Pregnancy Week By Week – The First Trimester

Pregnancy Week By Week - The First Trimester

Congratulations if you’ve just found out you’re pregnant! We’ve compiled this pregnancy week by week article because we know you’re probably dying to know what happens next!

Each week in your first trimester brings new and exciting developments – your baby is only tiny, but this stage lays important foundations for the rest of his or her life!

Do you want to know what your baby is doing in there, when you will feel their first movements or how long morning sickness can last?

Find out what will happen in your pregnancy week by week.

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Pregnancy Week By Week

So, let’s go! Here’s what you need to know about pregnancy week by week in the first trimester:

Pregnancy Week By Week: Week 1

You aren’t actually pregnant yet – in fact your period has just started!

Even though you have conceived your baby, gestation is counted from the first day of your last menstrual period.

This is so your estimated due date can be worked out as approximately 40 weeks from today.

Even early in pregnancy, there is no exact science to working out when your baby will be born. Only 3-5% of babies are actually born on their due date!

It can be a lot easier to tell excited family and friends a due month or even a due season.

At the moment, your baby is still a small, single celled egg (ovum) hiding in one of your ovaries.

The diet of both mother and father before conception can not only affect fertility and the pregnancy (for example, likelihood of gestational diabetes), but the future health of the baby too.

It’s a good idea for both of you to clean up your diet and make good lifestyle choices over the next few weeks, to increase the chances of conception and a healthy pregnancy and baby. Eating whole foods (protein, good fats, fruit, veggies, nuts, seeds, greens) and cutting out processed foods (grains, sugars) is ideal.

Women are usually advised to start taking folic acid supplements when trying to conceive or newly pregnant – but before you do, read this important article.

Read more about the first week of pregnancy.

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Pregnancy Week By Week: Week 2

Once your period finishes, the lining of your uterus (endometrium) will thicken in preparation for implantation of a fertilised egg.

This thickening is caused primarily by an increase in the hormone progesterone.

If implantation doesn’t happen, progesterone levels fall and your body gets rid of this thickened layer, which is your menstrual period.

An egg follicle on one of your ovaries gets ready to release an egg. This is known as the follicular phase.

Usually only one egg is released, although sometimes 2 or more eggs are released and are responsible for the birth of fraternal twins.

Unlike a man who produces new sperm through his life, a woman is born with a lifetime’s supply of eggs already in her ovaries.

Read more about the second week of pregnancy.

Pregnancy Week By Week: Week 3

This is it — the magic week when you conceive!

It takes about 10 hours for your partner’s sperm to reach your egg.

Fertilisation usually occurs in the fallopian tubes as the egg is swept down toward the uterus.

As soon as the egg is penetrated, it starts to rapidly divide.

It takes about 6 days to journey to the uterus and once there, will attach itself to the uterine wall (implantation).

Read more about week 3 of pregnancy.

Pregnancy Week By Week: Week 4

Your period may be due and not arrive – you may suspect you are pregnant.

Some women do experience implantation bleeding when the fertilised egg burros into the uterine wall.

You may begin experiencing some early signs of pregnancy.

If you do think you are pregnant, you are probably curious when you are due – our due date calculator will give you an estimated date.

The next six weeks are a critical stage of development for your baby so it’s important to address any health and lifestyle issues early on.

Consider a prenatal multivitamin (ask your natural health practitioner for a good one – supermarket stocked vitamins are not the best available).

Increase/ your dietary intake of folate rich foods to help your baby’s neural tube develop properly and avoid spina bifida. Find out more here.

Read more about week 4 of pregnancy.

Pregnancy Week By Week: Week 5

If you have confirmed your pregnancy by a home pregnancy test, you know you are definitely pregnant.

But your body could already be giving that away – your breasts and nipple may feel very tender.

You might have also felt some cramping and backache. If this is very painful, see your care provider.

Your baby is very tiny and looks a little bit like a tadpole. The placenta and umbilical cord have developed and are helping to nourish your baby as they will for the next 8 months.

Read more about week 5 of pregnancy.

Pregnancy Week By Week: Week 6

Pregnancy tiredness may have suddenly kicked in this week!You are making a baby after all, it’s ok to be more tired than normal.

You will have noticed you need to pee more often, especially in the middle of the night.

You may also be feeling a bit queasy already. Morning sickness affects most women and usually passes after the first trimester.

Some unlucky women develop hyperemesis gravidarum, which is a severe form of morning sickness.

No one is sure what causes morning sickness but it is suspected that the rising levels of HCG play a major part.

Your baby starts to look a little like a ‘jelly bean’ and has a bloodstream, and a heart which has started to beat and pump.

