Clomid (clomiphene) is a drug used to treat infertility caused by lack of ovulation due to hormonal problems. Clomid stimulates the release of hormones responsible for causing ovulation. Multiple births can be one of the side effects of taking Clomid. You are not supposed to take Clomid without talking to your health care provider especially if you have any of the following situations: pregnancy, uterine fibroids, liver disease, thyroid problem, ovarian cysts or enlarged ovaries, endometriosis, underdiagnosed vaginal bleeding, or any other chronic illnesses you have or that run in your family. Just like almost any medicine Clomid can cause side effects. No matter how mild or severe the side effects you experience are, make sure you call your doctor and report any of them, including abdominal swelling, abnormal uterine bleeding, abdominal tenderness headache, nausea, vomiting, diarrhea, abdominal pain, flushing, swellings, or breast tenderness.