First trimester: weeks 1 to 12

You're pregnant: congratulations! The first weeks of your pregnancy are a vital time as your body gets busy building a baby. How exciting!

Weeks 1-12 infographic

First trimester: key stages

The first trimester begins on the first day of your last period and lasts until the end of week 12. This means that by the time you know for sure you're pregnant, you might already be five or six weeks pregnant!

A lot happens during these first three months. The fertilised egg rapidly divides into layers of cells and implants in the wall of your womb where it carries on growing. These layers of cells become an embryo, which is what the baby is called at this stage.

During this trimester, your baby grows faster than at any other time. By six weeks, a heartbeat can usually be heard and by the end of week 12, your baby's bones, muscles and all the organs of the body have formed. At this point, your baby looks like a tiny human being and is now called a fetus. He or she will even be practising swallowing!

When am I due?

Find out your due date using our due date calculator!

When will I see a midwife?

Your first midwife appointment (also known as antenatal appointment) is the 'booking' appointment. This usually happens between week 8 and 10 of your pregnancy. Find out how to register with a midwife and when your appointments will be here.

Keeping your baby safe

There are some things that you can do during pregnancy that have an effect on your baby. Find out about them by clicking the link below.

Find the complete list of pregnancy dos and don'ts (and reasons why) here

Not sure whether you are pregnant?

Find out about the symptoms that mean you may be pregnant here.

Your physical and mental health in pregnancy

We also have lots of useful tips for coping with everyday pregnancy niggles. It’s common for women to experience symptoms such as morning sickness, cramp and indigestion during the first trimester. 

Don't forget that your mental health is just as important as your physical health. It's normal to feel some anxiety and stress but it shouldn't be ongoing. If what you’re feeling isn’t normal for you, talk to your GP or midwife about it. They are there to help. 

Exercise, such as yoga, has been shown to reduce anxiety and is a great way to stay active during your pregnancy, too.

Read more about mental wellbeing in pregnancy

Read more about diabetes and pregnancy

Read more about pregnancy with a high BMI

Read more about exercise and pregnancy

Read about the symptoms to look out for in pregnancy

Track your baby's development

Sign up to a free pregnancy email from our midwives to track your baby's development and give you reminders of all you need to know through the nine months of pregnancy. Click here to sign up.


Find out more about the first trimester


NHS Choices. Your pregnancy week by week (Page last reviewed: 28/02/2017 Next review due: 28/02/2020)

Macdonald S, Magill-Cuerden J (2012) Mayes’ Midwifery, 14th edition, London, Ballière Tindall

NICE (2008) Antenatal care for uncomplicated pregnancies, NICE Clinical Guidelines 62. National Institute for Health and Care Excellence

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Last reviewed on June 28th, 2018. Next review date June 28th, 2021.

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Please note that these comments are monitored but not answered by Tommy’s. Please call your GP or maternity unit if you have concerns about your health or your baby’s health.
  • By Midwife @Tommys on 4 Apr 2018 - 09:59

    Hi Jodie
    Not knowing the date of the first day of your last period does make it very difficult to work out how many weeks pregnant you currently are. The pregnancy test detects HCG levels in your urine, it can't accurately show how many weeks pregnant you are. When you go for your first scan, they will be able to measure the baby and give you a current gestation and an estimated due date for birth. Please get in touch if we can support you any further. Please take care of yourself.
    Sophie, Tommy's Midwife

  • By Ankush (not verified) on 30 Mar 2018 - 15:11

    Hi ... meh last periods was in feb may be on 24th or 25th .... so can u please tell me which week is going on n wht wuld b due date ......

  • By Midwife @Tommys on 4 Apr 2018 - 09:55

    Using your LMP of 25th Feb, you are approx 5 weeks pregnant today and would be due around the 2nd Dec 2018. But these dates may change slightly at your first scan depending on baby's measurements. Congratulations!
    If you need any more support or advice, please do get in touch!
    Sophie,Tommy's Midwife

  • By Odel (not verified) on 29 Mar 2018 - 21:01

    Hello, I'm 34yrs old and my LMP is Feb 16, G1P0. When could be my due date?

