How IVF actually works, day by day

An IVF cycle is roughly a month of structured medical work in which your ovaries grow many follicles instead of one. The procedure has been done over twelve million times worldwide since 1978. Here is what happens at each stage.

Days 1 to 3: starting

The cycle begins on day 2 or 3 of your period with a baseline ultrasound and bloodwork. Once the team confirms the ovaries are quiet (no large cysts, baseline hormones in range), you start nightly injections of FSH-containing medication. The first few days you feel almost nothing.

Days 4 to 10: stimulation

You go in for monitoring every two to three days. Each visit is a quick blood draw (estradiol, LH, progesterone) and a transvaginal ultrasound to count and measure follicles. The medication dose is adjusted based on response. Around day 5 to 7, an antagonist injection is added to prevent your body from ovulating early.

Physically you may feel bloated, full, sometimes bruised at injection sites. Mood swings are common. The follicles you see on the screen during scans are not eggs – they are fluid-filled sacs that contain eggs.

Day of trigger: precision timing

When the leading follicles reach about 17 to 18 mm, you are given a trigger shot – either hCG or Lupron – at a precisely scheduled time. The trigger finalises egg maturation. Egg retrieval is exactly 35 to 36 hours later.

Day of retrieval

A 20-minute outpatient procedure under sedation. A needle, guided by transvaginal ultrasound, aspirates fluid from each follicle. The fluid is examined under a microscope to find and count the eggs. You go home a few hours later. You will feel sore for 24 to 48 hours.

Days 0 to 5 in the lab

Day 0 is retrieval. Day 1 is the fertilisation report (how many of the mature eggs fertilised). Days 3, 5, and sometimes 6 are the embryo grading days. Most clinics now culture to day 5 (blastocyst stage) before transfer or freeze, because blastocysts implant at higher rates than earlier-stage embryos.

Transfer or freeze

If you are doing a fresh transfer, it usually happens on day 3 or day 5. More clinics are now preferring a “freeze-all” approach: cryopreserve all viable embryos and transfer them in a separate, hormonally-prepared cycle. The data on frozen versus fresh transfer is mixed but trending toward frozen for many indications.

The two-week wait

Nine to fourteen days after transfer, a blood beta hCG confirms or denies pregnancy. Strong rising betas (doubling every 48 hours early on) are reassuring. The first ultrasound at six to seven weeks confirms viability and location.

Questions worth asking your doctor

• What protocol are we on (antagonist, agonist, mini-IVF), and why is it the right one for me?
• What is the realistic egg yield and live-birth rate for someone my age and AMH at this clinic?
• Are we planning a fresh transfer or freeze-all? Why?
• What signs should I call about during stimulation – what would worry you?

This essay is educational. Every patient’s situation is different – the right plan is shaped in conversation with a fertility specialist who knows the full picture.