Fertilización in vitro

The first step is ovarian stimulation, where hormonal medications prompt the ovaries to produce multiple eggs instead of just one. This enhances the efficiency of egg harvesting and increases the likelihood of successful fertilization and embryo development during the IVF cycle.

During oocyte retrieval, a physician uses transvaginal ultrasound to visualize the ovaries. A needle guide assists in accurately inserting a thin needle through the vaginal wall into each ovarian follicle to retrieve the mature oocytes and follicular fluid, typically performed under sedation or anesthesia.

In conventional IVF, approximately 50,000 to 100,000 sperm are incubated with an oocyte for 12-18 hours for natural fertilization. Intracytoplasmic sperm injection (ICSI) involves injecting a single healthy sperm directly into the oocyte cytoplasm, improving fertilization rates in cases of male infertility or poor sperm quality.

Embryos can be transferred at the cleavage stage, typically 3 days after fertilization, or at the blastocyst stage, approximately 5 days post-fertilization. Blastocyst transfers are often preferred because they result in higher implantation rates and better embryo development and viability.

During embryo transfer, a thin catheter is inserted through the cervix into the uterus under transabdominal ultrasound guidance. The selected embryos are gently placed within 1 to 2 centimeters of the uterine fundus, the upper part of the uterus, in a sterile environment.

Ovarian stimulation uses hormonal medications to produce multiple mature eggs rather than the single egg released during a natural cycle. This increases the number of available oocytes for fertilization and improves the chances of obtaining viable embryos for transfer and successful pregnancy.

Following embryo transfer, patients typically wait approximately two weeks before undergoing a pregnancy test to determine if implantation has occurred and if pregnancy has been established. This test confirms whether the transferred embryos have successfully implanted in the uterine lining.