Question here is that why does IVF sometimes fail?
IVF treatment is an emotional, physical and financial roller coaster ride.Unfortunately, many couples will not get success in first cycle IVF and need to consider a second cycle.Following are the reasons,

Issues with the Follicles
Egg Abnormalities
Female Age
Abnormal Sperm
IVF Lab Factors
Embryo Selection Methods
Issues with the Uterus and Uterine Lining
Embryo Implantation Failure
Embryo Transfer Process

Issues with the Follicles

Eggs are contained in fluid-filled sacs called follicles. Fertility drugs are given in order to promote the growth of follicles. If the follicles are too small or not viable, this can lead to failure of the process.

Egg Abnormalities

The egg is the most important factor considered for the cause of IVF failure.
If the eggs that are produced for the process may not be viable for treatment,the possibility of success gets low.

Female Age

Age has a great impact on the egg. After age 30 egg quantity and quality begin to decline and the rate accelerates after age 35, so that by age 40 only about 10% of a woman’s eggs are normal. The decrease in egg number, when combined with poor egg quality, often translates into a lower chance of creating a normal embryo with IVF.

Abnormal Sperm

Sperm quality issues are another potential cause of an IVF cycle failure.This can generally be dealt with through sperm washing techniques and careful selection of healthiest sperm present.

IVF Lab Factors

In rare instances, errors on the part of the fertility center or a fertility specialist can lead to a failure of an in vitro fertilization (IVF) treatment. Modern technology and advanced techniques have helped reduced the already low possibility of fertility doctor error.

Embryo Selection Methods

An embryo is an egg that has been fertilized and has begun the process of cellular division.Timing is key when it comes to transferring embryos to the uterus.If the embryos are implanted too soon (i.e., before proper cellular division) or at some other poorly timed moment, the chances of successful pregnancy are reduced.
One more cause of a failed IVF cycle is that the embryos that were transferred did not have the normal number of chromosomes even though they looked like they were growing well in the laboratory. Embryos with abnormal numbers of chromosomes almost always result from an issue with the egg.

Issues with the Uterus and Uterine Lining

The lining of the uterus must grow to a certain thickness (at least 7 mm) in order for implantation to occur at a high rate.It’s important that fertility specialists consider the possibility of uterus or uterine lining issues before the transfer phase is even initiated.If the lining is not perfect, the transfer should be deferred.

Embryo Implantation Failure

There are times when the embryo simply fails to attach to the uterine lining, or instead implants on another part of the woman’s reproductive system, such as the fallopian tubes.

Embryo Transfer Process

The embryo transfer process is when the embryo is placed via catheter into a woman’s uterus. Sometimes mistakes made during this process result in failure. For instance, it’s possible for an embryo to become damaged or lost during the transfer phase of the treatment.

Will I need to undergo in vitro fertilization (IVF) again?

If the first IVF treatment proves unsuccessful, it is okay to perform a second IVF procedure as needed. This is common for many patients so do not feel discouraged if the first attempt fails.