In Vitro Fertilization (IVF)
In vitro fertilization (IVF) means “fertilization in glass,” which involves fertilization of a woman’s egg by a man’s sperm outside of the body and in a lab. In general, IVF offers the highest chance for conception. For many couples, a single attempt of IVF is more likely to be successful than many months of other treatments.
The reason for IVF’s high success rates is that it allows for the interaction of more eggs and sperm than any other procedure. Drugs increase the number of eggs a woman can produce in a month, and we evaluate those that are fertilized and develop into embryos to determine which ones are most likely to result in pregnancy. We place the embryo(s) into the uterus.
IVF is not appropriate for all couples. However, for virtually every diagnosis IVF offers the highest chance of pregnancy in the shortest period of time.
At TRM, we try to demystify the IVF process and make it easy to understand. We promise to give you realistic expectations of what IVF can and cannot do, so that you can make the best, most informed decision.
Which IVF strategy is right for you?
Ten couples with the same circumstances may make very different decisions. It is important to talk to a physician so she or he can help the patient determine which treatment is the best option. Patients often have the option to pursue either standard IVF or natural cycle IVF, depending on several factors.
For patients simply looking for the quickest route to pregnancy, standard IVF may be best. If a woman cannot make a lot of eggs, then natural cycle IVF (NC-IVF) may be the better choice. Some people will choose NC-IVF to avoid having any embryos in storage.
Why IVF increases chances of pregnancy
IVF maximizes pregnancy rates by using normal human biology to our advantage. In general, women are born with around two million eggs. Most of these eggs are in hibernation within the ovary. Every month a batch of these eggs comes out of hibernation.
Typically, one egg from this batch ovulates while others die. Unfortunately, there is no guarantee that the best quality egg is the one that will ovulate.
The reason most of the eggs die is because there is not enough follicle stimulating hormone (FSH) to support the growth of all of the eggs. One egg essentially steals the hormone and the other eggs degenerate.
By stimulating women with injections of FSH, the IVF process saves most of these eggs from being lost. The pregnancy rates are generally far higher than what occurs in a normal menstrual cycle, because multiple eggs are harvested, and the very best embryos are selected for placement in the uterus.
What are the risks of IVF?
Most couples proceed through IVF and pregnancy without difficulty, but there are some risks associated with IVF. There are risks to the mother and risks to the baby. However, unless the mother has twins or other underlying conditions, her pregnancy will not be considered “high risk.”
Risks to the mother
Multiple gestation, which is having twins or more, is the most common of all IVF-related risks. Twins occur in 20-30 percent of successful IVF cycles, and higher numbers of babies can also occur.
Multiple gestation places the babies at risk for preterm delivery, which involves health risks for the child (see below Risks to the baby). Mothers are more likely to have complications of pregnancy including preeclampsia, diabetes, blood clots, preterm labor, cesarean section and postpartum hemorrhage.
We adhere closely to the American Society for Reproductive Medicine (ASRM guidelines on number of embryos to transfer, thus maximizing chances of successful pregnancy while safely limiting the possibilities of twins and higher-order gestations of three or more babies.
Ovarian hyperstimulation syndrome (OHSS)
OHSS is a condition in which the ovaries get very large and filled with fluid in response to the gonadotropin medications. Factors are released by the ovaries that cause a woman’s blood vessels to leak fluid into the pelvis.
In mild forms of OHSS, a woman may have symptoms of bloating and pelvic discomfort; this occurs in 10-20 percent of gonadotropin cycles and resolves quickly after treatment ends.
In severe cases, a woman may have difficulty urinating, become dehydrated, gain weight rapidly, and have organ complications involving the lungs, kidneys and liver. This is rare, occurring in 1percent of cycles. These women may require hospitalization.
Women are at increased risk of blood clots when they have OHSS, and any symptoms of leg pain or difficulty breathing should be reported to a physician immediately.
Risk factors for OHSS include:
- Young age
- Low body weight
- Polycystic ovary syndrome (PCOS)
- Higher doses of gonadotropins
- High absolute or rapidly rising estrogen levels
- Previous episodes of OHSS
- High number of developing follicles.
Among women who conceive, symptoms of OHSS may worsen at the time pregnancy is detected and may take longer to completely resolve.
Ectopic pregnancies occur when a fertilized egg implants itself outside the uterus. The egg may implant in the fallopian tube, or less commonly, in the cervix, ovary or pelvic cavity. Ectopic pregnancies occur in 1-2 percent of all pregnancies.
