Natural Cycle IVF/ IVF Treatment Process

In women having regular periods, the ovaries produce an egg every month. Natural cycle IVF is a type of IVF treatment whereby we aim to retrieve the egg that one’s body has selected. Thus, no ovarian stimulating drugs are used unlike the conventional IVF treatment. It is usually used for women where medication is either unlikely to help in recruiting a higher number of eggs (clinically known as a ‘suboptimal ovarian reserve’ or those with a previous suboptimal response to ovarian stimulation ‘poor responders’) or in those with a very high risk of over-stimulation as a result of the medication (known as ‘ovarian hyper-stimulation syndrome’ (OHSS)).


The CRGH has been offering natural cycle IVF for several years. We are very pleased with the pregnancy rate considering the high average age of our natural cycle IVF patients and that a high percentage have had a previous poor response to fertility drugs.

As natural cycle IVF follows the normal menstrual cycle, usually only one egg is obtained. The entire process takes 15 days during which time the woman is monitored to track the development of her follicles, using ultrasound scans and blood tests. There is quite a high cancellation rate (approximately 30%) due to either high hormonal levels at the start of a cycle, arrest in follicular growth or premature ovulation. The egg collection is usually done using light sedation. Ultrasound guided follicular aspiration is done. In the aspirate of the follicle, the embryologist should be able to identify the egg. The egg is then placed in culture media in our laboratory.

The embryologists will prepare the sperm for insemination. If the sperm quality is good, the sperm will simply be mixed with the egg and fertilization will hopefully happen. If the sperm quality is poor, then ICSI may be performed. The following day the embryologists will look for signs of fertilization (day 1 after the egg collection). The next day they will check to see if the embryo has cleaved (day 2 after the egg collection). The embryo is transferred on D2 or D3 post egg collection.