In IVF applications, live pregnancy rates and take-home baby rates have been the issues that have occupied the minds and spirits of both hopeful couples and the treatment teams for more than 30 years since this method began to be used.
From the very first day IVF teams meet couples who wish to have children, they spend their lives considering countless options, thinking about which additional methods to apply and how to provide them with a healthy baby in their arms.
Thanks to recent developments, embryo freezing and thawing methods have become one of our most important opportunities to increase the probability of pregnancy. The rapid freezing and thawing method called vitrification has enabled us to achieve very successful pregnancy rates with embryo loss not exceeding 10–15% in laboratories that apply it properly.
The ability to freeze and thaw the embryos remaining after fresh embryo transfer with such high efficiency not only provides the opportunity for embryo transfer without the need for repeated, difficult, and costly treatments in case pregnancy is not achieved in the first transfer, but also offers pregnancy probabilities at least as high as, or even higher than, fresh embryo transfer. Thus, with a single ovarian stimulation treatment and egg retrieval procedure, together with fresh transfer, it becomes possible to perform at least two and sometimes three embryo transfers, achieving an overall pregnancy probability of 60–80%.
Additionally, thanks to this method, when problems such as insufficient development of the uterine lining (endometrium) during ovarian stimulation or excessive ovarian stimulation are encountered, fresh transfer can easily be canceled, and embryos can be frozen and later transferred into the uterus under more suitable conditions without decreasing, and even increasing, the probability of pregnancy.
Another problem where innovations in embryo freezing and thawing techniques create new options in IVF applications is decreased ovarian reserve. In such patients, due to the negative effects of drug treatments applied to achieve the maximum number of eggs on the uterine lining (endometrium), the chance of embryo implantation decreases. In this case, if fresh transfer is targeted, one faces a dilemma between softening stimulation treatments to obtain fewer eggs and embryos, or applying treatments to increase yield while compromising the quality of the endometrium. When vitrification (rapid freezing and thawing) is correctly applied to embryos, this problem can be easily eliminated. Treatments that allow us to obtain the highest number and quality of eggs and embryos can be applied without hesitation, embryos can be frozen and accumulated, and the uterine lining (endometrium) can later be prepared under ideal conditions for transfer, significantly increasing the chance of pregnancy.
If sufficient equipment and an experienced team are available in the IVF laboratory, the liberal use of these methods will open new horizons by significantly increasing pregnancy rates.
Op. Dr. Kaan Bozkurt / Obstetrics and Gynecology Specialist / İRENBE