One of the methods of infertility treatment - in vitro fertilization (IVF) - is a procedure for combining an egg with a sperm in a laboratory (in natural conditions, the process of conception takes place inside the female body). An egg is considered fertilized when a sperm cell has penetrated it. During IVF, fertilized eggs are monitored for 3 to 6 days, during which they divide and turn into embryos.
The best embryos are then placed in the woman's uterus for pregnancy (embryo transfer), or they can be frozen for future use. While the embryo is developing, it is surrounded by cells, which are a protective (zona) membrane. In the natural environment, as the embryo grows, it breaks this layer. But sometimes this does not happen, which is an obstacle to the onset of pregnancy.
In such cases, just before placing the embryo in a woman's body, laboratory staff make a small "incision" in its outer layer. This procedure is called assisted hatching. With its help, it will be easier for the embryo to penetrate the wall of the uterus, which will ultimately lead to the desired pregnancy.
How is assisted hatching done?
During the assisted hatching procedure, the outer layer of the embryo is artificially weakened by making a small hole in the vitelline layer (zona). This can be done in a variety of ways. One method involves applying a certain consistency of acid, called Tyrode's solution, to form a small hole in the tissue. Another method involves using laser technology to create a "crack" (window) in the layer.
Can Assisted Hatching Cause Problems With My Fetus During Pregnancy?
In rare cases, assisted hatching can destroy the embryo, rendering it unusable. More often, chemical hatching can pose a threat to the embryo; using a laser in skilled hands is safe.
Medications such as antibiotics and steroid hormones are sometimes prescribed to minimize risks up to the day before the hatching and embryo transfer procedure. Side effects from the use of these drugs are extremely rare.
It is worth remembering that the risk for identical twins when using assisted hatching may be slightly higher than the standard. However, this is, among other things, due to the fact that medical complications during pregnancy with identical twins increase in comparison with a conventional singleton pregnancy.
Will I benefit from assisted hatching?
Experts do not recommend using assisted hatching for all patients undergoing IVF treatment. Research suggests that assisted hatching can help increase the chances of pregnancy for women who failed to conceive in a previous IVF cycle and those women who were poorly predicted to become pregnant. There is also evidence of a positive effect of hatching on conception using previously frozen embryos.
However, only a doctor can help you assess the benefits and risks of assisted hatching in your case.
Are there any other reasons why an assisted hatching procedure should be performed?
With planned preimplantation diagnosis (PGD) - a modern method of detecting chromosomal and gene abnormalities in an embryo before transferring it to the uterine cavity - assisted hatching can simplify biopsy for analysis. This procedure is performed on the recommendation of a doctor or at the request of patients within the IVF cycle.
During PGD, about the fifth day after fertilization (blastocoel stage), a small amount of tissue is taken from the outer layer of the embryo (trophectoderm).
Thanks to the use of PGD, it became possible to exclude the risk of giving birth to a child with various genetic pathologies.
