In Vitro Fertilisation (IVF) is simple!

Get a sperm sample; you have probably done that already as a test. Get some eggs; mix them together. A few days of incubation in the laboratory and the resulting embryo can be placed in the uterus. J !!

It’s the eggs that are the problem that make the process so complicated.

A woman's ovary contains all her eggs. There is a hormonal communication between the hypothalamus (in the brain), the pituitary and the ovary to enable the egg (technically we call it the “primary oöcyte”) to be released. The hormones select the egg that will be used in a particular cycle and produce fluid around it. This fluid filled ball is called a follicle. A trigger hormone releases the egg at a time that allows the lining of the womb (uterus) to be nurtured to optimise implantation by the time an embryo reaches the womb. Mr Shaw can explain more of this in consultation.

The development of the oöcyte in the ovary is driven by Follicle Stimulating Hormone (FSH) released from the pituitary gland. However the  actual release of the oöcyte is dependent on a surge of Luteinising Hormone (LH), the trigger hormone, from the pituitary in the middle of the cycle. This hormone is the basis of most ovulation detector kits Ovulation occurs about 48hours after the LH surge. All of the different IVF protocols involve accessing the follicle after it has ripened but before it has released its egg. The commonest way to do this is with analogues of the hormone which drives the pituitary, Gonadotrophin Releasing Hormone (GnRH).

Both Mr Shaw and one of the fertility nurses will spend some time with you explaining what is described here. To see the diagram of Mr Shaw's description of the standard cycle click on the right hand graphic at the top of this page. Occasionally a different protocol is used in some patients, the "Antagonist Protocol". Click the left hand graphic to read about that.

Gonadotrophin Releasing Hormone (GnRH) is the hormone that is naturally produced by the hypothalamus to drive the pituitary.  The first job is to suppress your pituitary with an artificial version of this drug to ensure that you don’t have an LH surge during the stimulation phase.  If you do, the oöcytes may have all been released before we get to harvest them.

These artificial Analogues (GnRHa) of this hormone, if used continuously,  have the opposite effect of the natural hormone, ie suppress instead of stimulate the pituitary. So GnRHa are used to ensure that the pituitary is “down regulated”. They are taken either as a spray that you sniff or as an injection. Mr Shaw may choose a long or short version of this in your case. Its not about the time it takes, its about getting both quality and number of oöcytes.

This Suppression Phase mimics the menopause in terms of the fact that the ovary has its drive suppressed and so the circulating oestrogen declines. There is no evidence that it brings your own menopause forward. So the side effects include hot flashes, headaches, vaginal dryness, mood changes, stuffiness, redness, pain or irritation from the injection. They all subside when stimulation starts. Once the pituitary has been successfully suppressed as assessed by ultrasound of the ovary, then the Stimulation Phase may start.

The Stimulation Phase commences on a day that anticipates the planned date of oöcyte harvest. This phase involves an injection of FSH daily. You can see that the injections are not as bad as you might think ( http://www.youtube.com/watch?v=tmkyxzMsIxg ). Mr Shaw is very keen that you drink an abundance of fluids during this phase so there is ample available for follicular development.

The development of follicles is monitored by ultrasound of the ovaries and occasional blood tests. There may be some changes in the dose, depending on your response in this particular cycle.

The side effects at this phase include redness, pain or irritation from the injection , breast tenderness, fatigue, ovarian hyper stimulation syndrome (OHSS), pelvic pain and ovarian cysts. Occasionally the cycle has to be abandoned if there are too few or too many follicles developing.

Thirty-five hours before the planned harvest you should inject the trigger, human Chorionic Gonadotrophin (hCG). Until this moment all through the Stimulation phase you should have continued with the GnRHa spray or injections from the Suppression phase.

Egg retrieval is precisely scheduled to occur a specific number of hours after the hCG injection (typically 34 to 37). Timing is extremely important because the egg retrieval must occur before natural ovulation occurs. During this procedure, you will be given a sedative or anaesthesia.

Typically, the mature eggs are collected using an ultrasound-guided probe and needle. The needle is passed through the back wall of the vagina and into the ovary. The eggs are then drawn up into the needle. As with all surgical procedures the risks include haemorrhage and infection.

Not every follicle will yield an oöcyte and, when mixed with sperm, not every oöcyte will be fertilised. Indeed there is a risk that none will be.

The day of the harvest is the day when the man has to produce his sample. The quality of that sample will determine the way in which the sperm is introduced to the oöcyte.  Intra-Cytoplasmic Sperm Injection (ICSI) is available if necessary. In general the decision can be anticipated by the prior semen analysis. Mr Shaw will have discussed that in consultation, although the sample on the harvest day may influence that decision.

Embryos are then replaced on day 2 or more after the harvest. The timing of this will depend on the number and quality of your embryos in culture. The embryo transfer (ET) is described by patients as being somewhat like having a smear test only with less discomfort.

Two weeks later you perform a pregnancy test and call the nurse who has being looking after you with the result. We shall arrange a scan if it is positive and a follow up analysis consultation if negative. Mr Shaw is very keen to analyse the details of any unsuccessful cycle to look for clues as to how to improve outcome if a further attempt is being considered.

The national success rates from IVF are published by the Human Fertilisation and Embryology Authority (HFEA). They are summarised on the graph below.

If a pregnancy is achieved it may, like any natural pregnancy, miscarry or implant in the Fallopian Tube even if the tube is blocked. Multiple pregnancies (twins, triplets etc) may occur by a natural identical twinning process even if only one embryo is used.  However the more embryos that are placed in the uterus, the higher the pregnancy rate but also the higher the chance of non identical twins and other multiples.  The incidence of fetal abnormality after simple IVF is the same order of magnitude as for natural conception.

Good Luck to you in your cycle….