Pregnancy and baby

Getting pregnant

Thinking about your next pregnancy?

Media last reviewed: 28/01/2015

Next review due: 28/01/2017

Getting pregnant (conception) happens when a man’s sperm fertilises a woman’s egg. For some women, this happens quickly, but for others it can take longer. Out of every 100 couples trying for a baby, 80 to 90 will get pregnant within one year. The rest will take longer, or may need help to conceive.

To understand conception and pregnancy, it helps to know about the male and female sexual organs, and to understand how a woman’s monthly menstrual cycle and periods work.

The menstrual cycle is counted from the first day of a woman’s period (day one). Some time after her period she will ovulate, and then around 12-14 days after this she'll have her next period. The average cycle takes 28 days, but shorter or longer cycles are normal.

This page explains:

The best time to get pregnant

You're most likely to get pregnant if you have sex within a day or so of ovulation (releasing an egg from the ovary). This is usually about 14 days after the first day of your last period, if your cycle is around 28 days long.

An egg lives for about 12-24 hours after being released. For pregnancy to happen, the egg must be fertilised by a sperm within this time. If you want to get pregnant, having sex every couple of days will mean there are always sperm waiting in the fallopian tubes to meet the egg when it is released.

Sperm can live for up to seven days inside a woman's body. So if you've had sex in the days before ovulation, the sperm will have had time to travel up the fallopian tubes to "wait" for the egg to be released. It's difficult to know exactly when ovulation happens, unless you are practising natural family planning, or fertility awareness. 

The male sexual organs

The penis is made of erectile tissue. This tissue acts like a sponge and, when it becomes filled with blood, the penis becomes hard and erect. Men have two testes (testicles), which are glands where sperm are made and stored. The testes are contained in a bag of skin that hangs outside the body, called the scrotum.

The scrotum helps to keep the testes at a constant temperature, just below the temperature of the rest of the body. This is necessary for the sperm to be produced. When it's warm, the scrotum hangs down, away from the body, to help keep the testes cool. When it's cold, the scrotum draws up, closer to the body for warmth.

Two tubes, called the vas deferens, carry sperm from the testes to the prostate and other glands. These glands add secretions that are ejaculated along with the sperm. The urethra is a tube that runs down the length of the penis from the bladder, through the prostate gland to an opening at the tip of the penis. Sperm travel down this tube to be ejaculated.

Read about penis health.

The female sexual organs

A woman's reproductive system is made up of both external and internal organs. These are found in what is usually referred to as the pelvic area, the part of the body below the belly button.

The external organs are known as the vulva. This includes the opening of the vagina, the inner and outer lips (labia) and the clitoris.

The woman’s internal organs are made up of:

The pelvis: this is the bony structure around the hip area, which the baby will pass through when he or she is born.

Womb or uterus: the womb is about the size and shape of a small, upside-down pear. It is made of muscle and grows in size as the baby grows within it.

Fallopian tubes: these lead from the ovaries to the womb. Eggs are released from the ovaries into the fallopian tubes each month, and this is where fertilisation takes place. 

Ovaries: there are two ovaries, each about the size of an almond; they produce the eggs, or ova. 

Cervix: this is the neck of the womb. It is normally almost closed, with just a small opening through which blood passes during the monthly period. During labour, the cervix dilates (opens) to let the baby move from the uterus into the vagina.

Vagina: the vagina is a tube about three inches (8cm) long, which leads from the cervix down to the vulva, where it opens between the legs. The vagina is very elastic, so it can easily stretch around a man’s penis, or around a baby during labour.

Read about vagina health.

The woman’s monthly cycle

The video below shows what happens during the menstrual cycle. Ovulation occurs each month when an egg is released from one of the ovaries. Occasionally, more than one egg is released, usually within 24 hours of the first egg. At the same time, the lining of the womb begins to thicken and the mucus in the cervix becomes thinner, so that sperm can swim through it more easily.

The egg begins to travel slowly down the fallopian tube. If a man and a woman have recently had sex, the egg may be fertilised here by the man's sperm. The lining of the womb is now thick enough for the egg to be implanted in it after it has been fertilised.

