What Is In Vitro Fertilization?
In vitro fertilization (IVF) is a type of assistive reproductive technology (ART). It involves retrieving eggs from a woman’s ovaries and fertilizing them with sperm. This fertilized egg is called an embryo. The embryo can then be frozen for storage or transferred to a woman’s uterus.
Depending on your situation, IVF can utilize:
- your eggs and your partner’s sperm
- your eggs and donor sperm
- donor eggs and your partner’s sperm
- donor eggs and sperm
- donated embryos
Your embryos may also be implanted in a surrogate, or gestational carrier. This is a woman who carries your pregnancy for you.
The success rate of IVF varies. According to the American Pregnancy Association, the live birth rate for women under age 35 undergoing IVF is 30 to 35 percent. This rate falls to six to 10 percent for women over the age of 40. ( American Pregnancy Association )
Why Is IVF Performed?
IVF is used to help people with infertility who want to have a baby. IVF is expensive and invasive, so couples often try other fertility treatments first. These may include taking fertility drugs or having intrauterine insemination. During that procedure, sperm is transferred directly into a woman’s uterus.
Infertility issues for which IVF may be used include:
- reduced fertility in women over the age of 40
- blocked or damaged fallopian tubes
- reduced ovarian function
- uterine fibroids
- male infertility, such as low sperm count or abnormalities in sperm shape
- unexplained infertility
IVF may also be used if parents run the risk of passing a genetic disorder on to their offspring. A medical lab can test the embryos for genetic abnormalities. Only embryos without genetic defects are then implanted.
Preparing for IVF
Before beginning IVF, women will have ovarian reserve testing done. This involves testing a blood sample for the level of follicle stimulating hormone (FSH). The results of this test will give your doctor information about the size and quality of your eggs.
Your doctor will also examine your uterus. This may involve doing an ultrasound, which uses high-frequency sound waves to create images of internal structures. A scope may also be inserted through your vagina and into your uterus. These tests can reveal the health of your uterus and help the doctor determine the best way to implant the embryos.
Men will need to have their sperm tested. This involves giving a semen sample, which will be analyzed for the number, size, and shape of the sperm. If your sperm are weak or damaged, a procedure called intracytoplasmic sperm injection (ICSI) may be recommended. During ICSI, sperm are injected directly into the egg. ICSI can be performed as part of an IVF cycle.
Choosing to have IVF is a very personal decision. There are a number of factors to consider, such as:
- what you will do with any unused embryos
- how many embryos you wish to transfer. The more embryos transferred, the higher the risk of a multiple pregnancy. Most doctors will not transfer more than two embryos.
- the possibility of having twins, triplets, or a higher order multiple pregnancy
- the legal and emotional issues associated with using donated eggs, sperm, and embryos or a surrogate
- the financial, physical, and emotional stress associated with IVF
There are five steps involved in IVF:
- egg retrieval
- embryo culture
Normally, a woman produces one egg during each menstrual cycle. However, IVF requires multiple eggs. Using multiple eggs increases the chances of developing a viable embryo. Therefore, fertility drugs will be given to increase the number of eggs your body produces. During this time, regular blood tests and ultrasounds will be done to monitor the production of eggs and let your doctor know when to retrieve them.
Egg retrieval is called follicular aspiration. It is a surgical procedure. Your doctor will use an ultrasound wand to guide a needle through your vagina, into your ovary, and into an egg-containing follicle. The needle will suction eggs and fluid out of each follicle.
The male partner will now need to give a semen sample. The sperm will be mixed with the eggs in a petri dish. If that does not produce embryos, ICSI may be used.
The fertilized eggs will be monitored to ensure that they are dividing and developing. The embryos may be tested for genetic conditions at this time.
When the embryos are big enough, they can be implanted. This normally occurs three to five days after fertilization. Implantation involves having a thin tube called a catheter inserted into your vagina, past your cervix, and into your uterus.
Pregnancy occurs when the embryo implants itself in the uterine wall. This can take six to 10 days. A blood test will determine if you are pregnant.
Risks of IVF
As with any medical procedure, there are risks associated with IVF. Risks include:
- multiple pregnancies, which increases the risk of low birth weight and premature birth
- miscarriage (pregnancy loss)
- ectopic pregnancy (when the eggs implant outside the uterus)
- ovarian hyperstimulation syndrome (OHSS), which is an excess of fluid in the abdomen and chest (rare)
- bleeding, infection, or damage to the bowels or bladder (rare)