Because fertility science is complex and evolving, a lot of myths and misunderstandings have become widespread belief. As you begin or continue your fertility journey, it’s important for your own decision-making (and stress levels!) to be armed with science—not superstition. Here’s the truth behind many common fertility myths.

If I’ve been pregnant before, it’ll be easy to get pregnant again.

Declining egg quality can affect your future chances of pregnancy, even if you’ve been pregnant before. However, a prior history of getting pregnant does prove that everything was working well—so you can usually expect to succeed again.

I’m fertile as long as my cycles are regular.

A regular cycle is a good thing, but it’s important to keep maternal age in mind. The average age beyond which a woman can’t get pregnant is 42 years. Now, that’s just a statistical number. Your personal odds could be very different! But regular cycle or not, if you’re a woman over 38, it’s reasonable to be a little concerned about egg quality.

I can always count on IVF to get pregnant.

IVF unquestionably works better than anything else, but pregnancy rates are limited beyond age 40.

Fertility pills make better eggs.

Actually, fertility hormones only make more eggs. For better eggs, we hope supplements like CoQ10 are helpful. But fertility medications don’t improve egg quality by themselves.

My diet matters.

Good news: it doesn’t really. However, your weight can affect your chances of becoming pregnant. Learn more about it.

My stress levels matter.

The relationship between stress and fertility is complicated. The important thing to know is that the correlation isn’t clear: in other words, it’s great to keep your stress down (for many reasons!) but you shouldn’t stress about being stressed.

Lifting, sex, exercise, stress or alcohol cause miscarriages.

Actually, 94% of early losses are related to embryo quality. Of those, 90% are related to eggs. So miscarriages are absolutely not caused by exercise, sex, etc. Unfortunately, we often blame ourselves for losses that weren’t our fault, or even remotely under our control. Try to take it easy on yourself.

If I keep trying, it’ll pay off eventually.

Not necessarily. For example, if you have blocked tubes, are in menopause, or have a large fibroid inside your uterus, persistence may not help. What you really might need is a diagnosis, and a treatment plan. So go ahead and try a method for 2-4 cycles, but if you still aren’t getting results, it’s a good idea to get checked out or revisit your strategy.

Sexual position can make a difference.

Nope! Choose whatever position you like: it won’t make a difference.

If you’re more fit, you’ll be more fertile.

Loosely, it’s a good idea to have a BMI over 18.4 and under 30. But your fertility is significantly more related to genetics and other elements out of your control.

Progesterone supplements can prevent miscarriages.

We used to hope progesterone and blood thinners were effective. However, more recent evidence indicates that in the vast majority of cases, a loss is related to embryo quality…not hormones, or other health concerns. If you need to be certain, you can try PGS. Learn more about it

If my test results are normal, I’m fertile.

Fertility is about how long you’ve been trying. The first month (depending on age and other factors) you’ll likely have a 25-55% chance for success. By definition, the next month is less (because all the very fertile people are out of the running). By six months, it’s usually about a 5% chance for success. By 12 months, it’s a 2% chance for success per cycle. So if you tested normally but have been trying unsuccessfully for months and months to get pregnant, we can generally assume there’s  a fertility glitch of some kind.

You should abstain from sex for 2-4 days before trying.

Actually, abstinence really doesn’t make an impact.