In Vitro Fertilization (IVF)

Facts on In Vitro Fertilization (IVF)

Primary infertility, is the inability of a couple to become pregnant (regardless of cause) after one year of unprotected sexual intercourse using no birth control methods. This is in contrast to secondary infertility, which refers to a couple who cannot conceive a pregnancy when they have previously conceived together.

Primary infertility affects about 6.1 million people in the United States, representing about 10% of men and women of reproductive age. Assisted reproductive technologies (ARTs) are techniques to help a woman become pregnant, including in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and other similar procedures.

IVF was used successfully for the first time in the United States in 1981. More than 4 million babies have been born worldwide as a result of using in vitro fertilization techniques. IVF offers infertile couples a chance to have a child who is biologically related to them. In 2015, more than 1.6% of infants born in the US are a result of a pregnancy conceived by assisted reproductive technologies.

With IVF, a method of assisted reproduction, a man's sperm and the woman's egg are combined in a laboratory dish, where fertilization occurs. The resulting embryo or embryos is/are then transferred to the woman's uterus (womb) to implant and develop naturally. Usually, two to four embryos are placed in the woman's uterus at one time. Each attempt is called a cycle.

The term "test tube baby" has been used in the past to refer to children conceived with this technique. The first so-called test tube baby, Louise Brown, reached age 39 in 2017. She was born in England.

Only a small percentage of infertile couples actually use IVF. IVF is usually the treatment of choice for a woman with blocked, severely damaged, or no Fallopian tubes. IVF is also used to overcome infertility caused by endometriosis or problems with the sperm (such as low sperm count). Couples who simply can't conceive and have tried other infertility methods (such as intrauterine insemination) that have not worked for them can also try IVF.

Factors to Consider with In Vitro Fertilization

  • Age: Any woman who is still ovulating may try IVF, although success rates decline as a woman ages. Women under age 35 have the greatest chance of success with this technique.
  • Multiple births: Generally, in women who use IVF to establish a live birth, about 63% are single babies, 32% are twins, and 5% are triplets or more.
  • Cost: IVF is a costly procedure that, in many cases, is not covered by health insurance plans.
  • Reduced need for surgery: If a woman has IVF, she may not have to undergo surgery on her Fallopian tubes. It is estimated that the IVF technique has reduced such surgeries by half.
  • Safety: Studies suggest that in vitro fertilization is safe. A study covered nearly 1,000 children conceived through these methods in five European countries and found that the children monitored from birth to age 5 years, were as healthy as children conceived naturally. However, other studies have found a slightly increased risk of genetic disorders in children conceived through assisted reproductive technologies. In addition, adverse outcomes during pregnancy and the perinatal period are increased in pregnancies that resulted from IVF. Some or most of this increased risk is due to the fact that a greater proportion of IVF pregnancies involve multiple gestations. However, there is a slight increased risk of complications in singleton pregnancies resulting from IVF, possibly related to the age of the parents or to the underlying conditions which led to the infertility and need for IVF.

In Vitro Fertilization (IVF) Medical Definition

IVF, a laboratory procedure in which sperm are placed with an unfertilized egg in a Petri dish to achieve fertilization. The embryo is then transferred into the uterus to begin a pregnancy or cryopreserved (frozen) for future use. IVF was originally devised to permit women with damaged or absent Fallopian tubes to have a baby. Normally a mature egg is released from the ovary (ovulated), then enters the Fallopian tube, and waits in the neck of the tube for a sperm to fertilize it. With defective Fallopian tubes, this is not possible. The first IVF baby, Louise Joy Brown, was born in England in 1978.

In vitro fertilization literally means "fertilization in glass." A child born by in vitro fertilization is inaccurately known a "test tube baby."

Prior to the IVF Procedure

A number of screening tests are performed prior to beginning an IVF cycle. Tests typically include imaging studies such as a transvaginal ultrasound of the ovaries and uterus. In some cases, oral contraceptive pills are administered in the cycle prior to the treatment cycle. Sometimes another medication, leuprolide (Lupron) is also given during this phase, depending upon the protocol used. It may also be necessary to visualize the interior of the uterus using a procedure called hysteroscopy.