If the egg is not fertilised, it passes out of the body during the woman's monthly period, along with the lining of the womb, which is also shed. The egg is so small that it cannot be seen. 

Menstrual cycle: animation

This animation explains in detail how the menstrual cycle works.

Media last reviewed: 21/02/2015

Next review due: 21/02/2017

Pregnancy hormones

Hormones are chemicals that circulate in the blood of both men and women. They carry messages to different parts of the body, regulating certain activities and causing certain changes to take place. The female hormones, which include oestrogen and progesterone, control many of the events of a woman's monthly cycle, such as the release of the egg from the ovary and the thickening of the womb lining.

During pregnancy, your hormone levels change. As soon as you have conceived, the amount of oestrogen and progesterone in your blood increases. This causes the womb lining to build up, the blood supply to your womb and breasts to increase, and the muscles of your womb to relax to make room for the growing baby.

The increased hormone levels can affect how you feel. You may have mood swings, feel tearful or be easily irritated. For a while, you may feel that you can't control your emotions, but these symptoms should ease after the first three months of your pregnancy. 

Read more about what happens in pregnancy week by week.

Will it be a boy or a girl?

Both the man’s sperm and the woman’s egg play a part in determining the gender of a baby. Every normal human cell contains 46 chromosomes (23 pairs), except for the male sperm and female eggs. They contain 23 chromosomes each. When a sperm fertilises an egg, the 23 chromosomes from the father join with the 23 from the mother, making 46 in total.

X and Y chromosomes

Chromosomes are tiny threadlike structures that each carry about 2,000 genes. Genes determine a baby’s inherited characteristics, such as hair and eye colour, blood group, height and build.

A fertilised egg contains one sex chromosome from its mother and one from its father. The sex chromosome from the mother’s egg is always the same and is known as the X chromosome, but the sex chromosome from the father’s sperm may be an X or a Y chromosome.

If the egg is fertilised by a sperm containing an X chromosome, the baby will be a girl (XX). If the sperm contains a Y chromosome, the baby will be a boy (XY).

Find out about early signs of pregnancy, and where to get help if you're having problems getting pregnant.

If you’ve decided to have a baby, you and your partner should make sure you’re both as healthy as possible. This includes eating a healthy balanced dietstopping smoking and, for the woman, taking a folic acid supplement. You should also know about the risks of alcohol in pregnancy.

Page last reviewed: 22/01/2015

Next review due: 22/01/2017


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The 20 comments posted are personal views. Any information they give has not been checked and may not be accurate.

PatriciaM63 said on 02 September 2015

Tracking my ovulation was difficult for me because I have an irregular period because of PCOS. I found it easier to just do an ovulation test as charting my temperature and cervical mucus could be tedious.

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Question4u said on 18 July 2014

My friend last period was june 14 of 2014' and she has taken a pregnacy test tuesday july 15' 2014' she tested postive on the clear blue pregnacy test for 2-3 weeks pregnant. Also she has been with her long term boyfriend until july3rd. They split up. She hooked up with an ex july 6th. Can someone please give advice or knowledge on who the father may be. The ex or the long time boyfriend???? I told her it was bad but Anyone????

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Cassi1991x said on 27 April 2014

Hi, i am very confused! i have not had a period for 3 months now and i have been doing home pregnancy tests and they have all been coming up negative so i went to see my GP and told them what has been going on he then said he would refer me to the early pregnancy centre for a scan so they then could see what is happening with me, i went to the hospital on friday because i had some spotting off bleeding and had vaginal pains and i was very worried as i was doubled over in pain, i went up to the hospital and told them what has happened they then did a pregnancy test (urine) it came back positive so they then did an internal to see where the bleeding was coming from they had told me that my womb was closed so they then did some blood tests and they had come back negative results. i am confused if i am pregnant or not but i have been feeling sick and very tired lately, could i be pregnant even if it is showing up positive in my urine and negative in my bloods?

