SPERM MORPHOLOGY: DO WANT STRICT OR STANDARD, AND WHAT’S THE DIFFERENCE?

Strict morphology is

not designed to be a screening test for male infertility.It is far too sensitive for that

indication.In fact, using strict

morphology, only 5% of men will have normal sperm and thus be considered

fertile.Rather than use strict

morphology, W.H.O 3^rdedition morphologies are designed for

screening populations of men for infertility.

Under this classification system, up to 50% of m en will have normal

sperm.

In the 1950’s, McLeod, an andrologist, began to examine the

shape of sperm in men of proven fertility and sterility.His research led to a classification

system.Under McLeod’s classification

system, only the shape of the sperm head mattered and 50% of men had normal

sperm morphology.

Things sure have changed.

Now most labs use Strict Morphology—also known as Kruger

Morphology—or the World Health Organization standard, the W.H.O 4^th

edition.These methods take sperm head,

midpiece, and tail features into consideration.

In the early 1990s, when these categorization schemas were developed, 20

to 50% of men had abnormal sperm morphologic features.Now, only about 5% of men will have “normal”

sperm when these strict criteria are applied.

Why is that?

Well, no one knows for sure, but one can infer that part of

the problem lies in the way that sperm morphology information is used.Strict morphology is used to decide on when

to send a couple for ICSI rather than standard IVF.Couples with less than 5% normal forms have

better fertilization rates with ICSI compared to IVF.Used In this way, morphology assessments can

only determine which treatment option to pursue.

Strict morphology is not designed to be a screening test for

male infertility.Iit is far too

sensitive for that indication.In fact,

using strict morphology, only 5% of men will have normal sperm.Rather than use strict morphology, W.H.O 3^rd

edition morphologies are designed for screening populations of men for

infertility.Under this classification

system, up to 50% of men will have normal sperm.

Ask if your lab can do both Strict and

W.H.O 3^rdand report them simultaneously.That way doctors can get the information they

need and patients can avoid unnecessary worry.

Thanks,

Richard A Schoor MD FACS