Egg harvesting, formally called egg retrieval, is a short outpatient procedure where a doctor uses a thin needle guided by ultrasound to collect eggs directly from the ovaries. The procedure itself takes roughly 15 to 30 minutes, but the full process spans about two weeks of preparation beforehand. Whether you’re freezing eggs for later use or going through IVF, the steps are essentially the same.
Ovarian Stimulation: The Two-Week Buildup
Your ovaries normally release one egg per menstrual cycle. The goal of egg harvesting is to collect many eggs at once, so the process begins with injectable hormone medications that push your ovaries to develop multiple follicles (the small fluid-filled sacs that each contain an egg). These injections contain follicle-stimulating hormone, sometimes combined with luteinizing hormone, and are self-administered once or twice a day for roughly 7 to 14 days. Timing matters: each injection should happen at about the same time every day, within a 30-minute window.
During this phase, you’ll visit the clinic frequently for monitoring. Patients on injectable medications may need up to seven appointments over two weeks. At each visit, the clinic measures two things: the size of your developing follicles via transvaginal ultrasound, and your estrogen levels through a blood draw. Rising estrogen confirms the follicles are maturing. Follicles grow roughly 1 to 3 millimeters per day during the active growth phase, and the target size is 18 to 20 millimeters or larger. Your doctor uses these numbers to adjust medication doses mid-cycle and to pinpoint the right moment for the next step.
The Trigger Shot
When the lead follicles reach the target size and estrogen levels are climbing appropriately, you’ll take a precisely timed “trigger shot.” This injection mimics the natural hormone surge that tells your eggs to complete their final stage of maturation inside the follicle. It’s given exactly 35 to 37 hours before the scheduled retrieval, and the timing is non-negotiable. Too early or too late, and the eggs may not be at the right developmental stage, or they could ovulate on their own before the doctor can collect them. After the trigger shot, no further injections are needed.
The Day of Retrieval
You’ll be asked not to eat or drink for about seven hours before the procedure. Some clinics provide a pain-relief suppository to take an hour beforehand, and most use sedation or light anesthesia so you’re comfortable and drowsy throughout.
The retrieval uses a technique called transvaginal ultrasound aspiration. An ultrasound probe is inserted into the vagina to locate each mature follicle on the ovaries. A thin needle is then guided through the vaginal wall and into the follicles one by one. The needle connects to a gentle suction device that draws the fluid, and the egg within it, out of each follicle. The doctor works through all the visible follicles on both ovaries. The entire process typically takes 15 to 30 minutes.
How Many Eggs to Expect
On average, 10 to 20 eggs are retrieved per cycle, though this varies widely depending on age, ovarian reserve, and how your body responded to the medications. Not every egg collected will be usable. Some will be immature, meaning they haven’t completed the developmental stage needed for fertilization or freezing. A retrieval that yields 10 to 15 mature eggs is generally considered a good outcome.
What Happens in the Lab
Within an hour of collection, an embryologist examines each egg under a microscope. The surrounding cells are gently removed in a process called denuding, and each egg is assessed for maturity. Only eggs that have reached a specific developmental stage (called metaphase II) are suitable for the next step, whether that’s fertilization with sperm for IVF or freezing for future use.
If you’re freezing eggs, the lab uses a rapid-freezing method called vitrification. The eggs are placed in a protective solution, then gradually exposed to increasing concentrations of a cryoprotectant over a few minutes before being plunged into liquid nitrogen. This flash-freezing approach prevents ice crystals from forming inside the egg. When thawed later, about 74% of vitrified eggs survive the process, on average.
Recovery After the Procedure
Most people feel groggy from sedation for the first few hours and experience mild to moderate cramping and bloating for a day or two. Your ovaries are still enlarged from stimulation, and they need time to return to normal size. Here’s what the typical recovery timeline looks like:
- First 24 to 48 hours: Rest and stick to gentle walking. Avoid lifting anything heavy.
- 48 hours until your next period: Light stretching or restorative yoga is fine, but skip running, cycling, jumping, or weightlifting. High-impact activity while the ovaries are still swollen increases the risk of ovarian torsion, a painful twisting of the ovary.
- After your first post-retrieval period: Most people can gradually return to their normal exercise routine, including cardio and strength training, as long as there’s no lingering pain or bloating.
Mild soreness in the days following retrieval is expected. Sharp or severe cramping during any activity is a signal to stop and rest.
Risks and Side Effects
The most well-known complication is ovarian hyperstimulation syndrome, or OHSS, where the ovaries overreact to the stimulation medications. Moderate OHSS occurs in about 3 to 6% of cycles and causes abdominal bloating, discomfort, nausea, and vomiting from swollen ovaries. The severe form, which affects 0.1 to 3% of cycles, can cause fluid buildup in the abdomen or chest, breathing difficulty, and changes in blood clotting and kidney function. Severe OHSS requires medical attention. Your clinic monitors for early signs of OHSS during the stimulation phase and may adjust your protocol to lower the risk if your ovaries are responding aggressively.
Other potential side effects are those common to any needle-based procedure: minor bleeding, infection, or discomfort at the retrieval site. These are uncommon, and most people go home within an hour or two of waking up from sedation.