What is progesterone?

Progesterone is a natural steroid hormone and the most abundant progestogen of the human body. Progesterone is produced both in men and women. In women it is produced in the ovaries, the placenta and the adrenal glands. It is also produced in the lab and administered to humans externally.

What does it do?

Progesterone is mostly associated with the female reproductive system where prepares the lining of the womb for implantation and sustainment of the pregnancy. If pregnancy does not occur, progesterone decreases, causing menstruation.

Does every woman who has fertility treatment need to take it?

All IVF patients need luteal support with progesterone because of the fact that the treatment itself disrupts progesterone function and production by the corpus luteum.

Progesterone is administered in frozen embryo transfer cycles especially with down regulation.

External progesterone supplementation is also absolutely necessary for all women in donor-egg treatment as usually the endogenous hormones are either down regulated for some time or simply missing in women with premature ovarian failure.

How do you take it?

External progesterone can be taken in four ways: orally, vaginally, intramuscularly or subcutaneously.

Can you choose how to take it?

Usually, your doctor is the one responsible to decide which form is the most adequate for the patient.

Are there pros and cons to each method?

In Embryolab Fertility Clinic we use all methods according to each patient’s needs. Up until today it is not definitely clear if just one method is most advantageous on the ongoing pregnancy rate but there are certain pros and cons regarding the forms.

For instance the pills are easy to administer but can cause nausea especially in high doses. Vaginal progesterone (gel and pessaries) are not metabolised in the liver, so general symptoms such as nausea can be avoided, but on the other hand, it can be messy and cause thrush.

Intramuscular injections can be painful and cause skin reactions, although they may only last 24 hours and are very common for bleeding in early pregnancy.

The subcutaneous injections seem to be less painful and have fewer site-reactions but it is not clear if they have the same level of absorption.

Does progesterone have any side effects?

From our experience at Embryolab, the role of the international coordinator, as well as the international midwife, help us to have direct contact with our patients so that we can modify the progesterone intake method accordingly.

Can it affect your mood?

Progesterone is blamed for causing mood swings, headaches, fatigue, irritability and even depression. However, it is not proven that progesterone alone is the culprit for causing the blues as oestrogens also peak during treatment and pregnancy. Of course we should not forget the high levels of emotional and physical stress that the patients go through anyway.

When do you take it and for how long?

The administration of progesterone starts the very same day as egg collection and continues until the 9th week when the placenta takes over progesterone production. As for frozen cycles, progesterone is taken usually five days before embryo transfer until the placenta is capable of producing enough of this hormone.

Is it true that progesterone can stop miscarriages happening?

Progesterone’s role in maintaining the uterine lining so an embryo can implant and grow is absolutely necessary. The hormone can also prevent early miscarriage by relaxing the womb and thus reducing contractions.

Progesterone suppresses the autoimmune reaction of the mother in order to block the rejection of the baby by the mother’s antibodies. It also increases the blood circulation to the womb.

Artemis Karkanaki MD, MSc, PGCert, PhD
Gynaecologist, specialised in reproductive medicine and clinical embryology