Answer from: Raúl Olivares, MD
Theoretically, it is possible but very unlikely. The main reason is when patients are undergoing IVF, we usually recommend not to have sex during the process. Not because that could be a problem because obviously in natural circumstances if you don’t have sex, you cannot get pregnant. Sex itself is not an issue, but when the ovaries are stimulated, and we have done the egg collection, they tend to be tender, there is a risk of bleeding, and then we recommend avoiding sex until the day of the pregnancy test.
However, there have been natural pregnancies described, for example, in cryotransfer cases in which the natural cycle has been used. That means that we just check how the follicle grows, and on the day the follicle reaches 17-18 millimetres, we trigger the ovulation. Then, 5 days after that ovulation, we schedule the frozen embryo transfer, and the patients can have had sex in this cycle because it is not contraindicated. There is no hyperstimulation of the ovaries, and then despite transferring 1 embryo, there have been twins on the scan. That means that very likely the patients have got pregnant at the same time by the embryo that we have transferred and by the egg that the woman has ovulated. We know that because later has been confirmed that they were non-identical twins. Sometimes, we transfer an embryo, and the embryo can split into 2, but in these cases, they were babies of different gender, so a boy and a girl, so that means that they come from different eggs and if only transfer 1 embryo, that’s not possible.
Because of the short cycles that we use in IVF, it is not so common to happen as when we were working with long protocols. In long protocols, it sometimes happened that we started with a down-regulation before the patient even had the period, and in some cases, the patients didn’t have the period, and that was because they got pregnant. It wasn’t risky, there weren’t any problems with the pregnancy. Nowadays, most of the cycles are started on day 1 of your period, which means that if for any reason you get pregnant in the previous cycle of the IVF, you are not going to have a period, you are not going to start.
It is very unlikely to get pregnant naturally during the IVF cycle, it is not impossible and only in some specific cases like transfers within natural cycles.
Is there a possibility of getting pregnant during an IVF cycle naturally?
Conceiving naturally while proceeding with IVF treatment can occur. It is very uncommon, however, it is still possible. How is it possible to conceive naturally while undergoing IVF treatment? Can I have sex during fertility treatment?