Fertility treatments, including in vitro fertilization (IVF) and hormonal injections, can have several side effects. Common side effects include mood swings, headaches, and bloating. There is also a risk of ovarian hyperstimulation syndrome (OHSS), which can cause severe abdominal pain, nausea, and rapid weight gain. Additionally, multiple pregnancies (twins or more) are a potential risk, which can lead to complications during pregnancy.