Natural and modified-natural FET

In a natural-cycle frozen embryo transfer, the timing of the transfer is planned around a person's own spontaneous ovulation, tracked with scans and sometimes blood tests, without medicines to control the cycle. A modified-natural cycle follows the same principle but adds a trigger injection or limited hormone support around the time of ovulation, to make timing more predictable while still relying on the person's own follicle development. These approaches are generally considered for people who ovulate regularly. They are one of the two main ways of preparing the endometrium for FET, the other being a programmed, medicated cycle; your fertility team will advise which is more suitable for you.

Also known as: natural cycle FET, modified natural FET, true natural FET

Last reviewed: 9 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.