Four little buds have formed which will become arms and legs soon.

Read more about week 6 of pregnancy.

Pregnancy Week By Week: Week 7

Not much has changed from last week except your morning sickness could be getting worse.

Try to eat something dry like crackers first thing in the morning before you get out of bed. Keep eating small, frequent meals or snacks to avoid going too long without food. Some women swear by ginger in any form, others swear by acupressure bracelets. It might take you a while to find out what works best for you.

Your baby is now the size of a cherry, with arms and legs! Baby’s face is beginning to form, as well the teeth and tongue.

Read more about week 7 of pregnancy.

Pregnancy Week By Week: Week 8

You might have noticed a tiny bump appearing around your middle. Your clothes might be feeling a bit snug and uncomfortable.

Hormonal changes may be affecting your skin and you might see some pimples. Your blood volume is starting to increase and this can put pressure on the blood vessels in your nose and gums, increasing bleeding.

Your baby’s face has formed and the heart is beating regularly. Organs are beginning to form, as well as muscles and nerves. Baby’s skin is very thin and the brain and veins are still visible.

Read more about week 8 of pregnancy.

Pregnancy Week By Week: Week 9

Around this stage of pregnancy you might have noticed your bra is feeling uncomfortable. This is because your breasts are beginning to change in preparation for lactation after birth. It’s a good time to purchase some maternity bras that will see you through pregnancy.

While you can’t see what’s happening, your baby is developing very quickly now and looks like a person. You can’t feel it yet but your baby has started to move and flex arms and legs, as elbows and ankles have developed. The placenta has taken over nourishing your baby and is now completely developed.

Read more about week 9 of pregnancy.

Pregnancy Week By Week: Week 10

Are you feeling a little crazy and emotional? It’s pretty normal around this stage of pregnancy to experience some wild mood swings, thanks to pregnancy hormones.

Try to get enough rest and ask for your partner’s support and empathy.

Baby has been adding some finishing touches – hair and fingernails have started to grow.

Eye colour has been decided and the nervous system is beginning to develop.

Large muscles are also forming and your baby’s head has grown.

Read more about week 10 of pregnancy.

Pregnancy Week By Week: Week 11

Some pregnancy symptoms like morning sickness and tiredness may be easing by now. You could be feeling more energetic and this is a great time for you and your partner to start enjoying the idea of sharing your news (if you haven’t already!). You might be finding it hard to ‘hide’ your belly now.

Your diet should focus on fresh, wholefoods to help support your body as you nourish your growing baby. If you have any concerns about your health, make an appointment to see your care provider.

All of baby’s major organs are formed and starting to function. Movements are increasing and baby is able to suck and swallow. The placenta is supplying all nourishment and taking away waste.

Read more about week 11 of pregnancy.

Pregnancy Week By Week: Week 12

Around this time you may have decided to have an ultrasound to check on baby’s growth and development.

Your uterus is now above your pelvis and you may notice you don’t need to wee so often. You may need to think about buying some maternity pants about now, as your belly is beginning to pop!

Your baby’s eyes and ears are moving into the right position and vocal cords begin to form. Bones are beginning to harden and movements are more deliberate. Your baby’s sex organs are now visible but can be difficult to determine via ultrasound at this gestation.

Read more about week 12 of pregnancy.

Pregnancy Week By Week: Week 13

This is the last week of the first trimester! All your pregnancy symptoms may fade in the next few weeks as you enter the easy second trimester. Your baby belly will keep growing and you may feel some aches or pulling sensations around the lower abdomen. The ligaments supporting your uterus are stretching to accommodate your growing baby.

By now your baby has kidneys and is passing urine, adding to the fluid in the amniotic sac. Movements are definitely increasing and some women become aware of them, especially if they have been pregnant before.

The important phase of development for your baby has been completed and from now your baby will continue to mature and grow, in preparation for birth.

Read more about week 13 of pregnancy.

Enjoy the second trimester – it’s usually the most favourite trimester for pregnant women. The bump is finally noticeable, but not too big and uncomfortable, you get the ‘glow’ and your risk of miscarriage has dropped dramatically. Your moods tend to be more settled and energy much better than in the first trimester – so we hope you enjoy your next 13 weeks.

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Sam McCulloch enjoyed talking so much about birth she decided to become a birth educator and doula, supporting parents in making informed choices about their birth experience. In her spare time she writes novels. She is mother to three beautiful little humans.


  1. Please at which week is the best time to do a urine pregnancy test? I missed my period today. (When should I test my urine?) Thanks.

