In Vitro Fertilization (IVF):
An in vitro procedure is one that is performed in the laboratory. Most assisted reproductive technologies procedures use in vitro fertilization. Advances in these procedures have dramatically increased the rate of live births. IVF can be performed with a woman' s own eggs and sperm, or with donor eggs and sperm. IVF was used mainly to treat women with damaged fallopian tubes. Now it is used as a fertility treatment for woman with endometriosis, male fertility problems, or in unexplained infertility.
A standard IVF cycle has 4 stages:
- Ovarian stimulation: Clomiphenes like ovarian-stimulating drugs are used for the hyper stimulation of the ovaries to produce multiple eggs. Another drug (usually human chorionic gonadotropin [hCG]) is given after 8-14 days to nourish egg maturation.
- Egg Retrieval: The eggs are retrieved 34 - 36 hours after the hCG injection (before ovulation begins). To retrieve the eggs, the doctor inserts an ultrasound-guided probe into the vagina. A needle is then used to drain the liquid from the follicles, and several eggs are retrieved.
- Fertilization and Embryo Culture: The quality and maturity of the eggs are evaluated. Selected eggs are placed in a culture in the laboratory and transferred to an incubator. They are then inseminated with sperm, either by placing sperm together with the egg or injecting a single sperm into the egg.
- Embryo Transfer and Cryopreservation: One or more embryos are implanted in the uterus following egg retrieval (after 1 - 6 days). Excess embryos may be frozen and saved for future use. It takes about 2 weeks to determine if pregnancy has been achieved.
Other IVF procedures follow either of the 2 adaptations; gamete intrafallopian transfer (GIFT) or zygote intrafallopian transfer (ZIFT), which transfers the gametes (egg and sperm) into the fallopian tube rather than uterus. In GIFT, the egg is harvested as with IVF and mixed with sperm, and is then injected into the fallopian tube where fertilization occurs. In ZIFT, the egg is fertilized with sperm in the laboratory before being transferred to the fallopian tube. Woman with at least one functioning fallopian tube can only undergo this procedure.
All IVF cycles may not result in pregnancy and in live births. Success rates provided by fertility clinics are not always a reliable indicator as they depend on many variables, including the age of the patients.
The chances of IVF resulting in live birth are about:
40% for women below 35, 30% for women ages 35 – 37, and 20% for women ages 38 – 40 and 10% for women ages 41 – 42. Some women try acupuncture during an IVF cycle to increase their chances for pregnancy success. But there is no conclusive evidence that it boosts success rates.
In general, the overall risks for birth defects appear to be small. But the risk for genetic abnormalities and birth defects are not zero. The main risk of IVF is the consequences of multiple pregnancies. Multiple pregnancies increase the risks for a mother and her babies. In particular, there is increased risk for premature delivery and low birth weight. These factors can cause heart and lung problems and developmental disabilities in children.