Understanding the IVF process ?
The purpose of IVF treatment is to stimulate a woman’s ovaries with hormones to produce multiple follicles containing eggs. These eggs are retrieved and mixed (IVF) or injected (ICSI) with sperm and embryos are created.
How are a woman’s ovaries stimulated?
The first step of the process is the shutting down of the pituitary-ovarian hormones – this process is referred to as “down regulation”. Drugs are administered normally with daily subcutaneous injections. Down regulation can be started on day two or day 21 of a period depending on the type of protocol (long or short), it takes approximately two weeks for down regulation. Down regulation is confirmed by an ultrasound scan which will show a thin uterine lining and quiescent ovaries without any cyst. A blood test is also performed to check the hormonal level (Oestradiol) for the confirmation of down regulation or suppression.
Once down regulation is confirmed then daily injections can be started to stimulate the ovaries normally around 12-16 days.
A woman’s response to the stimulation process is monitored by ultrasound scanning and blood tests. Usually, three to four scans are necessary during a two week period of injections. In addition, blood tests are carried out to check hormone levels. The scans are usually internal scans which give a better picture of the uterus and the ovaries. During the scans the number and the size of the follicles are measured and the thickness and the texture of the lining of the womb are assessed. When follicles reach a diameter of 18 mm or over, the lining of the womb is at least 8 mm in thickness and the hormone levels correspond to the number of growing follicles, it is time to give the trigger injection (HCG) – this starts the maturation process of the egg. At this stage, all other injections will be stopped. Egg collection will be performed 36 hours after this trigger injection.
Egg collection is performed vaginally with ultrasound guidance under general anaesthesia. The fluid from each follicle is aspirated, then checked by an embryologist who identifies the egg in this fluid under a microscope, this process is repeated for each follicle. The number of follicles does not correspond to the number of eggs collected. Some follicles may not contain an egg.
- Egg collection takes an average of 20-30 minutes.
- Normally be allowed to go home after two hours – you will not be able to drive for 24 hours.
- You may have some discomfort or soreness in the tummy after the egg collection.
- There may be some spotting, nausea and vomiting.
- When the number of eggs is more than 15, there may the bloating of the abdomen.
If any of the symptoms becomes severe you should contact your clinic or a doctor.
Once the woman’s eggs have been collected she is given medication, including progesterone, to help prepare the lining of the womb to receive an embryo.
Unless using donor or a partners frozen semen sample – the patient’s partner is required to produce a semen sample on the day of egg collection at the clinic.
A man is advised to abstain for 2-3 days prior to producing the sample. If the period of abstinence is more than 7-10 days, the quality of the semen sample may become poor.
The sperm is then used to fertilise the collected eggs either via IVF of ICSI (sperm are selected and injected in to the egg). The eggs are then checked for fertilisation and then the embryos are checked for further cell division the next day. There should be 2-4 cells the next day (day 2) and 6-8 cells on the third day.
The fertilised eggs / embryos then continue to grow in the laboratory for one to five days before they are transferred back into the womb.
The embryo transfer is a simple procedure. The embryo(s) are loaded onto a catheter by an embryologist and then a doctor/nurse introduces the catheter gently into the uterine cavity and deposits the embryos. Embryo transfer is carried out under ultrasound guidance with a full bladder.
The final step in the process is to wait for 10 -14 days. Once this time has passed it is possible to measure HCG levels which will show whether the treatment has been successful in producing a positive pregnancy.