Chorionic gonadotrophin (Pregnyl)
How does it work?
Pregnyl injections contain the active ingredient chorionic gonadotrophin, which is a natural sex hormone also known as human chorionic gonadotropin or HCG.
In women, HCG is used together with other hormones called follicle stimulating hormone (FSH) and luteinising hormone (LH) in the treatment of infertility.
Normally, in the ovaries in women, FSH increases the number of growing follicles and stimulates their development. Within the follicles are the developing eggs. FSH also increases the production of oestrogen, and under the influence of this hormone, the largest follicle continues to develop. As the amount of oestrogen in the blood increases, this triggers a surge of another hormone called LH, which results in the release of an egg from the ovary (ovulation).
Pregnyl injections are used to stimulate follicules to mature and ovulation to occur in women who are having difficulties getting pregnant due to problems with their natural ovulation, or who are having in-vitro fertilisation (IVF) treatment.
Firstly, follicle development is stimulated with daily injections of FSH or FSH and LH. Once the follicles have developed appropriately, one injection of Pregnyl is given. The HCG in the Pregnyl injection mimics the action of luteinising hormone and causes the release of an egg from the ovary. The woman is usually advised to have sex on the day of the Pregnyl injection and the day after. Up to three repeat injections may given in the following nine days.
The Pregnyl injection stimulates the final maturation of eggs in the ovaries of women having IVF. For these women, the eggs will be collected 32 to 36 hours after the Pregnyl injection, for fertilisation in a laboratory.
HCG also mimics the action of luteinising hormone in men. The effect of this in men is to stimulate production of the male hormone, testosterone.
This medicine is used in the management of delayed puberty, undescended testicles and low sperm count in men, all of which are improved by increased testosterone levels. The injections are given two to three times a week for a few weeks, the length of treatment depending on the condition being treated.
Pregnyl injections are administered either under the skin (subcutaneously) or into a muscle (intramuscularly). If you are going to administer the injections yourself, your doctor will show you how to inject them under the skin.
What is it used for?
- Stimulating the release of eggs (ovulation) in women having treatment for infertility caused by problems with their natural ovulation.
- Stimulating the final maturation of eggs in women having in-vitro fertilisation (IVF) treatment.
- Low sperm count (oligospermia) in men.
- Delayed puberty in boys. This is when boys do not develop secondary sexual characteristics at the normal age (12 - 14 years old).
- Testicles which have not dropped in boys.
- Before fertility treatment is started your doctor will want to check the functioning of your adrenal glands and thyroid gland, and that you do not have tumours of the pituitary or hypothalamic glands in the brain, or higher than normal blood levels of a hormone called prolactin, all of which can affect fertility.
- In women, before fertility treatment is started your doctor will need to check the functioning of your ovaries using ultrasound and a blood test to measure your oestrogen levels. During treatment, these tests, as well as tests to measure the level of oestrogen in your urine, will need to be carried out at regular intervals until the follicles develop.
- During your fertility treatment, if your blood or urine tests show high levels of oestrogen, or if an ultrasound scan shows excessive development of follicles in your ovaries, this indicates that your ovaries may be overstimulated, which could lead to a dangerous syndrome called ovarian hyperstimulation syndrome (OHSS). Treatment with this medicine should not be given and you should not have sex, or use barrier contraception for at least four days.
- This medicine can itself also cause over-stimulation of the ovaries (OHSS). For this reason, it is important to tell your doctor immediately if you experience pain or swelling of the abdomen, weight gain, difficulty breathing, increased thirst, decreased urine output, nausea, vomiting and diarrhoea after having the injection. If your ovaries are overstimulated you should not have sex, or use barrier contraception for at least four days.
- If this treatment does result in pregnancy, there are a few risks that you should be aware of. You should discuss these with your doctor before starting treatment. Pregnancy following treatment with Choragon is more likely to result in a multiple pregnancy (twins or more) than if you had conceived naturally. This carries an increased risk of problems for the mother during the pregnancy, and at or around the time of birth. There is a greater risk of miscarriage or abortion in women having fertility treatment than in the general population. There may also be a slightly higher risk of your baby being born with physical defects. There is a slightly higher risk of an ectopic pregnancy (where a fertilised egg implants outside the uterus) after IVF treatment than in the general population.
Use with caution in
- Heart disease.
- Kidney disease.
- History of migraines.
- Boys who have not yet reached puberty.
- Women at risk of blood clots in the blood vessels (thromboembolism, eg deep vein thrombosis or pulmonary embolism), for example due to a personal or family history, or obesity.
- Women with polycystic ovary syndrome (PCOS).
Not to be used in
- Men and women with tumours of the pituitary or hypothalamic glands in the brain.
- Men with prostate, breast or testicular cancer.
- Women with breast, uterine or ovarian cancer.
- Women with vaginal bleeding of unknown cause.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- This medicine must not be used in women who are already pregnant or breastfeeding. Seek further medical advice from your doctor.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
- Changes in mood.
- Excessive fluid retention in the body tissues, resulting in swelling (oedema), particularly in men.
- Reactions at the injection site.
- Skin rashes.
- Enlargement of the breasts (gynaecomastia).
- Over-stimulation of the ovaries in women, causing the production of many eggs (ovarian hyperstimulation syndrome or OHSS - see warning section above).
- Blood clot formation in a vein (thromboembolism), usually of the leg (deep vein thrombosis) in women.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
This medicine is not known to affect other medicines. However, it is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while while having treatment with this one, to make sure that the combination is safe.
Other medicines containing the same active ingredient