4 Weeks Pregnant - Symptoms, Baby Development, Tips - Babylist

4 Weeks Pregnant

May 16, 2019

4 Weeks Pregnant

4 Weeks Pregnant
4 Weeks Pregnant

Your Baby at 4 Weeks

If you were to look at baby on an ultrasound at 4 weeks, you wouldn’t see much, but there’s actually a lot going on at this very early stage of your baby’s development. The fertilized egg has implanted into your uterus, and it’s quickly beginning to grow.

How Big is Your Baby?

Your baby is less than 0.05 inches long this week. That’s the size of a poppy seed.

Your Baby’s Development at 4 Weeks

  • Splitting in two: This week, the cells that will become your baby are turning from a blastocyst (which is basically a collection of cells) into your placenta and an embryo (which is a fertilized egg). To do that, it splits in two.
  • Prepping for development: Even though it’s a tiny dot of a thing that can barely be seen on an ultrasound, the gestational sac carries blueprints for your baby’s nose, toes and just about everything else hidden in their chromosomes.

4 Weeks Pregnant Ultrasound

Pregnancy Ultrasound Week 4

Photo by Tommy’s

Top Tip for 4 Weeks Pregnant

Add a prenatal vitamin with 600 mcg of folic acid to your daily routine (if you aren’t already taking one). Folic acid protects against birth defects and may even lower your kid’s blood pressure when they grow up. #preventativemedicine

4 Weeks Pregnant Symptoms

  • PMS vs. pregnancy symptoms: In those early days, many women find pregnancy symptoms tough to decipher from the typical PMS symptoms. After all, moodiness, fatigue, sore breasts, bloating and constipation can all be signs of PMS. But PMS eventually leads to a period and then goes away. Pregnancy symptoms linger—usually for the first trimester. Unsure? The only way to really know you’re pregnant is to take a pregnancy test
  • Missed period: It’s so early that you might not feel pregnant yet, but oh wait? Where’s Aunt Flo? Missing your period may be the first telltale sign of pregnancy and your motivation to take a pregnancy test.
  • Positive pregnancy test: Some home pregnancy tests are accurate at this point, but it could take another few days or even a week before you have enough hCG (a pregnancy hormone) in your urine for an at-home test to detect. If the at-home test was negative, you could schedule a blood test (which is super sensitive) at your doctor’s office or lab, or test again a few days later with another pee stick. If the at-home test was positive, you can feel pretty confident you’re pregnant.
  • Sore breasts: Before nausea, vomiting and extreme fatigue, what do many women notice? Sore or swollen boobs. It’s hard to believe that your body is already prepping for feeding a baby as early as 4 weeks but it is!
  • Fatigue: A pregnancy hormones surge and your body starts to produce more blood to nourish baby, you’re bound to feel more than a little tired. In fact, you may be downright exhausted.
  • Spotting: About 30% of women experience implantation bleeding when the embryo attaches to the wall of the uterus, so don’t be surprised if you have some light spotting. The bleeding tends to be a different color from a period.
  • Light cramps: Implantation cramps are also a thing. These mild aches should only stick around for a day or two.

Fun Fact

Four babies are born every second!

What Symptoms to Expect in the First Trimester

Not feeling symptoms yet? Brace yourself. The first trimester can be rough, as hormones surge and your body works hard to start making a baby.

Besides the sore boobs and fatigue, you might also experience these discomforts in the coming weeks:

  • Nausea and vomiting: About half of pregnant women get morning sickness (which really should be called all-day sickness); it usually crops up around week 6 and eases around week 12.
  • Food aversions: What goes hand-in-hand with the nausea? Getting grossed out by foods you used to love. You may find yourself majorly changing your eating habits.
  • Frequent urge to pee: Around 6 to 8 weeks, hormonal changes + extra blood flow causes kidneys to produce more urine than usual, so you might be heading to the bathroom a lot.
  • Constipation: A slow-down in your intestines can happen, and sometimes the iron in prenatal vitamins can stop you up. Load up on fiber and water, and try to stay physically active. Walks are your friend!
  • Mood swings: You’re tired, your metabolism is changing, you may be a bit stressed and hormones are wacky right now. It’s no wonder you cried at that Oreo commercial.

While these are all par for the pregnancy course, know that some pregnant women don’t get first trimester symptoms at all. Lack of symptoms doesn’t mean anything’s wrong—just that every pregnancy is different.

Partner Tip

The big news can be scary and exciting for both parties in different ways, so remember to be gentle with each other.

4 Weeks Baby Bumps from Real Moms


4-weeks-pregnant-bump-@faith in the wait








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Week 4 Pregnancy Checklist

  • Take four more home pregnancy tests. Just kidding! One’s enough.
  • Call your OB/GYN and make an appointment for your first prenatal visit, which will probably take place around week 8.
  • Whether you’ve been trying for months or this is a surprise, remember to take a deep breath. This is going to change everything, but that’s the point.
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