  • By Midwife @Tommys on 3 Apr 2018 - 16:29

    Hi Odel
    Using your LMP of Feb 16th, and presuming you have a regular cycle length of around 28 days , you would be due approx 23rd Nov 2018 This may change with your scan date according to your baby's growth measurements.
    All the best
    Sophie, Tommy's Midwife

  • By Alexis Miller (not verified) on 29 Mar 2018 - 17:30

    The first day of my last period was February 21st. When I didn’t have my period a week after that, I decided to take a couple pee tests, all came back positive. Called the doctor and was scheduled for April 26 (9 week mark because I didn’t know how far along I was but guessed 4 weeks). Do you know, roughly, how far along I am?

  • By Midwife @Tommys on 3 Apr 2018 - 10:51

    Hi Alexis
    Using your last menstrual period date of Feb 21st - you will be between 5-6 weeks pregnant today.
    This may be liable to change when you have your scan as the babys measurements will correlate to how many weeks you are and when your due date is likely to be.
    Sophie,Tommy's Midwife

  • By Anna (not verified) on 28 Mar 2018 - 15:11


    The first day of my last period was 12 of February of 2018 When would be my due date?

  • By Midwife @Tommys on 28 Mar 2018 - 15:14

    Your due date would be 20th November 2018 although when you have your early scans this date may be changed by a few days.

  • By Jiya (not verified) on 2 Apr 2018 - 19:15


    The first day of my last period was 18 of February of 2018 When would be my due date?

  • By Ches (not verified) on 25 Mar 2018 - 17:22

    My last period was 4th feb 2018
    How many weeks am I now?
    Nd when am i due?

  • By Midwife @Tommys on 26 Mar 2018 - 15:04

    You would be 7 weeks plus 2 days today and due date is 12/11 18.
    Sometimes these dates are altered slightly when you have your scan. Best wishes

  • By Qayat (not verified) on 23 Mar 2018 - 12:40

    My LMP was 29/12/2017 how many weeks pregnant am I n ma due date

  • By Midwife @Tommys on 23 Mar 2018 - 13:02

    Hi Qayat,
    If you have a regular 28 day cycle, then your due date will be about the 5th of October, however when you have your scan at about 11-13 weeks of pregnancy this will give you an official due date.
    Best wishes, Tommy's midwife.

  • By Paula (not verified) on 23 Mar 2018 - 11:15

    Hi my last period was 9th February can you help me work out my due date?

  • By Midwife @Tommys on 23 Mar 2018 - 12:59

    Hi Paula,
    If you have a regular 28 day cycle then your due date will be about the 16th November. When you have your dating scan at about 11-13 weeks of pregnancy, this will give you your official due date for the rest of the pregnancy.
    Best wishes, Tommy's midwife.

  • By Nabina (not verified) on 22 Mar 2018 - 13:11

    My last period is 31th jan 2018,, I have no idea how many week my pregnancy and due date

  • By Midwife @Tommys on 22 Mar 2018 - 15:57

    Hi Nabina, Thank you for your comment. Congratulations on your pregnancy.

    If your LMP was on the 31st Jan then your are due around the 5th November 2018 so that would make you around 7 weeks today. Hope this helps, Take care, Tommy's Midwives x

  • By Nafisa (not verified) on 21 Mar 2018 - 17:15

    Hello, the first day of my last mp was 26th jan, how many weeks pregnant am i? Got confused when i had as scan on the 10th march and the doctor said i was 6weeks 6days pregnant

  • By Midwife @Tommys on 22 Mar 2018 - 15:21

    Hi Nafisa,

    Thank you for your comment and congratulations on your pregnancy. If your LMP was 26th Jan then this will make you around 7 weeks and 5 days today, this will give you an estimated due date of around the 31st October 2018. It can be very normal for your dates to be out by a few days as this depends on when you ovulated and we can never be 100% when this occurs, but on average it is around the 14th day of your cycle. As you have had a scan, your midwife will go by the due date given to you on your scan as this is the most accurate.

