Hormone Delivery Routes for FET

For Frozen Embryo Transfer (FET), endometrial preparation requires estrogen and progesterone. Both have multiple delivery routes.

Estrogen — 4 Routes

• Oral (Progynova, Estrofem) — Convenient, widely used
• Sublingual — Bypasses first-pass metabolism, higher serum levels
• Vaginal — High uterine, low serum levels
• Transdermal patch (Climara, Estraderm) — Stable levels, fewer side effects

Progesterone — 3 Routes

• Vaginal (Crinone, Endometrin, Utrogestan) — Most popular, high uterine concentration
• Intramuscular (Progesterone in oil) — High serum, excellent efficacy
• Oral (Duphaston / dydrogesterone) — Convenient, Lotus I & II trials show non-inferiority to vaginal

Combination Strategies

Modern approach often combines vaginal + IM or vaginal + oral dydrogesterone for stable hormone levels.

Monitoring

Serum progesterone on day of transfer — if low, increase dose or change route.