When a couple conceives naturally, sperm from the man and the egg from the woman meet in the woman’s fallopian tubes. These are the tubes that join the ovaries to the uterus (womb). One sperm penetrates the egg and fertilises it. In IVF, this process of fertilisation happens outside the woman’s body. A woman’s eggs are surgically removed and fertilised in a laboratory using sperm that has been given as a sperm sample. Next, the fertilised egg, called an embryo, is surgically implanted into the woman's womb. Typically, one cycle of IVF takes between four and seven weeks
What happens during IVF may differ slightly from clinic to clinic, but a typical treatment follows the main steps below.
Step one: suppressing the natural menstrual cycle
You are given a medication that will suppress your natural menstrual cycle. This can make the medicines used in the next stage of treatment more effective.
This medication is given either as a daily injection (which you'll be taught to give yourself) or as a nasal spray. You continue this for about two weeks.
Once your natural cycle is suppressed, you take a fertility hormone called follicle stimulating hormone (FSH). This is another daily injection you give yourself, usually for about 10-12 days.
FSH increases the number of eggs your ovaries produce. This means more eggs can be collected and fertilised. With more fertilised eggs, the clinic has a greater choice of embryos to use in your treatment.
The clinic will keep an eye on you throughout the treatment. You will have vaginal ultrasound scans to monitor your ovaries and, in some cases, blood tests. About 34-38 hours before your eggs are due to be collected, you'll have a final hormone injection that helps your eggs to mature.
You'll be sedated and your eggs will be collected using a needle that's passed through the vagina and into each ovary under ultrasound guidance. This is a minor procedure that takes about 15 to 20 minutes.
Some women experience cramps or a small amount of vaginal bleeding after this procedure.
The collected eggs are mixed with your partner's or the donor's sperm in a laboratory. After 16-20 hours, they're checked to see if any have been fertilised.
In some cases, each egg may need to be injected individually with a single sperm. This is called intra-cytoplasmic sperm injection or ICSI. You can read more about ICSI on the Human Fertilisation and Embryology Authority (HFEA) website.
The fertilised eggs (embryos) continue to grow in the laboratory for up to six days before being transferred into the womb. The best one or two embryos will be chosen for transfer
After egg collection, you will be given hormone medicines to help prepare the lining of the womb to receive the embryo. This is usually given either as a pessary (which is placed inside the vagina), an injection, or a gel.
A few days after the eggs are collected, the embryos are transferred into the womb.
This is done using a thin tube called a catheter that's passed into the vagina. This procedure is simpler than egg collection and similar to having a cervical screening test, so you won't normally need to be sedated.
Around the time your partner's eggs are collected, you'll be asked to produce a fresh sperm sample. The sperm are washed and spun at a high speed, so the healthiest and most active sperm can be selected. If you're using donated sperm, it's thawed before being prepared in the same way.