    Hope this helps, Take Care, Tommy's Midwives x

  • By Jenny (not verified) on 21 Mar 2018 - 10:56

    Hello. Just took a home pregnancy test 2 days ago, which was positive. Also have a yeast infection. Can’t get into the doctor for 3 weeks. A doctor friend of mine said Monistat 7 was fine to use. Is it really ok? I miscarried on 2/20, i don’t want to jeopardize this pregnancy in any way.

  • By Midwife @Tommys on 21 Mar 2018 - 12:47

    Hi Jenny,
    Yes it is fine to use Monistat 7, however we would advise to use it vaginally only and to avoid any oral (via the mouth) treatments. Also just to be aware that treatment in pregnancy usually takes a little longer so will likely need the treatment for the full 7 days.
    Best wishes, Tommy's midwife.

  • By Kuenga (not verified) on 20 Mar 2018 - 14:49

    The first day of my last period was 23rd of January 2018. My period cycle is 32days on an average. When would be my due date?

  • By Midwife @Tommys on 21 Mar 2018 - 12:05

    From the information that you have provided, your due date would be about the 30th October however your first scan will give you a date that they will use during your pregnancy.
    Best wishes
    Tommy's midwife

  • By Lizbeth (not verified) on 15 Mar 2018 - 21:31

    Hi my last period was feb 2nd and i just found out i was pregnant on march 8th, ibe been experiencing menstral like cramps with no vaginal bleeding , is this normal because i asked my sister in law who is due in 3 months and zhe said she never experienced this.

  • By Midwife @Tommys on 16 Mar 2018 - 12:07

    Thank you for your comment and congratulations on your pregnancy.
    Its fairly common to have period type pain or similar in early pregnancy-it's related to your hormones and the womb starting to grow as your baby develops. Not everyone experiences these cramps however.
    If they are mild and not happening all the time then there is usually nothing to worry about.
    However if the cramps become very severe and not going away or if there is any bleeding then you should contact your doctor or hospital for further assessment.
    I have attached link with further information and advice about pains in early pregnancy

    Hope this helps
    Tommy's Midwife

  • By Gabriela (not verified) on 14 Mar 2018 - 02:04

    I had unprotected intercourse on February 21 and I have been using the restroom alot and my chest had been itching. I've taken 2 test and came back negative I have also been gaining weight. Is there a possibility I'm pregnant but the test still shows negative?

  • By Midwife @Tommys on 15 Mar 2018 - 15:58

    Hi Gabriela,
    Yes there is a chance that you could be pregnant and that it is just a little early to be taking a test. I would advise if that if your period does not come when due to then take a test. In the meant time to start taking a folic acid supplement in case you are pregnant. Best wishes, Tommy's midwives.

  • By Maryam (not verified) on 13 Mar 2018 - 21:15

    I had my last period on 19th of January.pls hw old is my pregnancy nw.

  • By Midwife @Tommys on 15 Mar 2018 - 15:55

    Hi, given the date of your last period and assuming that you have regular 28 days cycle, then you are about 7 weeks and 6 days pregnant, due about the 26th October. When you have your first scan then you will be given an official due date and this will be used for the rest of your pregnancy. If you have not already then we would advised for you to make an appointment with your GP and start taking a folic acid supplement. Best wishes, Tommy's midwives.

  • By feba (not verified) on 12 Mar 2018 - 19:30

    Hello, my LMP was 12th January 2018. I used the pregnancy test and its positive for having a two lines. Then i feel pregnant. After two days i consult a gynacologist.He said everything is ok. He gave vitamin tablets only. He also said March 23 -first scan.Is it correct? How old (how many weeks are my now?is my baby now? In these days i desire and thurst for sexual relationship.Is it wrong or have side effects? When would be my due date?

