How much sperm does it take to get pregnant?

Keep reading to learn how much sperm is needed to get pregnant!

We learned in grade school that sperm + egg = baby. However, what seemed like a simple equation at the time we now know is not always straightforward.

Unfortunately, nowadays, nearly one in 6 couples struggle with conceiving or carrying a child to term. Known as subfertility, the seeming inability to build a family comes with varying levels of anxiety that leads to questions and Googling at 2 am. 

Let’s get some answers to commonly asked questions about the male factor of sperm quality. 

How much sperm do you need to get pregnant?

Just one! Despite the average sperm count per ejaculate being 40 to 300 million, we only need one sperm to fertilize the one egg we ovulate each cycle.

On rare occasions, more than two sperm might fertilize one egg resulting in semi-identical twins but the typical beginning of a new human life involves just one sperm fusing with just one egg.

In fact, in a typical natural conception when the winning sperm penetrates the outer layer of the egg (ovum) known as the zona pellucida an enzymatic reaction happens to prevent other sperm from attempting penetration.

Aiming to have just one sperm out of up to 300,000 sperm penetrate one egg seems like pretty good chances, right? It’s like, if you throw 300,000 darts at a bull’s eye it shouldn’t take long for one to hit, right?

But are there other sperm factors that can increase your chances?

In her book entitled It Starts with the Egg, biotech litigation lawyer Rebecca Fett points out that contrary to popular belief, male factor issues account for nearly 50% of all cases of subfertility.

This may be surprising when you consider all the attention and effort women put into testing and tracking their fertility. It’s easy to forget that reproduction is a team sport!

When it seems like the issue may be male factor, it’s important to understand all the known factors in semen analysis that can impact a couples chance of his sperm meeting up with your egg. 

What is a normal sperm volume and counts?

Has your partner done a semen analysis? If so, you may have received a report with terms like total semen volume and total sperm count. Here’s what those parameters mean.

Volume

A typical man ejaculates 2-5 milliliter of semen per sample. This is the reference range for normal total semen volume and equates to roughly ½ to one teaspoon.

If the volume is significantly lower, the fertility specialist or urologist may dig a little deeper and look for prostate issues or issues with the seminal vesicles. If the volume is significantly higher, the sample may be too diluted, skewing another semen analysis parameter called sperm concentration. 

Count

One milliliter of semen typically contains between 40 million and 300 million sperm. This is the reference range for normal total sperm count, however, the results of a total sperm count analysis may vary from one lab to the next.

Also important to know: Even men with an average or “normal” sperm count may experience difficulty in the fertilization department. This is because beyond the total number of sperm in a milliliter of a man’s ejaculate, there are other factors that influence how well his swimmers can penetrate an egg.  

What are other factors of sperm health to consider?

Motility

Sperm are made to swim and motility refers to the way individual sperm swim. A semen analysis will reveal if the man’s sperm are mostly swimming in a straight line or perhaps even large circles.

This type of swimming is called progressive motility. One source reports that in order of the sperm to make it through the mucosal environment of the woman’s cervix, they need a measure of progressive motility that is at least 25 micrometers per second.  

As you can imagine, there’s a second type of motility called non-progresssive motility which - you guessed it - means the majority of the sperm do not travel in a straight line or small, tight circles.

If less than 32 percent of sperm are moving in a progressive, efficient fashion, the diagnosis of asthenozoospermia, or poor sperm motility, may be made.  

Shape

The shape and size (morphology) of your man’s swimmer is also assessed in a semen analysis. Normal sperm have an oval head with a long tail.

Pretty much everything else — small head, short tail, non-oval head, crooked or even double tail — is considered abnormal. The lab technician doing the semen analysis will assess the morphology of the sperm using a microscope and report on the percentage that appears to be normal. 

Having a large percentage of sperm with irregular shape or size is actually fairly common. This is why an analysis that shows normal morphology between 4% to 10% of total sperm is considered good.

The vast majority of sperm usually don’t look quite right under a microscope and that’s just fine. Interesting, eh? What’s more, a woman’s cervical fluid has the ability to filter out sperm with abnormal morphology in a sort of “survival of the fittest” natural selection to help only the best swimmers make it to the egg. 

All things considered, there’s a lot of work that could be done to better understand sperm morphology. Current techniques can be subjective and, like total sperm count, can vary from lab to lab.

It’s hard to say how well poor sperm morphology can predict the chance of conception and a healthy pregnancy. What we can say for certain - 100% abnormal morphology is going to make it harder to build a family. 

Learn more about measures of sperm quality and other factors related to male fertility here. 

How can I test my partner’s sperm?

Curious about your partner’s sperm? We have something that may satisfy your curiosity.

Our friends at YO have developed an in-home sperm test kit that tells you about your man’s sperm motility and sperm concentration. We think it’s nice to test at home. It’s also very considerate of them to ship the kit in an unmarked box.