AboutServicesMediaGalleryYour visitArticlesContact Book a consultation

Services

Frozen Embryo Transfer

A frozen embryo transfer (FET) uses an embryo frozen in an earlier IVF cycle. There are no stimulation injections and no egg collection: the womb lining is prepared, the embryo is thawed, and it is placed in the womb on the right day.

With Datuk Dr. Navdeep Singh Pannu, FRCOG, at Alpha IVF & Women's Specialists, Kota Damansara

Book a consultation Your first visit
Preparation
About 2–3 weeks, following your cycle or with hormones
Egg collection
None; the embryos are already frozen
Transfer
A few minutes, usually without sedation
Pregnancy test
About two weeks after the transfer

What it is

In IVF, good-quality embryos that are not transferred straight away can be frozen by vitrification, a very fast method that stops ice crystals forming. They are stored in liquid nitrogen until you need them.

For the transfer, the lining of the womb has to be ready on the same day as the embryo. In a natural cycle, scans (and sometimes blood or urine tests) follow your own ovulation and the transfer is timed from it. In a hormone-prepared cycle, oestrogen tablets or patches build up the lining, progesterone is added, and the transfer date is set in advance.

Sometimes all the embryos from a cycle are frozen on purpose (a "freeze-all"). This is done when a fresh transfer would be unsafe or less likely to work, for example with a high risk of ovarian hyperstimulation, while waiting for PGT results, or when the lining is not right.

Who it can help

  • Couples with spare embryos from an earlier IVF cycle
  • A freeze-all cycle to avoid ovarian hyperstimulation (OHSS)
  • Embryos waiting for PGT results
  • A lining that was not ready in the fresh cycle
  • Trying for a second child with stored embryos
  • Women with irregular cycles or PCOS (with a hormone-prepared cycle)

How it works

  1. Choosing the cycle

    A natural cycle often suits women with regular periods. A hormone-prepared cycle suits irregular cycles, PCOS, or a need for a fixed date. The choice is made with you.

  2. Preparing the lining

    Scans check the thickness and pattern of the lining. In a hormone cycle you take oestrogen for about two weeks; in a natural cycle the scans track your own follicle.

  3. Progesterone and timing

    Progesterone gets the lining ready to receive the embryo. The transfer day is set by how many days of progesterone match the age of the embryo.

  4. Thawing

    On the morning of the transfer, the embryologist thaws the embryo and checks that it has survived and is ready.

  5. Embryo transfer

    The embryo is passed into the womb through a thin, soft tube, guided by ultrasound. It takes a few minutes and you go home soon after.

  6. Pregnancy test

    A blood test about two weeks later. If you are taking hormone support, keep taking it until then, and for longer if you are pregnant.

Good to know

Side effects and risks

  • Side effects of the hormones, such as breast tenderness, bloating, headaches or spotting
  • A small chance that an embryo does not survive thawing
  • Some studies link fully hormone-prepared cycles with a slightly higher risk of high blood pressure in pregnancy, one reason a natural cycle may be suggested if you ovulate regularly
  • Twins or more if more than one embryo is transferred

No guarantees

A frozen transfer cannot promise a pregnancy. The chances depend mostly on the woman's age when the eggs were collected and the quality of the embryo.

Storage

Frozen embryos can be kept for years. There is a storage fee, so ask about the current terms and costs at your consultation.

Around the transfer

Carry on with normal daily life. Bed rest afterwards is not needed. The do's of IVF has more.

Questions people ask

Does freezing harm the embryo?

Vitrification is well established, and most good-quality embryos survive thawing. Babies born from frozen embryos have been followed for many years with reassuring results.

Natural or hormone cycle: which is better?

Neither suits everyone. A natural cycle uses fewer medicines but needs more scans to time; a hormone cycle gives a fixed date. Dr. Navdeep will suggest one based on your cycles and history.

Is the transfer painful?

Most women feel little more than during a smear test. A comfortably full bladder helps the scan.

How many embryos are thawed?

Usually one at a time, which keeps the risk of twins low. The others stay frozen for later.

Further reading

This page is general information and does not take your personal circumstances into account. Please speak to your doctor for advice that is right for you. Disclaimers