Yes. Weight does affect fertility. If you are a runner and are thin, and are not menstruating regularly, you may be infertile. Conversely, obesity can also result in infertility due to conversion of estrogen to testosterone in the fat tissues.
Too high or too low. If your weight is too high, your estrogen levels stay high, telling your brain not to trigger ovulation. If your weight is too low, you also may not ovulate. Also, you want to be in the range of your ideal body mass index to have the safest pregnancy. I have written a book call tick tock which discusses many aspects of fertility based on my own experiences.
Too thin. Most people don't realize that being "too thin" shuts off your pituitary and your body stops ovulating.
Yes. Being overweight or underweight can have a significant negative effect upon your fertility. Fat is a hormonally active tissue and there are numerous studies demonstrating decreased pregnancy rates in overweight people. Excess weight is also associated with higher miscarriage and birth defect rates as well as increased risks for serious maternal complications. Please discuss this with your dr.
Yes. Both overweight and underweight women may have a harder time conceving, even if they undergo infertility treatment.