Fertility Explained – chances of getting pregnant

So just what are the chances of getting pregnant? Here’s what other sex educators might not tell you about fertility.

Ok, I’m going to let you into a little secret. Just don’t tell any other sex educators I told you this. If you have penis in vagina sex without a condom or contraception, you won’t always get pregnant. In fact, it’s unlikely because chances of pregnancy are quite low. BUT WAIT!

Don’t run off to have bareback sex! This doesn’t mean it won’t happen. Some people have unprotected sex once or twice and they get pregnant straight away. However I’m just being honest with you.

Even though you should use contraception for penis in vagina sex, the risks of an unwanted pregnancy are lower than you might think. I’ll explain here, but first here’s a recap of how fertilisation works.

How fertilisation works

BISH fertility fertilisationAn egg is released from the ovary once in a menstrual cycle. If it meets with sperm while it is travelling down the fallopian tube then fertilisation and then pregnancy can start. If a sperm meets an egg at this stage then there is a 33% chance of fertilisation. Fertilised eggs then need to stick to the lining of the womb in order for a pregnancy to start. The egg dies around 20 hours after being released. After that it is not possible to get pregnant until the next egg is released in the next cycle.

So, as you can see, it’s harder than you might think to get pregnant, but this doesn’t mean you shouldn’t use contraception if you don’t want to get pregnant (keep reading). Also there’s is a ‘time of the month’ when you can’t get pregnant. How to work that out though? Well it’s very very difficult because it’s all about the menstrual cycle.

How the menstrual cycle works

BISH fertility 28 day menstrual cycleDay one of a menstrual cycle is the first day of a period. Periods last for a few days and this varies. Eggs are released from the ovary (ovulation) around half way through the cycle. So as you can see here – in a cycle that was 28 days long this would be around day 14. In order for pregnancy to start, an egg has to be fertilised within a 20 hour time slot when the egg is alive. As sperm can live inside someone for 5 – 7 days then the time to avoid sperm getting into the vagina is from day 9 to 15. Once the egg has died it’s not possible to get pregnant until another egg is released which happens after the next period.

So if you knew when ovulation was definitely going to happen then you could decide for yourself if it ‘safe’ to have sex or not. However, it’s really really hard to do that.

Why you need contraception

BISH fertility menstrual cycles are randomIf your cycles are *always* the same you can predict when you are going to be fertile and not fertile, but periods are random as you can see here. Because periods don’t always come when expected, the same is true for ovulation. This means that people may be having unsafe sex when they think they are safe from pregnancy. If only our bums change colour when we ovulate – like baboons.

Some people are able to use this as a method of having sex and without having babies: however it’s very very hard to do and not super effective – click here for more. But but but, it’s not as effective as using condoms or other methods of contraception. Also it’s actually much more likely that you will get a STI from unsafe sex than pregnant.

For more advice and a clinic near you go here

I think I’m infertile

Some people may have had sex a few times, not got pregnant and assumed that they were unable to have kids. Then they might think ‘I can’t get pregnant, so I won’t bother with contraception.’ They would be wrong. Remember, although pregnancy *can* happen the first time you have sex with someone it’s actually not that likely. However if you have sex regularly over the course of a year then it is much more likely.

The evidence

Here’s a paper which shows how people think they are infertile when they aren’t (and that this might make them decide not to use contraception).

The authors of this paper reckons that there is a 3.1% chance of pregnancy from a single, random act of sexual intercourse (which can increase to up to 9% leading up to ovulation and decreases to 1% at other times in the cycle).

Hope that’s cleared that up ….

© Justin Hancock 2018

40 thoughts on “Fertility Explained – chances of getting pregnant

  1. i had my panty on and my boyfriend was naked. He was humping and fingering me one after the other. After this, my panty was wet. I don’t know if it was pre cum or my vaginal discharge. Next we went to the washroom and I gave him a blowjob and he ejaculated. I then washed my hands and left. I might have touched my underwear for a second at that moment. I got my period 4 days later. 25 days have passed and I feel nauseous and dizzy. Could I be pregnant?

  2. Me and my girl dry humped naked 3 days after ovulation and there might have been a little sperm on my penis and she took a morning after pill 16 hours later… she is experiencing mild lower abdominal pain for 6 days since taking the pill

    is it normal?

  3. Hi my name is celine and in april i had sex with my boyfrriend and i had to go back away april was tge last time i saw my period and i didnt see it for may neither june and i took a pregnancy test but it was negative am i pregnant and my boyfriend actuall cum inside for me…but i dont know if i am he cum inaide me many times but this time he did in april i didnt see my period from then and i took the test in june like tye first starting of june what should i do im afarid my period never did this beforw

  4. Hey I was wondering because me and my boyfriend had intercourses and he just pre-ejaculated in me(well that’s what he told me) … is there a chance I could get pregnant?