  • By Midwife @Tommys on 13 Mar 2018 - 12:17

    Hi Feba,

    If your LMP was 12/1/18 then your first scan on March 23rd would be at 10 weeks. Your due date would be October 19th although this is only a guess date as your baby will arrive any time between 37-42 weeks.
    At the moment you are 8 weeks and 4 days. It is fine to have sex in early pregnancy providing that you haven't had any bleeding and it feels comfortable for you. You might need to experiment with positions.

    Have a good pregnancy and get in touch if you have any more questions
    Anna- Tommy's Midwife

  • By Aquarius (not verified) on 9 Mar 2018 - 21:17

    Hi Sophie.
    I just had my D & C procedure done on March 5, 2018 due to unviable pregnancy. And lately, I have been feeling some abdominal discomfort. Is this normal? I am still on medication (antibiotics) for 7 days. I am also on my sick leave. The doctor failed to inform me of what to expect after the procedure. My concers are:
    1. When will my regular menstruation come back?
    2. How soon can I recover?
    3.When can I start going to the gym?
    4.When will it be safe for sex?
    5.other info pls

    Thanking you in advance for the advice.

  • By Midwife @Tommys on 12 Mar 2018 - 10:22

    Hi, I hope you are feeling better today and that your discomfort is resolving. Recovery time varies but you should feel better and stronger each day. If you don't or if you are concerned please see your GP for advice.
    NHS have very good website to answer all your queries or you are welcome to call us on 0800 0147 800 if you need to talk. We are here Monday to Friday 9-5pm.

  • By Ash (not verified) on 9 Mar 2018 - 15:28

    Hello, iam 4 wk pregnant but i had an abdominal pain sometimes specially i feel pressure and mostly my pain started after pee , like periods pain .i am taking snooty is it safe

  • By Midwife @Tommys on 9 Mar 2018 - 16:14

    No I would not advise any medication in pregnancy without discussion with your doctor. Make an appointment as soon as you are able. Best wishes

  • By Crystal (not verified) on 9 Mar 2018 - 09:44


    The first day of my last period was 2nd of January 2018. My period cycle is 40 days on an average. When would be my due date?

  • By Midwife @Tommys on 9 Mar 2018 - 11:12

    If we go by your LMP (last period) your due date would be 11th October. However this date may be reviewed at your first scan as you have a long cycle length.

  • By maryann (not verified) on 7 Mar 2018 - 09:51

    My last period is 29th January,2018 and iam many weeks are my now?

  • By Midwife @Tommys on 7 Mar 2018 - 09:58

    Hi Maryann
    The most pregnant you could be is around 5 weeks using your last menstrual period date of 29th Jan 2018.
    The weeks may change slightly when you go for your first pregnancy scan.
    All the best
    Sophie, Tommy's Midwife

  • By tina (not verified) on 5 Mar 2018 - 14:33

    am 6 weeks pregnant, I have stomach ache recently and my doctor prescribed buscopan for me. is it safe to take

  • By Midwife @Tommys on 6 Mar 2018 - 14:36

    Hi Tina,
    Thank you for your post. You are concerned about taking buscopan whilst pregnant. There is no medical research that says that Buscopan is dangerous for the developing baby. For many drugs there is inadequate evidence available to establish whether the drug is 100% safe and it would be unethical to test drugs on pregnant women so we tend to err on the side of caution in pregnancy . It is in the first 12 weeks that the baby's major organs are developing. How bad are your symptoms? As the effects of the drug are not fully known could you try alternative non medical treatment for your stomach ache until after 12 weeks?
    The link below is for Medicines in pregnancy (BUMPS)
    they are a great resource into what you can and may not want to take. Your local pharmacist can also be a great person for information on drugs in pregnancy and whilst breastfeeding.
    I hope this helps Tina.
    Wishing you a great pregnancy
    Anna-Tommy's Midwives

  • By Mika Lane (not verified) on 5 Mar 2018 - 06:41

    Good day! my last menstruation is last January 10 2018 although my expectation is Jan. 07 2018 and my mentruation lasts for 7 days and more... For the month of Feb. I am expecting that my menstruation will starts at around Feb 13 2018 considering my 3 days delay routine of menstruation. But until now my menstruation is delayed. I used the pregnancy test and its positive for having a two lines. Now I feel pregnant, yes but how old is baby now.

