In vitro fertilization (IVF) is the most common and most effective type of assisted reproductive technology (ART) to help women become pregnant.
The procedure involves fertilizing an egg outside the body, in a laboratory dish, and then implanting it in a woman's uterus.
In a normal pregnancy a male sperm penetrates a woman's egg and fertilizes it inside her body after ovulation - when a mature egg has been released from the ovaries. The fertilized egg (now an embryo) then attaches itself to the wall of the uterus (womb) and begins developing into a baby. This is known as natural conception.
However, some women are unable to become pregnant through natural or unassisted conception and have to undergo fertility treatment to become pregnant.
If less expensive fertility techniques do not work, some women may decide to opt for IVF.
According to the American Society for Reproductive Medicine, about 1% of U.S. infants are conceived through IVF. To date, IVF has contributed to approximately 5 million births.
IVF techniques may differ depending on the clinic, but usually involves the following steps:
Step one - Suppressing the natural menstrual cycle
Women are given a drug (generally in the form of a daily injection) for about two weeks, which suppresses their natural menstrual cycle.
Step two - Super ovulation
Fertility drugs containing the fertility hormone FSH (follicle stimulating hormone), are administered to the woman. FSH makes the ovaries produce more eggs than normal. Vaginal ultrasound scans can monitor the process in the ovaries.
Step three - Retrieving the eggs
The eggs are collected through a minor surgical procedure known as "follicular aspiration". A very thin needle is inserted through the vagina and into an ovary. The needle - which is connected to a suction device - sucks the eggs out. This process is repeated for each ovary.
Step four - Insemination and fertilization
The eggs that have been collected are placed together with male sperm and kept in a environmentally controlled chamber. After a few hours the sperm eventually enters the egg. However, sometimes the sperm is directly injected into the egg, this is known as an intracytoplasmic sperm injection (ICSI).
The fertilized egg divides and becomes an embryo. At this point some centers offer pre-implantation genetic diagnosis (PGD) which can screen an embryo for genetic disorders (a somewhat controversial technique not always used).
Either one or two of the best embryos are selected for transfer.
The woman is then given progesterone or hCG (chorionic gonadotrophin) to help the lining of the womb receive the embryo.
Step five - Embryo transfer
Sometimes more than one embryo is placed in the womb. It is important that the doctor and the couple wishing to have a child discuss how many embryos should be transferred. Generally speaking, doctors should only transfer more than one embryo if there are no ideal embryos available.
The transfer is done via a a thin tube (catheter), which goes up the vagina and into the womb, successfully transferring the embryo. When the embryo sticks to the lining of the womb healthy embryo growth begins.
In-vitro fertilization is ideal for women who have not been able to become pregnant through regular unprotected intercourse or after 12 cycles of artificial insemination. IVF should be considered as an option if:
NEED TO PROVIDE HOSPITAL SUCCESS RATES
Some women may have reactions to the medications that are given during treatment. The side effects of the drugs given during IVF include:
Rarely, the drugs cause ovarian hyperstimulation syndrome (OHSS), this occurs when the ovaries over-respond to the gonadotrophins, resulting in far too many eggs developing in the ovaries, causing severe abdominal swelling and shortage of breath. If OHSS occurs, restarting the whole cycle with a lower dose of gonadotrophin should be considered.
The major cause of pregnancy loss in IVF is chromosomal imbalance in embryos.
When more than one embryo is transferred into the womb there is a risk of multiple pregnancies (an increased chance of producing twins or even triplets).
Intra-cytoplasmic sperm injection (ICSI) differs from conventional in vitro fertilisation (IVF) in that the embryologist selects a single sperm to be injected directly into an egg, instead of fertilisation taking place in a dish where many sperm are placed near an egg.
This procedure is most commonly used to overcome male infertility problems, although it may also be used where eggs cannot easily be penetrated by sperm, and occasionally in addition to sperm donation.
It can be used in teratozoospermia, because once the egg is fertilized, abnormal sperm morphology does not appear to influence blastocyst development or blastocyst morpholog. Even with severe teratozoospermia, microscopy can still detect the few sperm cells that have a "normal" morphology, allowing for optimal success rate.
ICSI enables fertilisation to happen when there are very few sperm available.
Your clinic may recommend ICSI if:
ICSI is generally performed following an in vitro fertilization procedure to extract one to several oocytes from a woman. The procedure is done under a microscope using multiple micromanipulation devices (micromanipulator, microinjectors and micropipettes).
A holding pipette stabilizes the mature oocyte with gentle suction applied by a microinjector. From the opposite side a thin, hollow glass micropipette is used to collect a single sperm, having immobilised it by cutting its tail with the point of the micropipette. The oocyte is pierced through the oolemma and directed to the inner part of the oocyte (cytoplasm). The sperm is then released into the oocyte. The pictured oocyte has an extruded polar body at about 12 o'clock indicating its maturity. The polar body is positioned at the 12 or 6 o'clock position, to ensure that the inserted micropipette does not disrupt the spindle inside the egg. After the procedure, the oocyte will be placed into cell culture and checked on the following day for signs of fertilization.
In contrast, in natural fertilization sperm compete and when the first sperm penetrates the oolemma, the oolemma hardens to block the entry of any other sperm.
Concern has been raised that in ICSI this sperm selection process is bypassed and the sperm is selected by the embryologist without any specific testing. However, in mid -2006 the FDA cleared a device that allows embryologists to select mature sperm for ICSI based on sperm binding to hyaluronan, the main constituent of the gel layer (cumulus oophorus) surrounding the oocyte. The device provides microscopic droplets of hyaluronan hydrogel attached to the culture dish. The embryologist places the prepared sperm on the microdot, selects and captures sperm that bind to the dot.
Basic research on the maturation of sperm shows that hyaluronan-binding sperm are more mature and show fewer DNA strand breaks and significantly lower levels of aneuploidy than the sperm population from which they were selected. A brand name for one such sperm selection device is PICSI.
A recent clinical trial showed a sharp reduction in miscarriage with embryos derived from PICSI sperm selection. 'Washed' or 'unwashed' sperm may be used in the process.
Live birth rate are significantly higher with progesterone for luteal support in ICSI cycles.Also, addition of a GNRH agonist for luteal support in ICSI cycles has been estimated to increase success rates,by a live birth rate RD of +16% (95% confidence interval +10 to +22%). Using ultra -high magnification during sperm selection (with the technique being called IMSI) has no evidence of increased live birth or miscarriage rates compared to standard ICSI.
Potential factors that may influence pregnancy rates (and live birth rates) in ICSI include level of DNA fragmentation as measured e.g. by Comet assay, advanced maternal age and semen quality.
There is some suggestion that birth defects are increased with the use of IVF in general, and ICSI specifically, though different studies show contradictory results.
In a summary position paper, the Practice Committee of the American Society of Reproductive Medicine has said it considers ICSI safe and effective therapy for male factor infertility, but may carry an increased risk for the transmission of selected genetic abnormalities to offspring, either through the procedure itself or through the increased inherent risk of such abnormalities in parents undergoing the procedure.
An online news story on MSNBC.com by Marilynn Marchione of the Associated Press, released on Saturday, May 5, 2012, discussed the risk of birth defects in ICSI versus natural conception or normal IVF; the following is a directly quoted segment of that release: "Test-tube babies have higher rates of birth defects, and doctors have long wondered: Is it because of certain fertility treatments or infertility itself?
A large new study from Australia suggests both may play a role. Compared to those conceived naturally, babies that resulted from simple IVF, or in vitro fertilization — mixing eggs and sperm in a lab dish — had no greater risk of birth defects once factors such as the mother's age and smoking were taken into account.