Your Baby is the size of a

Poppy seed

Congratulations! Though you’ll have conceived just 2 weeks ago, week 4 of your cycle marks the life-changing week where you find out you’re officially pregnant! Implantation occurs at this point, which may be indicated by cramping and a little spotting- which can easily be confused with a period, but a test should confirm your little bun in the oven. Your baby is now an ‘embryo’ and has implanted onto your uterine wall, while your body is busy getting to work on forming the placenta and amniotic sac for them!

Week 4

Length : 0.1 cm

Weight : 0 g

Week 4
Length : 0.1 cm
Weight : 0 g

Your Baby is the size of a

Poppy seed

Congratulations! Though you’ll have conceived just 2 weeks ago, week 4 of your cycle marks the life-changing week where you find out you’re officially pregnant! Implantation occurs at this point, which may be indicated by cramping and a little spotting- which can easily be confused with a period, but a test should confirm your little bun in the oven. Your baby is now an ‘embryo’ and has implanted onto your uterine wall, while your body is busy getting to work on forming the placenta and amniotic sac for them!

During week 4, implantation occurs. This happens around 6-12 days after conception and may be indicated by a little spotting (light bleeding), as the blastocyst buries itself and attaches to your uterine wall - easy to mistake for the start of your next period.

Depending on the number of days in your monthly cycle, you likely conceived around 2 weeks ago, and your tiny human is currently no bigger than the tip of a needle! Yet, in nine months' time, your gorgeous baby will fill a baby grow - how cool is that!

This little pinhead-sized ball of cells is growing at an unbelievable rate, and the fertilised egg is dividing over. The little embryo also splits in two, half forming your little one, and the other becomes the placenta. Your amniotic sac is beginning to form, as is the little yolk sac your baby will live in during its stay.

Your little blob has three layers, each beginning to grow into different parts of the body. The 'endoderm', which is the inner layer, starts to grow your baby's digestive system, as well as their liver and lungs. The middle layer, which is called the 'mesoderm', soon becomes the heart, bones, sex organs, kidneys, and muscles. Finally, the 'ectoderm', which is the outer layer which starts to transform into your baby's central nervous system, nails, hair, skin, and eyes.

As the baby's blood vessels start to form, their blood is now beginning to circulate and help with the development of their tiny heart. For the next few weeks, your baby is an 'embryo', and takes all the nourishment it needs from the yolk sac. Once you are around 12 to 14-weeks pregnant, the placenta will be fully formed and ready to take over all the hard work. This is when you'll start to feel more normal.

How are you feeling? The likelihood is you will feel normal as pregnancy symptoms don't tend to rear their heads for a few weeks yet. But there are certainly some tell-tale signs for many women which we covered in our rundown of early pregnancy symptoms. So, sit back, take a big breath, and relax as your body does all the hard work!

Oh, and congratulations!

Stay with us and we will take you step by step through your pregnancy with a weekly update on what your tiny human is up to! If you've not been taking prenatal vitamins, it's time to stock up on folic acid as the next few weeks are the most crucial to baby's development. Head here for everything you need to know on folic acid.

         

Many women don’t feel the symptoms of pregnancy during week four. However, about 50 percent of women will experience pregnancy symptoms during week five, and most women will notice symptoms around week six. If you are already experiencing pregnancy symptoms, they may include:

Spotting: Some women might notice light spotting, which can be attributed to implantation bleeding as the fertilised egg attaches itself to the uterine lining. It's usually lighter than a typical menstrual period and may occur around the time of your expected period.

Tender or swollen breasts
: Hormonal changes in early pregnancy can lead to breast tenderness or swelling as your body prepares for breastfeeding. You may notice increased sensitivity in your breasts, and they may feel fuller or heavier than usual.

Mood swings
: Fluctuating hormone levels can impact your mood even at this stage, causing you to feel more emotional than usual. You might find yourself experiencing mood swings, feeling more tearful, anxious, or irritable without a clear reason. Here’s some more advice on pregnancy emotions.

