Given all that doctors don’t understand about natural pregnancy and childbirth, it makes sense that the process of IVF is not perfect. IVF, or in-vitro fertilization, is one of the most well-known procedures in reproductive medicine. It involves several careful steps that include stimulating a woman’s ovaries and retrieving her eggs, as well as fertilization and transferring of embryos. While the process can be a huge undertaking for a couple, it gives infertile adults the hope that pregnancy is still possible for them.
About 64% of IVF treatments result in a pregnancy and live birth, and this number varies depending on several factors including age. The treatment can be a viable option for clients who struggle with endometriosis, low sperm count, or troubles with ovulation. As with any medical procedure, IVF is not guaranteed to work, but a better understanding of the main causes of IVF failure can help couples make the right choice for them.
- Abnormal Eggs
Females carry egg cells that carry chromosomes, or DNA. When the egg cells split, half of these chromosomes go in one direction, while the others move the opposite way. The result is an egg cell that evenly splits into two cells that are exactly the same. This is the normal process, but sometimes other factors get in the way of the cells dividing properly. As a woman gets older, the structure holding onto these egg cells- the spindle apparatus- gets weaker and may even break. This can cause an uneven split between the chromosomes, and eventually an unusable embryo.
Furthermore, a woman’s ovaries are prone to damage from free radicals or complications from producing estrogen and progesterone. A number of issues can develop in the ovaries, such as polycystic ovary syndrome and endometriosis. With that understanding, it’s easy to see how abnormal eggs can interfere with the IVF process.
Of course, there are things that can go wrong on the male side, as well. While eggs play the primary role in IVF, the sperm is important, too. A woman can only become pregnant if sperm is strong enough to direct itself to the female’s reproductive system. To help this process occur, there are receptors on the egg membrane and the sperm head that attract one another. A successful egg/sperm interaction happens when the head of the sperm releases enzymes that enter the egg. This allows the sperm to break into the egg and pour its DNA there. The chromosomes from the egg and the sperm are now in the same place, so they combine to create a fertilized egg.
While egg cells can have abnormalities, the incidence is even higher in sperm. That being said, a chromosomally abnormal sperm is incapable of fertilizing an egg, so pregnancies with abnormal chromosomes tend to be a result of egg cell abnormalities. Still, men with a low sperm count, or with sperm that aren’t able to penetrate an egg can diminish a woman’s chances of getting pregnant. In this case, IVF may not be enough, and males can turn to intracytoplasmic sperm injection.
- Limitations in Choosing Embryos
Once a successful egg/sperm interaction occurs and a viable embryo is formed, an IVF specialist- or embryologist- can make a selection. Modern medicine hasn’t advanced to the point where an embryologist can determine which embryos are chromosomally normal or abnormal, but there are precautions they can take. They look at the stage of cell development, its rate of division, and the grade of the embryo. Embryologists look for grade 1 or 2 embryos with a cell stage of 6 or higher for the greatest chance of a healthy pregnancy.
- Problems with the IVF Lab
Through extensive research, scientists have been able to make the closest determination possible of the ideal egg, sperm, and embryo environment. To recreate the qualities of a woman’s reproductive tract, an IVF lab needs to strictly control the temperature, humidity, pH level, and light. In addition, the concentrations of carbon dioxide and oxygen need to be just right for embryos to flourish. Labs that don’t closely monitor these controls will end up with fewer successful pregnancies and more disappointed clients.
Besides the environment itself, an IVF lab must keep up with the latest advancements in reproductive medicine, processes, and equipment. As with any doctor’s office, cleanliness and sanitation are of the utmost importance, as are qualified staff who are constantly learning about new developments and techniques. It’s crucial for couples to scout out all the possible IVF facilities available to find the best fit.
- Underperforming Procedures
Finally, there are two primary processes that must take place in order to clinch the highest chances of a successful pregnancy. First is obtaining the eggs, the number of which can range from 2 to more than 10. Some women have success with just a couple of eggs, but a general rule of thumb is that the more eggs the embryologist retrieves, the better. When a woman takes the drugs that rev up ovary stimulation, the egg retrieval process can get underway. Generally, the embryologist can get a better idea of how many eggs will be retrieved by counting the woman’s antral follicles through a vaginal ultrasound. Taking all these steps ensures the best chances at success, but there are still times where the procedures underperform.
Likewise, embryo transfer must be preceded by lots of preparation. The embryologist will do a trial run first to find the prime location for transfer. The doctor will create the most suitable conditions for the transfer by removing cervical mucus and cell debris. A muscle relaxant and soothing environment might be used to keep the uterus from contracting during the transfer process. Without these preparations, the embryo may not find its way to the right location and thus be rendered useless.
IVF is a complicated process, but each day specialists are learning more and more about how to achieve the best outcomes. These are the most common reasons why IVF fails, but it’s important for couples to explore all their options outside of in-vitro fertilization. Moreover, choosing a reputable IVF Clinic and getting educated on the process will make great leaps toward a successful pregnancy.