  5. My boyfriend gave me oral and afterwards I decided to go wipe myself with tissue. The tissue might’ve touched his penis (he didn’t ejaculate) for a split second before I wiped myself. Is there any chance of pregnancy? I had egg white (fertile) mucus 4 days ago

    1. If you re-read the article I think you’ll agree that it’s not possible to get pregnant from what you describe. Even if there was any sperm on the tissue, it would have died pretty quickly (because sperm needs semen to live). Also, if you were fertile 4 days ago then you are much less fertile now.

      1. IF there was precum, what are the chances there was sperm if the last time he ejaculated was a week ago? So sorry Justin, I’m just really stressed

  6. My husband and i would like to have a baby.
    I had sex two days before my period. My period lasted about 3 days it usually lasts about 5 days. (21 cycle).
    Aftrer a week, my husband and I tried again and we had sex 3 times but on different days.
    Could i be pregnant?

    1. As the article says, you are more likely to get pregnant after your period and before ovulation. So when you had sex 3 times but on different days, would be the time most likely to start a pregnancy. Advice from fertility experts is generally to just keep having penis in vagina sex (with ejaculation deep inside the vagina) on a regular basis. I can’t tell you if you are pregnant or not.

  7. i had sex with my boyfriend the third day of my fertile window .. and he cummed in me . i’m starting to feel nauseous and i’m having horrible cramps . i’m also having a burning sensation? am i pregnant

  8. Me and my boyfriend just had sex and he cummed in me for the first time . How likely is it that I’ll get pregnant?

    1. Sorry, but I have answered that in the article. It’s between 0% and 9%, depending on when it happened. This is a more basic guide You might want to think about getting emergency contraception

    2. I didn’t mean to reply to this but I couldn’t figure out how to make a separate comment. So me and my boyfriend had intercourse today and I ran out of my birth control about a week ago. And it’s 12 days until my period. He also came inside of me unprotected. Am I going to get pregnant?

      1. If you have not taken any birth control pills for over 2 days then it’s more likely that you can get pregnant (here’s a link to the NHS website about what to do about that). The effect of the pills would have worn off after a couple of days, so yes you could have got pregnant from this time and it would have been a good idea for you to have taken emergency contraception after the sex you had.

        I can’t tell you the exact likelihood of pregnancy because I don’t know when your ovulation happened. The article above should give you that information. If your period is late you will be able to take a pregnancy test. Hope that’s helpful.

        Justin (BISH)

  9. I and my bf were humphing naked I’m not sure if he pre ejaculated,so he was sitting down naked I pulled his P down so it won’t get in contact with my V,sat on the shaft naked twerked on it then stood up and wore my cloths and it happened 9 days after my period which has has 25days and above intervals, is there any chance of getting pregnant from this(not sure if he pre cum at all ),please reply Asap its making me suicidal …I’m from a deep Christian society and if I am it’ll be a disgrace??,pls reply Asap

    1. So please try to calmly read over the article again. In it I explain that it’s very very unlikely to get pregnant from what you describe. Also try and also this website

  10. My boyfriends condom came off inside me while we has sex, 3 days before ovalation.. can I be pregnant.. most the cum was in the condom

    1. As I’ve said in this post, it’s unlikely but it might be worth speaking to a sexual health service about emergency contraception and here’s more about going to a sexual health service

    1. You might be on day 14 but you can only work out if that was a higher risk day for pregnancy once you get your next period. Then you can work out whether you were ovulating around then or not. If you’ve had unprotected sex recently then check out Emergency Contraception

  11. sorry to be graphic, however me and my boyfriend sort of had unprotected sex 2 weeks ago it only went in for about 15 seconds and then we tried again 4 days ago and it was barely in for a minute but he didnt cum . im not entirely sure when my period is due but i think it is around this time of the month however it has not arrived yet, i cannot stop stressing and i feel sick all the time and paranoid as im only young and my mum would not approve.

    1. Hi Chloe
      It’s very unlikely that you are pregnant from this if he didn’t ejaculate inside your vagina (sorry to be graphic). Why do you keep doing this if you are so stressed about pregnancy? Perhaps you might want to talk about having different kinds of lower risk sex you could try or using condoms.

  12. So I had sex with a girl who has a boyfriend. I have been worrying about her period. Today I finally asked her and she said it was a week late. I used a condom, and I even pulled out before I ejaculated. She barely told me today that her and her boyfriend have been regularly having sex without condoms, using the pull out method. She finally told me that she had unprotected sex with him the same day I had sex with her. I just want to know where I stand in this possible pregnancy. I used a condom and pulled out before I ejaculated. They had unprotected sex and just pulled out before ejaculation. Help please! Thanks!

