If you are new to this channel, my name is Dr. Randy Morris and I am a U.S. board
certified physician expert in infertility. I take complicated scientific studies and
break them down to give you fact driven tips on how to improve your chances to become pregnant.
Before starting fertility treatment, any good fertility doctor will have you and
your partner complete some basic testing. This will include a test to look at sperm. This is
known as a semen analysis. Based on the results of a semen analysis, your doctor will determine
if you can attempt pregnancy using techniques like IUI or IVF. How did we get to this point?
Human sperm are pretty small, about 1/600th of an inch. That is too small to see without
the help of a microscope. The very first microscope in 1590 was not even powerful
enough to see sperm. It wasn’t until 1677 that a medical student named Johan Hamm became the first
person to see sperm. He called them animalcules spermatiques. He was able to see that sperm
had heads and tails and they were capable of moving. This was the very first semen analysis.
Since then, microscopes have improved a lot. By 1866, scientists started to
get the idea that semen characteristics could correlate with male fertility. Specifically,
scientists started to focus on the number of sperm, the movement of sperm and their shape or
appearance. The scientific term for evaluating the appearance of sperm is called morphology.
Eventually, scientists started learning what a normal human sperm was supposed to look like
and what abnormal sperm look like. Basically, a sperm has three parts. A head. A neck and a tail.
Abnormal sperm sometimes had very large heads, small heads or sometimes two heads. Necks could be
bent. Tails could be long, short or also double. Over the years, various studies have found some
link between the amount of abnormal looking sperm and male fertility. The basic idea is that if
you see a man with a large percentage of abnormal sperm, then those men would have worse fertility.
However, over time, the assessment of sperm became more strict. As scientists were focusing
on smaller and smaller features, many sperm that would have been considered normal looking in the
1970s, were considered abnormal by the late 1980s. As a result, the percentage of normal appearing
sperm that indicated normal fertility became smaller and smaller. Using today’s standard,
a man would be considered to have normal fertility if at least 4% of the sperm looked normal.
Men who have a low percentage of normal appearing sperm are said to have teratospermia. If 1-3% are
normal it is considered mild to moderate. If it's less than 1% then we call it severe teratospermia.
Many studies have examined the impact of sperm morphology on intrauterine
insemination (IUI) success in couples. Some of these studies have shown lower
IUI success rates when the normal sperm morphology was less than 4%.
It was therefore recommended that these couples skip IUI and go straight to IVF.
Some newer studies found that the IUI pregnancy rates were similar. One of the problems with
all of these studies was that the morphology assessment was done using a different semen
specimen than the actual specimen that was used for the IUI. This may be problematic,
as there can be significant variation in semen parameters between samples.
Recently, doctors performed a study looking at IUI success. This time,
they performed a morphology assessment on the same semen specimen that was used for the IUI.
They divided couples into three groups. Normal, which had more than 4% normal appearing sperm,
Mild teratospermia with 1-3% normal sperm and severe teratospermia who had less than
1% normal sperm. Couples were allowed to do multiple IUI cycles. What did they
find? There was no difference in the chance for pregnancy whether couples had a higher or lower
percentage of normal appearing sperm. Even the most severely abnormal cases, those with less
than 1% normal looking sperm, had a similar pregnancy rate as those diagnosed as normal.
Our Infertility TV bottom Line is this. In 2023,
the best available evidence demonstrates no difference in the chance for pregnancy
with IUI based on sperm morphology. Sperm morphology should not be used to determine
which couples can attempt pregnancy with IUI. If your physician is saying you have to go
directly to IVF based on your sperm morphology alone, it is time to get a second opinion.