In vitro fertilization is a process of fertilization where an egg is combined with sperm outside the body. After 2~3 or 5 days of embryo culture, the fertilized egg is then transferred to the woman’s uterus. Since both egg and sperm are collected and fertilized outside of the body, it is called the in vitro. Mature embryos are usually transferred back into the uterus, it is commonly called IVF-ET. It is not only a medical treatment but also a useful evaluation tool to figure out the quality and condition of egg and sperm, fertilization ability, and development ability of embryos.
In the early introduction of IVF, it was only performed when there was a problem with fallopian tube; however, with the rapid progress in IVF technology, it can be applied to following conditions or diseases.
When both fallopian tubes have been removed
Unsuccessful pregnancy after 3~4 times of artificial insemination
Severe pelvic adhesion
Uterine abnormalities or older women
Male infertility (oligoasthenozoospermia, teratozoospermia, azoospermia)
Unsuccessful pregnancy after 1.5~2 years of tying tubes or blocked tubes
Proximal tubal occlusion (6 months past tubal patency test)
Premature ovarian failure (egg donation)
Ovulation induction - Egg/sperm collection - In vitro Fertilization and culture - Embryo transfer - Pregnancy test
Ovulation induction is the stimulation of ovulation by medication to develop ovarian follicles. There are one-month-course and two-month-course, which depend on the case of each patient. Patients must stick to the doctor’s guideline. Ovulation inducing agent will be administered 2~3 days prior to period and will be continued for a week or two according to the maturity of follicles.
Once egg is fully mature, egg retrieval will be performed. The patient will be under sedation and complications are very rare. The process will take 20~30 minutes and the patient may need 2 hours of recovery period. For the male partner, he has to avoid intercourse for 3 days before the test. The semen should be gathered after a three day abstinence from sexual activity. He will come visit the clinic on the day of egg retrieval.
After 6 to 8 hours of culture, mature oocytes are placed to be fertilized. Approximately 18 hours after the procedure, the embryologists will check for fertilization. It may take 2~3 days or up to 5 days to fully culture the sample.
3 days or 5 days after egg retrieval, the embryos are placed into the uterus using a thin tube. If needed, special culture medium can be used to help embryos to implant.
After 12 days of egg retrieval, blood test will be performed to check pregnancy.
Intracytoplasmic Sperm Injection
In the past, the outcome of IVF for patients with low sperm count, low motility, or tetratozoospermia was not successful. However, nowadays, male factor infertility patients also can achieve successful fertilization by micromanipulation, which is to inject sperm directly into the egg. Especially, it is also possible to collect immature sperm from testicles or epididymis from some azoospermia patients and establish pregnancy using micromanipulation.
In order for an embryo to make a successful implantation in the uterus, it must break a hole in the zona pellucida, which is a process called ‘hatching.’ If the zona fellucida is thick or the pregnancy was not successful even with the great quality embryo, the embryologist will create a small hole in the zona pellucida to assist hatching.
Customized Embryo Transfer
Customization of embryo transfer is possible due to the characteristic of embryos and their developmental stages. The embryologist may use short-term culture (2 days after egg retrieval) or 5-day-cultured embryos to improve the convenience and success rate of pregnancy. Whether short or long does not make a difference in successful pregnancy.
Embryos can be preserved and transferred later. This may increase the chance of successful pregnancy per patient, lowers the potential cost of total treatment, and decrease the risk of gynecological complications due to multiple pregnancy. Cryopreservation is semipermanent and the embryos can be thawed at anytime when the endometrium is ready. However according to the Act 16, Bioethics and Safety Laws, embryos will only be stored up to 5 years. The survival rate of embryos is 2/3.