Risks & complications
As with any medical or surgical procedure, some patients undergoing IVF treatment will experience side effects and complications which include the following;
- Failure of IVF treatment;
- Multiple Pregnancy;
- Problems Associated with Ovarian Stimulation by Fertility Drugs;
- Side Effects of Fertility Drugs;
- Ovarian Hyperstimulation Syndrome (O.H.S.S.);
- Risks of Egg Collection;
- Fetal abnormalities.
Failure of IVF Treatment
This is the most common complication of treatment. The likely reasons for this failure are cancelled cycles (approximately 10% of treatment cycles will be abandoned before egg collection, generally due to poor response to the drugs), failure to collect eggs (about 1%), failure of fertilization (about 5%), and failure of implantation.
In the majority of patients, approximately 20% of the embryos implant after transfer to the uterus, so it is usual to transfer more than one embryo. This results in multiple pregnancies.
Although the prospect of twins or triplets may seem attractive to some couples, multiple pregnancies are associated with increased risks of maternal and fetal complications. Premature birth is the most important complication as babies born too soon may not live and, if they do survive, they are at increased risk of serious life long disabilities such as cerebral palsy and learning problems. Multiple pregnancies have a four-fold increase in the rate of preterm delivery and low birth weight compared to single pregnancy. The risk per pregnancy producing a child with cerebral palsy is 8 times greater in twin pregnancies and 47 times greater in triplet pregnancies than in singleton pregnancies.
Problems Associated with Ovarian Stimulation by Fertility Drugs
Fertility drugs that stimulate ovulation are rarely associated with complications. There are potential problems that may occur and these include: side effects of fertility drugs, ovarian hyperstimulation syndrome (OHSS), adnexal torsion (ovarian twisting) and the theoretical risk of ovarian cancer.
Side Effects of Fertility Drugs
These can include local reactions e.g. mild bruises and soreness at the site of injections. There is also a small risk of a generalized allergic reaction. Other drugs such as GnRH agonists may cause headaches, mood changes, hot flushes and vaginal dryness in some women, similar to those experienced at the menopause. However all of these side effects are rare, are usually short-lived and are no cause for concern.
Approximately 15% of women will develop simple cysts while on treatment. These cysts may produce oestrogen, and sometimes are associated with poor IVF outcomes. If this happens, the woman will be advised to continue taking GnRH agonist drugs until the cysts resolve by themselves. Sometimes aspiration of cysts may be required.
Ovarian Hyperstimulation Syndrome - OHSS
This is the most serious complication of IVF. Any woman undergoing ovulation induction is at risk of developing OHSS, although some more than others. The exact mechanism is not understood but the ovaries respond in an excessive fashion to the stimulating drugs. The ovaries swell and very high levels of oestrogen are produced. Ovarian swelling causes abdominal discomfort and pain. Most women feel sick and nauseated. Fluid may accumulate in the abdomen and sometimes around the lungs and heart causing further problems. Two per cent of women will have severe symptoms and require admission to hospital, and even an intensive care unit. Rarely, severe OHSS can be a life threatening complication. Every effort is made during monitoring to prevent OHSS but, despite every care, a small number of women (about 3% of the treatment cycles) develop the condition. Young women and those with polycystic ovaries are most at risk.
Risks of Egg Collection
As with any surgical procedure, there are potential risks associated with egg collection. Most women experience mild to moderate discomfort. Bleeding may occur during or after egg collection, from the ovary or from the skin of the vagina. The bleeding is usually minimal and is very rarely a problem.
There is a less than 1% chance of the following complications:-
- Pelvic infection
- Bleeding or blood vessel injury
- Urinary retention
- Side effects of the anesthetic agents
As IVF, and particularly ICSI, bypass the normal processes for reproductive selection and fertilization, it is theoretically possible that these pregnancies might be associated with a higher incidence of genetic and other fetal abnormalities than pregnancies that are conceived naturally. However, long-term follow up studies have been reassuring, showing at most a ~1% increase in fetal abnormalities. There is however evidence that fertility problems (i.e. sperm abnormalities) may be passed to children when ICSI is used to treat men with severe sperm abnormalities. Such couples are offered genetic counseling prior to treatment e.g. cystic fibrosis, y microdeletions.