In vitro fertilization (IVF) is a multi-step fertility treatment where eggs are collected from the ovaries, fertilized with sperm in a laboratory, and then transferred back into the uterus as embryos. A single cycle typically takes four to six weeks from start to finish, though preparation and testing can add time before that clock starts. Here’s what actually happens at each stage.
Testing Before You Start
Before any IVF cycle begins, your clinic will run baseline blood work and imaging to understand how your body is likely to respond to treatment. Two key hormone levels guide the process. FSH (follicle-stimulating hormone) is drawn in the first five days of your menstrual cycle, with levels at or below 10 IU/L considered normal. AMH (anti-Müllerian hormone) can be tested on any day of your cycle and gives a picture of your remaining egg supply. Levels below 5 pmol/L suggest a reduced ovarian reserve, which affects how aggressively your stimulation protocol will be designed.
You’ll also have an ultrasound to count the small follicles visible on each ovary, along with screening for infectious diseases, a uterine evaluation, and a semen analysis for your partner or sperm donor. These results shape every decision your clinic makes going forward, from medication doses to timing.
Ovarian Stimulation
In a natural cycle, your body releases one egg per month. IVF needs more than that to work with, so you’ll take daily hormone injections to push your ovaries to develop multiple eggs at once. The primary medication is a synthetic form of FSH, the same hormone your brain naturally sends to your ovaries. Most protocols call for daily injections over 10 to 14 days, with 12 days being a common target.
During this phase, you’ll visit the clinic every two to three days for blood draws and ultrasounds. Your doctor is tracking how many follicles are growing and how large they’re getting. Based on those numbers, your medication dose may be adjusted up or down. When enough follicles reach the right size, you’ll take a final “trigger shot” that matures the eggs and sets up the precise timing for retrieval, usually 34 to 36 hours later.
Ovarian Hyperstimulation Syndrome
The main risk during stimulation is ovarian hyperstimulation syndrome (OHSS), where the ovaries overreact to the hormones. Mild cases cause bloating, nausea, and abdominal tenderness. Severe cases, which are less common, can bring rapid weight gain (more than 2.2 pounds in 24 hours), shortness of breath, decreased urination, and blood clots. Your clinic monitors for early signs during those frequent check-in appointments, and medication adjustments or a different trigger shot can lower the risk significantly.
Egg Retrieval
Egg retrieval is a short surgical procedure, usually lasting 15 to 30 minutes. A thin needle attached to an ultrasound probe is guided through the vaginal wall into each ovarian follicle, where fluid containing the egg is gently suctioned out. You’ll feel nothing during the procedure itself because you’ll be under some form of anesthesia, most commonly IV sedation. Some clinics use general anesthesia, a spinal block, or local anesthesia with sedation depending on your medical history and their standard practice.
Afterward, expect cramping and bloating similar to a heavy period. Most people take one to two days off work. The number of eggs collected varies widely, but your clinic will call you the same day or the next morning with a count and an update on how many were mature enough for fertilization.
Fertilization and Embryo Development
Once the eggs are in the lab, sperm is introduced either by placing it around each egg in a dish (conventional IVF) or by injecting a single sperm directly into each egg (a technique called ICSI, commonly used when sperm quality is a concern). The embryology team checks the next morning to see how many eggs fertilized successfully.
A fertilized egg starts as a single cell called a zygote, containing genetic material from both parents. It divides into two cells, then four, then eight, continuing to multiply over the next several days. By day five or six, a healthy embryo has reached the blastocyst stage, a ball of 70 to 100 cells with two distinct structures: an outer layer that will become the placenta and an inner cluster that will become the baby. Not every fertilized egg makes it to this stage. It’s normal for the number to drop at each checkpoint.
Genetic Testing
If you opt for preimplantation genetic testing (PGT-A), a few cells are biopsied from the outer layer of each blastocyst and sent to a genetics lab. The test checks whether the embryo has the correct number of chromosomes. Embryos with extra or missing chromosomes are the leading cause of implantation failure and early miscarriage. Once a genetically normal embryo is identified and transferred, the chance of a successful pregnancy holds relatively steady regardless of the patient’s age, which is a significant advantage for people in their late 30s and 40s. Results typically take one to two weeks, meaning the embryos are frozen while you wait.
Embryo Transfer
The transfer itself is one of the simplest parts of the process. A thin catheter is threaded through the cervix, and a single embryo (sometimes two) is placed into the uterine lining. It takes about five minutes, requires no anesthesia, and feels similar to a Pap smear. You can go home shortly after.
You’ll have a choice between a fresh transfer, done three to five days after egg retrieval in the same cycle, or a frozen transfer, done in a later cycle after the embryos have been cryopreserved. Frozen transfers have become increasingly common, and the data supports that shift. A study of nearly 2,900 patients found that frozen embryo transfers produced a clinical pregnancy rate of 47% compared to 35% for fresh transfers. Live birth rates were also significantly higher in the frozen group (39% vs. 16%), and rates of preterm delivery, low birth weight, and first-trimester miscarriage were all lower.
The reason for the difference comes down to timing. After ovarian stimulation, hormone levels are elevated and the uterine lining may not be in its most receptive state. Waiting a cycle allows your body to recover and lets the clinic prepare your lining under more controlled conditions.
The Two-Week Wait and Pregnancy Test
After transfer, there is nothing to do but wait. About 9 to 12 days later, you’ll have a blood test measuring the pregnancy hormone hCG. A positive result leads to a follow-up blood draw two days later to confirm levels are rising, then an ultrasound around six to seven weeks to check for a heartbeat. During this stretch, you’ll typically continue progesterone supplementation (usually vaginal suppositories or injections) to support the uterine lining.
Success Rates by Age
Age is the single biggest factor in IVF outcomes because egg quality declines over time. Live birth rates after one egg retrieval cycle, including all fresh and frozen transfers from that collection, break down roughly as follows:
- Under 35: 58%
- 35 to 37: 49%
- 38 to 39: 32%
- 40 to 42: 26%
- 43 and older: 14%
These numbers represent one complete cycle, meaning every usable embryo from a single egg retrieval. Many people go through more than one cycle, and cumulative success rates over two or three cycles are considerably higher. Clinics vary in their outcomes, so asking for clinic-specific data at your consultation is worth doing.
What It Costs
In the U.S., the average cost of a single IVF cycle in 2026 is $23,474. That figure includes everything, but the bill typically arrives in pieces. The base clinic fee covers monitoring appointments, egg retrieval, anesthesia, lab work, and embryo transfer, running $8,000 to $14,000. Medications are billed separately and range from $3,000 to $7,000 depending on your protocol and dosing. Genetic testing, embryo freezing, and storage fees add thousands more on top of that.
Insurance coverage varies dramatically by state and employer. Some states mandate IVF coverage, others don’t cover it at all. Many clinics offer multi-cycle discount packages or financing plans, and some employers now include fertility benefits through third-party programs. It’s worth checking all of these before your first appointment, since out-of-pocket costs are one of the most common reasons people delay or stop treatment.