The Short Answer
IVF — in vitro fertilization — is when doctors take eggs from your ovaries, fertilize them with sperm in a lab, and put one of the resulting embryos back into your uterus. A single cycle takes about four to six weeks from your first injection to a pregnancy test. There are five main stages: stimulating your ovaries, retrieving the eggs, fertilizing them in the lab, doing the transfer, and then the two-week wait. Each stage has a clear purpose — and once you know what's happening and why, the whole thing feels a lot less scary.
The Five Stages of an IVF Cycle
Stage 1: Ovarian Stimulation (Days 1–12)
Normally, your body releases one egg a month. IVF changes that. You inject hormone medications every day for 10 to 14 days to coax your ovaries into growing multiple follicles — the small sacs that hold eggs — at the same time. More eggs means more embryos to work with, and more chances at a successful transfer.
During those two weeks, you'll go in for monitoring appointments every couple of days — early-morning blood draws and an ultrasound to see how your follicles are growing. When they're big enough, you take a "trigger shot" to finish maturing the eggs. Retrieval happens exactly 36 hours later. The timing matters, so you'll know the date and time well in advance.
Most people experience bloating, mood swings, and some tenderness during stimulation. It's not fun, but it's manageable. About 1–3% of patients have a stronger overreaction called OHSS — your clinic watches for it and can step in if needed.
Stage 2: Egg Retrieval
The retrieval itself is a 15- to 20-minute procedure done under light sedation — the ASRM patient guide on IVF has more detail on each phase — you're not awake for it. Your doctor uses a thin needle, guided by ultrasound, to collect the fluid and eggs from each follicle. You go home an hour or so later. Most people feel crampy and tired for a day, then bounce back pretty quickly.
How many eggs you get depends on your age and how your ovaries responded. Women under 35 often retrieve 10–20 eggs. That number falls with age. Not every egg will be mature, and not every mature egg will fertilize — your clinic will give you updates at each step over the next few days.
Stage 3: Fertilization and Embryo Development (Days 1–6 in the Lab)
Once your eggs are in the lab, the embryologists get to work. They either put the eggs in a dish with prepared sperm and let fertilization happen naturally, or — if there's a sperm issue — they inject a single sperm directly into each egg. That second approach is called ICSI, and it's used a lot.
Over the next five or six days, the fertilized eggs grow into embryos. The team watches them develop to a stage called a blastocyst, which is the best point for a transfer or freezing. Not every fertilized egg makes it that far — usually about 40–60% do. If you're doing genetic testing on the embryos, the lab takes a small biopsy at this stage and freezes everything while you wait for results.
Stage 4: Embryo Transfer
The transfer is the easiest part. You're awake. A thin tube goes through your cervix into your uterus, the embryo is placed, and it's done in 5–10 minutes. Most people compare it to a Pap smear. You'll need a full bladder so the doctor can see what they're doing on ultrasound. No sedation needed.
A lot of clinics now freeze all the embryos after retrieval and do the transfer in a separate cycle a month or two later. That "freeze-all" approach lets your body recover from all the stimulation hormones before asking it to support an embryo. Research shows it often leads to better results, especially for patients who responded strongly to the medications.
Stage 5: The Two-Week Wait
After the transfer, you wait about 10–14 days for a blood test to confirm whether it worked. There's nothing clinical to do during this time — just progesterone supplements and a lot of waiting. This is universally agreed to be the hardest part. Some people feel cramping or early pregnancy symptoms; others feel nothing. Neither one tells you anything useful. See our guide on surviving the two-week wait if you're dreading it.
A positive test is a good sign, but not the finish line — the pregnancy still needs to progress. Most clinics check your numbers at two points to make sure things are moving in the right direction before scheduling an ultrasound at around 6 weeks.
How long does IVF take from start to finish?
One full cycle — first injection to pregnancy test — takes about four to six weeks. If you're doing a frozen embryo transfer in a separate cycle, add another four to six weeks. From your first consultation to a confirmed pregnancy, plan for three to six months once you factor in testing, cycle prep, and wait times.
How many eggs do they usually retrieve?
It varies a lot by age and how your ovaries respond. A rough guide: women under 35 average 12–20 eggs; ages 35–37 average 10–15; ages 38–40 average 8–12; and over 40 the numbers fall further. These are just averages — your AMH test and a follicle count before you start give a better picture of what to expect for you specifically. See our AMH guide for more on that.
What if the first cycle doesn't work?
A failed first cycle is more common than most people expect — nationally, around half of cycles at any age don't result in a live birth. That's hard to hear, but it doesn't mean IVF won't work for you. Most clinics do a debrief to look at what happened at each stage, and sometimes a small protocol change makes a difference. Most people who succeed with IVF do so within three cycles. Our post on IVF success rates by age has the full data.
What are IVF success rates?
According to CDC data, live birth rates per egg retrieval are roughly 45–55% for women under 35, 35–45% for ages 35–37, 25–35% for ages 38–40, and under 15% for women over 40. These are national averages — individual clinic numbers vary, which is why looking at a specific clinic's CDC data before choosing matters. Our directory shows those numbers for all 524 clinics.
Who is IVF actually for?
IVF is usually recommended when tubes are blocked, there's a significant sperm issue, simpler treatments haven't worked, or you need genetic screening of embryos before transfer. It's also the main path for same-sex couples and single parents. Your doctor will recommend it based on what's actually going on for you — it's not always the first step, and it shouldn't be.
Find the Right Clinic
Every IVF clinic has a different mix of strengths — some are better for complex cases, some for older patients, some for LGBTQ+ families. Browse our directory of 524 fertility clinics to compare CDC success rates and services. Or use our free matching tool to find a clinic that fits your situation.