As with many medical procedures, fertility treatment carries a small risk of complications. We try to minimise these risks by identifying those individual women most at risk and by monitoring their treatment cycle even more closely. The most common complications are as follows:
Ovarian Hyperstimulation Syndrome (OHSS)
Whilst receiving FSH injections, some women may experience abdominal bloating, breast tenderness and abdominal discomfort. For the majority of such women these symptoms are usually short-lived and cease when the treatment finishes.
Occasionally a woman’s ovaries may over-respond to the fertility injections and produce too many follicles. If this happens and treatment continues, there is a risk of developing OHSS. This is a complication of ovarian stimulation arising in approximately 5% of women undergoing fertility treatment. It is caused by the over-sensitivity of the ovaries to the fertility drugs, and is more common in young women with polycystic ovaries.
The symptoms of OHSS include lower abdominal pain, with swelling of the abdomen as a result of the ovaries becoming very large and fluid collecting around the ovaries. Women at risk of developing OHSS are advised to stop the FSH injections whilst continuing with the Gn RH agonist or antagonist. This is called coasting. The level of oestrogen is monitored until it drops to a safe level, then egg collection is arranged. In rare occasions, we may recommend that the egg collection is cancelled. In some cases, we may decide to proceed with the egg collection and freeze all available embryos for future use.
A few women, however, will still develop OHSS in the two weeks following egg collection. The majority of these women will develop a mild or moderate form of OHSS. Their ovaries will become enlarged and multiple cysts and ascites (fluid in the abdominal cavity) may develop, causing abdominal discomfort.
In exceptional cases, severe OHSS may occur in 1.0-1.5% of those women undergoing IVF. This is characterised by nausea, vomiting, abdominal pain and distension. The distension may cause breathlessness and weakness. Hospital admission may be needed to relieve the symptoms. The majority (75%) of such women who suffer from this, however, are pregnant, and those who are not will recover by the time they have their next period. The careful monitoring and coasting perfomed in this unit reduces the risk of developing severe OHSS.
There is a risk of miscarriage in all pregnancies especially in the early weeks. This risk is approximately 25% and is the same for pregnancies conceived by IVF as those conceived naturally. The risk of miscarriage is higher in women in their late thirties and forties. Early pregnancy is closely monitored to ensure that everything is progressing normally.
An ectopic pregnancy is a pregnancy occurring somewhere other than in the uterus, most commonly in the fallopian tubes. The incidence of ectopic pregnancy with fertility treatment is approximately 2.5%. It is a potentially serious condition but can be detected very early in the pregnancy by ultrasound scan. We therefore carry out a vaginal ultrasound scan two weeks after the confirmation of pregnancy.
Fertility treatment brings with it an increased incidence of multiple pregnancy. Problems are more commonly seen in triplet or higher-order multiple pregnancies, but may also occur with twin pregnancies. Because of the greater chance of pre-term labour and delivery, there is an increased risk of the babies being born before they are mature enough to survive and a greater risk of complications associated with prematurity if they do.
If a woman does conceive a multiple pregnancy, careful ante-natal management is advised.
The risk of multiple pregnancy can be reduced by transferring one embryo at a time.