When the treatment cycle begins, medications known as gonadotrophins are given daily by injection to promote maturation of ovarian follicles containing eggs. The woman is taught to administer the injections at home. Blood tests are carried out to measure hormone levels. While the goal is to stimulate production of multiple follicles, the actual number of developing follicles varies widely. Some women may produce 20 or more follicles, while others produce only two to three per cycle. During this so-called stimulation phase, transvaginal ultrasounds are performed frequently to assess maturation of the follicles and are performed daily toward the end of the stimulation phase.

When, according to the ultrasound results, the follicles are mature, the woman administers an injection of human chorionic gonadotrophin (hCG). It is critical for the success of the procedure to take this injection at precisely the correct time to stimulate ovulation (release of eggs from the ovary).

Egg Retrieval and Fertilization

The egg retrieval procedure is performed 34 to 36 hours after the hCG injection is given. In this procedure, performed under ultrasound guidance, the surgeon inserts a needle through the vagina into the woman's ovary to remove the fluid containing mature eggs from the follicles, which contains the mature eggs. General anesthesia is not required for this procedure, but the woman may require sedation.

The procedure takes about 20 to 30 minutes and is performed on an outpatient basis. The woman is generally advised to rest for the remainder of the day of the procedure. Some light spotting and/or mild cramping may occur after the egg retrieval.

The fluid removed from the follicles is examined in the laboratory to make sure eggs are present.

Simulatneously, the man provides a semen sample. He is asked not to have sexual intercourse for a few days before the eggs are retrieved from the woman, and before he produces a semen sample (usually by masturbation). The sperm are separated from the semen in the laboratory.

The active sperm are combined in the laboratory dish with the eggs. This is the actual process of in vitro fertilization. In some cases, a sperm cell will be manually inserted into the egg in a process known as intracystoplasmic sperm injection (ICSI). This step is done for a variety of reasons including poor sperm quality or other suspicions that fertilization may be difficult. Some clinics may perform ICSI on a fraction of the eggs which have been harvested.

About 18 hours after this fertilization procedure, it is possible to determine if the egg or eggs have been fertilized and they have begun to divide into embryos. They are incubated and observed over the next 2 to 3 days or longer.

Embryo Transfer

The woman will be informed by the laboratory about the status of the fertilization process including the number of eggs that were successfully fertilized. The embryo transfer to the woman's uterus is typically scheduled 3 to 5 days after the egg retrieval, depending upon the maturation of the embryos.

The number of embryos to be transferred will be decided jointly by the doctor and the woman herself. This can vary from one embryo to several. In making a recommendation about the number of embryos to transfer, the doctor will consider the woman's age and reproductive history, the quality and appearance of the fertilized embryos, and the risk of multiple gestations.

During the procedure, the doctor transfers the embryos into the woman's uterus through the cervix with a catheter (a long slender tube). This procedure is done using a speculum in a manner similar to a pelvic exam. Anesthesia is not required for this procedure. The woman should then remain in a supine position for at least one hour.

After Embryo Transfer

This is known as the luteal phase of the cycle, and the woman is given the hormone progesterone, either as injections or vaginal suppositories. Sometimes progesterone in both forms will be given. Progesterone administration continues for the next 2 weeks. A pregnancy test is scheduled for two weeks following the embryo transfer. If implantation is successful (the egg or eggs attach to the uterine wall and grow), the pregnancy test result should be positive.

What Are the Risks of In Vitro Fertilization?

There are rare risks associated with any surgical procedure such as the egg retrieval procedure necessary for IVF. These include bleeding, infection, and damage to the bowel or other organs in the area.

One risk that is specific to the medications used for stimulation is known as ovarian hyperstimulation syndrome (OHSS). OHSS is seen in certain women who take medications to stimulate the ovaries and affects up to 10% of women who undergo IVF. Symptoms can range from mild to severe. In mild cases, a woman may experience bloating, mild pain or cramping, and weight gain. Severe cases are characterized by excessive weight gain (for example, over 10 pounds in a few days), shortness of breath, and severe pain or swelling in the abdomen. Severe cases may need to be managed in the hospital. Treatment includes rest, hydration, and avoidance of strenuous activity. OHSS generally resolves on its own once the cycle is over.

