3weeks
pregnant

Highlights this week

By the end of this week, you're likely to get a positive pregnancy test!

Your baby-to-be is implanting into the lining of your uterus.

You may have early pregnancy symptoms. (But many women don't.)

Baby development at 3 weeks

Your baby is just a tiny ball made of hundreds of constantly multiplying cells, and your body is going into overdrive to support it!

The cells that are developing into a placenta have started to produce the pregnancy hormone hCG (human chorionic gonadotropin). This hormone tells your ovaries to stop releasing eggs and boosts production of estrogen and progesterone, which stop your uterus (womb) from shedding its lining. HCG is also the hormone that turns a pregnancy test positive. By the end of this week you may be able to take one and get a positive result!

Meanwhile, amniotic fluid is beginning to form in the cavity that will become the amniotic sac. This fluid will cushion your baby in the weeks and months ahead. Right now, your little baby is receiving oxygen and nutrients from the wall of your uterus. By the end of next week, the placenta will have developed enough to take over this task.

blastocyst which will develop into embryo and placenta

Your baby at 3 weeks

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Implantation

Pregnancy symptoms at three weeks

You may start to notice that your bra is chafing or feeling uncomfortable. This is because pregnancy makes your breasts and nipples more sensitive. You may also notice a tingle or prickle in your breasts caused by extra blood flow.

Some women get food cravings early in their pregnancy. You may notice that your food preferences have changed, and that favourite foods and drinks are suddenly unappetizing. Aversions to tea, coffee, alcohol, fried food, and eggs are common among moms-to-be.

The pregnancy hormones may also be having an effect on you, so don't be surprised if you feel tired and weepy. During the day, you may feel exhausted and struggle to stay awake. This is because your body is preparing itself to support your baby.

Your body at 3 weeks

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How your life is changing

At three weeks of pregnancy, you may still be unsure if you are actually pregnant. It is difficult to tell when you conceived, which is why pregnancy is dated from the day of your last period.

The clearest sign that you are pregnant is a missed period. If your period is still a week or so away, it may be best to wait a little longer before taking a pregnancy test.

In the meantime, if you are feeling tired and emotional, treat yourself to some rest and relaxation. A warm (but not too warm!) bath with a few drops of essential oils will help you to unwind. Pamper yourself with some luxurious body lotion and light some scented candles to create a relaxed environment. If your partner is willing, you could also ask for a soothing massage to release tension.

What you need to know

Tiredness can be difficult to cope with. Get tips on how to cope with tiredness during pregnancy.
Still unsure that you are pregnant? Check out the top 10 signs of pregnancy.
Many moms experience morning sickness in early pregnancy. Find out when it starts.
Pregnancy tests: how soon is too soon?

Pregnancy Tip

"If you're feeling tired and need a nap, take it! Your body is creating a little human being, so don't feel guilty for needing some extra rest."
Simone

Four weeks pregnant

Sources

BabyCenter's editorial team is committed to providing the most helpful and trustworthy pregnancy and parenting information in the world. When creating and updating content, we rely on credible sources: respected health organizations, professional groups of doctors and other experts, and published studies in peer-reviewed journals. We believe you should always know the source of the information you're seeing. Learn more about our editorial and medical review policies.

Bailey J. 2014. Hormonal cycles: fertilization and early development. In: Marshal J and Raynor M. ed. Myles Textbook for Midwives. 16th ed. Edinburgh: Churchill Livingstone, 91-100

Brown HL. 2016. Conception and prenatal development. Professional version. www.merckmanuals.comOpens a new window [Accessed May 2018]

Cole LA. 2009. New discoveries on the biology and detection of human chorionic gonadotrophin. Reprod Biol Endocrinol7:8. www.ncbi.nlm.nih.govOpens a new window [Accessed June 2018]

Hill MA. 2018a. Embryology: week 2. University of New South Wales Embryology. embryology.med.unsw.edu.auOpens a new window [Accessed May 2018]

Hill MA. 2018b. Embryology: placenta development. University of New South Wales Embryology. embryology.med.unsw.edu.auOpens a new window [Accessed May 2018]

Moore KL, Persuad TVN and Torchia MG. 2016. The Developing Human: Clinically oriented embryology. 10th edition. Philadelphia: Elsevier, 64. mymedicallibrary.files.wordpress.comOpens a new window [Accessed May2018]

NHS. 2017. You and your baby at 0-8 weeks pregnant. NHS Choices, Health A-Z, pregnancy and baby. www.nhs.ukOpens a new window [Accessed May 2018]