07 Apr In Vitro Fertilisation (IVF)
In vitro fertilisation or IVF involves the following steps:
- Patient is given hormone injections to stimulate ovulation. The hormone causes her ovaries to produce many eggs.
- The gynaecologist removes the eggs from the ovaries through the vagina under ultrasound guidance.
- The eggs are examined under a microscope. Mature eggs are selected.
- This is combined with sperm in a laboratory culture dish, and then placed in an incubator.
- Fertilization is confirmed under the microscope approximately 18-24 hours later.
- After 44-72 hours the laboratory scientist selects “healthy” embryos.
- One to three embryos are transferred by the gynaecologist back into the woman’s womb.
Nowadays, Intra Cytoplasmic Sperm Injection (ICSI), a modification of IVF, is more commonly used. In this procedure, a laboratory scientist, using a microscope and micro tools, injects one sperm into an egg. This technique improves chances of fertilization.
IVF raises a number of concerns. Complications, miscarriage or birth defects associated with IVF are still controversial. A recent study from Australia shows that low birth weight (LBW) and preterm birth, are more frequent even in singleton babies born through IVF. Although ICSI does not cause more birth defects or miscarriages than standard IVF, the long-term effects are still unknown.
The transfer of multiple embryos in IVF procedures causes approximately 30% of all IVF pregnancies to result in having multiple births (e.g., twins or triplets which are associated with health risks to both mother and baby. These are premature birth, low birth weight, long-term disability and early death. The Centre for Disease Control and Prevention (CDC), USA reported that the risk of low birth weight is seven times higher among twins, than for single births.
ICSI/IVF can result in a variety of medical risks to the mother. In about 5-10% of IVF procedures, the use of hormones to induce ovulation can lead to a condition called ovarian hyperstimulation syndrome. Mild cases of ovarian hyperstimulation syndrome may cause the ovaries to become swollen and painful. Fluid may accumulate in the abdominal cavity and chest, the woman may feel bloated, nauseous, and experience vomiting or lack of appetite. Severe ovarian hyperstimulation syndrome, which occurs in less that 1% of cases, can lead to stroke, kidney failure or heart attack, due to too much fluid in the body. Occasionally, vaginal bleeding and infection of the lower abdomen can occur during egg retrieval.
According to the Ministry of Health Singapore, in 2001 there were 350 pregnancies, a 22.4% pregnancy rate out of 1561 infertile couples treated by IVF.