How does IVF work in surrogacy?

In surrogacy, IVF (in vitro fertilization) creates embryos from the intended parents' or donors' eggs and sperm in a laboratory, freezes them, and later transfers one embryo into the gestational surrogate's prepared uterus. The sequence: 1) the egg provider takes 10 to 14 days of stimulation injections and has a retrieval; 2) eggs are fertilized, usually by ICSI, and grown 5 to 7 days to the blastocyst stage; 3) blastocysts are graded, often biopsied for PGT-A, and vitrified; 4) the surrogate completes a frozen embryo transfer cycle of 3 to 5 weeks of estrogen and progesterone; 5) one embryo is transferred in a 10-minute office procedure; 6) a blood pregnancy test follows 9 to 11 days later. The surrogate has no genetic link to the embryo.