Pregnancy
Pregnancy success rates are similar with day three or five embryo transfer

In IVF treatment, embryos are traditionally transferred in the uterus three days after fertilisation. Due to improvements in laboratory techniques, this is now also possible after five days. It was assumed that this increases the chance of a successful pregnancy. Now, a new study by Radboud university medical center and Amsterdam UMC shows that the day of transfer does not influence the success rate of the IVF trajectory.
One out of thirty children in the Netherlands is conceived via in vitro fertilisation, or IVF for short. In this procedure, egg cells are fertilised outside the body and grown in the laboratory for several days. One or more embryos are then transferred back in the uterus and the rest is frozen.
Traditionally, the laboratory phase lasts three days. Due to technical improvements, embryo transfer is now also possible after five days. The idea is that only viable embryos remain after five days, which increases the chance of a successful pregnancy. However, this leaves fewer embryos in the freezer.
Previous research has shown that the chance of success after the first transfer is indeed higher when this takes place on day five than on day three. But these studies did not evaluate the results of the entire IVF trajectory, including any subsequent transfer of frozen embryos.
The same number of pregnancies
The study was conducted in 21 Dutch IVF centres among more than 1,200 women. At least four embryos had to be available for transfer two days after fertilisation. In half of the women, embryos were transferred on day three, in the other half on day five. The outcome was the chance of a successful pregnancy during the entire IVF trajectory. This turned out to be the same in both groups, around sixty per cent.
Researcher Simone Cornelisse said: “Ultimately, IVF is about a successful pregnancy, and not only about the chances of success after the first transfer. Abroad, where IVF care is not insured, clinics often advertise their success rates from the first transfer on day five.
“In doing so, they provide an incomplete representation of the situation. Our study shows that women should have a choice about the moment of transfer.”
Personal decision
Other results from the study may influence that choice. As in previous research, there was a higher chance of a successful pregnancy after the first transfer on day five. There were also fewer miscarriages in that group.
On the other hand, if the embryos were transferred on day three, more could be frozen for later use and the risk of premature birth was somewhat lower. Both choices have advantages and disadvantages, but do not make any difference to the overall success rate.
“It is a very personal decision,” says clinical embryologist Liliana Ramos, one of the study leaders.
“For some people, getting pregnant as quickly as possible is very important, for example if the woman is older. Someone else attaches more value to a larger number of frozen embryos or wants to keep the chance of premature birth as small as possible. There is no guideline regarding the day of transfer. Therefore, a couple who want to become pregnant must discuss it with the doctor and make a choice together.”
Entrepreneur1 week agoFuture Fertility raises Series A financing to scale AI tools redefining fertility care worldwide
Entrepreneur4 weeks agoThree sessions that show exactly where women’s health is heading in 2026
News4 weeks agoTwo weeks left to make your mark in women’s cardiovascular health
Fertility2 weeks agoFuture Fertility partners with Japan’s leading IVF provider, Kato Ladies Clinic
Menopause2 weeks agoMore research needed to understand link between brain fog and menopause, expert says
Mental health1 week agoLifting weights shows mental health and cognitive benefits in older women, study finds
Insight3 weeks agoSelf-employment linked to better cardiovascular health outcomes in Hispanic women
Entrepreneur3 weeks agoFlora Fertility closes US$5m seed round
















