Determining success rates for couples for MS/IUI

I saw in your blog you wrote about determining the success rates for couples on a more case-by-case basis, rather than just everyone going off the 15%/natural cycle or 18%/Clomid cycle (or that is what I gathered from it anyways).  I was wondering how exactly this is done?  If I knew I had a higher chance of success due to certain factors, I would be more willing to make the leap.  Even though MS has said "the majority of couples become pregnant after a few cycles," when I figure the 18% x 3 = 54% that's only a little over half, and of course a small % will miscarry, leaving it to about half in my opinion, after 3 cycles.

My husband & I are young (27), healthy, the only issue is I have irregular cycles which was easily remedied with Clomid as I got pregnant my 2nd cycle of it for my last child.  I have never had a miscarriage, and my 1st pregnancy was also a suspected vanishing twin pregnancy, so obviously I ovulated more than 1 egg WITHOUT the Clomid.  But I know no one can tell you for sure exactly what % success rate you may have, but perhaps there is a way to know if a given couple has a higher or lower chance?

thanks,

momof2boys  :)

P.S.  I know you have a lot of ?'s to answer already! 

The percentages hold up pretty well.  Remember, most all of the women ongoing Microsort are fertile and have not had problems getting pregnant before.  The issue is the very small number of sperm that are available after the sort for insemination.  This is not a factor with IVF which is why the pregnancy rates are so high with IVF.   IVF works very well on fertile women.

Dr. P

momof2boys:

Even though MS has said "the majority of couples become pregnant after a few cycles," when I figure the 18% x 3 = 54% that's only a little over half

You can't just multiply the numbers together for cumulative odds. (Example: Suppose the odds are 50% and you did 2 cycles, 50% x 2 would be 100%!  Obviously if the odds are 50% per try you aren't guaranteed success in two tries.  The correct answer for 50% and 2 cycles is 75%.)

If the odds are 18% per cycle, after 3 cycles, about 45% of women will get pregnant.
See: http://www.in-gender.com/XYU/ART/Cumulative-Odds.aspx  (I have a pretty graph of this)

But this is just a statistical model -- in reality, who has 3 identical cycles?
 

(note, I am just talking about calculating cumulative statistics above, nothing specific to MicroSort!)

oh you're totally right    yes i am definitely NOT the math whiz!!  and my DH told me that before, but I forgot.  like if it's 18%/cycle, it doesn't double if you try 2X!!  but I had heard someone from Microsort say "the majority of women get pregnant after 3 cycles" but even with your correct statistic of 45%, that is still incorrect.  They shouldn't say that then, it can be misleading. 

But yes I totally goofed on that, Dr. P must think I'm a genius! 

momof2boys:

I had heard someone from Microsort say "the majority of women get pregnant after 3 cycles" but even with your correct statistic of 45%, that is still incorrect.  They shouldn't say that then, it can be misleading.

LOL, the math is confusing for sure.  But, that doesn't necessarily mean that what MicroSort is saying is misleading.  They are talking about actual results for which they have the data; I am just doing a straight calculation  on cumulative odds of 18% for 3 tries. 

It also depends on the age of the patient and many other factors, but I would agree that the statement that 'most couples are pregnant after 3 cycles of IUI' is misleading and they should not be telling people that.  You math is very good and correct.  I get about 45% of couple being pregnant after 3 cycles with an 18% success rate with my math.  When you look at the couples that drop out after 1 or 2 cycles (possible poor response or poor sperm), you are probably looking at selection bias in the remaining  couples trying a 3rd time so of the couples trying a third time, probably more than half are successful.  But it is still misleading to say it.  I hope this clears things up.

I am still confused about why the results are so low.  I know that there are fewer sperm after the sort, but it only takes one sperm to get pregnant.

 

you should check out The Miracle of Life dvd, so interesting!

The pregnancy rate in a natural cycle with a young and fertile couple is 20-25% per month.  The number of sperm we are using is 400 time less than a natural cycle with a MicroSort cycle.  We rely on IUI and timing to even approach what is seen in a natural cycle.