IVF (In Vitro Fertilisation) is the process by which eggs are removed from your ovaries and mixed with sperm in a laboratory culture dish. Fertilisation takes place in this dish, "in vitro", which means "in glass".
Thousands of IVF babies have been born in the UK since the first in 1978. In 2009, nearly two per cent of all the babies born in the UK were conceived as a result of IVF treatment.
How might we benefit from IVF?
IVF is likely to be recommended for the following fertility problems:
- If you have blocked or damaged fallopian tubes.
- If your partner has a minor problem with his sperm. Major problems are better treated using ICSI (intracytoplasmic sperm injection).
- If you have tried fertility drugs, such as clomiphene, or another fertility treatment such as IUI (intrauterine insemination), without success.
- If you have been trying to conceive for at least two years, or less if you are 40 years or more. This is if a cause hasn't been found to explain why you have not become pregnant.
How is IVF done?
IVF follows a series of steps, starting with fertility drugs to help you produce as many eggs as possible.
You will probably need to take fertility drugs to stimulate your ovaries to develop mature eggs ready for fertilisation. During your normal menstrual cycle you release one egg per month. You can choose not to take drugs to stimulate your ovaries, but your odds of getting pregnant will be better with more eggs.
Your fertility specialist will offer treatment to control your menstrual cycle. Drugs called gonadotrophin-releasing hormone (GnRH) analogues (pituitary agonists) suppress or stop your cycle. You take these daily for about two weeks by tablet or injection. If you have endometriosis you may take Cetrotide to control your cycle and improve your chances of success.
You will then have daily hormone injections for 12 days. These stimulate your ovaries to release a greater number of mature eggs than usual (ovulation induction). The hormones used are gonadotrophins follicle stimulating hormone (FSH) and luteinising hormone (LH).
Women respond to these fertility drugs in different ways, and they may have strong side-effects. Your doctor will closely monitor you to make sure that you are cared for if this happens.
By monitoring your blood hormone levels, your doctor can detect when your eggs are mature. An injection of human chorionic gonadotrophin (hCG) will trigger the release of your eggs between 34 hours and 38 hours before they are collected.
Egg retrieval and sperm collection
An ultrasound scan will show when your eggs are ready to be retrieved. You'll be given an anaesthetic which will make you drowsy but still conscious.
Your doctor will then remove the eggs from your ovaries. Your doctor will use a fine, hollow needle attached to an ultrasound scan probe. The probe helps to locate the follicles that contain the eggs. You may feel mild discomfort during the procedure, but if you feel pain later on your specialist will prescribe painkillers.
While your eggs are being collected, your partner will need to provide a fresh sample of semen. If donated sperm or frozen sperm are being used, the sample is taken from the freezer. The sperm is washed and the best-quality sperm extracted ready to fertilise the eggs. The sperm is then combined with the eggs in a dish and left to culture in an incubator.
Fertilisation and embryo transfer
Within one day of combining the eggs and sperm, the dish is checked to see if any eggs have been fertilised. If they have, they'll be kept for between two days and five days before being transferred back into your uterus.
Any fertilised eggs will each have become a ball of cells called an embryo. They may also be referred to by your specialist as blastocysts, if the embryos are being transferred at the later blastocyst stage, at about day five. The healthiest embryos are chosen to be inserted into your uterus.
By now you will have been helping your uterus (womb) to prepare for the embryo by taking progesterone, which helps thicken its lining. You receive this by injection, pessary or gel. If your uterus lining (endometrium) is too thin, the embryos are unlikely to implant. If this is the case, the IVF cycle will unfortunately be abandoned.
Usually, one or two embryos are transferred with a thin catheter (tube) through your cervix into your uterus. Your fertility specialist may use ultrasound to guide him.
To avoid the risk of a high order multiple pregnancy, no more than three embryos can be legally transferred. The number of embryos that are transferred will depend on your age and your chances of success. This in turn depends on your particular fertility problem.
If you are under 40 you can have a maximum of two embryos transferred to your uterus. If you are under 37, and a suitable candidate, you may be recommended for elective Single Embryo Transfer (eSET). eSET can increase your chance of having a healthy single baby at term, and improve your and your baby's health.
If you are 40 years or over you can receive three embryos per cycle, because you have a smaller chance of conceiving with your own eggs. However, if the eggs are donated, only two can be transferred.
If there are any extra embryos, these may be frozen for future use. This is in case the first cycle doesn't succeed, or you want another baby after your successful treatment.
IVF normally involves transferring embryos at about two to three days after fertilisation. Another option is to wait until about five days after fertilisation when the ball of cells has developed into a blastocyst. Only the healthiest embryos will reach the blastocyst stage in vitro. You may have a better chance of having a healthy pregnancy after blastocyst transfer.
Most clinics offer blastocyst transfer to all patients depending on quality and number of embryos available. However some clinics offer blastocyst transfer only if:
Your clinic will probably advise you to rest for about 30 minutes immediately after your treatment. Though there's no evidence to suggest this increases your chances of becoming pregnant. In a successful cycle, one or more embryos will implant in your uterine wall and will continue to grow. You can take a pregnancy test in about two weeks.
Once your pregnancy has been confirmed following IVF, you should have an early ultrasound scan at about six weeks. This is to check that the embryo has implanted in your uterus.
How long will IVF treatment last?
One cycle of IVF takes between four weeks and six weeks to complete. You and your partner can expect to spend about half a day at your clinic for the egg retrieval and fertilisation procedures. You'll go back between two days and three days later for the embryos to be transferred to your uterus, or between five days and six days with blastocyst transfer.
What's the success rate of IVF?
The success rates depends on your particular fertility problem and your age. The younger you are, and the healthier your eggs are, the higher your chances of success.
Based on figures from 2009, the percentage of cycles for women in the UK using their own fresh eggs which result in a live birth are:
32 per cent if you are under 35
27 per cent if you are between 35 and 37
19 per cent if you are between 38 and 39
13 per cent if you are between 40 and 42
five per cent if you are between 43 and 44
two per cent if you are 45 or over
If you have been pregnant or have had a baby before, you have an increased chance of success.
If you are within a healthy weight range, with a body mass index (BMI) of between 18.5 and 25, you are more likely to be successful. If you are overweight or underweight you may increase your chance of success by getting nearer to your ideal weight for your height before you start treatment.
What are the advantages of IVF?
For most children conceived by IVF there are no long-term problems.
IVF can offer you a chance of having a baby if you are unable to conceive naturally, for example if you have blocked, damaged or missing fallopian tubes.
What are the disadvantages of IVF?
IVF increases your risk of certain complications, such as:
- A multiple birth, when more than one embryo is transferred to your uterus. Many couples consider twins to be a blessing. But a multiple pregnancy increases your risk of having a premature baby or a baby with a low birth weight.
- Side-effects from fertility drugs are usually mild, and include hot flushes, headaches and nausea. However, you will need to be closely monitored for signs of ovarian hyperstimulation syndrome (OHSS). Having this may mean a stay in hospital while your over-stimulated ovaries settle down.
- An increased risk of ectopic pregnancy, where an embryo implants in a fallopian tube or in your abdominal cavity. This is more likely if you have previously had problems affecting your fallopian tubes.
- You may be more likely to have a baby with a birth defect such as spina bifida if you conceive with IVF. One study showed an increase in birth defects from about three per cent in naturally conceived babies to about six per cent after IVF. But this increased risk could also be due to the parents' age, or other fertility problems.
Despite these risks, many parents still go on to give birth to much-wanted, much-loved babies through IVF.
Information source: babycentre.co.uk. This article is for information purposes only. For proper medical advice on IVF consult your doctor.