The stages of IVF have different risks associated with them. During ovarian stimulation, women can get ovarian hyperstimulation syndrome (OHSS), which causes swollen, painful ovaries. Nearly 30 percent of IVF patients experience at least a mild case of OHSS [source: CDC]. Mild cases can usually be treated with over-the-counter pain medication and a reduction in activity level -- OHSS generally resolves on its own in the absence of pregnancy. In moderate cases, which are less common, ovaries swell and fluid accumulates in the abdominal cavities. Symptoms of moderate OHSS include heartburn, gas, nausea, vomiting and loss of appetite. About 1 to 2 percent of women undergoing IVF develop severe OHSS, which may require hospitalization and involves sudden and excessive weight gain, severe abdominal pain with nausea or vomiting, and shortness of breath [source: CDC].
During egg retrieval, risk depends on the retrieval process. Transvaginal ultrasound aspiration carries a small risk of bleeding and infection and, sometimes, damage to surrounding structures like the bowel and bladder. The risks associated with laparoscopy include difficulty breathing, chest infection, allergic reactions to medications and nerve damage -- the same as with any surgery in which anesthesia is required.
When more than one embryo is transferred, there is always the risk of a multiple pregnancy. An infertile couple may take this as good news, but the presence of more than one embryo increases the risk to the embryos and to the mother. The most common is premature delivery. The babies could develop complications after birth or be born too early to survive. About 5 percent of IVF pregnancies are ectopic, which means that the fertilized egg develops outside the uterus, usually in the fallopian tubes [source: American Society for Reproductive Medicine]. This complication, unfortunately, requires immediate destruction of the fetus.