What is IVF: step by step
1. Ovarian stimulation
Daily injections encourage several follicles to develop rather than the single one of a natural cycle.
Dose. ESHRE (2026) defines conventional dosing as 150–225 IU, stating there are limited indications to deviate. For predicted high responders, a reduced dose of 100 to under 150 IU is probably recommended to lower OHSS risk. For predicted low responders, doses above 300 IU are not recommended — a strong recommendation, because higher doses do not improve oocyte yield or live birth while adding cost and side effects.
Protocol. The GnRH antagonist protocol is recommended over agonist protocols in the general IVF population, given comparable efficacy and better safety. The fixed antagonist protocol is probably preferred over the flexible one.
Worth knowing: adjusting the dose mid-stimulation, up or down, is probably not recommended. The starting dose therefore needs to be right from the outset — which is why pre-treatment assessment matters more than mid-cycle adjustment.
2. Monitoring
Ultrasound tracks follicle growth. ESHRE notes that adding oestradiol to ultrasound monitoring is probably not recommended, and neither is routine monitoring of endometrial thickness during stimulation.
One measurement that is probably recommended: serum progesterone on the day of trigger, in cycles planning a fresh transfer. Where high, you should be counselled about potentially lower pregnancy rates, and any decision to defer transfer weighed alongside oocyte number, embryo number and quality.
3. Trigger
An injection matures the eggs, timed for retrieval about 36 hours later. Follicles are most often triggered at 16–22 mm.
Where OHSS risk is high, a GnRH agonist trigger with freeze-all is recommended to minimise severe OHSS — strong. Dopamine agonists are also recommended to reduce early OHSS risk, particularly with an hCG trigger.
4. Egg retrieval
A short procedure under sedation, using ultrasound-guided needle aspiration. Expect cramping and some spotting afterwards.
Contact your clinic the same day for severe or worsening pain, marked bloating, breathlessness, reduced urine output, or weight gain over about a kilogram in 24 hours.
5. Fertilisation
Conventional IVF or ICSI. Normal fertilisation is assessed at 17 ± 1 hours. Laboratory benchmarks: fertilisation rate competency at least 60%, benchmark 75%.
6. Embryo culture
Cultured to day 3 or day 5. Blastocyst development rate on day 5, per normally fertilised egg: competency at least 40%, benchmark 60%. Not all embryos reach blastocyst — that is expected, not a failure.
7. Transfer
Brief, no anaesthetic needed. Afterwards, bed rest does not improve success rates. Normal activity is fine, and nothing you do in an ordinary day will dislodge the embryo.
8. Luteal support
Progesterone is recommended. Where dydrogesterone is used, ESHRE (2026) records published reports of an association with congenital malformations, causality not established — worth discussing with your doctor.
9. The wait
A pregnancy test around two weeks after transfer.
What to ask before starting
Your clinic's live birth rate per cycle started for your age band — not per transfer, which excludes cycles that never reached transfer.
Frequently Asked Questions
What is IVF in simple terms?▾
IVF means fertilising eggs with sperm outside the body. Eggs are collected from the ovaries after hormone stimulation, combined with sperm in a laboratory, and the resulting embryo is transferred back into the uterus. One cycle takes approximately 5–6 weeks.
Is IVF painful?▾
The daily injections are mildly uncomfortable. Egg retrieval is done under sedation and most patients feel period-like cramping afterwards. The embryo transfer is usually painless — similar to a cervical smear. Most patients find the emotional stress of waiting for results more difficult than the physical procedures.
How many IVF cycles does it take to get pregnant?▾
Most successful IVF pregnancies occur within 2–3 cycles. Cumulative live birth rates across 3 cycles are 60–70% for women under 40 (ESHRE data). Per-cycle success depends primarily on age. A fresh egg collection plus 2–3 frozen transfers from surplus embryos can constitute multiple attempts from one stimulation.
What is the difference between IVF and ICSI?▾
In conventional IVF, 50,000+ sperm are placed with each egg and fertilisation happens naturally. In ICSI, a single sperm is injected directly into each egg. ICSI is used for male factor infertility, low sperm counts, or previous failed fertilisation. Most Indian clinics use ICSI for all IVF cycles.