    1. Hey. It’s extremely unlikely that the sex you had with her will result in pregnancy. Condoms are like 98.5% effective, in combination with you pulling out this makes it nearly 100% effective (I’m talking 99.9999999999%). So *if* she is pregnant then it is very likely to be from other sex she’s having. If they’ve successfully been pulling out then it’s unlikely that she’s pregnant. Remember also (like I say on this page) that periods are random – they can be late for many reasons.

  13. So my period is four days late. I had unprotected anal sex at the beginning of my ovulation cycle however my period last month was six days late so my periods are clearly irregular. Also I was sick during my ovulation day which I know can effect when my period is I’m super scared all my friends say I’m freaking out for nothing but I’m 15 and it’s very scary

    1. The only way you can get pregnant from anal sex is if the semen leaked out of the anus again and into the vagina – this is very very very very very unlikely. As you say, your periods are not regular so you just have to try and wait. You might want to consider using condoms for anal sex (if you’re not already). Condoms can reduce any STI risk for anal sex (also it’s important to use water based lube with condoms too) and it might also help with your anxiety about unplanned pregnancy too. You might also want to think about other kinds of sex you may enjoy too. More about that here.

  14. hi!

    im a bit concern, I had unprotected sex with my boyfriend after a day of my period ends. I had my period from the beginning of April 5 until April 12. we had unprotected sex during April 13 at night. Although, he didnt ejaculate or cum the whole night due that he was really drunk. He’s penis was dry but im still worried that he could have had pre-cum while he was inside of me.
    The next morning, i took an emergency pill( 4 dose of marvelon) and 4 dose after 12 hours.

    is there a bigger risk of me getting pregnant? thanks

    1. If he didn’t ejaculate inside of you then it is very unlikely that you are pregnant. There’s more about this here. I notice that you took an every day contraceptive pill as an emergency contraceptive – although this can work it’s not usually recommended. Marvelon is the kind of pill which you can take every day to prevent pregnancy, you might want to think about if you are going to have penis in vagina sex – or condoms of course.

  15. Great piece. Good to hear a sex educator say that sex doesn’t always lead to pregnancy, but that you still need to protect yourself.

    It’s true that natural family planning is not as easy as popping a pill, or putting on a condom, and yes you need specialist support, but it’s a great option once you’re over 20 and your body has settled down. Teenage hormones are a bit tricky which makes it harder to read the standard fertility signs (i.e. changes to waking temperature and vaginal fluid).

    With specialist support natural methods can be over 99% effective. Without support, e.g. learning it from a book or an app, they’re only 75% effective – not great at all. Here’s more info from the fpa: http://www.fpa.org.uk/contraception-help/natural-family-planning

  16. i need i long time sex period my dick siza is 7 inch and it wirth is 3 inch and very strong in sex relation but i discharte very soon what i can do ?

  17. Hi Bish,

    Absolutely brilliant flyer, as always! Some feedback for you below…

    I just wanted to highlight that “penis in vagina sex” is not the only way to get pregnant. As Jake has quite rightly raised there is a possibility of pregnancy occurring through semen entering the vagina, perhaps on a person’s hand immediately after ejaculation. For example, a man and woman are masturbating themselves, the man ejaculates on his hand, he then puts his hand inside the girl’s vagina. Pregnancy has been known to occur this way and we teach young people about this it is something we always highlight.

    Hope this is useful.

    Thanks and keep up the good work!

    Sex and Relationship Education Worker

    1. Hi Nadia

      Thanks for your feedback.

      The chances of someone getting pregnant from this are so low that I think we need to put it in perspective. I get lots of young people that are very worried about the risks of pregnancy from masturbation: this is in part due to teaching around this. I’ve tried to answer some of these concerns here as it is one of the most frequently asked questions I get http://bishuk.com/2010/07/18/mutual-masturbation-and-dry-humping/

      I always hear that there are stories of people getting pregnant from just masturbation or even from anal sex, but I think we need to be careful of these stories in our teaching.

      Thanks for commenting, keep up the good work yourself.


  18. hi, so i want wondering if ejactulating on the girl’s clitoris could get her pregnant. my gf said she was ovulataing but we did not have “penis and vagina” intercourse. we were fooling around and while she was on top of me, i came. but she was simply just on top of the tip of my penis. it wasnt inside of her. please email me back!

    1. Hi Jake

      It is *possible* to get pregnant this way but it’s very unlikely. If you are concerned your gf could get emergency contraception (within 5 days) from a clinic near you (click the yellow button on the right), if you are in the UK.


      1. Hi bish,

        i was wondering if i could get pregnant after a day of my period ends. he did not ejaculate inside of me nor didnt cum the whole night.

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