By Neus Ferrando Gilabert BSc, MSc (embryologist).
Last Update: 11/05/2015

Many women choose to delay motherhood due to personal, family or work reasons. However, it could be the case that, in the future, she experiences trouble conceiving. It should be taken into account that, from age 35, chances of naturally having a child decrease, since oocyte quality diminishes over time.

Nonetheless, thanks to egg freezing and vitrification, cryopreserving the eggs at a young age is possible. Eggs are frozen in an ultra-fast way using a cryoprotectant to avoid any damage to the eggs. Egg freezing is therefore seen as a way of preserving the fertility of those women who are not planning to have children for the time being.

This assisted reproductive technology (ART) allows the woman not to become a slave of her own age or her own family, occupational, or financial situation. Given that the risk of aging disappears, frozen eggs can be used whenever the woman wishes as long as she is still of childbearing age.


The first step when a woman decides to freeze her eggs is performing a hormone analysis in which the ovarian reserve is evaluated. A transvaginal ultrasound is also necessary to verify there are no unexpected alterations. Once these tests are done and the results show everything is working as it should, ovarian stimulation is scheduled.

To stimulate the ovaries, gonadotropins are administered. The purpose of this medication is triggering the production or more than a single egg. Ovarian stimulation may last longer than expected or the other way round, since it depends on each woman’s response to it. The ovaries will be monitored throughout the process to check follicle growth after the trigger. When the majority of the follicles have reached a 16-18 mm size, then follicular puncture will be carried out for egg retrieval.

Follicular puncture stands for a simple procedure in which an ultrasound-guided needle is inserted through the uterine wall for oocyte retrieval. During the whole process, which lasts about 15 minutes, the women is under sedation or anesthesia. Thus, the process is not painful.

Once the eggs are retrieved in the operating room, they are brought to the IVF laboratory, where specialists in Embryology will proceed with the vitrification process.

It is not until the layer of cells covering the egg is removed that the rate of oocyte maturation can be analyzed, since eggs should be cryopreserved at metaphase II. After vitrifying them, they will be stored in nitrogen at minus 196°C until they are required by the patient.

If you are considering freezing your oocytes to have a baby in the future, we recommend that you use "The Calculator". In 3 simple steps, it will show you a list of clinics that fit your preferences and meet our strict quality criteria. Moreover, you will receive a report via email with useful tips to visit a fertility clinic for the first time.

Treatment with frozen eggs

When the woman wants to use the cryopreserved eggs, the beginning of the treatment will be scheduled. The ocytes will be thawed and then microinjected through the ICSI technique either using the partner’s own sperm or donor sperm.

Then, the embryos will be cultured. Only the highest quality embryos will be transferred to the patient, who will have undergone prior preparation of the endometrium. A clinical hCG test will be done two weeks later (2WW) to check whether she is pregnant or not.


It is known that women’s ovarian reserve decreases exponentially with age. Over the years, follicular reserve and oocyte quality diminish; therefore, women who delay motherhood have to resort to donor eggs.

Freezing the own oocytes has many advantages, mainly because this way the oocytes do not age. Thus, chances of getting pregnant will be high no matter the age of the woman, since the oocytes used are those she produced at a younger age, which quality is better than that of those produced at an older age.

This technique is not only indicated in cases of women who wish to delay motherhood but also among women who are about to start some kind of aggressive treatment such as chemotherapy. In these cases, they can preserve their fertility to have a baby once they have overcome this disease.

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Authors and contributors

 Neus Ferrando Gilabert
BSc, MSc
Bachelor's Degree in Biology from the University of Valencia (UV). Postgraduate Course in Biotechnology of Human Assisted Reproduction from the Miguel Hernández University of Elche (UMH). Experience managing Embryology and Andrology Labs at Centro Médico Manzanera (Logroño, Spain). More information
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One comment

    1. Marlene

      Hello there! I’m starting my hormone injections on Nov 26th and I’m hoping my egg retrieval will be due to early December, what do you think? Is anybody else going through it again? I’m 29 and I’m planning to be a mother at age 35 or later, that’s why I’ve decided to do this.