Cancelled Cycles In some cases, if a woman does not respond sufficiently to the medications and an insufficient number of follicles is produced or matured, the cycle may be cancelled. If this occurs, no eggs are retrieved.

What Are Other Assisted Reproduction Techniques?

The following procedures have been used as alternatives to IVF but are not discussed in detail in this article:

  • Gamete intrafallopian transfer (GIFT): Gamete intrafallopian transfer is similar to IVF. It is used when a woman has at least one normal Fallopian tube. Eggs are placed in this tube along with a man's sperm to fertilize there. This accounts for only a small portion of assisted reproductive technology procedures in the US. Some couples opt for this procedure if they object to fertilization that occurs outside the woman's body.
  • Zygote intrafallopian transfer (ZIFT): Zygote intrafallopian transfer refers to a procedure in which a woman's eggs are taken from her ovaries, fertilized in the laboratory, and inserted into her Fallopian tubes rather than the uterus. ZIFT is even less common than GIFT.
  • Embryo cryopreservation (frozen fertilized egg and sperm) is available when more embryos are created than are transferred to the woman's uterus. These can be transferred during a future cycle. In this case a woman would take medications to prepare her uterus to receive the embryos at the appropriate time.

What Are the Success Rates for In Vitro Fertilization?

The live birth rate for one cycle varies by maternal age. According to the Society of Assisted Reproductive Technologies (SART) in 2014:

  • The live birth rate per IVF cycle is 54% among women younger than 35 years of age and 42% for those aged 35 to 37 years.
  • The success rate ranges from 3.9% to 13.3% in those older than 40 years of age.
  • Pregnancy in women older than 44 years of age is rare.

When reviewing statistics for different IVF programs, it is important to understand what is actually being reported. A pregnancy rate may include so-called chemical pregnancies, in which the pregnancy test is positive but the pregnancy ends before a viable fetus can be demonstrated only by ultrasound. The pregnancy rate is also different from the live birth rate, since it includes all pregnancies that may or may not lead to a live birth. Even live birth rates may vary among different clinics because the selection criteria for patients and the number of embryos typically transferred varies.

The rate of miscarriages with IVF pregnancies is the same as that with pregnancies conceived spontaneously. Ectopic pregnancy occurs in about 1% of cases. An ectopic pregnancy is a serious condition that requires emergency medical care. With an ectopic pregnancy, the fetus develops outside the uterus and typically does not survive.

Egg and Sperm Donors

Donors may contribute the egg or the sperm (or even a frozen embryo) to an IVF program when a partner is not able to produce the egg or sperm.

  • Egg donation: Sometimes eggs are used from another woman if the recipient has impaired ovaries or has a genetic disease that could be passed on to her baby. The egg donor may be anonymous or known (such as a relative for a designated donor). Ideally, the donor should be aged 21 to 30 years. The donor takes the medications for the stimulation phase of the IVF cycle. The donor's eggs are removed the same way they are with IVF. The recipient takes increasing doses of estrogen to synchronize her hormone levels in preparation for the embryo transfer. Both the donor and recipient should talk with a counselor about the psychological aspects of this procedure. Everyone signs a consent form to cover the legal issues of such a donation. Success rates for this type of donation are higher than the rates with conventional IVF. The rate of multiple pregnancies is high, and doctors try to transfer only two embryos per cycle.
  • Sperm donation: This can be routinely done for women whose male partners have impaired sperm or low sperm counts, or if the partner has a genetic disease that could be transmitted to the baby. Donation may be anonymous from a sperm bank. In some cases, a male partner may "bank" sperm if he anticipates problems with chemotherapy or other medical conditions that may affect his sperm later in life.
  • Embryo donation: Receiving a donor embryo (usually from a frozen embryo created in the laboratory from another couple) is the earliest form of adoption. The donor couple must sign an advance directive regarding embryo ownership and disposition. Those directives should include statements regarding (1) embryo donation to another couple, (2) donation of the embryos for research, or (3) disposition of the embryos after thawing.
Reviewed on 12/19/2017
Sources: References

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