Overview
A frozen embryo transfer (FET) cycle involves thawing embryos previously frozen from a fresh IVF cycle and transferring them into a woman’s uterus, eliminating the need for another round of hormone stimulation and egg retrieval.
Why It's Done:
Embryo freezing offers flexibility for couples who aren’t ready for pregnancy immediately but plan to conceive later. It’s also employed to prevent ovarian hyperstimulation syndrome (OHSS) in cases of high hormone production during ovarian stimulation. Additionally, excess embryos from IVF cycles may be frozen to mitigate the risks associated with multiple pregnancies. Pre-implantation genetic screening may be recommended for couples with hereditary genetic diseases to ensure the transfer of healthy embryos. Moreover, fertility preservation through embryo freezing is an option for women undergoing cancer treatments that could compromise fertility.
How do You prepare?
Consulting a reproductive endocrinologist specializing in the field is the initial step. Both partners typically undergo various screenings before commencing an IVF cycle. For women, tests include ovarian reserve testing to assess egg quality and quantity through blood tests and ultrasonography. Evaluation of the uterine lining may involve procedures like hysteroscopy. Men undergo semen analysis as part of their fertility assessment. Both partners undergo infectious disease screening for HIV, Hepatitis B, and Hepatitis C.
What to Expect:
Patients will receive a thorough explanation of the procedure, which involves multiple steps:
- Ovarian Stimulation:
- Hormonal medications (FSH/HMG injections) stimulate the ovaries to produce multiple eggs.
- Vaginal ultrasound monitors follicle development, while blood tests track hormonal responses.
- Medications prevent premature egg release and promote egg maturation.
- Egg Collection:
- Retrieval is typically scheduled 34 to 36 hours after the final injection, performed under sedation.
- Transvaginal ultrasound-guided aspiration retrieves eggs from follicles using a thin needle and suction device.
- Patients may experience cramping and fullness post-retrieval.
- Sperm Retrieval:
- Partner’s semen sample is provided through masturbation on the day of egg retrieval.
- Alternative methods like testicular aspiration may be used, or donor sperm can be utilized.
- Fertilization:
- Two methods are commonly employed:
- Conventional insemination: Mixing healthy sperm and mature eggs in a culture medium.
- Intracytoplasmic sperm injection (ICSI): Directly injecting a single healthy sperm into each mature egg.
- Two methods are commonly employed:
- Embryo Transfer:
- Progesterone supplements prepare the uterine lining for implantation.
- Transfer usually occurs two to five days post-egg retrieval.
- The number of embryos transferred depends on factors like age and egg count, with extra embryos frozen for future use.
- The procedure, typically painless, involves inserting a catheter into the uterus via the vagina and cervix. Embryos suspended in fluid are gently pushed into the uterus using a syringe attached to the catheter.
Patients may experience mild cramping during the procedure.
Results/Post-Procedure:
Following embryo transfer, patients can typically resume their regular daily activities. However, caution should be exercised as the ovaries may still be enlarged, potentially causing discomfort with vigorous activity.
It’s advisable to promptly contact the doctor if experiencing any of the following side effects:
- High fever
- Abdominal pain
- Urinary issues
Around 12 days to two weeks post-embryo transfer, a blood test (beta-hCG) is conducted to ascertain pregnancy.