Hormone treatment
When ovulation normally occurs, one egg is released from the ovary. The aim of the hormone treatment for IVF is to make the ovary produce multiple eggs. On every day of the reproductive life (from birth to approximately 50 years) of a woman, many eggs are available for ovulation. If the right set of hormone signals are present, some of these eggs start to develop towards ovulation. The best, most advanced egg becomes dominant and releases hormones into the surrounding ovary which suppresses the remaining susceptible eggs. The hormone treatment used in IVF recruits more of the eggs that usually would have been suppressed and wasted to ovulate. Put another way, the IVF hormone treatment allows more eggs to get to the point of ovulation.
What happens to you - The procedure & methods
There are four types of hormone / drugs used in the first half of an IVF treatment cycle.
- Oral Contraceptive Pill or related hormones are used to provide a reliably constant hormone environment prior to the use of the actual treatment for IVF. This is a highly successful method of ensuring the maximum proportion of patients can commence treatment
- Gonadotrophin Releasing Hormone Agonist (GnRH agonist). Synarel (Nafarelin) and Lucrin (Luprelide) are the brand names (and chemical names) of these drugs. They are almost identical to hormones produced by an area of the brain called the Hypothalamus. These drugs initially stimulate a gland at the base of the brain, called the Pituitary Gland, to release the ovulation hormone, called Follicle Stimulating Hormone (FSH). After a brief period of release the Pituitary gland then stops producing FSH so there is no further attempt to ovulate. The drug is used up until the time of egg collection. Suppression of the body’s natural urge to ovulate is necessary to prevent selection of just one egg and to maximize pregnancy rates from IVF.
- Follicle Stimulating Hormone (FSH). This hormone is given daily by injection, which is different to its natural pattern of release. Given in this fashion the FSH forces the ovary to make available more eggs than would normally be the case.
- Human Chorionic Gonadotrophin (HCG). Normally a hormone known as luteinising hormone (LH) is released from the pituitary gland to finally make the ovary release an egg. HCG is very similar in chemical structure to LH and is used to mimic this message. It promotes final maturation of the eggs, which have developed as a result of FSH treatment. Ovulation does not occur as the eggs are collected 2 to 4 hours before this would naturally happen.
What you have to do
Synarel is given by nasal spray, twice daily
Lucrin is given as an injection, once a day
FSH requires daily injection.
These injections are subcutaneous, that is just underneath the skin, and can be administered by yourself or your partner. If preferred you may attend the Fertility Centre for these injections.
HCG requires an intra-muscular injection, that is deeper into the arm, buttock or thigh.
Benefits & Advantages
As mentioned above, the aim of IVF hormone stimulation is to obtain more eggs than would normally be the case. The main advantage is that this gives the scientist a greater chance of producing at least one top quality embryo. The main benefit is that this maximizes pregnancy rates. In fact when ovarian hormone stimulation is not used pregnancy rates are less than 5%.
Monitoring treatment response
There are two types of monitoring used to see how the ovary is responding to FSH treatment. These are blood tests for hormone levels, which assess how well the ovary is functioning, and ultrasound to see how the follicles are developing.
- Hormone blood testing is usually performed on several occasions throughout your treatment. A test is carried out the day prior to the commencement of treatment with Gonadotrophin Releasing Hormone Agonist (Synarel), then again on the first day of FSH therapy, followed by a thired test on the 8th day of FSH therapy. The final test is performed two or three days prior to the egg collection procedure. These tests measure the levels of the hormones Oestradiol, Progesterone and Luteinising Hormone (LH) in your blood. Essentially the higher the Oestradiol level the greater your response to treatment. As a rough guide one egg is collected for every 1000 units of Oestradiol measured in the blood.
- Ultrasound monitoring is performed on the 8th day of FSH therapy and then on one or two more occasions prior to the egg collection procedure. The ultrasound is performed using the trans-vaginal approach. An instrument is placed in the vagina which will produce a picture on the ultrasound screen. The number of follicles being produced by the FSH therapy can be visualized. The higher the number of follicles the greater the number of eggs that might be retrieved. Not all follicles contain eggs however. Generally we expect to retrieve eggs from 60% of follicles. This number is highly variable.
Luteal phase hormone support
Following embryo transfer it is usual to provide some ongoing hormone treatment to ensure that the lining of the uterus remains as receptive as possible to the developing embryo. This hormone treatment is one of two types: Human Chorionic Gonadotrophin or Progesterone..
- Human Chorionic Gonadotrophin (HCG) is intended to stimulate the ovary to produce Progesterone which in turn tends to keep the uterus receptive to the developing embryo. This treatment is given by injection on days 3 and 5 after egg collection.
- Progesterone is the hormone which is usually produced by the ovary to help maintain the lining of the uterus. It needs to be given by intravaginal pessary usually twice daily from the day of egg collection. It also needs to be continued throughout early pregnancy. As HCG is just as effective in most instances it is usually preferred. However, when a large number of eggs have been collected and there is a higher risk of Hyperstimulation Syndrome, Progesterone is used so that the ovary is not stimulated further.