IVF in expert hands is a safe treatment. The main risks are associated with ovarian stimulation, the egg pickup procedure and with features of any resulting pregnancies.
In some women, ovarian stimulation produces large numbers of follicles (more than 15-20) and very high oestrogen levels (greater than 15,000 pmol/L). This is known as ovarian hyperstimulation syndrome (OHSS). OHSS can be of varying degrees of severity. Typically, OHSS is associated with swelling of the tummy due to the ovaries becoming enlarged. OHSS can also cause blood vessels to become “leaky”. Fluid leaking into the tummy will worsen abdominal distension and may cause changes in bowel activity (diarrhoea or constipation) as well as nausea and vomiting. In severe cases, fluid can accumulate in the lungs and clots can form in blood vessels. The risk of the severe form of OHSS occurring is around 1%, but there are now very effective strategies for preventing severe OHSS altogether. Women who are slim, young and have polycystic ovaries are the ones most at risk for developing OHSS.
The risks associated with the egg pickup are bleeding, infection and inadvertently puncturing a nearby structure such as bowel. The risk of damaging another structure like bowel during egg pickup is extremely low, less than 1%.
One important pregnancy-related risk linked with IVF is the production of twin and triplet pregnancies if more than one embryo was transferred. Such pregnancies are riskier than those with only one baby (singletons) since they have an increased chance of very premature delivery that can sometimes result in developmental problems for some children. In Australia, over 80% of all embryo transfers involve only one embryo so this keeps the rates of IVF twins and triplets low. Another important pregnancy-related risk that occurs during IVF is ectopic pregnancy, which is a pregnancy located in an abnormal position outside of the womb, most often in one of the Fallopian tubes. Ectopic pregnancies are a medical emergency because they may rupture and cause severe internal bleeding. Treating ectopic pregnancies often involves surgery to remove the affected tube.