Who should be treated with in vitro fertilization?
In vitro fertilization can be used as an effective treatment for infertility of all causes except for women with infertility caused by an anatomic problem with the uterus, such as severe intrauterine adhesions.
It is generally used in couples who have failed to conceive after at least one year of trying who also have one or more of the following:
- Male factor infertility (low sperm count or low motility). ICSI is an IVF procedure that can fertilize eggs even with poor sperm quality.
- Reduced ovarian reserve, which means lower quantity (and sometimes quantity) of eggs. A day 3 FSH and estradiol test and antral follicle counts are often done as screening tests for egg quantity (and quality). Reduced egg quantity and quality is usually treated with either IVF, or with IVF using egg donation from another woman.
- Blocked fallopian tubes or pelvic adhesions with distorted pelvic anatomy. Women that have had tubal ligation and are considering tubal reversal surgery as well as men that are considering vasectomy reversal surgery might also consider IVF.
- Failed 2-4 cycles of Ovarian stimulation with intrauterine insemination
- Advanced female age - over about 38 years of age.
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- Severe endometriosis
- Unexplained infertility when inseminations have failed - unexplained infertility means standard fertility tests have not found the cause of the fertility issue.
How does IVF improve fertility?
In vitro fertilization increases the efficiency of human reproduction, which is often not very efficient naturally. Essentially, we are involved in a numbers game that worsens as the female partner ages. IVF takes multiple eggs and after careful culture for 3-5 days of those eggs that fertilize, transfer one or more of the embryos back to the uterus. Any remaining can be frozen for future use by the couple. In a sense, it is like cramming many months of "natural" attempts into one menstrual cycle. By transferring the fertilized embryo(s) directly to the uterine cavity, fertility is improved for many couples that have sperm issues (fertilization defects), or issues on the female side related to egg pickup from the ovary or tubal transport of the embryo to the uterus.
Therefore, with IVF:
- The body is forced to produce multiple follicles and eggs (only one follicle with one egg inside develops in a natural menstrual cycle)
- Eggs are taken out of the ovaries when they're ready (release and tubal pickup of the egg can be inefficient naturally)
- Fertilization is coerced in the lab (sperm or egg issues can cause fertilization problems in a natural situation)
- Embryos are cultured for several days and then pick the best one (or more) for transfer to the female (selection of the best one(s) increases the chance of success)
The process of in vitro fertilization - how is IVF done?
- Basic screening tests are performed on both partners at all IVF clinics.
- In general, some testing of “Ovarian reserve” should be done on the female prior to starting the injections. Day 3 FSH testing as well as antral follicle counts for this purpose tests give some ability to predict whether her ovaries will respond well to the drugs (make sufficient follicles and eggs). The number of eggs retrieved correlates strongly with IVF success rates.
- The woman is stimulated with injected medications to develop multiple follicles in the ovaries. Each follicle contains a microscopic egg. These injections continue to stimulate follicle and egg growth and development for about 8 - 10 days.
- Blood and ultrasound testing is done every 1-3 days to monitor the development of the follicles (egg-containing structures) in the ovaries.
- Minimum number of 3 follicles is needed to develop to maturity in order to be able to proceed with the egg retrieval. About 90% of women under 40 with a normal FSH and normal antral follicle counts will develop at least this minimum number of follicles. If this many mature follicles cannot be obtained from the stimulation process - cycle is cancelled (not proceed to egg retrieval). Criteria for cancellation can vary between IVF centres.
- When a sufficient number of the woman's follicles are mature, a transvaginal ultrasound-guided egg retrieval (egg aspiration) procedure is performed to remove the eggs from the follicles.
- The eggs are then fertilized in the laboratory with her partner's sperm. If the sperm (or the eggs) are of poor quality, the ICSI procedure might be used to aid in fertilization.
- The embryos are cultured in the IVF laboratory for 2-6 days.
- The embryo transfer procedure is done which places the embryos in the woman's uterus where they will hopefully implant and develop to result in a live birth. This is like a Pap smear for the woman. There should be no discomfort.
- If there are leftover embryos (of sufficient quality) beyond the number that is transferred, many couples prefer to have them frozen (cryopreserved) for use in a future cycle. Embryo cryopreservation can be used for another attempt at having a baby if the "fresh" cycle fails - or as an attempt to have another child if the fresh cycle is successful.
- Blastocyst transfer of 2 embryos allows high pregnancy rates and almost no risk for triplets or higher
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