Pregnancy calendar

weeks pregnant

4 weeks pregnant - all you need to know

Congratulations on your exciting news! Tommy’s midwives are here to guide you through every stage of your pregnancy and help you get to know your growing baby.

4 weeks infographic.

Tommy’s midwives are here to support you by telling you everything you need to know about week 4 of pregnancy: advice on common pregnancy symptoms, practical actions, such as the ‘booking’ appointment and what’s happening with your baby.

Before week 4

Congratulations on your exciting news! If your periods are usually regular, conception is likely to happen in the middle of weeks one to four. You are very unlikely to know you're pregnant at this stage.

It may sound odd but pregnancies are measured from the first day of your last period rather than the day you actually conceived your baby. This is because it's not always easy to be sure of the exact date you became pregnant.

“I spent the entire week my period was due running to the loo, just to double check I didn’t have my period. My boobs felt tender - but that can be a sign of PMT too. I took an early test in the end and couldn’t believe it when it showed positive.” Ayida, mum of one

Although a fertilised egg may have implanted in your womb just two weeks ago, if the first day of your last period was four weeks ago, you are officially four weeks pregnant! This may seem odd if you think you can definitely date the pregnancy more recently.

Get weekly updates on your baby's development from our expert midwives straight to your inbox.

What does my baby look like?

The tiny person inside you is the size of a poppy seed. A little dot, measuring about 2mm.

The baby may be miniscule but big things are happening! The fertilised egg has snuggled into the side of your womb. It divides into layers of cells that will eventually become different parts of your baby’s body.

Your baby’s nervous system and heart are developing. Amazingly your tiny dot already has some of its own blood vessels and blood is starting to circulate. A string of these blood vessels connects you to your baby. This will eventually become the umbilical cord.

Right now, your poppy seed is known as an embryo. They get their energy and nourishment from a yolk sac (until the placenta takes over in a few weeks). Your baby is surrounded by amniotic fluid within the amniotic sac, providing a comfy cushion for them throughout your pregnancy.

Your symptoms - what happens in week 4

Early symptoms of pregnancy

Bleeding or spotting

You might notice some very light bleeding, or ‘spotting’, known as implantation bleeding. This can be caused by your little seed burrowing into the lining of your womb. It often happens around the time your period would have been due and is relatively common.

You may also have some period-like cramping in these early weeks.

If you notice any bleeding at any stage of your pregnancy, though, it's important to get it checked out by your doctor or midwife.

Sore boobs

This week, a surge in progesterone can start to make your boobs feel tender, heavy and sore - a bit like how they might feel before your period.

Remarkably, these are pregnancy hormones already preparing your body to produce milk. This tenderness usually eases off by the end of the first trimester.

Find out how to deal with first trimester pregnancy complaints or read more early pregnancy symptoms here.

Things to do in week 4

Smoking and alcohol in pregnancy

It’s time to quit cigarettes and alcohol. Both can be harmful to your growing baby because the toxins pass through the placenta.

Here’s our guide to avoiding alcohol during pregnancy.

Find out more about the effects of smoking in pregnancy.

And if you’re still struggling to stop smoking, these ten steps towards quitting could help.

If you use street or recreational drugs, stop or ask your doctor for advice on stopping safely.


Sexually transmitted infections (STIs) such as chlamydia, gonorrhoea, syphilis and genital herpes can affect your baby's health during pregnancy or birth.

If you think you or your partner might have an STI, go for a check-up as soon as you can. Your doctor or midwife can tell you where you can find your nearest sexual health clinic.

Don't worry, nobody will judge you and it's important to be checked as soon as possible.

Continue (or start) taking these supplements

There are two vitamins that are very important in pregnancy and that you can take as supplements: Folic acid and vitamin D.

Folic acid is naturally present in leafy vegetables, fruits and berries, beans and wholegrain products - but keep taking folic acid supplements too, until at least week 12 because you can't get enough through food alone to build up the level of folic acid that your baby needs.

Folic acid helps in the formation of your baby's nervous system and reduces the risk of spina bifida, which is where the baby's spine doesn't close up properly.

You should take:

  • 10 micrograms of vitamin D each day throughout your pregnancy and if you breastfeed
  • 400 micrograms of folic acid each day – you should take this from before you are pregnant until you are 12 weeks pregnant

Find out more about important supplements in pregnancy.

