Male Infertility- ASRM Fact Sheet

PATIENT FACT SHEET from ASRM (American Society for Reproductive Medicine)Infertility Specialist Examining Sperm


Sperm Shape (Morphology): Does It Affect Fertility?

How do doctors decide if a man might have a fertility


For many years, experts have focused on semen analysis, but research studies show that the number of sperm (count) and the movement of sperm (motility) do not always predict fertility very well by themselves.


It may also be useful to look at the shape of the sperm (morphology),
which is also one of the important parts of the semen evaluation.
An updated way of determining sperm shape is called the
Kruger's strict morphology method. Kruger morphology is
a useful system that helps doctors determine if a sperm is
normally shaped or not. It was originally used to predict
the success of in vitro fertilization (IVF), a fertility treatment
in which the sperm are mixed with the woman's egg
in a laboratory.


More recently, it has been used to tell if
intracytoplasmic sperm injection (ICSI) is a necessary
treatment. ICSI is a procedure that helps a sperm fertilize
an egg by injecting a single sperm directly into the center
of the egg.


Even though it is used for these purposes, not all physicians
and scientists are sure that strict morphology method alone
predicts success with IVF or whether it indicates the need
for ICSI.

Characteristics of normal sperm

A normal sperm has:

• a smooth, oval shaped head that is 5-6 micrometers long
and 2.5-3.5 micrometers around (less than the size of a
needle point)

• a well defined cap (acrosome) that covers 40% to 70% of
the sperm head

• no visible defect of neck, midpiece, or tail

• no fluid droplets in the sperm head that are bigger than
one-half of the sperm head size

Intercourse versus artificial insemination


For patients with fertility problems, sperm morphology may have an effect on your ability to achieve a pregnancy. If the strict sperm morphology is more than 4%, there may be little difference in success whether timed intercourse or artificial insemination is utilized.

In vitro fertilization


A successful pregnancy using IVF depends on many of
factors: how many eggs are fertilized, whether the fertilized
eggs grow into embryos, and whether the embryo implants
in the woman's uterus. When strict morphology is 4% or
less, eggs may have a better chance of fertilization with the
use of ICSI.


Frequently asked questions


If an abnormally shaped sperm fertilizes the egg, does
that mean that my child will have genetic abnormalities?


There's no scientific link between the shape of a sperm and
its chromosomal content. Once the sperm penetrates the
egg, fertilization has a good chance of taking place.
However, there may be some male offspring who will
inherit the same type of morphology abnormalities.
Whether routine investigation of Y-chromosome abnormalities
should be initiated when low morphology is noted is


Are there any substances that I can reduce or eliminate
exposure to (e.g., alcohol, tobacco, caffeine) in order to
improve the shape of my sperm?

Studies haven't shown a clear link between abnormal sperm
shape and these factors, but it's a good idea to try to eliminate
use of tobacco and recreational drugs and limit your
consumption of alcohol. These substances reduce sperm
production and function in several ways. They may hurt
sperm DNA (material that carries your genes) quality.
Studies have not shown a clear link between caffeine consumption
and changes in sperm shape.


Are there any dietary supplements or vitamins that I
can take to improve morphology?

Dietary supplements or vitamins have not been clearly
shown to improve sperm morphology. Some specialists do
recommend that you take a daily multivitamin to improve a
number of body functions, including reproductive health.

Created 2008
The American Society for Reproductive Medicine grants permission to photocopy this fact sheet and distribute it to patients.

Topics: Testing

Lisa Rosenthal

Lisa has over twenty-five years of experience in the fertility field. After her personal infertility journey, she felt dissatisfied with the lack of comprehensive services available to support her. She was determined to help others undergoing fertility treatment. Lisa has been with RMACT for seven years and is currently Patient Advocate and Blog Editor-in-Chief.

Lisa is the teacher and founder of Fertile Yoga, a program designed to support men and women on their quest for their families through gentle movement and meditation.

Lisa’s true passion is supporting patients getting into treatment, being able to stay in treatment and staying whole and complete throughout the process. Lisa is also a Certified Grief Recovery Specialist, which is helpful in her work with fertility patients.

Her experience also includes working with RESOLVE: The National Infertility Association and The American Fertility Association (now Path2Parenthood), where she was Educational Coordinator, Conference Director and Assistant Executive Director.

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