Embryo develops from the fertilization of the female egg cell by the male sperm cell. In ICSI (Intra cytoplasmic sperm injection) these embryos can be either;
- Transferred into the uterus of the female in same ovulation cycle from which her eggs were retrieved, this is recognized as stimulated Cycle Embryo Transfer.
2. They can be frozen to transfer during her later cycles and this is called Delayed Embryo Transfer.
Delayed Embryo Transfer:
During the natural menstrual or non-stimulated cycle, there is a rise in levels of estrogen just before ovulation. This rise in estrogen level triggers ovulation and in response to ovulation ovaries start to produce progesterone. Later the Progesterone prompts development of the endometrial lining at the accurate level to promote the implantation of the fertilized egg for successful pregnancy and growth of fetus. This harmonization creates the superlative atmosphere for conception.
During ICSI treatment the ovaries are stimulated by administration of medications, resulting in increased levels of estrogen as compared to natural cycles. This falsely-induces rise in estrogen which in turn provokes premature progesterone production in some cases. If progesterone levels upsurge too early, it results in quick development of the endometrial lining which is detrimental to successful embryo implantation.
Beforehand, Delayed Embryo Transfer was not a worthwhile choice since the freezing process resulted in less sustainable embryos with high rates of embryo injury. With the technical advances in the Vitrification (a flash-freezing technique) and cryopreservation (freezing and storing) process, success rates for frozen embryo survival are currently equivalent to fresh embryos transfer or in some instances delayed implantation has a higher success rate and increases the chance of a successful pregnancy and birth as it provides embryos with natural womb environment.
At Australian Concept Infertility Medical Center, during ovarian stimulation we monitor carefully your estrogen and progesterone levels. In case, if level of estrogen or progesterone becomes too high during your treatment, we will notify and recommend you for the cryopreservation (Vitrification) of all your embryos with the intent of maximizing your chances of success. The actual Embryo Transfer then takes places during a natural cycle as part of our Delayed Embryo Transfer program.
Besides this we also monitor your endometrial lining thickness. Possibility of embryo implantation decreases in case of too thin endometrial lining, in such cases your embryos will be cryopreserved, and these Frozen Embryos will then be subsequently transferred.
The Advantages of Frozen Embryos:
- In case your fresh transfer is unsuccessful, frozen embryos provides additional cycle opportunities for success from a given egg retrieval.
- Subsequent FET cycles are less costly for patients. Expenses of both medication and treatment are less than in a fresh cycle.
- An FET cycle is easier for patients.
- Negative consequences of elevated progesterone levels on pregnancy overcomes by Freezing all embryos for future FET(s).
- Risk of ovarian hyper stimulation syndrome (OHSS rarely occurs in less than 1 percent of patients) during delayed embryo transfer while maintaining excellent success rates.
- Genetic testing can also be done for frozen embryos. This is called pre-implantation genetic diagnosis (PGD). Once the physician retrieves the eggs, after their fertilization the embryologists will biopsy each suitable embryo on day 5 or 6 of development.
- Vitrified embryos maintain reproductive potential to grow your family in the future.