Tell the GP you are pregnant

Once you know you’re pregnant, make an appointment to see your doctor or a midwife to get any advice you need and to be booked in for your pregnancy care appointmentspregnancy care appointments. If you make a GP appointment, they will set you up for midwife appointments or you can call the maternity unit in the local hospital and refer yourself that way.

However you book it, your first appointment with the midwife will not take place until after week 8, the ‘booking’ appointment. This can make it an anxious time but reading through these dos and donts of pregnancy may help.

This is an important time to talk about any health issues you have to make sure your pregnancy goes well. It is very important to tell your doctor about any medication you may be on, especially long-term medicines for conditions, such as asthma, epilepsy, mental health conditions, diabetes, hormone therapy, heart problems and so on. Your doctor can make sure you are on the safest medication for you and baby.

It is very important that you do not stop taking medication without talking to your GP or specialist

Find out what questions you'll be asked at the booking appointment.

If you have an existing mental health problem

If you have a pre-existing mental health condition and take medication, tell your doctor and the person who prescribed the medication that you’re pregnant as soon as possible.

They will talk to you about whether your medication is safe in pregnancy or whether you should consider a different treatment.

Find out more about your mental wellbeing in pregnancy.

What are my chances of miscarrying?

It’s a sad thing to think about, but up to one in five pregnancies will end in miscarriage in the first three months.

If you do have light bleeding, spotting or stomach pains, this doesn't mean you are going to miscarry. However, you should always speak to your doctor or midwife and ask for advice.

Find out the other symptoms you should contact your midwife about.


1. NHS Choices.You and your baby at 0–8 weeks pregnant, NHS Choices: (Page last reviewed: 28/02/2017 Next review due: 28/02/2020)

2. NHS Choices. Vaginal bleeding in pregnancy (Page last reviewed: 26/01/2018  Next review due: 26/01/2021)

5. NHS Choices. Signs and symptoms of pregnancy (Page last reviewed: 06/10/2016 ;Next review due: 06/10/2019)

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    Last reviewed on June 22nd, 2018. Next review date June 22nd, 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 tolulopeabimbol... (not verified) on 16 Jan 2020 - 08:04

      I am bleeding in my 4th week of pregnancy and am feeling pains what is about and what can I do

    • By Helen (not verified) on 12 Jan 2020 - 15:35

      l had 3 miscarriage then ectopic pregnancy which my left tube was removed all like 3years ago, later tried to be pregnant but not coming,hsg test shows blockage of the right tube that remains so no major hope until now that l just felt my breast is painful, missed period and pregnancy test positive,but very worried so as not to experience what happened in the past

    • By Ks (not verified) on 20 Dec 2019 - 16:13

      I have confirmed implantation bleeding by my midwife which is brown but it smells odd is this normal? Please help

    • By m (not verified) on 17 Jan 2020 - 10:44

      when did you start this bleeding before/after your period was due?

    • By Stephanie (not verified) on 18 Dec 2019 - 11:29

      Hi, I have just found out I’m 4-5 weeks pregnant, I was prescribed metformin 6 months ago to help with PCOS, but stopped taking it 2 months ago as I found it wasn’t helping me, however I was told to keep taking it even if I did conceive. My question is should I start taking it again now I am pregnant?

    • By Natalie (not verified) on 16 Dec 2019 - 14:54

      I haven't had my periods since last month could I be pregnant

    • By Anonymous (not verified) on 20 Nov 2019 - 21:45

      Hi On the 27th of September I went to the doctor to take my 1st depo provera short and the next day my period begin sinces then I haven't seen my period could I be pregnant?

    • By Julia (not verified) on 14 Nov 2019 - 15:17

      Hi i did home pregnancy test and the result says i concived more than 3 weeks ago 5+weeks and my last period was on 14 September so i want to know when did i actually convinced?

    • By Midwife @Tommys on 19 Nov 2019 - 12:17

      Hi Julia,
      If you use our pregnancy calculator, in the link below, you can enter your last period date and your average length of cycle, it will then calculate your due date, how many weeks you are currently and will then help you to work backwards to work out roughly when you conceived. Tommy's Midwife

    • By Tumi (not verified) on 24 Oct 2019 - 10:38

      Hi there plz help I'm Tumi 28 last years October i had a miscarriage i was 3 months pregnant and didn't go for womb scrub now I'm pregnant scared what is might happen to my baby

    • By Nosiphowe (not verified) on 14 Oct 2019 - 18:34

      I have been having unprotected sex for the past 2 months .then this month I missed my periods due date by 5 days then on the 6th day I experienced heavy bleeding the. The blood got lighter and clotting .could be possible that I was experiencing a miscarrage

    • By Florence Susan scott (not verified) on 1 Oct 2019 - 20:28

      I really need to know been having some pains in my abdomen
      And I have Missed my period for one month
      Do you think it a sign of pregnancy

    • By J Salmond (not verified) on 15 Nov 2019 - 20:24

      Please see a GP. Sounds like you are pregnant. Good luck xx

    • By Grace (not verified) on 22 Sep 2019 - 13:11

      Hi. I just want to know if i had sex on august 24 and was pregnant when I had my OB check up on September 20, how many weeks is my baby?

