The Very Important Difference Between Sterility, Infertility, and Subfertility

Difference Between Sterility and Infertility

Sterility, infertility, subfertility, primary, secondary… there are many ways to say you’re struggling to conceive, but what exactly do they all mean?

Despite best intentions, sometimes navigating the tumultuous sea of infertility can be confusing. Even the most basic concepts of genetics can be overwhelming, terms are unfamiliar, and treatments are varied. Sometimes it can feel like the more you look into infertility, the more futile and disappointing it becomes.

Biology has never been a simple field to explain. Humans are fascinating and multi-layered individuals, with unique aspects setting them apart from other mammals. Complex structures and systems all coincide with one another in chemical and overlapping ways. While this is sure to excite a more scientific crowd, it may not be what you’re trying to find if you’re just looking for a few explanations as to why you and your partner may be having trouble with conception.

Being able to get a bit of clarity during this time is priceless, and while it’s always important to talk with your doctor first, it’s also nice to have a few clear pieces of information that you can share with friends and family- reducing the need to explain these emotionally charged and heavily nuanced situations yourself.

Difference Between Sterility and Infertility: What is Sterility?

Sterility and Infertility - Sterile Woman

Sterility is classically defined as being “incapable of producing offspring”. Which means that there is either no sperm or no eggs, produced that are capable of creating a viable pregnancy.

Sterility can occur in both men and women but is actually surprisingly rare. Sterility only occurs in cases where a woman experiences anovulation, or a complete lack of egg production and/or egg release. Anovulation can either be chronic (happening all the time) or occasional. Anovulation can occur for a variety of reasons, sometimes being hormonal linked or be due to some sort of functional problems within the bodily systems that create, store, and release eggs.


In men, Azoospermia is a known cause of sterility. Azoospermia is a medical condition in which a man’s semen contains no sperm. There are three main classifications of Azoospermia: Pretesticular, Testicular, and Posttesticular. Much like anovulation, the cause of Azoospermia can be linked to either hormonal problems or functional issues.

Hormonal problems occur when a person’s body does not release or create enough of specific hormones to be able to properly create gametes (eggs or sperm). A number of different hormonal imbalances can cause sterility, but again, they are usually rare.

Functional issues generally relate to the form and function of the organs responsible for the production and release of gametes. These can be small or malformed ovaries and testicles, for example. There are many organs that are responsible for the creation and release of gametes, should a problem occur in any of these, it’s considered functional.

Modern medicine has created some viable treatments for causes of sterility. Things like hormone replacement therapies and surgical interventions can sometimes help to turn the table around on a diagnosis of sterility. So if you’ve been given one of these diagnoses, it’s important to remember to seriously talk with your doctor about any options that could be available to you. Should many other options fail to address the problems of sterility, surrogacy and donor materials can remain a great choice for couples struggling with these problems.

Difference Between Sterility and Infertility: What is Infertility?


Difference Between Sterility and Infertility - Woman Who Suffered With Infertility


Infertility is essentially any problem that causes couples to struggle to conceive after having unprotected sex for one year or more. Infertility can also be applied to couples who have only been able to achieve sporadic pregnancy, and generally speaking, those pregnancies are not viable.

Much like sterility, infertility can be caused by a number of hormonal and functional issues. Where a sterile woman doesn’t produce or release any eggs, an infertile woman may create or release a few eggs. Infertility can also refer to a woman who creates gametes normally but has difficulty successfully carrying a child.

In men, infertility may be caused by issues in the way that sperm cells function, where they may create them normally, they may only create few cells, or cells that don’t move very well. There can also be problems that occur within the delivery system of semen itself. Meaning that while the man produces adequate sperm, they have no way of getting out of his body.

Infertility is generally the catch-all term that is used to describe any problem that makes creating a child of your own difficult. So you may be asking yourself why there’s even a need to understand the differences in these terms? The importance of understanding the different types of conception troubles is boiled down to understanding how best to approach treatment.

Difference Between Sterility and Infertility: What is Subfertility?



Difference Between Sterility and Infertility - Subfertility

Subfertility is the failure to conceive after a normally expected amount of time having unprotected sex. When conception takes longer than average. So both the man and the woman are capable of producing and releasing gametes normally, and the woman can carry a pregnancy to term. Subfertility can have roots in both infertility and sterility. It is the best way to explain that you’re having troubles conceiving, but aren’t quite sure of the cause yet.

Subfertility can also be applied to idiopathic infertility or infertility that doesn’t have a clear cause. Primary and secondary infertility are both types of subfertility.

Primary infertility is applied to couples who are struggling to conceive their first child. Secondary infertility applies to those that have been able to conceive one child but are having problems having the second.

Basically, you can look at the terms subfertility, infertility, and sterility of different levels of the same problem: you’re having trouble conceiving a child.

Reality of Definitions

Whatever your specific diagnosis happens to be, it doesn’t change the reality of the situation you face. Any diagnosis of fertility issues is a difficult one to hear. While treatments for most fertility issues exist thanks to modern medicine, they are often emotionally and physically taxing.

It’s important to find a support system that works best for you and your partner and use it. Self-care during this time is really important. Finding ways to talk to your friends and family about the choices you face can be difficult, but necessary. Don’t discount your feelings and make sure to take the best care of yourself possible. Because eventually, a child is going to need you as a parent.