Being overweight, with a BMI of 30 or above, may mean it takes a bit longer to conceive a wanted pregnancy buty few obese women are infertile. It's recommended if you are actively seeking to become pregnant that you try to lose some weight before becoming pregnant, as some of the risks associated with pregnancy increase with greater BMI. These risks need to be kept in perspective - for example, the overall risk of early miscarriage is one in 5, and if your BMI is over 30 the risk is one in 4. If you don't want to become pregnant, it's important to find a contraceptive method that suits you. You should not be denied the vast majority of contraceptive methods on the basis of your BMI alone.