    • By Natalie (not verified) on 2 Aug 2019 - 13:14

      Hi I've recently had a very light bleed that lasted 2 days but only when I wiped then I started with bad headache and light headed lower tummy cramps some lake yellowish or white discharge tired but I'm not due on till between 14th and 17th August could this be a sigh of pregnancy or is it to early thanks you for reading be happy for some one to comment as I don't no what's happening with my body and symptoms

    • By Lucy (not verified) on 25 Jul 2019 - 16:34

      Hi..i was suppose to have my period on the 7th till 10 july 2019..but now its the 25th i still ddnt get my i pregnant?

    • By Zain (not verified) on 25 Aug 2019 - 19:12

      Hi, you can have a pregnancy test at ur home. If u r not having the period this month, you have a chance of becoming pregnant. Don't think too much and have a check up at home or hospital. Thank you

    • By Caz (not verified) on 23 Jul 2019 - 16:14

      I had a miscarriage in 2018 and I've now found out that I'm pregnant again- I went to see a private consultant to have a internal scan as I was bleeding a lot and I was scared I was losing the baby. All is well I'm 5/6 weeks so really happy. The consultant put me on progesterone pessaries for 4 weeks to stop the bleeding, I'm concerned as I've read that it mask/delay a miscarriage- I don't know what to do .

    • By adeela (not verified) on 31 Jul 2019 - 01:59

      Hi there
      I just want to tell you relax
      What's going on will not change if you stressed
      I've had two miscarriages then a healthy baby and then again two miscarriages in Oct 2018 and Jan 2019
      Now I just did HPT and it's positive
      Hoping for the best
      I'm having abdominal cramps
      Going to visit a gynecologist soon
      Fingers crossed

    • By Louise (not verified) on 17 Aug 2019 - 20:58

      Hi I found out I was pregnant on 8th August which test said 2-3 weeks and I was bleeding was at d hospital and scan showed sac but nothing in it as doctor said I was too early or may be losing I wanted to ask was any one had same and had ok results pleas I am now 4 weeks and still bleeding heavy thank you .

    • By Danielle (not verified) on 8 Sep 2019 - 19:48

      I read your post and i found out i am four weeks and for 5 days now everytime i pee i either spot or blood drips in the toilet. I went to the er yesterday and they said they baby was fine however we are on miscarriage watch. It kills me because no doctors give me any answers and dont want a miscarriage.. i want to be excited but so worried if something is wrong. How long does implantation bleeding last???

    • By Aarohi (not verified) on 8 Jul 2019 - 05:06

      Hello I had period one month ago. After that I feel nausea and vomiting and feel like a pregency. On this month I had bleeding on the same day of period. Is it pregency or miscarriage

    • By Kim (not verified) on 7 Jul 2019 - 18:49

      Hi I've just found out I'm pregnant after having 4 miscarriages in the last 2 years I've been to see the RMC and they cant find a reason for it but ive had 3 pregnancies that resulted in preterm birth with my ex, I was talked into sterilisation after my 3rd and had it reversed privately 2 years ago and now I'm terrified this pregnancy is going to end in miscarriage too. What can I do?

    • By Pregantwith#7 (not verified) on 31 Jul 2019 - 21:36

      Hi, A girlfriend of mine kept getting pregnant and then losing the baby 5 months or further into her pregnancies, no one could figure it out for years. Finally they did some testing and found that there is a hormone in her body that detects pregnancy as toxic and it attacks the baby which was causing her to miscarry. She is now 8 months pregnant and doing great! She has to get a shot every once in a while that tricks that specific hormone into thinking her pregnancy is not toxic. I think you should talk to your doctor about it and see if they can test you for it. My girlfriend lost too many babies all at different stages and if they would have tested her after the first time, this would have not kept on going.
      Good luck!

