You and Your Baby at Week 4 of Your Pregnancy

Your baby is the size of a poppy seed!

(10 minute read)

Article at a glance

  • 4 weeks pregnant
  • The baby's development at week 4
  • Pregnancy symptoms at week 4
  • Tips for a healthy pregnancy at week 4

4 Weeks Pregnant

Week4: baby the size of a poppy seed

At week 4, the embryo has now reached your uterus, where it can start developing into your baby. This is the very beginning of your pregnancy!

Many women may not even realise that they're pregnant until week 4. This period, which continues the implantation process started in week 3, is the first stage of your baby's development. Understanding the changes occurring in your body and how your baby grows and develops over the next 9-ish months will really help you to navigate your pregnancy and associated symptoms.

How Big is Baby at 4 Weeks?

At week 4, your baby is in the beginning stages of development. The embryo is tiny, roughly the size of a poppy seed, measuring about 0.04 inches (1 mm) in length. Despite its minuscule size, the foundation for its major organs and systems is being laid. You may feel very tired at this stage while your body works to support your baby's rapid growth.

The Baby's Development at Week 4

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While the baby is only the size of a poppy seed, your body is already adjusting to pregnancy.

Hormonal Changes: The increase in pregnancy hormones like human chorionic gonadotropin (hCG) and progesterone starts to affect your body. You could feel tired, emotional or nauseous. Be sure to rest up, take care of yourself and tell your employer so they can support you during this time. There is no obligation to share your news with your employer at this stage but it may help with taking time to rest if needed.

Uterine Changes: Your uterus is preparing to support the growth of your baby for the next nine months. You may have a need to go to the toilet often. Many women report needing to wee on a regular basis, but the amount that actually comes out is minimal (some liken it to feeling like you need to wee like an elephant, but the reality is more like a hamster wee!).

Blood Volume Increase: There's a slight increase in blood volume to support the developing embryo. This can make you feel hot and tired. Again, rest if you need to.

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Pregnancy Symptoms at Week 4

At four weeks, some women may not experience any symptoms, while others may start noticing changes. Common symptoms include:

Missed or Lighter Period: This is often the first sign of pregnancy, especially if your period is pretty regular!

Breast Changes: Due to hormonal changes, your breasts may feel tender or swollen. To make yourself more comfortable, try wearing a non-wired bra or crop top.

Mild Cramping and Spotting: Light spotting and cramping can occur due to implantation. Some women mistake this for their period, and this is why pregnancy can be missed at week 4.

Fatigue: Increased progesterone levels can make you feel unusually tired. Rest as much as you need! Your body is working overtime to support your growing baby.

Nausea: Some women may start experiencing morning sickness, though it's more common in later weeks. Morning sickness can also happen all day - every body and every pregnancy is different.

Heightened Sense of Smell: Many women report a heightened sense of smell, which can lead to food aversions or cravings. This symptom can be amazing - you may find you can smell food and drink when you're nowhere near it's being served!

If you're not experiencing any symptoms, then know that this can be entirely normal. If you're ever worried, then book an appointment with your GP.

Tips for a Healthy Pregnancy at Week 4

  1. Prenatal Care: Schedule your first prenatal appointment. Remember that it's down to you to tell your GP that you're pregnant but it's then down to your GP to refer you. Your first appointment will be a booking appointment, and after this, you should be booked for your 12-week scan.
  2. Healthy Diet: You may not feel up to it but try as best you can to eat a healthy balanced diet. If you're struggling with sickness, then speak to your GP.
  3. Stay Hydrated: Drink plenty of water to stay hydrated - drink to thirst, as you normally would before pregnancy.
  4. Avoid Harmful Substances: Refrain from alcohol, tobacco, and drugs. Limit caffeine intake.
  5. Rest: Get plenty of rest and sleep to support your body's increased demands.

Week 4 is a period of significant but invisible changes. Your baby, though just the size of a poppy seed, is rapidly developing, and your body is preparing to nurture this new life for the months to come. Paying attention to your health and well-being during this time is vital for a healthy pregnancy.


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