The twelve days after the transfer: what really happens, day by day

The transfer takes ten minutes. The wait that follows lasts twelve days, and this is what patients talk to me about most. Here is the biological timeline, based on the transfer of a five-day-old blastocyst, which is the most common scenario today.

The timeline

• Day 0: the transfer. The embryo is placed in the uterine cavity. It floats in a tiny volume of fluid; it cannot ‘fall’, and standing up makes no difference.
• Day 1: the blastocyst emerges from its shell, the zona pellucida. This is hatching.
• Days 1 to 3: it attaches to the endometrium, then begins to burrow into it. This is implantation itself.
• Days 3 to 5: the cells of the future placenta penetrate the lining and begin to produce hCG. Light bleeding may occur at this stage; this does not indicate either failure or success.
• Days 5 to 7: hCG becomes detectable in the blood, albeit at very low levels.
• Days 9 to 12: Blood tests become reliable. This is the date set by the clinic.

Symptoms: why they don’t tell the whole story

Tender breasts, bloating, cramps, tiredness, mild nausea, frequent urge to urinate: all these signs are caused by the progesterone you are taking, whether or not you are pregnant. This is why studies on early symptoms find no predictive value: pregnant women and those who are not describe exactly the same sensations, because they are receiving the same treatment.

The complete absence of symptoms is not a sign either. Many pregnancies progress without any symptoms being felt.

Early testing: why I advise against it

A urine test carried out on the seventh or eighth day mainly produces false negatives, and false positives if hCG induction has been used — the substance takes around ten days to clear the system. It adds a source of anxiety that provides no useful information. Many women test anyway, and I’m not here to lecture: but you need to be aware that a negative test on day 8 means nothing, and you must have decided this in advance.

What is allowed

Walking, working, driving, flying, showering, leading a normal life. Strict bed rest has been studied and does not improve outcomes; in some studies, it actually worsens hormone levels, not to mention the risk of blood clots. Moderate exercise is possible; high-impact activities and diving should be avoided. Very hot baths, saunas and steam rooms are not recommended. Sexual intercourse is permitted unless otherwise advised by your doctor.

Diet: follow the same recommendations as for a pregnant woman, starting now. No alcohol, no tobacco, caffeine limited to two cups, and the usual precautions regarding raw foods.

Treatment that must not be stopped

Progesterone, and oestradiol if you are on hormone replacement therapy, should be continued until the next blood test and, in the event of pregnancy, until the tenth or twelfth week. This is the most important point throughout this entire period: stopping treatment early can cause a pregnancy to fail. If you have any doubts about a dose or have missed a dose, call the clinic on the same day. The full protocol is described here.

The result

A level above 100 IU/l at twelve days indicates a good prognosis; between 25 and 50, a repeat test is required after 48 hours, ensuring that the level approximately doubles. A low level that is rising slowly may indicate a pregnancy that will not take hold, or an ectopic pregnancy, which requires close monitoring. The first ultrasound scan takes place at around seven weeks.

If the test is negative, stopping treatment triggers a period within a few days. A new transfer can be scheduled as early as the next cycle if there are any frozen embryos remaining, but there is no obligation to proceed immediately. When to start again and when to change strategy is discussed elsewhere.

Frequently asked questions

Source: https://fertilitegrece.com/en/blog/after-embryo-transfer-days/ — Triada Baloukoudis, IVF patient coordination in Greece. General information, not medical or legal advice. Printed on