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Medicines for frozen embryo transfer
A frozen embryo transfer (FET) is usually prepared with medicines that build up the womb lining and then support it. Estrogen tablets or patches grow the lining first; progesterone is added a few days before the transfer and continued afterwards. Some FET cycles use few or no medicines and follow natural ovulation instead.
Watch the video
In this video, in Hindi, our fertility specialist explains the medicines used in a frozen embryo transfer cycle.
Estrogen tablets before FET
Estrogen is started early in the cycle, as tablets, patches or gel, to thicken the womb lining. Scans show when the lining is ready, usually after about two weeks. The dose and the form are chosen by the doctor.
Progesterone support after FET
Progesterone prepares the lining to receive the embryo. It is started a set number of days before the transfer, matched to the age of the embryo, and usually continued into early pregnancy. It may be given as vaginal tablets or gel, injections, or tablets. Do not stop it on your own after a positive test.
Natural-cycle FET
Women who ovulate regularly may have an FET in a natural cycle, with scans to time ovulation and sometimes a trigger injection, usually without estrogen tablets.
Aspirin and heparin in IVF
Low-dose aspirin or heparin injections are used only for specific reasons, such as certain blood-clotting disorders. They are not needed by every woman, and they are prescribed only after the relevant tests.
Patches, gels and other forms of estrogen
Estrogen can be given as tablets, skin patches or gel. Tablets are most often used. Patches are changed on set days and should be pressed firmly in place; if a patch falls off, put on a new one and tell the clinic. Whatever the form, the aim is the same: a lining of good thickness and appearance on scan before progesterone is started.
What the scans check
After about ten to fourteen days of estrogen, a scan measures the lining. If it is thick enough, the progesterone start date and the transfer date are fixed. If it is still thin, estrogen may be continued for longer, or the plan adjusted. Blood tests are sometimes added to check hormone levels.
Timing the transfer to progesterone
The embryo has to meet a lining that is at the matching stage. A day 5 blastocyst is usually transferred on the sixth day of progesterone, counting the first day as day one, and a day 3 embryo a little earlier. This is why progesterone must be started on exactly the day and time you are given.
Common side effects
- Estrogen: breast tenderness, mild nausea, headaches or spotting.
- Progesterone: bloating, tiredness, mood changes and, with pessaries, a white discharge.
Tell the clinic about a severe headache, weakness, a change in vision, leg pain or swelling, chest pain or sudden breathlessness, as these need checking at once.
After a positive test
If the pregnancy test is positive, estrogen and progesterone are usually continued for several more weeks, until the placenta takes over. Do not stop them yourself; your doctor decides the right time and way to end them. An early scan confirms the pregnancy in the womb.
Keeping track of your medicines
- Keep a written chart of every medicine, its time and its start date.
- Set phone alarms for each dose.
- Carry enough medicine when you travel, and keep a spare pack of progesterone.
- Bring the chart to each visit, so the team can see exactly what you have taken.
Medicines for other health problems
Tell the team about every other medicine you take, such as thyroid tablets, blood pressure medicines, inhalers or supplements. Most can be continued safely, but some need a change before or during pregnancy. Do not stop any regular medicine without asking.
If the transfer is postponed
Sometimes the lining is not ready, a cyst is seen, or there is an illness in the family, and the transfer has to be moved. If this happens, the doctor will tell you whether to stop the medicines and wait for a period, or to continue and re-check. The frozen embryos stay safely stored in the meantime, so a short delay does not harm them.
Do not change medicines on your own
Please take every FET medicine exactly as advised, and ask before stopping or changing anything. Read more about frozen embryo transfer and the beta hCG test after transfer.
Questions about FET medicines
Why are estrogen tablets given before FET?
To build up the womb lining before the transfer. Scans show when it is ready.
How long is progesterone continued after FET?
Usually into early pregnancy, for as long as your doctor advises. Do not stop it on your own.
Can FET be done without medicines?
Yes, with few or no medicines, in a natural cycle for women who ovulate regularly, with scans to time the transfer.
Do all women need aspirin or heparin in IVF?
No. They are used only for specific reasons, such as certain clotting disorders, after the relevant tests.
What if I miss a dose of progesterone?
Call your clinic for advice. Do not take a double dose unless told to.
When is the frozen embryo transferred after starting progesterone?
A day 5 blastocyst is usually transferred on the sixth day of progesterone, counting the first day as day one, and a day 3 embryo a little earlier. Your clinic fixes the exact day.
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What you read here explains fertility care in general terms and cannot replace a consultation. Decisions about your own care should be made with a doctor who knows your history and has seen you. We do not carry out or offer sex determination of any kind, which is prohibited by law in India under the PCPNDT Act.