Ectopic pregnancies are more common during fertility treatments, because many women with infertility have tubal dysfunction, and because medications often cause the release of multiple eggs, thereby increasing the possibility that not all fertilized eggs move through the tubes into the uterus.
Ectopic pregnancies require emergency medical treatment.
Adnexal torsion (ovarian twisting)
This is a rare complication that occurs in one percent of cycles. As the ovaries enlarge, they may twist, cutting off their blood supply and causing severe abdominal pain, nausea, vomiting, and sometimes low grade fevers. Treatment involves surgical untwisting of the ovary.
Egg retrieval risks
Internal bleeding is a rare complication. However, any time a needle is placed into the pelvis (such as with an egg retrieval) blood vessels can be lacerated. Usually this bleeding spontaneously resolves, but in extremely rare cases (less than one percent) surgical therapy may be required to stop internal bleeding.
Damage to surrounding organs including the bowel and bladder are possible, though very rare. Pelvic infection may also occur, but is rare as well. It occurs more commonly among women with ovarian endometriomas (a type of ovarian cyst) that are drained at the time of egg retrieval. Finally, pelvic discomfort is common after the procedure.
Not a known risk: ovarian cancer
Risks to the baby
The exact risks to children conceived after IVF are difficult to study and quantify. While some studies illustrate a higher risk to children born after IVF cycles, it is possible that these risks are due to the underlying state of infertility and are not exclusively due to the IVF treatment itself.
The most common risk to babies born after IVF is related to multiple gestation, which can cause premature birth. Other complications include a small increase in the risk of birth defects and pregnancy complications as described below.
Multiple gestation resulting in preterm birth
The degree of impairment due to preterm birth is related to the timing of the birth; children born more prematurely have more severe complications and greater risk of long-term impairment. Prematurity may result in complications involving:
- Pulmonary immaturity and difficulty breathing
- Cerebral hemorrhage (bleeding in the brain, possibly causing long-term handicaps)
- Intestinal infection and inflammation (necrotizing enterocolitis)
- Visual impairment including blindness
- Poor growth.
The baseline risk of a major birth defect for all children in the United States is 3-5 percent. IVF pregnancies have an approximately 1-2 percent higher chance of having a major birth defect (predominately cardiovascular and musculoskeletal abnormalities).
The cause for this increased risk is unknown, but theories include:
- Underlying cause of infertility predisposes to abnormalities
- IVF treatment may pose risk
- Pregnancies derived by IVF are scrutinized more closely, so people are more likely to detect abnormalities in this population (ascertainment bias).
Recent attention has focused on the increased incidence of gene imprinting disorders (including Angelman syndrome and Beckwith-Wiedemann syndrome) after IVF cycles. However, it is unclear whether these disorders are present in the infertile couple or are induced by the IVF treatment.
Abnormal gene imprinting may lead to aberrant gene expression and subsequent birth defects or cancer later in life. Theories of how IVF may induce such gene changes include changes induced by the extended embryo culture.
It is important to remember that there is no conclusive evidence that IVF causes these disorders, and that overall, an exceedingly small number of infants are actually affected with these disorders.
Infants born as the result of IVF cycles involving intracytoplasmic sperm injection (ICSI) have been shown in some studies to also have an increased risk of birth defects, particularly a condition known as hypospadias that involves an abnormal location of the urethra on the penis. This can easily be corrected in childhood with urologic surgery.
Again, this risk is not dramatically higher than the risk for the general population, and a small number of infants are actually affected with these disorders. Infants born after ICSI cycles also demonstrate a higher incidence of karyotype (number of chromosomes) disorders, which are more common among men with abnormal semen characteristics who require ICSI for successful fertilization.
As most men with such sperm abnormalities are otherwise completely healthy and normal, it is impossible to know if such inherited genetic abnormalities pose any health risks to offspring. Continued research over time may help resolve this controversy.
Pregnancy complications for the baby
Pregnancies achieved through IVF have complications more frequently than pregnancies conceived naturally. Controversy exists regarding whether they are caused by the infertility itself or the fertility treatment. Complications include slight increases in:
- Perinatal mortality
- Low birth weight (after birth, growth and intelligence are normal)
- Preterm delivery.
Other conditions that may occur more commonly after IVF cycles include gestational diabetes, preeclampsia, and placenta previa, all of which may pose risks to the fetus. However, current data is unclear about the cause and prevalence of these complications among infertile women after IVF.
In summary, research demonstrates a small but real increase in risk of adverse outcomes during pregnancy after IVF. It is important to remember that these risks are small and that the development of IVF and ICSI has allowed countless couples to conceive and deliver healthy children.