    • By RIRI (not verified) on 4 Jul 2019 - 05:09

      Hello, Me and my boyfriend been ttc for some time now and I was supposed to get my period on the 30th of June but it's July 4th now . I don't wanna get too hyped up in case its just my period. He did have cancer wen he was 16 and he is 22 now so i wonder if that could be an issue. Idk really about the symptoms Im having. I've been feeling tired lately
      More than usual . Even during the day I wnna just take a nap. I never felt like this before . Even on my period. My other symptom I feel is bloated. Even though my period is still not here I feel bloated. And also tender boobs. I just wondering if I could be pregnant. Or should I wait to take a pregnancy test. Is it too early still ?

    • By Jenn (not verified) on 25 Jun 2019 - 01:22

      Based off my periods would put me at 4 weeks but our local health department put 6 weeks. Had a ttansvaginal ultrasound last week but said there is no baby in the uterus. My HCG is 295. I have had light bleeding. I have had 3 natural healthy births never miscarried.. is this normal to not detect an embryo? Took blood today and tomorrow again.. just worried.

    • By Camila (not verified) on 24 Jun 2019 - 10:20

      I had my last periods on the 26 to 30th of may 2019.Am now worried cx am 2 days late for me periods. Can I be pregnant?

    • By grace (not verified) on 6 Jul 2019 - 07:21

      I had my last period on 30 may could it be possible to get pregnant

    • By Nicole (not verified) on 18 Jun 2019 - 05:00

      Last period was on the 22 of May. Was trying for a baby on June 3-6th. It’s been two weeks from the 3rd. Pregnancy test are saying no... my period supposed come in 2 days. Was it to early to test? Could the test be wrong since it was to early or?

    • By Holly (not verified) on 20 Jun 2019 - 03:31

      Yes it could be too early yet, though some pregnancy tests can show up as early as 5 days of a missed period. I know mine was 1 day late I tested and I’m happy to find out I’m pregnant!!!! I tried to test one to two weeks earlier and nothing happened it was negative then. If your period is couple days late I would retry again to take pregnancy test if still negative you should go to your doctor to get checked out or you can wait few days and see what happens.

    • By Sandra (not verified) on 18 Jun 2019 - 04:27

      Hi there I had embryo transfer on 6th of June and on 28th I did test which came back positive. Week before test I was feeling tired,hungry from early morning and on test day my boobs was hurting,my mood was swinging and belly was bloated. But 2 days later all symptoms disappeared. Now only nipples sensitive and nothing else I would feel. Should I be worried? My scan is due on 16th of July.

    • By KJ (not verified) on 24 Jun 2019 - 07:54

      The same exact thing happened to me. I was relieved I didn’t feel as miserable the past two days, but it did make me concerned. My doctor says this is normal. Try not to stress try to think positive.

    • By N (not verified) on 16 Jun 2019 - 20:14

      hi,I had my last period on the 13 may cycle is normally 31 days and I never of today my period haven't came as yet..I have slight breast pain and cramps but that's normal , I usually have those ..I took a pregnancy test this morning and it came negative.. I'm a bit worried because last 2 year I had a molor pregnancy and I'm wondering if that would happen to me again..with my molor I didn't get any symptoms at all besides the missed period,now I'm scared thinking it would happen again..plz help me ..thanks

    • By Susan (not verified) on 16 Jun 2019 - 17:51

      am wondering if I could be pregnant,I got my jadell implanon removed on 24th May,I have been having regular sex,I ve not seen my periods yet,my stomach is getting hard,am having back and abdominal pains. I am testing negative in every single test I do for urine,I feel much pregnant,this is my third child. help me could I be pregnant

    • By Bdol (not verified) on 12 Jun 2019 - 09:55

      Hi, I took a test 5 days which said I’m pregnant 1-2 weeks.. Had been havin the normal sore boobs. Yesterday I went to the doctor & his test came back negative. He sent me to get bloods done now awaiting them to come back. I also took my own test yesterday & it again said pregnant 1-2 weeks. However, I had some spottin this mornin.. Would it be sign of this being a chemical pregnancy & the spottin being my period about to begin. I suffered a miscarriage 5 months ago. Thanks for your help

    • By Innocentia (not verified) on 3 Jun 2019 - 21:39

      My last period was on the 15 may and I was supposed to have my period on the first of June so I want to know that I could be pregnant or what

    • By Timma (not verified) on 22 May 2019 - 13:12

      I had sex on 7th of April which was after my menstruation, I went for Prgnacy test and I was told I am 6weeks pregnant.
      Pls I need to know why it's 6weeks instead of 4weeks

    • By Vimala (not verified) on 18 May 2019 - 12:17

      I think I am 4 week pregnancy but I had mild back and abdominal pain its normal

    • By Susan (not verified) on 16 Jun 2019 - 17:30

      I am in the fourth week now, having cramps,and back aches,, what's the problem...I think we share the same problem

    • By hector (not verified) on 17 May 2019 - 11:35

      Test shows that my wife is 4 weeks pregnant but we had the first sex less than three this possible?

