The World's first IVF baby was born following IVF treatment during a natural cycle.
Natural cycle or mild stimulation IVF cannot be considered as a first line treatment for most people, who achieve higher success rates in a stimulated IVF cycle.
Natural cycle IVF is an IVF or ICSI cycle in which one egg is collected from your ovary during your natural menstrual cycle. Low levels of drugs may be used to stimulate egg production.
Couples who might benefit from natural or mild IVF cycles include:
Women with low ovarian reserve (based on hormone results FSH, AMH etc) or women who have responded poorly to previous IVF cycles with standard ovarian stimulation (sometimes called "poor responders"). For these women even though natural cycle IVF will not have a high success rate, it can be the only option before treatment with oocyte donation
Women with extremely high risk for ovarian hyperstimulation syndrome (OHSS) or women who have previously been hospitalised due to OHSS
Women with a contradiction to IVF drug stimulation either due to a history of cancer, medical history or an allergic reaction to medications
Advantages of natural cycle IVF or mild stimulation could include:
Low cost per cycle, as you will use no or very few medications. The IVF cycle itself is also cheaper
The short and long term side effects from drugs are minimised
Treatment can be repeated every month without waiting for 2-3 months as is the usual practice for stimulated cycles
The risk of ovarian hyperstimulation syndrome (OHSS) is practically eliminated
There is some evidence suggesting that stimulating the ovaries could have a negative impact on the endometrium affecting success rates
However, Natural Cycle IVF is not for everyone and does have disadvantages:
Lower success rate when compared directly with stimulated IVF
In only 50-70% of cycles an embryo will be available to be transferred to the womb
There are usually no surplus embryos to cryopreserve
If you are interested in natural IVF or mild stimulation, you can discuss this with your doctor at your consultation to establish whether it would be the best option for you.