, believed that the uterus is a cup and when you turn it upside down, the contents (embryos) fall out due to gravity. In truth, the uterine cavity is like a Jell-O mold, and the embryos like mini-marshmallows: no matter how you spin the Tupperware container, those marshmallows don’t budge. The uterus is that container. Otherwise, we wouldn’t let patients get up to empty their bladders as soon as the transfer is done.
It took a study some years ago to show that there was no difference in pregnancy rates between patients who had absolutely no restrictions on activity post transfer, compared to those who were told to use bed rest for 2-3 days afterwards. However, many patients are not comfortable with the idea of normal activity and put themselves at restriction because of the prior customs; to compromise, we suggest that they follow a “couch potato” prescription, while clarifying the fact that activity level will neither help nor hinder embryo implantation.
One restriction that does seem to be valid, is avoiding heat: bathing, especially hot baths, as well as saunas, hot yoga, heating pads, or anything that may raise the local temperature. There are studies from Scandinavia showing increases in neural tube defects in fetuses of pregnant women who use saunas.
Not doing anything too active also makes sense because of the post retrieval ovarian condition, where ovaries full of corpus luteum cysts are prone to torsion or rupture with high impact activity. Common sense dictates that low impact, mild exercise (slow walking, treadmill) is permitted, as long as the patient has no resulting discomfort, recognizes it is not harmful, and will not second-guess herself, if she does not conceive.
There is much recent data suggesting the uselessness of bed rest in pregnancy, and possible increased risk of thrombotic episodes. Given the high hormonal state in an IVF cycle (although less so for frozen transfer cycles), the same concerns should hold true.
So the bottom line is that virtually nothing the patient does post transfer will influence the outcome of the cycle, although taking a middle ground between bed rest and vigorous exercise to relieve worry and stress is warranted.