  • By Midwife @Tommys on 6 Mar 2018 - 12:47

    Hi Mika!
    If your last period was in January and the first day of your last period was the 7th you are now around 8 weeks pregnant. It would be good to see your GP and get an appointment to meet your midwife. In the meantime it is important to take folic acid and vitamin d or a pregnancy vitamin that may include these nutrients. If you have any other questions you can email us at [email protected] or follow this link.
    Warmest wishes
    Anna-Tommy's Midwife

  • By Scragfinch (not verified) on 2 Mar 2018 - 11:15

    Hello. I had a stillbirth 5 months ago at 34 weeks due to a silent placental abruption. I have just found out I'm pregnant again and am pleased but very nervous. I want to get a referal to a top obsteatrician I have heard of. What is the best way of doing this? Can my GP do it? I have lost confidence in the midwife checks and think I need a lot more care this time. Many thanks.

  • By Midwife @Tommys on 2 Mar 2018 - 13:10

    I am so sorry to hear about the loss of your baby and it is completely understandable that you are feeling very nervous upon finding out that you are pregnant again. For this pregnancy you will be referral to a consultant at the hospital you choose to book at, you do have the option to request a particular consultant if you would like to, just tell your midwife at your booking appointment. You will have extra appointments, tests and scans in this pregnancy as part of guidelines. We do also have a research centre based in Manchester called the Rainbow clinic who specialise in caring for pregnant women who have had a stillbirth previously, if you would like more information about this then please do email us [email protected] Best wishes, Tommy's midwives x

  • By Sonia (not verified) on 28 Feb 2018 - 05:32

    Hi Tommy,

    When I was 6 weeks pregnant, I got a slight bleeding and we checked with the doctor. On scanning the baby was fine. I have dark brown/light coffee color discharge in the morning when I wake up and check. Doctor says it's not acceptable to get color change like this and and given me some medicine. But it continues every morning and disappears after 10 am usually. Then I could see white discharge only. I am totally worried since this is my first pregnancy. Now I am on 7th week (I had my last periods on Jan 9th). Please advise.


  • By Midwife @Tommys on 28 Feb 2018 - 12:31

    Hi Sonia
    It sounds as if you may have a thrush infection (the white discharge) which should be treated with thrush cream suitable for pregnancy. Antibiotics can also commonly cause thrush, if this was the medication the dr gave to you- i presume you have an infection of some sort. Please continue to take the medication the dr prescribed, but i do recommend that you go back to be reviewed again in view of the discharge/vaginal loss.
    Please take good care of yourself,
    Sophie,Tommy's Midwife

  • By Sohana (not verified) on 26 Feb 2018 - 13:53

    Hi dear,
    I had my last period on 27 december 2017. I was supposed to have my next mens on 27th january but I missed. I did a test and it's positive. As usual, my pregnancy duration will be almost 8 weeks since last period. But I know it's not coz we had sex with protection except only once that's on 20 January 2018, 7 days before my last period. So what week am I in?

    Also people advising me to see OB for prenatal vitamins. Is it necessary now or I can just intake folic acid and Vitamin D tablets from pharmacy stores?

    People advising me to stop drinking tea but if I stop, I will have constipation. Coz tea is my daily routine to avoid constipation. Should I stop even if I have constipation or I can carry on just the tea. I stopped coffee.

    Thanks for your advice!

  • By Rashidat (not verified) on 22 Feb 2018 - 09:48

    I had my last period 14th December, 2017, did a urine p.t,and positive since January 11th. I have been having series of nausea and vomiting, chills at night,and light abdominal cramps.

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