Facing one or more unsuccessful cycles of IVF is devastating and frustrating. When a couple fails to achieve pregnancy following several cycles of IVF after using three good embryos are known to be going through a recurrent or repeated implantation failure.
A healthy egg gives birth to a healthy embryo. Any abnormalities in the egg can result in a chromosomally abnormal embryo. Egg after fusing with the sperm plays a major role in cell division and chromosomal duplication to form an embryo.
As the oocyte or eggs age, the spindle apparatus or the structure that is responsible for the chromosomal separation and equal distribution becomes prone to breakage. This leads to an abnormal or anomalous distribution of chromosomes which results in the formation of a chromosomally abnormal embryo.
As a woman ages, the free radicals or the reactive oxygen species in her body increases. These free radicals present in her ovaries, react with her eggs causing damage to its DNA and thus reducing its quality.
Abnormalities in the sperm may lead to an unfertilized egg. There are three major roles of a sperm: to reach the egg through the fallopian tube, penetrate through the outer membrane of the egg and release half of its genetic material or the sperm DNA to produce an embryo. So it is important to select the best quality sperm under high magnification during IVF for successful fertilization.
Sometimes even a high-quality sperm that is chromosomally normal may lack enzymes required to break through the zona pellucida or the outer shell of the egg. Low quality, morphologically abnormal and less motile sperm may not be able to reach the egg to fertilize it.
Embryo selection plays a crucial role in successful implantation. It is a natural function of the uterus to reject the embryos that are abnormal. This means the chromosomally abnormal embryo cannot survive and it results in implantation failure or miscarriage. Sadly, it’s difficult to morphologically distinguish chromosomally normal embryos from abnormal ones. So, an investigation of embryo health is important for a successful pregnancy.
Successful implantation also depends on the endometrial environment. There are various structural, hormonal and immunological factors that affect an ideal uterine environment. Structural uterine factors such as the abnormal shape of the uterus, fibroids, polyps, scarring, difficult cervix and intrauterine adhesions can lead to an implantation failure. Other main uterine issue includes a thin endometrium due to an early rise in the progesterone prior to the egg retrieval in an IVF cycle.
Both paternal and maternal health matters in the success of an IVF pregnancy. Consumption of alcohol, smoking, and drugs can lead to lots of complications during implantation and pregnancy.
Improper management of systematic diseases like diabetes and hypertension and unhealthy body weight also results in IVF failures. Autoimmune disorders such as antiphospholipid syndrome and blood clotting disorders can lead to miscarriages.