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DEAR MAYO CLINIC: My husband and I are in our late 30s and considering in vitro fertilization. How many embryos are typically implanted, and how often is in vitro successful? Who is a good candidate for this procedure?
ANSWER: In vitro fertilization (IVF) is a procedure that can be used to help couples who are dealing with infertility issues conceive a child. It is the most commonly used and most effective form of assisted reproductive technology available today.
About 10 to 15 percent of couples in the United States have trouble getting pregnant. In general, a couple is defined as having fertility problems when they have been trying to get pregnant without success for six months or more and the woman is older than 35. For women younger than 35, doctors typically recommend couples try to get pregnant for 12 months before going through a fertility evaluation.
In vitro fertilization involves taking eggs from a woman’s ovaries and fertilizing them with sperm in a laboratory. The resulting embryos are cultured in the lab for several days. During that time, they are monitored closely to gauge how well they are developing. The embryos that grow best are placed into the woman’s uterus. About a week and a half after embryos are placed in the uterus, a pregnancy test is performed.
Traditionally, multiple embryos were implanted during an IVF treatment to raise the chances for a successful pregnancy with at least one of them. In the last 10 to 15 years, however, IVF success rates have increased enough that it’s now possible to implant just a single embryo, decreasing the risk of a multiple pregnancy.
The success rate of IVF depends on many factors. Age is one of the most important. The younger a woman is, the more likely she is to get pregnant and give birth to a healthy baby using her own eggs with IVF. For women age 34 and younger, the chance of pregnancy with one round of IVF is about 60 percent. For women who are 40, the success rate is about 25 percent. At age 45, the success rate for IVF is around just 1 percent. IVF can be performed with eggs donated from another woman, and that can increase the chance for success.
Other factors that make a difference include whether the embryos are fresh or frozen. The birth rate with frozen embryos is slightly lower than with fresh embryos. Women who have given birth before are more likely to get pregnant using IVF than those who have never given birth.
The cause of infertility also can have an effect on IVF success. For example, having a normal supply of eggs increases a woman’s chances of being able to get pregnant with IVF. Women who have endometriosis — a condition in which tissue that normally lines the inside of the uterus grows outside of the uterus — are less likely to get pregnant using IVF than are women who have blocked or damaged fallopian tubes.
Lifestyle can make a difference, too. Women who smoke typically have fewer eggs retrieved during IVF. Smoking can lower a woman’s chance of success using IVF by about 50 percent. Using alcohol, recreational drugs, lots of caffeine — more than 200 milligrams a day — and certain medications also can hurt a woman’s chances of getting pregnant with IVF.
As you consider IVF, it’s important to keep in mind that this procedure should not be used as the first step in dealing with infertility. A variety of less aggressive, less expensive treatment options are available that should be tried before turning to IVF. These alternatives may include medications to stimulate ovulation, as well as minimally invasive procedures to correct problems that can lead to infertility, such as blocked fallopian tubes.
Before you make up your mind about IVF, talk to your doctor or visit with a reproductive endocrinologist to discuss which infertility treatments are right for your situation. — Jani Jensen, M.D., Reproductive Endocrinology & Infertility, Mayo Clinic, Rochester, Minn.