IVF explained: stim, retrieval, transfer, success rates by age

The four phases of an IVF cycle

Phase 1 — Stimulation (8–14 days): daily injections of FSH (and usually LH) push the ovaries to mature multiple eggs at once instead of one. You'll have monitoring ultrasounds and bloodwork every 1–3 days.

Phase 2 — Trigger and retrieval (1 day): a 'trigger shot' (hCG or Lupron) finalizes egg maturation. Eggs are retrieved 34–36 hours later under IV sedation in a 20–30 minute outpatient procedure.

Phase 3 — Fertilization and culture (1–6 days): eggs meet sperm in the lab (conventional IVF or ICSI). Embryos are watched for 3 days (cleavage stage) or 5–6 days (blastocyst stage).

Phase 4 — Transfer (1 day): a single embryo is placed into the uterus via a thin catheter. No anesthesia. A pregnancy test follows 9–12 days later.

Fresh vs frozen transfer

Many clinics now do a 'freeze-all' cycle — all viable embryos are frozen, and transfer happens in a later cycle when hormone levels have normalized. Frozen transfer rates have caught up to or surpassed fresh transfer rates in many centers and reduce the risk of ovarian hyperstimulation.

Live birth rates by age (per egg retrieval)

From CDC ART data (most recent published): under 35: ~50% live birth per intended retrieval; 35–37: ~38%; 38–40: ~25%; 41–42: ~13%; over 42: ~4%. These numbers improve when looking at cumulative live birth across multiple transfers from a single retrieval.

What it costs

A single IVF cycle in the US averages $15,000–$25,000 for the medical portion, plus $3,000–$7,000 in medications. Add-ons (ICSI, PGT-A, freezing, storage, anesthesia) can push the all-in cost to $25,000–$35,000+. Multi-cycle and refund packages may lower the per-cycle cost.