Most Women Do Not Use Their Frozen Eggs

Nearly half of women who chose to freeze their eggs in their 30s were able to have babies later in life when they returned to the fertility clinic, a new study finds.

However, many women who had frozen their eggs had not returned to the fertility clinic or chose fertility treatments that involved their frozen eggs, according to non-peer-reviewed research presented at the 39th annual meeting of the European Society of Human Reproduction and Embryology (ESHRE).

The study included 843 women who underwent elective oocyte cryopreservation (egg freezing) for non-medical reasons between 2009 and 2019. They were 36 years old on average, and most of them did not have partners.

By May 2022, 231 (27%) women had returned to the fertility center for treatment. The average age was 40, and the majority had partners upon their return. Of those, 48% used their frozen eggs as part of their fertility treatment.

Another 50 women (22%) had intrauterine insemination, which refers to sperm delivery directly into the womb, while 71 (31%) had fertility treatments such as in vitro fertilization (IVF) using fresh eggs. On average, women who used frozen eggs were 42 years old, while those whose treatment involved fresh eggs were 39.

Of all 231 women who returned to the fertility clinic, 46% gave birth to a live baby. The miscarriage rate was 31%, compared to the overall miscarriage rate of 10% to 20%

Women who had treatment with fresh eggs were more likely to have a baby compared to those who used their frozen eggs, 48% and 41%, respectively. However, the miscarriage rates were lower in women who used frozen eggs (22%) than in those using fresh eggs (29%).

The researchers say the choice of whether to use fresh or frozen eggs is made based on what treatment is best for each individual woman, and age is an essential factor to consider. In the study, women who used frozen eggs were generally older.

'We cannot really compare the two groups as there will be many differences that could underlie any disparity in pregnancy and birth rates. However, women who had frozen their eggs had several options open to them, and we found positive rates of pregnancy and birth regardless of whether the women had fertility treatment with fresh or frozen eggs," says Ezgi Darici, a clinical fellow at the Centre for Reproductive Medicine at Universitair Ziekenhuis Brussel (Belgium).

The study has limitations, such as a relatively small number of participants. Moreover, it is a retrospective study, meaning it assesses events that have happened in the past.

Elective oocyte cryopreservation involves controlled ovarian stimulation with injection medication and ultrasound-guided egg retrieval. The retrieved eggs are then stored in the fertility clinic. The procedure is expensive, as total costs range from $9000 to $17,000 per cycle with an additional $300 to $500 annual storage fee.

However, freezing eggs does not guarantee future live birth. Research suggests that women under 35 with normal ovarian reserve have the highest chance of giving birth using frozen eggs.

An earlier study of 645 women who chose elective oocyte cryopreservation found that only 54 (8.4%) used their frozen eggs during the 18 years period. Among women who did, 17 (31.5%) achieved at least one live birth. The birth rates were the highest among women aged 35 and younger (63.6%), compared to those 36–39 years (42.3%) and women 40 years and older (17.6%).

The new study suggests that egg freezing may help older women to get pregnant, but more evidence is needed to determine how useful elective oocyte cryopreservation is.