Recurrent implantation failure (RIF) refers to cases in which women have had three failed in vitro fertilization (IVF) attempts with good quality embryos. The failure of embryo implantation can be a consequence of uterine, male, or embryo factors, or the specific type of IVF protocol. Recurrent implantation failure is one of the most challenging and frustrating situation in the field of IVF. This repeated failure is equally disappointing for doctor and patients.
Causes of repeatedly implantation failure:-
Many factors can contribute for negative results like
Advanced maternal age: - Maternal age plays a crucial role in the quality of the embryos that are used for IVF. Pregnancy rates also have been found to be decreased as maternal age increases. Delivery rate is also affected by both maternal age and embryo quality.
Sperm factor: - There is a higher incidence of chromosomal aneuploidies in sperms, lower chances of success and higher chances of miscarriage. There are higher chances of success and pregnancy as well as lower chances of miscarriage rates in men who had higher percentage of euploid sperms.
Thick zona pellucida: - the zona pellucida naturally hardness after fertilization. Increase zona hardening may occur with the age of female. If zona becomes thick so, failure of zona rupture cause implantation failure. Thin zona embryos have good chances of implantation.
Genetics factors: - genetic factors play an important role in the occurrence of recurrent implantation failure. Although some of these factors, such as numerical chromosomal aneuploidies are known to be causative factors, there are some other factors that solely increase susceptibility to this event. Like parental abnormalities, embryonic aneuploidies and etc.
Endometrial polyp: - Endometrial polyps also appear to be the most commonly detected abnormality in patients with recurrent implantation failures after IVF. It is suggested that polyps have higher incidence in women with endometriosis. Women who had polypectomy had higher chances of implantation than women who had no intervention.
Fibroids: - fibroids can reduce the chance of implantation in many ways. Their impact on fertility may depend on their size, location and number. Subserous fibroid doesn’t effect on fertility but submucous fibroids reduce the chances of implantation.
Congenital anomalies: - A congenital abnormality of the uterus is a malformation present from birth. Most common congenital uterine abnormality is septate uterus, a band of muscle or fibrous tissue divides the uterus into two parts. This condition can cause repeat miscarriages. Doctor may recommend surgery to repair the uterus. A bicornuate uterus, also called a heart-shaped uterus, has two cavities or spaces instead of one. Most women with a bicornuate uterus will not have trouble getting pregnant but may have a higher risk of miscarriage.
Obesity: -Increased BMI (> 25 kg/m2) has also been shown to impact implantation rate. More oocytes are collected, there are higher chances of increased quality of embryo for transfer, and with fewer oocytes come a higher likelihood of negative pregnancy outcome due to fewer good quality embryos. Obese women required more gonadotropin stimulation cycles, yet they had statistically fewer oocytes for collection. This suggests that the oocyte quality and follicular development might be affected by obesity.
Adenomyosis: - Adenomyosis occurs when the tissue that normally lines the uterus grows into the muscular wall of the uterus. It effect implantation as it usually affect the junction zone of uterus by overlying the endometrium. This is difficult to diagnose on ultrasound.
Smoking: - Cigarette toxins might play a role in disrupting corpus luteum formation and implantation of the embryo. In women undergoing IVF, smoking patients were found to have lower estradiol levels during ovarian stimulation. Pregnancy rates have been shown to be lower overall among smokers when compared with non-smokers
Stress: - It has been shown that elevated levels of cortisol, also known as “the stress hormone,” can cause miscarriage within the first 3 weeks after conception in comparison with women with low cortisol levels. IVF failure was also associated with higher rates of post-IVF anxiety in comparison with women who were able to become pregnant successfully.