Mother Nature’s Fertility Rate

kali's picture

One of the most common misconceptions (pun intended) that I come across in patients who have recently started trying to conceive is that pregnancy is relatively easy to achieve. Lots of new patients come to my office frustrated that they haven’t fallen pregnant in their first couple of cycles of trying to conceive - and I totally understand why! But let me help you understand your fertility a little better by explaining something your high school health teacher never did:


Mother nature’s fertility rate is about 20%.


That’s right. Although it depends on your age, the likelihood of you falling pregnant in a given cycle is about 20% (if you’re healthy and age 30). That means for every 100 people who try to get pregnant in a cycle, 20 will fall pregnant and 80 will have to try again.


80/100 will have to try again.


Does that surprise you?  It shocks a lot of my patients.


And as we age, the natural fertility rate unfortunately declines as both egg and sperm quality start to shift.


For reference, here is a breakdown of mother nature’s fertility rate by maternal age (source: the American Society for Reproductive Medicine).


Your chance of falling pregnant naturally this cycle is approximately:

Age 25: 25%

Age 30: 20%

Age 35: 15%

Age 40: <5%

It’s really important to understand these numbers when you’re TTC, because it can feel so frustrating when you’ve been lead to believe that achieving pregnancy is super easy, and it isn’t happening straight away.  I very clearly remember my high school health teacher warning our class to be very careful to always use contraceptive agents - she told us she fell pregnant the first cycle she tried for both of her kids, and that it’s as easy as stopping your pill/IUD/condom use and bam! We’d be pregnant too.


Falling pregnant takes time for most of us. If only 20% of healthy 30 year olds fall pregnant in a cycle, that means that 80% have to try more than once. 


It’s why we tell you to try for 12 months before we start getting concerned if you’re <35, and for 6 months if you’re >35.  Mother nature’s fertility rate isn’t 100%.


Of course, there are lots of ways that you can work on improving your chances of pregnancy each month.  One of the most important targets is egg/sperm quality - something we work on with every single patient at Acubalance.


My colleagues have written some great blog posts about this recently - check out Dr Damm’s latest article on fueling egg and sperm quality here.


I say all of this to educate, but also to help you take a deep breath and take some of the pressure off of each cycle. If it didn’t happen this month, you’re not alone - in fact, you’re amongst the majority.  Keep at it, focus on your egg and a sperm quality, and you’ll be doing your best to make it into the 20% next month.


Fingers crossed for you, and sending baby dust your way.

In health,


Dr K