    • By Danielle (not verified) on 5 Jul 2019 - 17:20

      Yes, because they go by the date of the first day of her last period, not by the conception date.

    • By Suzy Arambula (not verified) on 14 Aug 2019 - 18:18

      Yes because it goes by the LMP (last menstrual period) not by the conception date. Like for instance me, I conceived July 27th yet as of Today I'm 4 weeks, but my last LMP was July 13th. It's crazy but it's always gonna be two weeks before the conception date. Your due date is based off of the first day of her last menstrual period. So they count it back two weeks to first day of your last period. Therefore as of Today I'm 4 weeks pregnant yet I should've just started my period on August 10th.

    • By Meliz (not verified) on 8 May 2019 - 12:19

      Hi,am 4 weeks pregnant.2days ago I started having lower abdomen and back pains and light bleeding.i went for utrasound scan but nothing was detected yet..the doc recommended bed rest and repeat scan after I at risk of miscarriage.. please advise

    • By Patricia (not verified) on 25 May 2019 - 20:33

      Yes, your experiencing a threatening miscarriage and need to rest alot and be stress free
      But it does not mean that you will miss arry

    • By Priyanka (not verified) on 5 May 2019 - 04:46

      Hi I am 29 yr old
      I had my ivf on April 15 2019
      And I had my beta hcg test on 27 and it was 165 and it came positive
      And second test was on 29 and it was 715
      By this I am happy but quit after 5 days I had seen a light brown spotting in like a thread after that I could not see it again but having light cramps is it a sign of miscarriage I am worried plZ help me out

    • By halima (not verified) on 25 Apr 2019 - 17:12

      I am four weeks n and some days pregnant Bush just notice pain in my abdominal like the same pain I feel while menstrating though have logde a complain to d doctor n he said I should go and do scan,, is it not too Early. just being scared

    • By Natasha (not verified) on 16 Apr 2019 - 22:24

      Good day, 3 weeks ago i had spotting not much but it latsted for 2 -3days. Still no sighn of period. Sore breasts is the most commen thing i have right now. The sorness began 5 days ago. No spotting or bleeding. I do have to go to the bathroom often. I am a mother of 3 but unfortunitly i lost my twins in January. Im so scared that i might be pregnant and find out to late .... I took a pregnacy test it was sort of positive (Control line was dark, but the test line was pink more on the white side.) You can immideatly see the second line (Test line). Must i wait a few more days to do a nother test or go to the docter. Thank you so much for your help.

    • By Meezie (not verified) on 2 Apr 2019 - 22:55

      Hi I follow a period calendar and my last period was the 9 March 2019 this being my first date of period on the 13 March I went to GP as I was having labour like pains but no spotting and GP said it's urin infection and I was put on antibiotics I am meant to be 7 weeks now and went for an ultra sound and it showed 4 weeks the GP advised I could have counted me out and advised a scan is repeated in 2 weeks but if I counted me out then if I am 4 weeks now it means I should have had a period the date I visited the GP first time round ? She also mentioned I could have ovulated later which I don't understand how it affects how far I am.when I returned from the doctor today a when I wiped me I saw a bit of blood and after that there was no blood again please can you advise what this could be ? The doctor did another pregnancy test today and it was postive and she advised it rules out missed miscarriage

    • By Midwife @Tommys on 24 Apr 2019 - 16:34

      Hi Meezie
      Ovulation occurs around 10-16 days before the next period and may not always be at the same time in your cycle. Conception can take place up to 24 hours after this-as explained in this link-
      The scan may have been performed too early to be accurate-dating scans are most accurate after 8 weeks. Hopefully by now you have had your second scan and been given a more accurate gestation for your pregnancy

    • By edna (not verified) on 24 Mar 2019 - 22:05

      Hi pls I remove my family planing implant ealy February some brown sport then now March I have not see my period and having pains in my breast and pains in d low part of my stomach tested negative last week am just confuse pls I want to know if am pregnant

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