Obesity is a chronic condition that causes significant morbidity and mortality in people in the United States and around the world. Traditional means of weight loss include diet, exercise, behavioral modifications, and surgery. New weight loss medications, glucagon-like peptide-1 receptor agonists, are revolutionizing the management of weight loss but have implications for fertility and pregnancy. Obesity is associated with infertility and may affect response to ovulation induction medications. In pregnancy, obesity increases the risks of spontaneous abortion, birth defects, gestational diabetes, hypertensive disorders of pregnancy, cesarean delivery, and stillbirth. Lifestyle changes alone for weight loss have not improved outcomes. Glucagon-like peptide-1 receptor agonists and new medications targeting gut hormones can help people achieve their weight loss goals but are contraindicated in pregnancy. Obstetrician-gynecologists should work with patients to manage these medications before they become pregnant, between pregnancies, and after delivery.