Factors Affect The IVF Success Rate

 

Naturally, in any one month, it is estimated that  the chance of conceiving for any young and healthy heterosexual couples  is only 22 percent. Thus, it may take several months to conceive even under the best of normal circumstances.

In many ways, IVF is a lot like fertile couples attempting to conceive. The chances to get pregnant are consistent each month up to 4 or 5 cycles. Actually, the pregnancy rate per cycle in much higher than normal pregnancy when IVF is done because more than one embryo is transferred, in order to improve the chances. The pregnancy rates max out at about 40% after 2-3  embryos transferred depending on age the patient and the addition of more embryos only increases the multiple pregnancy rate (5 to 8% for triplet and 20 to 25% for twins).
Unfortunately, not every patient conceives with her first IVF cycle.
Although our take home pregnancy rates with IVF are consistently high at approximately 60%, there always patients fail to conceive with each IVF cycle and it is very difficult for patients to do multiple IVF cycles, both emotionally and financially. Together, fertility doctors and patients will have to review the treatment plan to see if any affecting factors could be changed or protocol be improved to have a greater chance for success with the next attempt.

There is no doubt that IVF helps to diagnose problems of fertilization and embryo development that could not be assessed by any other method. It is both a diagnostic and therapeutic procedure. The complexity of human reproduction means that many factors may play a role in the success or failure of IVF.

In order to gain some understanding of the factors that may affect the outcome of IVF, I will try and to dissect the IVF procedure to see which factors are present which may affect outcome.

   1. Patient Selection

    a.  Age
    b.  Diagnosis; male and female
    c.  Ovarian reserve
    d.  Smoking
    e.  Other pre-IVF evaluations; HSG, SIS, anti-sperm antibodies, acrosome reaction

   2. Stimulation Protocols

    a.  General Stimulation Flow Sheet
    b.  Long vs. Short Lupron
    c.  Antagonist
    d.  FSH vs. HMG
    e.  Premature Luteinization
    f.  Fluid in cavity during stimulation

   3. Egg and Embryo Factors

    a.  Number of eggs
    b.  Fragmentation
    c.  Embryo growth
    d.  Immature eggs at retrieval
    e.  Fractured zona
    f.  Polyspermy

   4. Embryo Transfer Technique

    a.  Day 3 transfer
    b.  Blastocyst transfer
    c.  Trial transfer

   5. Immune Factors
      
   6. Sperm Factors

    a.  Balanced translocations.
    b.  Y-Chromosome micro deletions.
    c.  Cystic Fibrosis mutations.
    d.  DNA fragmentation

   7. Factors in the Lab

    a.  Air quality
    b.  Temperature
    c.  Light