Fasting during the month of Ramadan does not seem to have a significant effect on IVF/ICSI outcome although it significantly reduces anxiety and depression, which may be associated with the procedure. Fertility can actually be boosted by the practice of fasting and there is no contraindication to fertility treatments during this period. Simple modifications in the timings of medications and injections can help you rub this process smoothly with good results.
This issue really depends on where in your cycle you will be during Ramadan. Fasting can cause some changes in your metabolism (something called ketosis) which may affect implantation. Secondly, if you are at extra risk for OHSS, we would not want you being committed to fasting. We would recommend you to discuss this with your doctor before proceeding.