What is in vitro fertilization (IVF)?
LAST UPDATED: Jan 10, 2022
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The term “in vitro” means outside the body. During in vitro fertilization (IVF), reproductive specialists retrieve mature eggs from a woman’s ovaries and fertilize them outside of the body in a fertility clinic or other medical facility using a man’s sperm. The fertilized eggs (known as embryos) are frozen and stored for later use or implanted into a woman’s uterus (Choe, 2021).
IVF is a common and effective form of fertility treatment, or assisted reproductive technology (ART). By some estimates, ART now accounts for about 2% of all infants born in the U.S.
While IVF has helped millions of couples overcome infertility issues, the chance of pregnancy and live birth following IVF are, in some cases, low (Sunderam, 2018).
What is IVF?
In vitro fertilization is a form of assisted reproductive technology, or ART. That means it can help people who can’t conceive naturally have a baby.
In some cases, IVF is performed using a couple’s own eggs, sperm, and implanting the embryo into the woman's uterus. In other cases, “donors” provide either the eggs or the sperm, or a gestational carrier (known as a surrogate) may carry the fertilized egg to maturity (Murugappan, 2018).
While it does help some people conceive, IVF is not appropriate for all couples experiencing fertility problems. For example, women with fibroids or polyps may not be good candidates for the procedure (Choe, 2021).
If infertility stems primarily from poor sperm quality (e.g., oligospermia and azoospermia)—something that is the sole cause of infertility in about 20% of cases—, some other fertility procedures (such as intrauterine insemination, or IUI) may be a better choice (Starosta, 2020).
IVF vs. IUI
IUI stands for intrauterine insemination. Along with IVF, it’s one of the most popular infertility treatments (Starosta, 2020).
During IUI, a healthcare provider collects a man’s sperm and then artificially inseminates it into a partner’s or surrogate’s uterus. This can raise the odds of successful egg fertilization. In some cases, the woman simultaneously undergoes ovarian stimulation therapy, which involves medications that can increase her fertility.
IUI may be a better option than IVF when a couple’s fertility issues are related to the health of a man’s sperm. It may also be preferable to IVF in cases of unexplained infertility, which means that health care professionals cannot identify the source of a couple’s fertility challenges. IUI is also an option for same-sex female couples using donor sperm (Starosta, 2020).
How does IVF work?
IVF is a multi-step procedure—sometimes called a “cycle”—that begins with healthcare providers trying to get to the bottom of why a couple is struggling with infertility (Choe, 2021).
If it’s determined that the procedure is appropriate, the first step usually begins at a specific stage of a woman’s menstrual cycle—usually about two weeks before they ovulate (Starosta, 2020).
Here’s a simplified overview of a typical IVF cycle.
Step 1: Ovarian stimulation treatment
Ovarian stimulation encourages a woman’s ovaries to produce multiple healthy and mature eggs (oocytes). Typically, a woman will only produce one healthy oocyte during ovulation. But more are needed during IVF to ensure that a healthy and fertilizable egg is available for later implantation in the uterus (He, 2021).
Stimulation takes the form of injected hormone medications or other fertility drugs. Ideally, this stimulation will ensure that roughly 10 to 20 mature eggs are available for retrieval during the next stage of the IVF process (Choe, 2021).
Step 2: Egg retrieval
The next stage involves the extraction (retrieval) of the mature oocytes from a woman’s ovaries. This egg retrieval procedure requires sedation or anesthesia, and it usually takes anywhere from 30-60 minutes.
During the procedure—which also goes by the name transvaginal oocyte retrieval or oocyte pickup—an ultrasound device is inserted into the vagina. This helps the healthcare professional to see into the ovaries. Using a specialized needle attached to this ultrasound device, the expert pushes the needle through the vaginal wall and extracts the follicular fluid and egg from the ovaries (Singhal, 2017).
Step 3: Egg fertilization
The mature and healthy eggs are fertilized using sperm from a partner or donor. This happens in an incubator that provides an environment similar to the one inside the body for 12-18 hours—a time frame usually enough for one sperm to penetrate and fertilize the egg.
However, if the sperm are not healthy—for example, if they can’t move—a couple’s fertility team may perform what’s called intracytoplasmic sperm injection or ICSI. This involves injecting a single sperm directly into the oocyte. This bypasses the need for the sperm to penetrate the egg by itself (Choe, 2021).
Step 4: Embryo transfer
Roughly 3-5 days after the eggs have been fertilized, one or more healthy fertilized eggs—a.k.a embryos—are transferred into the uterus.
The number of embryos varies depending on a woman’s age. Implanting more embryos increases the odds of a live birth, although it also raises the odds of multiple gestations (meaning twins, triplets, etc.).
This transfer is usually coupled with medications that encourage successful implantation and pregnancy. Meanwhile, any healthy embryos that weren’t implanted are typically frozen so that they can be used later if needed (Choe, 2021).
If a person has had eggs or embryos frozen in the past, the IVF procedure does not include the egg-retrieval step mentioned above.
IVF risks and side-effects
Ovarian stimulation presents some risks. Some estimates have found that between 3–6% of women who undergo stimulation develop mild or moderate ovarian hyperstimulation syndrome (OHSS). OHSS can cause swelling of the reproductive organs, as well as bleeding, pain, and other symptoms. Meanwhile, between 1–3% of women may develop severe or critical OHSS, which can lead to organ damage. Fortunately, OHSS is usually detected early, which lowers the odds of a severe case (Alteri, 2019; Timmons, 2019).
While many may not consider this a drawback, the chance of having twins is higher among people who undergo IVF. Approximately 35% of infants conceived with the help of assisted reproductive technology are twins (Sunderam, 2018).
IVF success rates
It’s hard to predict how successful someone’s IVF procedure will be, meaning how likely an IVF cycle will result in a baby being born. If you look at statistics about IVF, success rates depend on several factors, including how many eggs are transferred, and most importantly, the age of the person carrying the embryo.
For example, for women under age 35 who use their own eggs, about half of embryo transfers result in a live birth. For women 43 and older, the rate was 12%. But again, this rate is different from person to person. The CDC has an IVF Success Estimator tool that helps calculate the estimated success rate based on age and other factors (CDC, 2018).
The cost of IVF can vary greatly from state to state, from clinic to clinic, and from person to person. For example, there may be additional costs if you need to freeze your eggs or embryos or undergo genetic testing to determine the health of your retrieved eggs.
However, as a very rough estimate, you could pay something in the range of $14,000–$16,000 for a single IVF cycle (UMMC, n.d.).
IVF has helped millions of couples overcome infertility. While the procedure is not guaranteed to work and can be costly, it often provides the best chance of parenthood for those with fertility challenges. A fertility specialist can help you determine if IVF is a good treatment option for you.
If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.
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