    1. If you have regular periods and you have missed yours then you should take a home test just to be sure, If that test comes back negative wait another week and if you still have not had your period test again or go see a doctor.

  2. Well I have learn plenty from reading on this site and it as help me alot..I will continued to look and read here it give u good help in everything thanks alot

  3. My period started the 8th of February. I had unprotected sex the 14th of February. I had what I thought was a period again on the 19th of February but it was mainly just spotting that lasted 4 days. I didn’t have a period in March but had unprotected sex on the 11th of March. My question is did I get pregnant in February or March?

  4. I have got to say this is probably one of the best websites I’ve visited to know about my baby I am currently 8weeks I think and sugfering heart burn terribly and my mum will not let me not eat she’s constantly feeding me. This is my first child and I am extremely excited so being able to read about how thoroughly my child is developing up until 13 weeks and is really intriguing. You’ve helped me a great deal so thank you

  5. My periods are irregular. But i had one January 3rd and February 3rd. They always last about 5 days. Since then i havent had a period and it is not May 10th. I dont want to get my hopes up. I had almost all symptoms. Recently my stomach hurts a little and feels all fuzzy inside. I noticed blue veins in and around my breasts last night. I pee all the time. And when i lay down it feels like my tummy is hard and up a little. I hope i am preggers. But home tests dont work for me. They never have. Any ideas??

  6. My ovulation period was 14 days ago. Now I have missed my period today, though I do experience irregular menstruation. My stomach is very warm and hot which is unusual. Am I pregnant?

  7. I’ve learn a lot from this site! I think I’m pregnant but I guess I should wait one more week before taking a home pregnancy test.

  8. I’ve been having bloating, cramps, a lot of peeing, cravings and nausea. I can also feel something hard in my stomach. Am I pregnant?

  9. i am going to start from the month of July. i saw my period on the 4th of july and it ended on the 7.i ought normally to menstrate on the 1 of August which did not happen but instead i had a slight bleeding on the 5 of august which ende on the 7. i have not yet taken a test but i feel some stiffness in my belly and even when i have not eating, my lower abdomen show as if i just ate. could it be that i am pregnant

  10. my breasts have been hurting lately and have veins my nipples have turned darker im afraid to test coz i don’t want to get my hopes up i don’t know whether i should wait and see with the months or what

  11. Hi there.

    I usually get my period the last tuesday of each month like clock work. …. last month like clock work i got it as per usual and then two weeks later i got my period again (which was not normal)…. im not sure if it could be because of my exercise routine i started….but now i haven’t gotten my period for the month of September…baring in mind i got it earlier this month as mentioned….. i have missedy period by two days now. Could there be a possibility that im pregnant or has my period just change.

    1. Sorry meant to say that i got it earlier this month which isn’t normal because i usually get it the last tuesday of each month. Which i have now missed by two days

  12. Hi everyone I’m new to all this Iam 6weeks pregnanti have had stomach cramps back ache headaches sleepy feeling sick an going toilet a lot I’m so excited ….I tested the day after my missed period and test came bk neg but I new I was pregnant so tested 2 days later and had 4 positive test …… If you think ur pregnant only way to no for sure is take a test

  13. I found out 3 days ago that I was pregnant through two possitive tests after 9 days missed period. I am excited an nervous. I am young and scared, please, does anyone have advice?

  14. Hello!
    I have been experiencing some of the pregnancy symptoms bloating,nausea,vomiting,peeing in the middle of thw night,drinking lots of water,constipation and i had unprotected sex with my partner on my fertile days,now i am startin to see veins on my stomaxh and breast and my nipples are becoming dark…i toom two pregnacy test n ther werw negative o took them wen i started seeing pregnancy symptoms…my period is suppose to start on the 2nd of November…could i be preganant?

  15. Hello!
    I have been experiencing some of the pregnancy symptoms bloating,nausea,vomiting,peeing in the middle of thw night,drinking lots of water,constipation and i had unprotected sex with my partner on my fertile days,now i am startin to see veins on my stomaxh and breast and my nipples are becoming dark…i toom two pregnacy test n ther werw negative o took them wen i started seeing pregnancy symptoms…my period is suppose to start on the 2nd of November…could i be pregnant..n i forhot to say my tummy is stiff…i had unprotected sex on the 13 n 14 of October n i was fertile on those days

  16. Hello, I am now 13 weeks my periods has never been regular. I have not had a period none of this year andaybe once or twice last year. I found out I was pregnant at 6 weeks. The following week at 7 weeks I had gone to the bathroom and blood started gushing out as if I was on my period and there were blood clots to I thought I had a miscarriage. I called the doctor and explained what happened the nurse said it sounds like I was having a miscarriage. I went to doctor about 3 weeks later. My HGC levels were off the charts sky high. They tested my HGC levels and also did a ultrasound there was a baby still with a good heart but my levels were still too high for one baby to be in the womb. The APN said it sounds like I was pregnant with twins and had a miscarriage with the other because my beta levels were to high for just one baby. I was really shocked because I didn’t think I was pregnant anymore with the episode of bleeding.

