EmbryoTransfer

Embryotransfer, or embryo transfer, is a medical procedure used in assisted reproductive technology to place an embryo into a female’s uterus with the goal of establishing pregnancy. It is a central step of in vitro fertilization (IVF) and related treatments.

In a typical IVF cycle, the ovaries are stimulated to produce multiple eggs, which are retrieved. Eggs are fertilized in the laboratory and embryos are cultured for a few days (cleavage stage) or longer (blastocyst stage). One or more embryos are then loaded into a thin catheter and transferred through the cervix into the uterine cavity. Luteal-phase support with progesterone is commonly used after transfer. A pregnancy test is usually performed about two weeks later.

There are two main approaches: fresh embryo transfer, performed in the same cycle as egg retrieval, and frozen embryo transfer (FET), where embryos are cryopreserved and transferred in a subsequent cycle after endometrial preparation. FET can offer flexible scheduling and, in some patients, higher success rates.

Indications include a range of infertility factors such as tubal disease, male-factor infertility, endometriosis, diminished ovarian reserve, or prior unsuccessful IVF cycles, as well as scenarios involving donor gametes or preimplantation genetic testing. Outcomes depend on maternal age, embryo quality, uterine receptivity, and overall prognosis. Many programs promote single embryo transfer when appropriate to reduce the risk of multiple pregnancies, which carry higher maternal and perinatal risks.

Risks associated with embryotransfer include miscarriage, ectopic pregnancy, and ovarian hyperstimulation syndrome from prior stimulation. The procedure is regulated differently across countries and guided by clinical protocols and ethical considerations.