Progesterone after embryo transfer: what you need to know about the most poorly explained treatment

After an embryo transfer, the endometrium must be maintained by progesterone to allow and then support implantation. In a natural cycle, the corpus luteum produces it. After egg retrieval, the corpus luteum does not function properly; in a hormone-supplemented cycle, it does not exist at all. Hence the need for supplementation, which is not a precaution but a necessity.

Routes of administration

The vaginal route — capsules, tablets or gel — is the most commonly used. It delivers progesterone directly to the uterus, with a high local effect and few systemic effects. Its drawbacks are practical: discharge, irritation, and the unpleasant sensation that ‘it’s coming out’, although this does not prevent absorption.

The intramuscular route, involving daily oil-based injections, produces high and consistent blood levels. It is painful, causes indurations, and requires a nurse or a trained partner. Some clinics combine this with the vaginal route for patients who have experienced treatment failure.

The subcutaneous route, which is more recent, offers a less painful alternative with comparable efficacy.

Oral administration alone is insufficient for luteal phase support: first-pass metabolism in the liver breaks down a large proportion of the drug and causes drowsiness and dizziness. It should not be used as a substitute for the other routes.

Meta-analyses do not show any clear superiority of one route over another in a standard IVF cycle. The choice therefore depends on the clinic’s protocol and your tolerance — a point worth raising if a particular route is unbearable for you.

Side effects, and why they can be misleading

Breast tenderness, bloating, drowsiness, mood swings, mild nausea, vaginal discharge. These symptoms are exactly like those of early pregnancy, and this is the main source of confusion during the post-transfer waiting period: they are caused by the treatment, not by a possible implantation. The article on the twelve days following the transfer goes into this in more detail.

Duration

Until the blood test in all cases. If the test is positive, treatment continues until at least the eighth week, and most often until the tenth or twelfth week, when the placenta takes over. Recent data suggest that treatment may be stopped at around eight weeks in cycles with a functional corpus luteum, but in a fully hormone-supplemented cycle — that is, in most frozen embryo transfers and egg donations — continuing treatment until ten to twelve weeks remains the norm. It is the doctor who sets the date, never you.

Missed doses

If you realise you’ve missed a dose within a few hours, take it and carry on as normal. If the missed dose is some time ago or has happened repeatedly, call the clinic on the same day. Never double a dose on your own initiative. There is a real risk of premature termination: an ongoing pregnancy may be lost.

Some practical tips that patients share with one another, which are accurate: inserting the vaginal capsules in the evening at bedtime reduces discharge; a thin sanitary towel prevents discomfort; for oil-based injections, warming the ampoule in your hands and alternating sides reduces hardening.

A word on blood tests

Some clinics monitor progesterone levels before transfer, particularly in hormone-supplemented cycles: a low level the day before transfer is associated with lower implantation rates, and this can be corrected by adding a dose. Not all clinics do this; it is a legitimate question to ask, especially following a failed transfer of a good-quality embryo. The article on recurrent failure explores other possible causes.

Frequently asked questions

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