The causes of implantation failure are diverse and especially due to different maternal factors as uterine abnormalities, hormonal or metabolic disorders, infections, immunological factors, thrombophilias as well as other less common ones.
Most fertility specialists believe that in more than 95% of IVF failures it is due to arrest of the embryos. Embryonic arrest is quite often due to chromosomal or other genetic abnormalities in those embryos that made them too “weak” to continue normal development and sustained implantation.
Chromosomal Issues
One of the major factors in IVF failure is chromosomal abnormalities in the embryo. This is true for all human embryos, whether naturally conceived or developed in the embryology lab. These abnormalities are the reason behind most miscarriages as well as failure to implant in an IVF cycle.
Couples who experience RIF despite the transfer of good-quality embryos should be offered appropriate investigations to rule out an underlying cause. The main treatment strategy in couples with implantation failure is to improve the quality of the embryo transferred and the receptivity of the endometrium.
When an embryo fails to implant, there can only be two logical reasons: the embryo is not good enough (genetically abnormal), or the endometrium is not “receptive” (doesn't allow the embryo to implant) enough.
Around 5% of women are expected to suffer from two consecutive pregnancy losses, almost 75% are due to an implantation failure, and therefore are never recognized as clinical pregnancies [3].
Understanding embryo transfer success rates
Higher quality embryos are associated with a 79% live birth rate with good quality at 64%. Poor quality embryos, however, are associated with a low birth rate of 28%.
“For most couples – and certainly those where the woman is younger than 40 and those of any age using donor eggs – two-thirds will achieve a live birth after five or six treatment cycles. This will take, on average, two years and is similar to rates that couples conceiving naturally take in one year.”
Early pregnancy loss can be grouped into two different categories based on when the loss happens. Sometimes the embryo just won't implant, which is still a loss for the patient, though not technically considered a miscarriage.
As you can see in the graph below, 48 per cent of women who were aged 30-31 when they started treatment had a baby after one stimulated cycle. This increased to 61 per cent after two cycles and 67 per cent after three cycles. This measurement is known as the 'cumulative live birth rate'.
“The most common reason that IVF fails across all ages is poor embryo quality due to poor egg quality.
Studies show that women in their 20s and 30s have the most success when getting pregnant through IVF and other reproductive technologies. According to the CDC, the average percentages of assisted reproductive technology (ART) cycles that lead to a live birth are: 31% in women younger than 35 years of age.
Screen for underlying health conditions – Sometimes underlying health conditions can prevent an embryo from implanting. These can include uterine problems, hormonal issues, thyroid problems, diabetes, and many others. Even a prior infection can cause implantation troubles.
Progesterone is what stabilizes the uterine lining and makes it “sticky” enough for an embryo to attach. Without enough progesterone, it can be more difficult for an embryo to successfully implant. Progesterone stabilizes the uterine lining and makes it “sticky” enough for an embryo to attach.
A number of conditions that cause inflammation and scarring, such as fibroids, polyps, adenomyosis, hydrosalpinges and endometriosis, can impact the structure of the uterine environment. Sometimes, the presence of these conditions can make it more difficult for the embryo to implant in the wall of the uterus.
A doctor performs an embryo transfer in a fertility clinic. Although many women abandon IVF treatment after three or four unsuccessful attempts, a study shows the odds of success continue to rise through as many as nine cycles. Too many women give up on in vitro fertilization too soon, a new study suggests.
One study from the UK which looked at 184,269 complete cycles, found that on average there was a 29% chance for a live birth after one cycle, while the chance for a live birth went up to 43% after six complete cycles.
IVF success rates for IVI clinics
There is of course no easy answer to how many IVF cycles you need to get pregnant. It could be one cycle for nearly 69% of our patients, or it could be two or three cycles. Everyone is a unique case.
When good quality embryos are transferred, the implantation rate is higher and there is no difference in pregnancy rate. Double embryo transfers should be limited to patients with repeated implantation failure or repeated pregnancy loss.
Typically an 8A on D3 is the best grade. These embryos show that there are 6-8 evenly sized cells, with no or less than 10% fragmentation. These embryos have more uneven or irregularly shaped cells with 25-50% fragmentation. These embryos show 50% or more fragmentation.
Fifty-two percent of embryos achieving the top two grades (5AA and 6AA) were euploid, but 48% were abnormal. Conversely, 63% of embryos graded <3. were abnormal, but 37% were euploid.
Mental stress can lead to an increased endogenous level of epinephrine. Excessive epinephrine level may interfere with the decidual differentiation of human endometrial stromal cells and thus affect embryo implantation.
How soon after failed Frozen embryo transfer (FET) can I try again? Answer: It is generally recommended to wait at least one menstrual cycle (which in some cases can be more than a month) after a failed FET before attempting another one.