Morning sickness
: While morning sickness typically begins around week five for most women, some may start experiencing nausea and vomiting as early as week four. Morning sickness can occur at any time of the day and may vary in severity from mild queasiness to frequent vomiting. Here are some tips for combatting morning sickness.

Cramping
: Mild cramping is common in early pregnancy as the uterus undergoes changes to accommodate the growing embryo. These cramps may feel similar to menstrual cramps and are often accompanied by spotting. However, if you experience severe or persistent cramping, it's important to speak to your GP.

Fatigue
: Fatigue is a common symptom in early pregnancy due to hormonal changes and the body's increased energy demands. You may feel more tired than usual, even after getting enough rest, as your body works hard to support the developing embryo.

Gas and bloating
: Hormonal changes can slow down digestion, leading to increased gas and bloating. You may feel gassier than usual and experience bloating, which can contribute to discomfort or a feeling of fullness in your abdomen.

Remember, everyone's experience of pregnancy symptoms can vary, and not everyone will experience the same symptoms or severity. If you have any concerns about your symptoms or pregnancy, it's important to speak with your GP or midwife when you get registered with them. 

Tell your partner you're pregnant.

If you're not already, start taking a prenatal vitamin with at least 400 micrograms of folic acid, and remember to take it daily. Here are some of the best prenatal vitamins.

You could also call your GP and let them know you’re pregnant. They’ll likely discuss arranging your booking appointment, which happens around week eight.

Begin the habit of going to bed early and napping when you can. Most women feel more worn out than they've ever felt before, and this is a great way to combat that fatigue.

Who knew we'd ever find cause to celebrate the rising number on a scale? Okay, maybe you aren't celebrating per say, but it is perhaps the one time in your life you should consider documenting your weight gain. Get creative! Give your baby book the perfect start with a record of your ever-expanding baby bump. 

Ways to Document Your Growth

  • Taking a profile picture each week. Use a small marker or poster board as a sign to hold, naming the week, to help you more easily distinguish between weeks. Make this photo record even more dramatic by taking pictures in the same location each week, perhaps framed by a doorway for visual reference to your changing waistline. If you're thinking weekly photo shoots aren't your cup of tea, one-a-month photos work, too!
  • Using written word! As often as you think it, document each little landmark in a journal, like when you make the switch to maternity clothing, or your belly button no longer claims its allegiance to the "innie" club, or your partner is at the helm of all leg shaving. These moments seem unforgettable, but in years to come, you'll treasure these tiny details.
  • Wrapping ribbon around your waist. Go to your local craft store and purchase a bag of baby-related (or any theme) charms. Each month, tie a charm at the precise point where it meets. As the charms accumulate, you'll have a tangible, charming reminder of this journey.

No matter how you choose to document your pregnancy journey, make sure you relish in the amazing changes that are taking place inside of you. Remember, each pound is helping to nourish and sustain that little life inside.

At a Glance

  • Implantation: Around 6-12 days after conception, expect light spotting as the blastocyst attaches to the uterine wall.
  • Ready, Set, Grow: Currently no bigger than the tip of a needle, but growing rapidly over the next nine months.
  • Pumping Blood: Blood is now beginning to circulate and help with the development of their tiny heart.
  • Symptoms Incoming: You may not feel pregnancy symptoms yet, but expect them to start in the next few weeks.
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Louise Broadbridge

Expert Midwife

Hi, my name is Louise, I am a registered senior midwife, founder of Let's Talk Birth and Baby antenatal classes and the face behind instagram's The Honest Midwife. I have taught over 100,000 expectant parents since starting my antenatal classes which have 5* reviews.

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The information on the Your Baby Club website is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always discuss any health concerns with a qualified healthcare provider and carefully review all guidance that comes with any medications or supplements before taking.