Morphology. What does it mean?

We were told we had a morphology issue since we came in at 10% strict morphology based on the Kruger scale. My RE told us our 10% had cut our chances at a natural conception in half, but since there were good numbers, it wasn't dire or anything like that.

In looking at information about the acceptable ranges for morphology, I've run across many different numbers. I just read "Strict Morphology (Kruger Test) For Sperm Function" and now completely understand what the numbers mean.

"The strict morphology of the sperm predicts a man's fertility potential (fertilizing capacity) even in cases where the sperm count, motility and/or regular morphology of the SA are normal." Due to the very strict rules, "relatively few sperm are rated as 'normal' or perfect during this test, as compared to the 'estimated crude morphology' done during a regular semen analysis (WHO criteria)."

To sum it all up, here is what the numbers mean:

~WHO criteria of regular s/a looks for at least 30% normal sperm. The tests aren't that strict, so many more sperm are considered "normal".

The strict Kruger test looks much, much closer:
~ strict morphology score over 14%: Normal; fertilizing capacity excellent.
~ strict morphology score 4-14%: Abnormal; possibly decreased or impaired fertilizing capacity.
~ strict morphology score 0-3%: Abnormal; severe impairment or probable inability to fertilize.

I'm really glad I found this breakdown. I've seen some websites say that anything over 4% on the strict Kruger test is "normal" and it's not. My RE's determination now makes sense. If I look at 10% being between the lowest "normal" level of 14% and the lowest level of "abnormal" but acceptable of 4%, I see that it really does decrease our chances by 50%! Actually, 9% would be the mark where fertility was decreased by 50%, but it's pretty close.

Bummer. We've got a bigger morphology problem than I had first thought. When I first saw 10% and saw that 14% was what they looked for, I was like "no big deal! We're only 4% away!" But we're not. We're 50% decreased fertility. IVF is looking like the smarter choice a little more each and every day.

NOTE: This is all still a huge numbers game. Someone with 2% morphology and 200 million sperm is going to be "better off" than someone with 14% morphology and 5 million sperm. This post is simply discussing how when dealing with small percentage points where 14% is the top and 4% is the bottom, a few points mean a lot more than my first glance.