Different IVF types: conventional IVF, ICSI, FET, and mild stimulation

Conventional IVF: The Standard Approach

In conventional IVF, mature eggs are placed in a culture dish with prepared sperm and fertilization occurs naturally over several hours. This approach is used when sperm counts and motility fall within acceptable ranges and prior fertilization has been successful. It is less interventional than ICSI and preserves the natural selection process at the fertilization stage. Fertilization rates typically range from 60–80 percent in favorable cases.

ICSI: Intracytoplasmic Sperm Injection

ICSI involves injecting a single sperm directly into each mature egg under a high-powered microscope. It is the standard of care when male factor infertility is present (low count, poor motility, or abnormal morphology), when sperm is retrieved surgically, or when prior conventional IVF cycles produced poor fertilization. ICSI is also commonly used when eggs will undergo preimplantation genetic testing (PGT), because the controlled environment reduces contamination risk. ICSI does not guarantee better outcomes than conventional IVF in couples without male factor infertility.

Fresh Transfer vs Frozen Embryo Transfer (FET)

A fresh transfer places an embryo into the uterus in the same cycle as egg retrieval. A frozen transfer cryopreserves embryos and transfers them later, after a separate uterine preparation phase. FET has become increasingly common because it allows time to: recover from stimulation, obtain PGT results if biopsy was performed, synchronize the uterine lining more precisely, and avoid elevated progesterone that can occur in stimulation cycles. Several large studies suggest FET may have slightly higher live birth rates in certain populations, though results depend heavily on individual clinic protocols.

Mild Stimulation IVF

Mild stimulation IVF (mini-IVF) uses lower doses of fertility medications or natural cycle approaches to retrieve fewer eggs intentionally. It is sometimes considered for women with very low ovarian reserve who respond poorly to standard doses, or for those seeking to reduce cost, medication burden, and OHSS risk. The tradeoff is fewer eggs retrieved and fewer embryos available. Success rates per cycle are generally lower, but per-embryo metrics can be comparable. Mild stim is not appropriate for all patients — your doctor’s recommendation should be based on your specific response history and diagnosis.

PGT-A, PGT-M, and PGT-SR: What Testing Adds

Preimplantation genetic testing involves biopsying embryo cells at day 5–6 to screen for chromosomal abnormalities (PGT-A), specific inherited conditions (PGT-M), or chromosomal structural rearrangements (PGT-SR). PGT-A can improve the rate of transferring chromosomally normal embryos and reduce miscarriage risk in high-risk populations. However, it adds cost, carries a small embryo loss risk from biopsy, and does not improve live birth rates when the population already has a high proportion of normal embryos. Discuss with your specialist whether testing makes sense for your specific situation.

Choosing Between Options: Decision Guide

• Specific male factor diagnosis? ICSI likely indicated.
• Planning genetic testing? ICSI typically required alongside PGT.
• OHSS risk or high estrogen in a prior cycle? FET preferred.
• Previous fresh transfers failed without clear cause? FET worth considering.
• Respond poorly to stimulation? Discuss mild stim or natural cycle options.

Key Takeaways

This article on Different IVF types: conventional IVF, ICSI, FET, and mild stimulation is designed to give you clear, evidence-informed steps to discuss with your care team. Every fertility journey, pregnancy, and IVF cycle is unique — use this as a starting framework and build your individual plan with your doctor, midwife, or registered dietitian. For safety-critical decisions, current evidence and your clinical team always take precedence over general guidance.

Visual Guide

Keep this one practical: use the first image to understand the context, then apply one actionable step today before moving to the next section.