IVF is the most effective treatment for women with absent, blocked or damaged fallopian tubes, for whom it was first developed. It is now used to treat a wide range of fertility problems.
Fertility drugs are used to stimulate the ovaries to produce multiple follicles.
Each follicle should contain one egg. The chances of pregnancy are increased if more than one egg can be obtained and fertilised. The response to stimulation is monitored by ultrasound scan measuring the number and size of the developing follicles in the ovaries and by measuring the blood oestrogen level.
The ultrasound does not show the eggs themselves, but the fluid-filled sacs (follicles) containing the eggs. The ultrasound scans are performed at intervals during the treatment cycle. A typical cycle would require 4 ultrasound scans. When the leading follicle reaches the optimum size of (17-22mm), preparations will be made for egg collection. An oestradiol assay will also be carried out prior to administering hCG, to help determine the timing of egg collection.
The final preparation for egg collection involves a hormonal injection given to the woman 36-40 hours pre-operatively. This mimics the natural process which triggers the eggs to complete their maturation making them ready for fertilisation.
The eggs are collected vaginally using ultrasound guidance, under general or local anaesthesia. The ultrasound probe is introduced into the vagina, the ovaries are visualised and then an aspiration needle (attached to the probe) is passed through the top of the vagina into the follicles. The fluid in each follicle is aspirated and then examined under a microscope for the eggs to be identified. It is difficult to predict the number of eggs available from the ultrasound scan picture. We therefore frequently collect either more or fewer eggs than we had anticipated pre-operatively.
In rare circumstances we fail to collect any eggs despite the appearance of follicles on the scan picture. If this occurs, the treatment cycle cannot proceed to embryo transfer and you will be given an appointment to see the doctor to discuss your future options.
Embryo transfer
After egg collection, the eggs are incubated for a short time and the sperm is then added to the eggs and incubated in the laboratory for a further 18-24 hours. Providing that the semen is normal, approximately 65–75% of the eggs will fertilise on average although it can be highly variable from one cycle to another. The first signs of fertilisation are shown by the presence of two pronuclei within the egg. If this has occurred, the fertilised egg should then divide into two, and subsequently three, four or more cell embryos. The fertilised eggs (now called embryos) are transferred to the uterus 2-5 days after egg collection. A maximum number of two embryos are transferred in women under 40. It is becoming more common for us to transfer embryos at the blastocyst stage (5-6 days after egg collection). In this situation it is recommended that one embryo is transferred due to the increased chance of multiple pregnancy.
It is important that you are aware that there is always a possibility that a low proportion or even none of the eggs fertilise. If this occurs you will be seen by the clinician to discuss your future options.
The embryo transfer procedure is one of the most important events in IVF. It is generally a painless procedure, similar to a cervical smear and on average takes up to 15 minutes. On rare occasions this procedure may take longer. An abdominal scan is generally performed to confirm the correct position of the transfer catheter within the uterine cavity prior to replacement.
We encourage the male partners to be present during this special time, if they wish to do so. After the procedure, women are encouraged to carry on with their normal routine as there is no evidence to suggest that bed rest has a positive effect. Additional progesterone in the form of vaginal pessaries or injections are given following egg collection until the pregnancy test is done 2 weeks later. If the pregnancy test is positive the progesterone is continued until the second pregnancy scan at 8-9 weeks.
Cancelled treatment cycles
Unfortunately not all patients respond to the medication and sometimes it may be necessary to abandon the treatment cycle before egg collection. Future management will be discussed and another treatment cycle may be arranged for a later date, perhaps with a different combination of fertility drugs.
Drugs used in infertility treatment
A variety of drug regimens are used in the treatment cycles and different combinations of drugs may be given to different patients. These combinations may also differ from cycle to cycle. Your doctor will decide which is the most suitable for you.
The basic approach in using these drugs is to supress the hormones produced by the pituitary gland using a Gn-RH agonist or antagonist, and to stimulate egg production using fertility injections of follicle-stimulating hormone (FSH).
The drugs most commonly used are administered subcutaneously (under the skin) and most women find it easy to inject themselves once they have been taught by our nurses. The Gn RH agonist or antagonist is administered either as a subcutaneous injection or as a nasal spray. All of the drugs used during your treatment are available from our on-site pharmacy. The pharmacy is open 6 days a week and offers competitive prices.