  17. Hi my name is morgen im feeling waird tingaling and moving in my belly its like somthing is pinching me it hurts all of a sudden I get pain I took a test at the docter maybe it was to erly im not saying I could be pregnet but theres chances anyway it cameout negative and if im pregnet why doesn’t my belly grow ?
    With my mom it happend the same thing she was prego and the stupid docters said she wasnt prego when she was her belly never grow she lost the baby

  18. I didn’t even take my own test right off the bat… Me and my fiance went to the Hospital to check me for a bladder infection, which came back as positive… But then the doctor also informed us that we’re expecting. And based on the first day of my last period, I’d be like 5 weeks right now.

  19. Ok so I’m now 21 days late for my period, I am usually on time within a day or so, I have never been able to use home pregnancy test (they don’t work for me) so I went and got a blood test 2 days late it came back neg. 1 week later my dr sent me for another blood test as my period still hadn’t come, that too was negative!! I am now 21 days late still no sign of my period but all the symptoms of being pregnant!!! ( I have 3 other children) I am due to get my results back tomorrow but what could be going on if it comes back negative again!! My husband and I want another baby and I’m worried I’ve manifested all my symptoms in my head. Any help would be greatly appreciated xx

  20. Hi,I am Constance. I had my last period on the 28th March, and had unprotected sex on 7th April and 11th April, and on 12th April I took morning after pills,but they didn’t work out,because am still pregnant, so I want to know when exactly did I fell pregnant?

  21. I’m 6 weeks pregnant , I had sexual intercourse with my boyfriend, and now we’re experiencing spotting. Is sex okay ? I don’t have an appointmeny until the 27th of July; Is spotting normal or no ?

  22. Hello! I’m Brianna and I have been experiencing bleeding last month and this mont . Last month I was heavy one day (with blood clots) and I lightened up the next three days then it stopped. My periods usually last 8-9 days and extremely heavy. Then we had unprotected sexual intercourse 4 weeks ago and again a week ag . But I’ve been experiencing urinating more, eating more, headaches, constantly exhausted, and spottin . I don’t know if I’m pregnant because the tests don’t work on m . I’m 15 and my parents don’t know. How do I find out if I am or not?!

  23. Hi me and my husband have been trying for a baby for 5 months now the last few week I feel as though I am pregnant keep feeling very sick, very tired, keep peeing all the time & keep felling fluttery feeling in my lower stomach & it feels hard my boobs feel different to. I have done 4 test and they have all been negative but I had the same problem when I was pregnant with my twin sons my doctor sent me for blood test they kept coming back negative in the end he had to send me for a hormone test which came back that I was

  24. Just a quick reassurance question, I took a home pregnancy test last month, it was positive. I have my last period July 20. Which would make me 7 weeks today. I went to the doctors at 5 weeks and the ultrasound showed only my gest. Sac. But no embryo. They said it might not be growing properly and I might have to go in for a DnC. I have not gone back for a reasonable amount of reasons,I have to call for a new health insurance in order to make an appointment. I’m worried if they are right. Are you supposed to see an embryo at 5 weeks ? They took my hormone levels too and they were showed at 5 weeks.

  25. Hi, I was supposed to get my period at the end of october but i didnt and i did have unprotected sex before that and on November 5th o started spotting very light redish/pinkish n spotted for 6 days and on the 16 again i spotted for just a couple hours. Ive had all the symptoms of pregnancy could i be pregnant i took a pregnancy test and it came back negative. Please let me know as soon as possible.

  26. I had protected sex and a week or two after I saw brownish discharge on my pants in the morning. Then my period came 5 days early with pregnancy symptoms and it wasn’t as heavy as my usual flow, I usually have a 30 days cycle but this was 26 days. I took a home test two days after my period and it came back negative but since then I’ve not been myself, I’ve been really tired and yawning, heartburn every day. Just wanting to lay down all day long. Am I pregnant?

  27. I have been having my periods late for the past 2 months and the dates differ, my cycle is 21 days but this days my periods come 3 or 4 days late.. have been having sore breast and itching tummy and sometimes i experience pain below my bellybutton. Does this mean am pregnant? I am scared to go to the doctor but i really wanna know

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