Pregnancy: Week 4
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4 Weeks Pregnant

What to expect at 4 weeks pregnant? Week 4 marks the beginning of the embryonic period. From this point until week 10, all of your baby’s organs will begin to develop, and some will even start to function. It’s an exciting time in your life, but it’s important to remember that week 4 is also the time when your little one is the most vulnerable, and fetus development may be impacted by anything he/she interferes with. The embryo is now the size of a poppy seed, and it consists of two layers: the epiblast and hypoblast.

Pregnancy Symptoms at 4 Weeks

Pregnancy Symptoms at 4 WeeksPregnancy Symptoms at 4 Weeks

What to Expect:

Although you’re already one month pregnant, and the first one-third of the first trimester has now passed, you start “feeling” pregnant just now.

  • Stomach cramps may be present, and their intensity can range from mild to very painful.
  • Some light bleeding or spotting may be noticed — it is called breakthrough bleeding, and usually occurs due to hormone changes. Even if harmless, it’s a good idea to check with your ob-gyn to make sure that your baby is not at a risk.
  • During the fourth week of pregnancy, you may even start to feel a little queasy. That’s because morning sickness is setting in, and you will soon wake up feeling nauseated.
  • Some mommies-to-be experience severe vomiting along with persistent nausea, a condition known as hyperemesis gravidarum. If you can’t keep anything down, and you vomit everything you eat, see your doctor right away.
  • Fatigue is normal during this period, so don’t worry if you feel tired. Rest properly if needed, and avoid strenuous activities such as HIIT workouts, or lengthy exercising programs.

Your Baby at 4 Weeks

How big is a baby at 4 weeks? Your baby isn’t bigger than a poppy seed at this point. But there’s plenty going on inside your baby. The embryo is splitting into three different sections, one carrying different organs. In one section, the brain and central nervous system begin to form, with neural tubes starting to develop. In the other two sections, the heart and circulatory systems are developing, while the lungs and intestines are at very early stages of development.

4 weeks pregnant

The primitive placenta is also made up from two layers, with cells tunneling into the uterus to facilitate blood flow to the embryo. This ensures that the developed placenta will provide nutrients and oxygen to the baby when it starts to function at the end of week 4. During this time, the amniotic sac that houses your baby is present, filled with amniotic fluid that cushions him/her during the development process. The yolk sac is also present, producing the baby’s red blood cells and delivering essential nutrients until the placenta is fully developed and can take this task over.

Ultrasound Images of 4 Week Pregnancy


4 weeks pregnant fetus
Baby at 4 weeks pregnancy ultrasound image
4 weeks-pregnant ultrasound photos
4 weeks-pregnant fetal

Bellies at 4 Weeks


4 weeks pregnant with twins belly
4 weeks pregnant belly photo
4 weeks pregnant belly pictures
4 weeks pregnant belly

Pregnancy Tips

  • If you’re currently taking any form of medication, whether prescribed or over-the-counter, make sure to ask your doctor if it’s safe to continue taking them. Keep in mind that some drugs can interfere with your baby’s development, and since she’s the most vulnerable during week 4, this must be avoided at all costs.
  • If you haven’t already, you should start taking a multivitamin supplement that contains at least 400mcg of folic acid. If you’ve been taking it for some time already, you’ll need a bit more, so choose a supplement with at least 600mcg of folic acid.
  • Looking after your teeth is very important during week 4, specifically because moms-to-be are usually very prone to bleeding from gums while pregnant. Brush your teeth regularly, and floss every day to prevent plaque buildup.