Fertility myths and facts

Dr Joanna Pike

Reviewed by Dr Joanna Pike on Mar 26, 2020

Fertility myths and facts

There are many sources of information on trying for a baby, but we don’t always know for sure what is true and what isn’t. Read more to discover that some of the ‘facts’ we may take for granted are in fact just myths, and then uncover the truth.

Myths about when you can get pregnant

It's impossible to get pregnant the first time you have unprotected sex.

It is a common myth that you can't get pregnant the first time you have unprotected sex. This is simply not true. There is always a possibility that you will get pregnant if you have unprotected sex – even the very first time. If you are having unprotected sex and don't want to get pregnant, you will need to choose a method of contraception that will suit you.
If you have had unprotected sex, find out when you can do a pregnancy test.

It's possible to get pregnant at any time of the month.

To get pregnant, you need to have sex on the days leading up to and around when you ovulate. The day prior to ovulation, and the day of ovulation itself, being your two most fertile days. Once the egg has gone (usually within a day of ovulation) you cannot get pregnant until after your next menstrual cycle has started. Methods that tell you after you have ovulated are of no help if you are trying to conceive.

You can only conceive on two days each cycle.

This is not true. The 'fertile window' lasts up to 6 days. You are at your most fertile the day you ovulate and the day before. However, because sperm can survive for up to five days, having sex on the days leading up to ovulation can increase your chances of getting pregnant.

  • Clearblue Ovulation Tests can help you pinpoint up to four days when you are most fertile.

If you have sex during your period you can't get pregnant..

It's unlikely that you'll get pregnant, but not impossible. You are fertile on the days leading up to and around the time of ovulation – due to the lifespan of sperm – and if you have a short cycle you could be ovulating just after your period. So you could be fertile very early in your cycle when you are still bleeding.

Menstrual cycles are always 28 days long and every woman ovulates on Day 14.

The average menstrual cycle is 28 days long, but every woman is unique and nearly 50% of women’s cycles vary in length by 7 days or more1. In a recent study of over 800 women, only 14% of women with a 28 day cycle actually ovulated on day 14.  The day of ovulation ranged from day 11 to day 20.2 As menstrual cycles vary in length, so does the timing of ovulation, so it can be difficult to know when your fertile days are.

Myths about contraception

If you forget to start the next pack of contraceptive pills after the 7-day break, you can't get pregnant.

No, it is possible to get pregnant. One of the ways the pill works is to prevent you from ovulating. If you forget to take any of the pills, the effectiveness of the pill as a contraceptive will be reduced.

I never used a hormonal birth control method, so we should get pregnant as soon as we start trying.

Just because your hormones haven’t been affected by hormonal contraceptives doesn't necessarily put you at an advantage. Your body may be better able to regulate itself but this doesn't mean you can get pregnant any more easily. Your fertility can be influenced by many factors other than contraceptives.

Myths about when to take a pregnancy test

You can do a pregnancy test as soon as you have had sex.

No you can't. It takes about six to seven days after an egg is fertilised (after having sex) before your body starts to produce the pregnancy hormone (hCG), and a few more days before the level is high enough to be detected by a pregnancy test. Clearblue Pregnancy Tests can be used up to six days before you miss your period (5 days before you expect your period), although the pregnancy hormone levels in your urine may not be high enough to be detected. So if you test early and you get a 'Not Pregnant' test result, we recommend you test again when you expect your period.

  • If you have irregular cycles, it's a good idea to allow for your longest cycle in recent months before testing
  • If you are testing from the day you expect your period, you can test any time of the day
  • If testing early you should use the first urine of the day
  • To get an accurate result, avoid drinking a lot of any liquid (including water) before testing
  • If you get a 'not pregnant' result:
    • If you tested early, test again when your period is expected
    • If you tested on or after the day your period is expected, wait for three days and test again

If your second pregnancy test still gives you a 'Not Pregnant' result and you still haven't had your period, you should see your doctor

You need to wait several days after you've missed a period before you can do a Clearblue pregnancy test.

Not true. All Clearblue Pregnancy Tests are over 99% accurate from the day you expect your period. In fact, you can use Clearblue Digital Ultra Early Pregnancy Test up to 6 days before you miss your period (5 days before you expect your period). 
If you test early and get a 'Pregnant' result you can trust it. However, if you test early and you get a 'Not Pregnant' test result, we recommend you test again when your period is expected. You should always read the in-pack leaflet before carrying out a pregnancy test.

When can I take a pregnancy test?

Fertile days

All you need to know about testing early for pregnancy.

Find out


Myths about methods to identify your fertile days

You'll get pregnant quickly if you track your temperature.

A woman's body temperature rises after she has ovulated by which time it is too late to optimize the chances of conception in that menstrual cycle.

How to know when you ovulate ?

Fertile days

Due to the variability in women’s menstrual cycles, it can be difficult to know when YOUR fertile days are. Accurately identify your fertile days

Learn More


Being stressed will stop me getting pregnant and using an Ovulation Test will make it worse

While stress is never healthy, unless it’s interrupting your periods or sex life it won’t stop you conceiving. It has been suggested that using ovulation tests to time intercourse on the most fertile days can be stressful, but a study by Prof. William Ledger and Clearblue found that using these tests is no more stressful than trying to conceive without them. In fact, in this study 77% more women got pregnant in the group that were using the tests3. Also remember it’s normal for sex to start to feel mechanical if you’ve been trying for a baby for a while. This is something a lot of couples experience and it doesn’t mean there’s anything wrong with your relationship. Most couples accept that baby-making sex can be different..

Other myths

I conceived my first baby easily, so the next pregnancy should be easy

There’s no sure way of knowing. You’ll be older, you may have less time to be spontaneous with your sex life and you may even have a different partner – all of these influence your chances of pregnancy. If you are under 35 and have been trying to get pregnant for a year, talk to your doctor (six months if you are over 35).

  1. Creinin MD., et al. Contraception (2004) 70: 289-92
  2. Johnson S., Marriott L. Inaccuracy of the calendar/App based methods for predicting day of ovulation in women who are actively trying to conceive. Presented at ESHRE. July 2017: Geneva
  3. Tiplady S et al. Human Reproduction. (2013) 28(1): 138-151.

Digital Ovulation Test: pinpoints your 2 most fertile days

In every cycle there are only a few days when a woman can conceive, so having sex on these days is very important if you are trying to get pregnant.