IVF has been practised for the past 40 years, yet we have been unable to get a success rate of 100%. This is because there are a number of a factor which comes into play to determine the outcome of an IVF cycle. The two main clinical factors are
- The quality of the embryo
- The quality of the uterus lining (the endometrium)
Quality of the embryo
This, in turn, depends on the quality of the sperm and egg. A good sperm and egg make a good embryo. If the sperm has poor motility or a poor morphology, it will not yield a good embryo. Similarly, the egg needs to be of a good quality. As the age of the woman increases the quality of eggs starts coming down. If AMH is low indicating a failing ovary the egg quality is poor.
The quality of the embryo also depends on the lab conditions. If the air In the laboratory or incubator has a poor quality (ie high VOCs, high particulate count in the air) or the temperature and humidity are not optimum the growth of embryo will not occur in a proper way leading to slow division of cells and fragmentation. The media in which embryos are grown is also vital as it determines the immediate pH and temperature, besides providing nutrition for the growth of the embryo.
The quality of embryo also depends on the skills of the embryologist. The embryologist should be skilled to do procedures fast so as not to expose the embryo to the outside air.
Quality of the sperm
Poor sperm quality can be due to infections of the genital tract, genetic, childhood mumps, undescended testis, stress, and dietary deficiencies.
Quality of uterus lining
The lining may not be optimum because of previous infections or surgery. Infections like tuberculosis destroy the lining. Most IVF cycle where a good embryo has formed the cause of failure is a poor lining – termed as recurrent implantation failure. The lining is assessed by its thickness which should be more than 8 mm, morphology and blood flow which is checked by ultrasound.
It is important for couples to understand that many times no cause of failure can be determined. It is a science where much is left to chance. Once the embryo is deposited in the uterus there is little an IVF specialist can do to ensure that it grows further. While the laboratory growth is under the control of the IVF specialist, once deposited there is no external control and most growth occurs naturally
Stress has been seen to significantly contribute to failure. Hence, it is imperative for the patient to relax. They should take proper counselling and continue the counselling even after embryo transfer. Yoga and meditation help considerably. They can also join support groups with couples undergoing similar treatment. They must constantly be in touch with their doctor to allay all fears.