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sayabalaji said on 23 April 2014

hi, I am 26 and I am trying to get pregnant. my last period was n 4th April and we had unprotected sex on 17th, 18, 19th and 20th april. Today I am feeling bloated and very tired and sleepy all day. I also have mild cramps. My husband says i could be pregnant but I am confused if it is too early to know. Please advice when to take a pregnancy test.

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YOUNG AND NEED HELP said on 20 November 2013

Hi, i'm a bit worried i'm 16 and i have been on the implant for about 6 months now, i was having normal period for all this time, like never late, i started to have some weird symptoms like, feeling sick, feeling dizzy, craving things, smelling things more, have tender breast and veins all over them, they have also increased in cup size in about 3 weeks and i keep having really bad abdominal cramps, and have lost interest in tobacco. I researched it and found out it could be a sign of pregnancy. I was 19 days late this month so i decided to take a test, I took two cheap pregnancy tests and they both said negative but i keep having all these symptoms and they seem to be getting worse:/ i have been on my period for 2 days now and its a bit lighter than usual i'm just wondering what to do because i don't really know much about the subject, i don't know if i should do another test or see a doctor? i did read that when on the implant because of the hormones it releases it could have an invalid result on the test? Someone please help.

Thank you.

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joan4gav2013 said on 13 November 2013

Hi I need advice. Me n my partner had our daughter Megan 16th January 2013 she is 10 month on sat 16 the Nov. I wouldn't stop bleeding after I gave birth for at least 8 weeks then NEA had bleed but now I won't stop and have bled just over 4weeks now the last 2 days I have stopped so I hope its now gona stop. And I right start getting normal regular monthly s they r not heavy so my self and partner have still been having sex as we do still want another bby We are not using contraception we r not trying for bby but we aren't not trying. How long is the norm for trying for your 2nd bby plzzzz I need advice we took 3 year to fall pregnant not shy of 4 year

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hajju said on 16 September 2013

am 31 had my first baby at 29,took pills for over a year,stopped april2013,but uptill now is yet to concieve.i took culmid twice on the third cycle now.pls advice me

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FrankieGreenie said on 31 July 2013

My fiancé and I have been trying for a baby for 8 months, we are both young, 20 and 24. We have been monitoring menstrual cycles, taking conception vitamins etc. but still no luck. Any advice? We can't wait to have out own little child.

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kcshady11 said on 06 June 2013

Hi I'm 31 years old I had my last period on the 3rd may I stopped taking my pill on the 16th may as me and my husband are TTC I had my withdrawal bleed its been 3 weeks now and I haven't had my period yet I've had two test to see if I was pregnant but come back negative I've lost clear discharge I've also had been feeling sick just for a few odd mornings the odd time I've also felt as if my periods are coming as I now and again get the period pain but it soon go

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kcshady11 said on 06 June 2013

Hi I'm 31 years old I stopped taking my pill on the 16th may I had a withdrawal bleed but I haven't yet had a period witch it's been about 3 weeks now since coming off my pill I've took two test but negative. I've been getting white clear discharge also had for a couple of morning feeling sick but that didn't last. My last period was in the 3rd may so I'm not really to sure what's going on really any advice would be grate full

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harleyclaire said on 03 April 2013

hi i had my period on 21-3-13 til 26-3-13 and today 3-4-13 i have noticed a light pink bleed and a few cramps i regularly have unprotected sex although he does pull out im just wondering if it could possibly be the implantation of a pregnancy? also i will be very fertile as i had a baby 17 weeks ago. any help or advice would be great thanks!!

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khushi123 said on 20 March 2013

hi i would like some 1 to help me put my mind at rest i just found out im pregnant.few days ago i started to bleed so had to go for a scan and i am 9 weeks pregnant i had unprotected sex on 25th of january but that was only 8 weeks ago im really confused because we used condoms before that please help me .

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kd22 said on 24 February 2013

Since coming off the pill in November my cycle now seems to be every 30 days. How do i now work out when i'm ovulating?

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30sumthing said on 15 January 2013

My partner is on medication that causes him to take ages to ejaculate. When he does he is never actually inside me. We do have intercourse though. What is the chance of us ever conceiving?

