3 Weeks of Pregnancy
Highlights this week
The two-week wait
If you're ready to be pregnant, the next weeks may feel like the longest of your life. You're in the so-called two-week wait (TWW), the interval between when you may have conceived and when you can get a positive pregnancy test. Home pregnancy tests are only accurate on (or after) the first day of your missed period, so hold off on taking one just yet.
Implantation
Your developing blastocyst has travelled down your fallopian tube to your uterus – and by the end of the week or the beginning of next, it may implant itself in the lush uterine lining. (Before it implants, the blastocyst sheds its clear outer shell in a process called "hatching"!) You probably won't be aware all this is happening, though some women experience mild implantation bleeding or implantation cramping.
Baby development at 3 weeks
Your developing baby is a tiny ball of several hundred cells that are multiplying and burrowing into the lining of your uterus. The cells in the middle will become the embryo. The cells on the outside will become the placenta, the pancake-shaped organ that delivers oxygen and nutrients to your baby and carries away waste.
Cells are multiplying
3 weeks pregnant body
Implantation
Connecting to you
Your baby-to-be is receiving oxygen and nutrients (and discarding waste) through a primitive circulation system made up of microscopic tunnels that connect to the blood vessels in your uterine wall. The placenta will eventually take over this task around the end of the first trimester.
The cells that will become the placenta are pumping out the pregnancy hormone hCG. It tells your ovaries to stop releasing eggs and keep producing progesterone, which prevents your uterus from shedding its lining – and its tiny passenger. Once there's enough hCG in your urine, you'll get a positive pregnancy test result.
Early pregnancy hormones
Amniotic fluid is beginning to collect within the amniotic sac. This fluid will cushion your baby in the weeks and months ahead, and it's what may eventually come gushing out of you if your water breaks before or during labor.
Amniotic fluid
Pregnancy symptoms during week 3
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When you're waiting to learn whether you're pregnant or not, or just finding out, it's normal to be anxious. If you're feeling stressed or worried, talk to your partner or a trusted friend. Or, try writing down everything that's bothering you. Journaling can improve your emotional well-being, mental clarity, and even physical health.
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Hot baths are okay during pregnancy as long as they aren't too hot. But avoid steam baths, hot tubs, and saunas. Elevated body temperature, especially early in pregnancy, has been associated with an increased risk of neural tube defects in babies.
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Eat pregnancy-friendly foods such as fruits and vegetables, low-mercury fish, and whole grains. Choose foods containing vitamin C (like strawberries, citrus fruits, bell peppers, and tomatoes), iron (like beef, poultry, soy products, and spinach), and calcium (like Greek yogurt, fortified cereal, and pasteurized cheese). For snack ideas, check out 10 of our favorite healthy snacks for expecting moms.
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While you're trying to conceive and once you get pregnant, experts recommend limiting caffeine to about one cup of coffee a day. It's important to watch your caffeine intake because having too much can affect your pregnancy and your baby. See how much caffeine is in different foods and drinks so you can stay under the recommended daily limit.
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If you need help quitting smoking, drinking, or taking drugs, talk to your healthcare provider and ask for a referral to a program or counselor.
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When pregnancy-related sleep problems hit in a few months, be ready for them. Create better habits around sleep and work on good sleep practices like establishing a regular bedtime routine and making your bedroom a sleep sanctuary.
Pregnancy checklist at 3 weeks pregnant
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Some women feel pregnant even before the test is positive, but most don't. If you have pregnancy symptoms this week, they may feel like PMS. But don't worry if you haven't felt anything different yet. Even at 5 weeks pregnant, only half of women feel pregnancy symptoms.
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The hormone progesterone relaxes muscles throughout your body, including in your digestive tract. These relaxed muscles slow down your digestion, which can lead to gas and bloating and create uncomfortable sensations in your gut. About half of pregnant women experience constipation at some point during their pregnancy. To keep things moving, stay hydrated and eat high-fiber foods like whole grains, fruits, and vegetables.
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Some women say their sore breasts in early pregnancy are like an exaggerated version of how they feel before a period. Your breasts may feel swollen, tender, or tingly – and your nipples may be extra sensitive and uncomfortable. Later in pregnancy, you may notice your nipples getting darker.
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You may have a bit of light bleeding (spotting) this week. This is implantation bleeding – it can happen around the time the fertilized egg implants in your uterus. It's a lot lighter than a typical period, and only lasts for one to three days. (If you have pain along with bleeding, call your healthcare provider immediately. This can be a sign of an ectopic pregnancy.)
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If you're charting your temperature, it should stay elevated this week. To keep track, use a basal body thermometer and take your temperature after you wake up in the morning, before you get out of bed.
