Evaluating birth rate after multiple cycles of freeze-all IVF

This study looked at the overall birth rate using multiple in vitro fertilization (IVF) cycles and freezing all embryos. It found that when using multiple cycles, the birth rate varied widely depending on the woman’s age and cause of infertility.

In vitro fertilization (IVF) is an infertility technique in which the ovaries are stimulated to produce multiple oocytes (eggs), and the oocytes are collected and fertilized. After fertilization, the embryos can either be transferred while they are fresh or frozen to transfer in a future menstrual cycle. Freezing embryos allows fewer embryos to be transferred per cycle, avoiding the health risks of twins or triplets. Freezing all of the embryos also reduces the risk of ovarian hyperstimulation syndrome (OHSS), a potentially serious condition in which the ovaries respond too strongly to the fertility medications.

The first round of IVF is typically the most likely to be successful. However, it is not clear what the cumulative birth rate is from multiple rounds of freeze-all IVF. 

This study included records of 20,687 women who used freeze-all IVF. 43.30% of the patients were younger than age 31, and 6.16% were age 40 or older. The most common causes of infertility were an issue with the Fallopian tubes (67.97%) and male infertility (31.80%). There were also patients who did not ovulate regularly (12.12%) or who had endometriosis (9.78%).

Based on the data, the researchers created two statistical models to predict the chances of birth after each complete cycle. For a woman less than 31 years, the cumulative birth rate after five cycles would be between 77.11% and 91.82%. For a woman aged 35 to 37, the birth rate after five cycles was estimated between 53.94% and 80.01%. For a woman age 38 to 40, it was estimated between 33.15% and 55.93%, while for those over 40 years, it was estimated between 8.71% and 14.71%.

The chances of birth from each single IVF cycle decreased over the course of multiple cycles. However, the total cumulative birth rate increased.

This study found that up to five freeze-all IVF cycles can continue to increase the cumulative birth rate.

These statistical models predict birth rates for couples who are similar to the couples in the study. It may be less accurate for patients whose background or health history is uncommon.