The range of healthy weight is defined by a measurement known as the body mass index (BMI). You can calculate your BMI here.
You are healthy if your BMI is between 20 and 25.
Women who have a BMI of more than 29 can take longer to get pregnant than women whose weight is normal. If you are overweight (a BMI of more than 29) and you have irregular periods, or no periods at all, losing weight may increase your chances of getting pregnant. If your weight gets down to the normal range, your ovaries may start working again. Women who take part in group exercise and diet programmes have a better chance of loosing weight and getting pregnant than those who try to lose weight on their own. If you are underweight (you have a BMI under 19) and you have irregular periods, or no periods at all, you may find that if your weight gets back up to the normal range your ovaries will start working again, and so improve your chances of getting pregnant. If you are a man and you are overweight (a BMI of more than 29), your fertility is likely to be lower than normal.