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chezzie said on 07 November 2012


I am wondering how i work when i ovulate?

i'm 21 next month and My periods are irregular, and have been since i started nearly 8 years ago. I have periods every 8-9 months however sometimes can have an odd period, and have only ever had a period a month apart once.

I have been on the pill three times. once when i was 16, for 6 months, once finised periods went back to 8-9 months apart, i went back on pill again when i was 17, and same outcome.

I then had overaies checked when i was 18, and showed my eggs were large, but was told that was normal for my age, and any changes are likley to happen in few years time. also have hormones checked regularly and they always come back fine.

since then i have been off pill until 4 months ago, when was put on a diferent pill for 3 months, nothig has changed yet.

In this time i have only used protetion once, and have been in a relation ship since 14 to 19, and then now in another relationship of 5 months, and never fallen pregnate.

my concern is am i able to and when am i likely to, so i know.

doctors keep wanting to put me on pill to stop me getting preggers and to kick start periods, but not worked. dont see point in being pill if not likley to get preggers.

if anyone can help that be great :)

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pbslwc said on 05 September 2012

You state that the best time to pregnant is usually 14 days after the start of a period. This is not strictly correct and only applies to a woman with a 28 day cycle. The correct information (but sometimes more difficult to calculate) is that ovulation occurs 14 days before the onset of the next period. It is vital information for someone with,say, a 35 day cycle who will ovulate on day 21

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mrsbabydust12 said on 20 August 2012

Me and my partner have been trying for a baby since I had my son 2 years ago. My partner is not my sons biological dad. We have been unsuccessful. My periods are regular every 28 days and last for 5 days. My last period lasted 3 days and I have got 10 days till my next periods due. I usually get bloated and very tender breasts no earlier than 3 days before my due period however 3 days ago I started getting sensative nipples white sticky discharge and really bad back ache. Can anyone please help does it sound like I could be pregnant ? Has anybody else gone through this and ended up pregnant ?

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sausagesarah1987 said on 03 February 2012

I'm 24 years old and I already have a healthy 4 year old daughter and I had no problems during pregnancy or birth that I'm aware of.
Me and my husband started trying for a baby again last year after coming off the pill and I got pregnant almost instantly, as we did with our daughter. In July at 8 weeks I had a miscarriage, it went on for about 6 weeks and I had medical management but not a d and c. I was given the all clear at the end of August and have been trying ever since. Since then I have had completely irregular periods, some have been long, some very short, some I have missed altogether. I've been to my gp several times and to no avail. I've had blood tests, 3 internals, and was treated for thrush 2 months ago. I've not had any further advice and feel at a loose end. I don't know when I'm ovulating and so don't know when to try (we're trying as regularly as we can). I'm not sure whether to go back on the pill for a while to try and regulate my periods? I have rhesus negative blood, I don't know if that can have anything to do with it? I don't feel very comfortable about going back to the gp again as I feel I'm wasting their time. Any advice anybody could give me would be great, I'm feeling at a loose end at the moment =(

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aisha193 said on 02 February 2012

me and my partner are trying to get pregnant with our second baby, but having no luck at all, my 2nd period came on 4 weeks,3rd period came on 3 weeks 3days, 4th period came on 4 weeks, and before i had my daughter i had period just before 4 weeks, is this normal; i even got a ovulating kit and followed ovulate calenda and not having any luck at all is there any vitamins could help me incresse getting pregnant or even any fetiliey suppliment to take to incresse my chance to get pregnant and why dose it take so long to get pregnant again, my daughter is 10 months now, can someone give me advise please i need advise please.

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Rookieblue said on 23 September 2011


I came off the Pill April 8th, had my first period April 12 th, then nothing until July 21st, then again August 22nd - so im thinking im now in a 32 day cycle? Ive been ill twice since my last period, upset stomach, tight chest, tired, but think thats just coincidence? I'm due on today 23rdSept, and ive a lot of white clear discharge since Tuesday - is this normal? don't really feel like my period is coming and i dont feel bloated??confused - any advice? I've now got a 3 year old, but i can't remember having any sysmptoms the first time>> help!!

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