IVF steps: what happens and how long it takes

IVF follows five basic steps: ovarian stimulation, egg retrieval, fertilization, embryo growth in the lab, and embryo transfer. After the embryos grow, the path splits. Some people have an embryo placed in the uterus a few days after retrieval. Others have their embryos frozen and transferred in a later cycle.

Your clinic's calendar is the one to follow, and this page shows where each date on it fits. If you feel unwell at any point, the warning signs are near the end, with what to do for each.

How long each IVF stage takes

On average, the time from the first fertility medicines to the pregnancy test is about four to six weeks. That estimate leaves out the tests before you start. It also leaves out a frozen transfer, which happens in a later cycle with its own medicines and visits.

Stage	What happens	Timing
Before you start	Exams, fertility tests, sometimes birth control pills or estrogen	Before the cycle begins
1. Stimulation	Daily hormone shots and monitoring visits, ending with the trigger	Most last 8 to 14 days
2. Egg retrieval	Eggs collected under sedation	34 to 36 hours after the trigger; home the same day
3. Fertilization	Eggs and sperm are put together in the lab	After retrieval
4. Embryo growth	Embryos grow in the lab	Up to day 5 or 6 after retrieval
5a. Fresh transfer	An embryo is placed in the uterus	3 or 5 days after retrieval
5b. Frozen transfer	The lining is prepared, then a thawed embryo is placed	A later cycle; in a medicated cycle, about 2 weeks of estradiol before the lining check
Pregnancy test	A blood test for the pregnancy hormone	About 9 to 14 days after transfer

Before you start

You will have a full medical exam and fertility tests first. Your doctor may also give you birth control pills or estrogen. These can stop ovarian cysts from forming and help control the timing of your cycle.

This is a good time to set yourself up for the busy weeks ahead. Save your clinic's latest calendar where you can find it fast, and put the after-hours number in your phone, because instructions can change between visits.

Step 1: Stimulation and the trigger

Normally your body grows one egg a month. In IVF, hormone shots help several eggs grow at once. Each egg grows inside a small fluid sac called a follicle.

Most stimulations last 8 to 14 days. During this time you go in for blood tests and vaginal ultrasounds. They show how the follicles are growing and how your hormone levels are rising. Visits may be as often as every day.

When the follicles are ready, your clinic will give you a trigger medicine plan and an exact time to take it. The trigger helps the eggs finish maturing, and retrieval is timed from it. Read more in IVF stimulation and IVF stimulation protocols.

Step 2: Egg retrieval

Egg retrieval happens 34 to 36 hours after the trigger, and you go home the same day. You get medicine through an IV that makes you sleep. The doctor then uses an ultrasound to guide a thin needle into each follicle and draw out the fluid and eggs.

Some people have cramping that day, and it usually eases by the next day. See egg retrieval day and egg retrieval recovery.

Step 3: Fertilization

The lab puts eggs and sperm together. Sometimes they mix in a dish. Sometimes a single sperm is injected into each egg, which is called ICSI. Your IVF team decides which is right for you, based on things like your diagnosis and your past treatment.

Step 4: Embryo growth in the lab

A fertilized egg is now an embryo. Most times in IVF, embryos are grown to the blastocyst stage, which is day 5 or 6 after retrieval.

Expect the numbers to change as the days go by. Not every egg collected is mature, not every mature egg fertilizes, and some embryos stop growing in the lab. So the count of eggs, then fertilized eggs, then embryos suitable for freezing or transfer can each be smaller than the one before. Embryo development explains the daily lab reports and what each count means.

After embryo growth: fresh transfer or freezing

Once the embryos have grown, there are two choices. Your clinic will tell you which one fits your cycle, and the plan can change based on how your body and your embryos respond.

Fresh transfer. An embryo is placed in your uterus in the same cycle, 3 or 5 days after retrieval. Any other embryos suitable for freezing may be frozen for later. See fresh embryo transfer.

Freezing, then a later frozen transfer. No embryo is transferred this cycle. Instead, embryos suitable for freezing are stored. A clinic may choose this when it is safer or works better than transferring a few days after retrieval. Freezing also makes genetic testing of embryos possible, if you choose it. This is called a freeze-all cycle. Read more in embryo freezing.

