In vitro fertilization (IVF) is a complex series of procedures used to help with fertility or prevent genetic problems and assist with the conception of a child. IVF is one of the most effective forms of assisted reproductive technology (ART).
During IVF, mature eggs are collected from ovaries and fertilized by sperm in a laboratory. Then, one or more fertilized eggs (embryos) are transferred to the uterus. A full cycle of IVF takes about two to three weeks, but sometimes the steps are divided into different parts, making the process longer.
IVF can be performed using a couple’s own eggs and sperm or with donor eggs, donor sperm, or donor embryos. In some instances, a gestational carrier, someone who has an embryo implanted in their uterus, may be utilized.
The success rate of IVF leading to a healthy baby depends on several factors, including age and the cause of infertility. The procedures can be time-consuming, expensive, and invasive, and the transfer of multiple embryos can result in multiple pregnancies. Your healthcare team can help you understand the process, risks, and whether IVF is right for you.
Why is IVF Performed?
In vitro fertilization is primarily a treatment for infertility or genetic problems. Before considering IVF, other less invasive treatments, such as fertility drugs to stimulate egg production or intrauterine insemination (IUI), where sperm is placed directly into the uterus, might be attempted.
IVF is often recommended as a primary treatment for infertility in individuals over 40 or when specific health conditions are present, such as:
- Fallopian tube damage or blockage: This prevents eggs from traveling from the ovaries to the uterus for fertilization.
- Ovulation disorders: Infrequent or absent ovulation means fewer eggs are available for fertilization.
- Endometriosis: This condition, where tissue similar to the uterine lining grows outside the uterus, can affect the ovaries, uterus, and fallopian tubes.
- Uterine fibroids: These tumors in the uterus can interfere with embryo implantation.
- Previous surgery to prevent pregnancy: IVF can be an alternative to surgery to reverse tubal ligation.
- Sperm issues: Low sperm count, poor sperm motility, or abnormal sperm morphology can hinder fertilization. A male infertility specialist can help determine the underlying cause.
- Unexplained infertility: When the cause of infertility cannot be determined through standard testing.
- Genetic disorders: Preimplantation genetic testing (PGT) can be performed on embryos to screen for specific genetic problems before transfer.
- Fertility preservation: Individuals undergoing cancer treatment (radiation or chemotherapy) can freeze eggs or embryos for future use.
IVF may also be used when a gestational carrier is necessary due to the absence of a functional uterus or serious health risks associated with pregnancy.
What are the Risks Associated with IVF?
IVF carries several potential risks, both short-term and long-term, including:
- Stress: The emotional, physical, and financial demands of IVF can be significant. Counseling and support from family and friends are essential.
- Egg retrieval complications: Bleeding, infection, or damage to the bowel, bladder, or blood vessels can occur during egg retrieval, which involves using a needle to extract eggs from the ovaries. Anesthesia also carries risks.
- Ovarian hyperstimulation syndrome (OHSS): This condition causes swollen and painful ovaries due to fertility medications used to stimulate ovulation. Symptoms range from mild abdominal pain and bloating to more severe rapid weight gain and shortness of breath.
- Miscarriage: The miscarriage rate with IVF using fresh embryos is similar to natural conception rates, increasing with the pregnant person’s age.
- Ectopic pregnancy: A fertilized egg implants outside the uterus, often in a fallopian tube. This is a nonviable pregnancy.
- Multiple pregnancy: Transferring multiple embryos increases the risk of twins, triplets, or higher-order multiple pregnancies, which carry risks like pregnancy-related high blood pressure, diabetes, premature labor and delivery, low birth weight, and birth defects.
- Birth defects: While maternal age is the primary risk factor, IVF is associated with a slightly higher risk of certain birth defects, like heart or digestive problems. More research is needed to determine if IVF is the direct cause.
- Premature delivery and low birth weight: IVF may slightly increase the risk of premature birth and low birth weight.
- Cancer: Earlier studies suggested a possible link between fertility drugs and ovarian tumors, but more recent research doesn’t support a significantly higher risk of breast, endometrial, cervical, or ovarian cancer after IVF.
How to Prepare for IVF
Finding a reputable fertility clinic is the first step. In the United States, the Centers for Disease Control and Prevention (CDC) and the Society for Assisted Reproductive Technology (SART) provide online information about clinic pregnancy and live birth rates. It is important to discuss the costs of each step of the IVF procedure in detail with a clinic representative.
Before starting an IVF cycle using your own eggs and sperm, both partners typically undergo various screening tests:
- Ovarian reserve testing: Blood tests and ultrasound to assess the quantity and quality of eggs.
- Semen analysis: Evaluation of sperm count, motility, and morphology.
- Infectious disease screening: Testing for HIV and other infectious diseases.
