There is increasing evidence that excess weight significantly reduces the chance of pregnancy. Overweight women and their babies are also at increased risk during pregnancy. For such patients a weight management programme should be prescribed and appropriate information and resources be made available to the patient.

If either partner smokes they should be advised to quit. Fertility can improve after quitting, and IVF success rates are higher in women who have stopped smoking than in women who continue to smoke during the ovarian stimulation, egg retrieval and embryo transfer treatment phases.

There is also evidence that male smoking decreases success rates with IVF. It is not known whether this effect is caused directly by the sperm, or whether it represents a negative effect on the egg and embryo quality through passive exposure (second hand exposure).
For both partners, stopping smoking and reducing alcohol intake also will help the overall chances of success.