Many people don't realize that obesity can affect your fertility. This is true for both men and women. Let's talk about women first. In women, obesity is associated many times with something called Polycystic Ovarian Syndrome or PCOS. Obesity is also associated with irregular menstrual periods, which can be secondary to anovulation or not ovulating. All of these things can lead to infertility or the inability to get pregnant.
In men, obesity can negatively affect the quality of the sperm count and can cause infertility in men. The good news is that, if you lose weight, your fertility can improve. I've actually seen this in my practice. I perform weight loss surgery and many of my patients lose a substantial amount of weight in a year or so.
Many patients who were unable to get pregnant before, now are actually able to get pregnant. Something to remember though, is that if you are actively losing weight, you may want to wait until your weight loss has plateaued before you try to get pregnant, because that will just be healthier for you and for the baby. Those are just some of the ways obesity and fertility are related.