So frozen embryos can come from either route: a freeze-all cycle, or embryos left over after a fresh transfer. Fresh vs frozen transfer compares the two.

Step 5: Embryo transfer

Transfer is quick. A thin tube called a catheter goes through your cervix into your uterus, and the embryo is placed through it. No anesthesia is needed, though some people feel mild cramping. Your team decides how many embryos to transfer, aiming for the best chance of pregnancy with the lowest chance of twins or more. See embryo transfer day.

A frozen transfer uses an embryo from an earlier retrieval, so another egg collection is not needed. It still takes its own cycle of medicines and visits. In a programmed (medicated) cycle, you take the hormone estradiol to build up the lining of your uterus. An ultrasound after about 2 weeks checks whether it is thick enough. When it is, you add progesterone. Its start time matters, because the thaw and transfer are timed to it. Some clinics use a modified natural cycle instead. Read frozen embryo transfer, natural FET and medicated FET.

After transfer: the pregnancy test

After transfer, you may take the hormone progesterone to help the embryo attach. The pregnancy test comes about 9 to 14 days after transfer. It is a blood test that checks for hCG, the pregnancy hormone, and your clinic sets the date. Read after embryo transfer.

Why an IVF plan can change

IVF does not always go in a straight line, and a change is your team adjusting to what the tests show. These are the main reasons:

• Too few follicles grow. Stimulation may be stopped, and your team will talk with you about other ways to manage your treatment.
• Too strong a response. If the risk of ovarian hyperstimulation syndrome (OHSS) is high, the team may freeze all embryos for a later transfer, or stop the cycle.
• Retrieval is called off. Rarely, retrieval is cancelled shortly before it is due because ovulation happened early or hormone levels dropped.
• The lining is slow. Before a frozen transfer, the lining sometimes takes longer to thicken than expected. That can move the transfer date and may mean extra hormones and more monitoring.

If your cycle is stopped or a transfer moves, cancelled cycle or postponed transfer explains what to ask next. If you are freezing eggs rather than making embryos, the steps are shorter. See the egg freezing timeline.

Your IVF milestone checklist

Use this list in your own notes, so you can see what is done and what to ask about next.

• Exams, tests and consent forms done
• Medicine plan and start date confirmed
• Latest calendar and after-hours number saved
• First stimulation shot given
• Monitoring visits booked
• Trigger medicine plan and exact time written down
• Retrieval day ride home arranged
• Fertilization report received
• Embryo updates received (day 3, day 5 or 6)
• Plan confirmed: fresh transfer, or freezing and a later frozen transfer
• Transfer date and time confirmed
• Pregnancy test date written down

When to get help

Call your clinic right away, day or night, if you have:

• A fever of 100.4°F (38°C) or higher.
• Heavy bleeding: soaking a full-size pad with bright red blood in less than an hour, or bleeding heavier than a period. Before a transfer, call for bleeding your clinic did not tell you to expect or a brown, watery discharge. After one, call for any bleeding.
• Belly or pelvic pain that is severe, gets worse, or isn't eased by the pain relief your clinic recommended.
• Pain and bloating in your belly, or bloating that is getting worse.
• Nausea and vomiting, nausea that won't go away, or you can't keep fluids down.
• Peeing less than usual, even if you are not thirsty.
• Fast weight gain. Your clinic will tell you its number, but do not wait to reach a weight threshold if you feel unwell.
• Before a transfer: sudden belly pain, dizziness, lightheadedness, or feeling faint.
• Pain, redness or warmth in an arm or leg.
• Blood in your urine, or pain when you pee or poop.
• Discharge from your vagina that smells bad, after a retrieval.

Belly pain, bloating and vomiting can be signs of OHSS, so do not wait for your next visit.

Tell your clinic at your next contact about other milder symptoms that are new, don't go away or slowly get worse.

Key takeaway

Each IVF stage has its own timing, and a frozen transfer adds a later cycle. Keep your clinic's latest calendar close and check the date for your next step at each visit. Know which signs mean calling the clinic and which mean calling 911.