What is Normal for Sperm Morphology?

Morphology is the size and shape of the sperm. The sperm is split into 3 parts: the head, midsection, and tail. The head contains the DNA, the midsection contains the mitochondria which provides energy for the tail, and a long tail allows the sperm to propel forward. The acrosome ‘cap’ on the head contains enzymes which help the sperm penetrate the outer membrane of an egg to permit fertilization.

There can be issues with each part of the sperm, which is usually broken down on a semen analysis. Some possible issues with morphology can be a head that is too large or too small, a misshapen tail, or a double head or double tail. Further testing can show if there is DNA fragmentation (this is not shown on a standard semen analysis).

The semen analysis will have a percentage, which represents how many of the sperm have a normal shape and size.

Normal Sperm Morphology has been drastically decreasing over the years.

In 1980, the normal sperm morphology of a semen analysis was 80.5% (this means only 19.5% are abnormal)

In 1992, normal sperm morphology was expected to only be >30%

By 1999, expected morphology was 14%

Currently the benchmark for normal sperm has dropped to 4% (this means that 96% are abnormal!)

Some labs still use the criteria from the 1999 WHO numbers (14%). So, for numbers from 4-14%, it will depend on which criteria the lab uses. Some labs will further break it down and say that anything less than 4% is poor fertility, 5-14% is good (but decreased) fertility potential, and above 14% is excellent fertility potential.

Some doctors see no concern in having low morphology values, while others do. It really just depends which doctor you see and which criteria the lab they have uses, whether you will get positive or negative news back. I think it really depends case by case whether or not a low morphology matters. At this point in time, it is an endemic that is happening to male fertility. But, there are many lifestyle changes that can bring a poor morphology number up. This includes eating a healthy diet rich in antioxidants, lean proteins, and fiber. Men can also make sure their BMI is in a normal range, exercise regularly, quit alcohol, quit any drugs including marijuana, quit smoking, avoid hot tubs and saunas, wear loose-fitting underwear, and lower their daily stress.

While morphology is not the MOST important thing to look at on a semen analysis (concentration and progressive motility are), it is still important to know what this number means. A further investigation can tell us whether or not the DNA has been fragmented. The DNA is in the head—so if the head is abnormal, it is highly likely that those sperm do have some DNA fragmentation. DNA fragmentation is exactly how it sounds—the DNA is broken. This can cause infertility, but these sperm can still fertilize an egg and then cause a miscarriage (men are actually responsible for many cases of recurrent miscarriages because of this). So, if you want to know how much the low morphology can affect conception and the health of your baby, you can do a semen analysis for DNA fragmentation. Most fertility centers do not do this test first, and it is usually not covered by insurance and is not cheap. But, it’s worth the extra information if you have suffered from recurrent miscarriages or failed IVF cycles.