Normally, one egg is produced from the ovaries in each cycle. During in vitro fertilization, the ovaries are stimulated by hormones to produce more number of eggs per cycle. The number of eggs produced is dependent upon the dose of hormones used. While ovarian stimulation by low dose of hormone results in the production of around ten eggs per cycle, this number may increase to 20 to 30 eggs with higher dose of hormones.
As per the statistics provided by the National Institutes of Health, ovarian stimulation by high doses of hormones can lead to the development of a condition called as ovarian hyper-stimulation syndrome (OHSS) in 10% of patients undergoing IVF. The condition is characterized by fluid accumulation in the ovaries, which may eventually leak into the chest and abdominal cavities. The condition has the potential of turning life threatening. In fact, a recent study found that OHSS is the leading cause of maternal deaths in women who underwent high dose IVF in England and New South Wales. Another recently conducted study has linked high dose IVF to lower birth weights of babies.
Apart from developing OHSS, many side effects of hormones used during IVF can be attributed to Lupron. This is the medicine used to suppress the ovaries prior to their stimulation by hormones like the follicle stimulating hormone (FSH) and the Luteinizing hormone (LH). Though used commonly, readers would be surprised to know that Lupron has not been approved by the FDA for use in IVF. The drug has been associated with deleterious effects like liver disorders, joint aches, pain in bones, muscle and bone loss and even memory loss in certain cases.
Low Dose Form Of IVF Is Safer
Many fertility clinics across Europe and Japan now employ low dose forms of IVF, According to the proponents of this technique, the low dose form of IVF is much safer compared to the high dose form of therapy. In this form of IVF, the ovaries are not suppressed at the beginning of the cycle and the hormone used for stimulating the ovaries are in low dose. Although the number of eggs released is much less compared to high dose IVF, the patient experiences fewer side effects.
The critics of low dose IVF say that the procedure takes a longer time to get the results, but proponents of this form of therapy say that the cost of treatment per cycle is less than one-thirds of that incurred in high dose IVF. And as there are fewer side effects, patients do not require hospitalization for them, cutting down the expenditure further. Moreover, mild stimulation of the ovaries results in the production of healthier eggs which in turn leads to a higher birth rate. As the dose of hormones used is low, the women experience lesser physical and emotional discomfort.
In vitro fertilization is a form of assisted reproductive technology which normally involves five steps:
- Stimulation of the ovaries by means of fertility drugs so that ovaries produces more than one egg per cycle. During this step, the woman is made to undergo repeated trans-vaginal ultrasounds so observe the ovaries.
- Retrieval of the eggs from the follicles. This is an ultrasound guided technique wherein eggs are sucked out from their follicles. The process is carried out as an outpatient procedure under mild sedation.
- Insemination and fertilization of the eggs, wherein the eggs are kept with sperms in laboratory conditions till the time they are successfully fertilized. If the fertilization does not take place spontaneously, then the eggs are injected with sperms, a process called as intra-cytoplasmic sperm injection (ICSI).
- Embryo culture is the step wherein the fertilized egg is watched judiciously in environmentally controlled conditions till the time it starts dividing. The fertilized eggs may be screened for hereditary diseases, a process called as pre-implantation genetic diagnosis (PGD). This procedure helps the parents and the physicians to decide which embryos are most suitable for implantation. However, this procedure is not carried out in all the fertility clinics.
- Embryo transfer is the process wherein the fertilized embryo which has begun dividing, is placed back into the woman’s womb. It is normally done 4 to 5 days after fertilization has taken place. Once the embryo has been successfully implanted into the woman’s womb, it grows there and the IVF procedure is deemed successful. The unused embryos can be frozen and used at a later date.