- Practice embryo transfer: To determine the depth of the uterus and optimize the transfer technique.
- Uterine exam: Checking the uterine lining via sonohysterography or hysteroscopy to identify any abnormalities.
Prior to beginning IVF, consider these key questions:
- How many embryos will be transferred? Discuss the optimal number of embryos to transfer with your doctor, considering age, egg quality, and medical history.
- What will you do with extra embryos? Decide whether to freeze extra embryos for future use, donate them, or discard them.
- How will you handle a multiple pregnancy? Understand the risks associated with multiple pregnancies and discuss options like fetal reduction.
- Have you considered the risks of using donor eggs, sperm, or embryos, or a gestational carrier? Counselors and attorneys specializing in donor issues can help you understand the legal and emotional implications.
What to Expect During the IVF Process
A single IVF cycle typically takes two to three weeks, and multiple cycles may be necessary. The steps involved include:
Stimulating Egg Production
The IVF cycle begins with hormone medications to stimulate the ovaries to produce multiple eggs, instead of the single egg that typically develops each month. Medications used may include:
- Ovarian stimulation: Injections of follicle-stimulating hormone (FSH), luteinizing hormone (LH), or both, to stimulate follicle development.
- Egg maturation: Human chorionic gonadotropin (HCG) or other medications to trigger egg maturation and release.
- Ovulation prevention: Medications to prevent premature ovulation.
- Uterine lining preparation: Progesterone supplements to prepare the uterine lining for embryo implantation.
Image depicting in vitro fertilization process with egg retrieval, fertilization, and embryo transfer.
Regular monitoring is crucial during ovarian stimulation, including:
- Vaginal ultrasounds: To track follicle development.
- Blood tests: To monitor hormone levels (estrogen and progesterone).
In some cases, an IVF cycle may be canceled due to insufficient follicle development, premature ovulation, or other medical issues.
Egg Retrieval
Egg retrieval is performed 34 to 36 hours after the final fertility medication injection and before ovulation. The procedure involves:
- Administration of medication for relaxation and pain relief.
- Transvaginal ultrasound aspiration: A thin needle guided by ultrasound is inserted through the vagina into the follicles to collect the eggs.
Image illustrating the egg retrieval technique using transvaginal ultrasound aspiration.
After the procedure, cramping and feelings of fullness or pressure may occur. The retrieved eggs are placed in a liquid that supports their development and are mixed with sperm to attempt fertilization.
Sperm Retrieval
If using the partner’s sperm, a semen sample is collected on the morning of egg retrieval through masturbation or other methods. Alternatively, sperm can be collected and frozen in advance. Donor sperm can also be used. The sperm are then separated from the semen fluid in the lab.
Fertilization
Two common methods are used for fertilization:
- Conventional insemination: Healthy sperm and mature eggs are mixed and incubated.
- Intracytoplasmic sperm injection (ICSI): A single healthy sperm is injected directly into each mature egg, often used in cases of poor semen quality.
Image depicting intracytoplasmic sperm injection (ICSI), where a single sperm is injected into an egg.
Other procedures that may be recommended include:
- Assisted hatching: A hole is made in the embryo’s outer layer to facilitate hatching and implantation.
- Preimplantation genetic testing (PGT): A small sample of cells is removed from the embryo and tested for genetic diseases or chromosomal abnormalities.
Embryo Transfer
Embryo transfer is performed two to six days after egg retrieval. The procedure involves:
- A catheter is inserted through the vagina and cervix into the uterus.
- One or more embryos are placed in the uterus using a syringe.
Image of a blastocyst, a rapidly dividing ball of cells formed five to six days after fertilization.
Following the embryo transfer, you can resume your normal routine, but avoid vigorous activities. Common side effects include mild cramping, bloating, and breast tenderness.
Understanding IVF Results
A blood test is performed at least 12 days after egg retrieval to determine pregnancy.
- If pregnant: You will be referred to an obstetrician for prenatal care.
- If not pregnant: Progesterone supplements are stopped, and menstruation should occur within a week. If you wish to try another IVF cycle, your healthcare team will suggest steps to improve your chances of success.
The chances of a successful pregnancy and live birth after IVF depend on factors such as:
- Maternal age: Younger individuals have higher success rates.
- Embryo status: More developed embryos are associated with higher pregnancy rates.
- Reproductive history: Individuals who have previously given birth have a higher likelihood of success.
- Cause of infertility: Certain conditions, like severe endometriosis, can lower success rates.
- Lifestyle factors: Smoking and obesity can negatively impact IVF outcomes.
Discuss any relevant factors with your healthcare team to understand how they may affect your chances of a successful pregnancy.
Clinical Trials and Further Research
Ongoing clinical trials explore new tests and procedures to improve IVF outcomes. Consult with your healthcare provider to learn more about participating in relevant studies.
