What happens in the first 3 weeks of pregnancy?
Congratulations, mummies! Your day is here. But are you worried and confused about what’s happening in the initial weeks? Here is your guide to pregnancy weeks 1-3.

Weeks 1-3: How Big Is Your Baby?
At weeks 1-2, your baby is just a twinkle in your eye because you aren’t actually pregnant yet. By week 3, your embryo is finally there, but really tiny—slightly smaller than a poppy seed!

Your Baby’s Development In Weeks 1-3
During weeks 1-2, you aren’t pregnant but your body is preparing for ovulation and your uterus is getting ready for the arrival of a fertilised egg.
By week 3, things are starting to happen! Your fertilised egg is now moving towards your womb, along the fallopian tube.
By the time your egg reaches the womb, it will become a mass of over 100 cells and will be now called an embryo. Once in your womb, your little embryo burrows into the lining of your uterus in a process known as implantation.
You probably won’t know until the 10th to 20th week, but the sex of your baby is determined at the moment of fertilisation.
Meanwhile, just after the egg is released, the follicle it came from gets a new tenant called the corpus luteum, a yellowish body of cells that occupies the space left by the egg, according to BabyCenter. The corpus luteum will produce enough pregnancy hormones, progesterone and estrogen to nourish and support your baby until the placenta takes over around the 10th week.

You’re not officially pregnant during weeks 1-2, and you’ve started your last period. So it will take a couple of weeks until you can confirm the news with a pregnancy test. During these weeks, you’re shedding the lining of your uterus along with last month’s unfertilised egg and you are getting ready for the starting point of your pregnancy.
Pregnancy Symptoms In Weeks 1-3
It may be too early to confirm through a pregnancy test, and there will be no visible physical changes in your body yet, but you may already be experiencing some early signs that you are indeed pregnant.
- Once your period is over, you may notice your cervical mucus changes in consistency and colour—it goes from thick, sticky and creamy, to thin, gooey and increased in volume as the right time for conception approaches.
- Towards the end of week 3 as your embryo implants in your uterine lining, you may notice a tiny bit of spotting, known as “implantation bleeding.”
- You may notice your breasts are tender and swollen, slightly more exaggerated than how they feel before your period.
- Some women feel mild cramps in their abdomen that can be mistaken for the post-menstrual syndrome (PMS), but it’s actually an early sign of pregnancy.
- You may feel more tired than usual.
- You have a weird, metallic taste in your mouth (don’t worry, this fades during the 2nd trimester)
- Your sense of smell may be heightened—don’t be surprised if your favourite perfume suddenly doesn’t smell so good!
- If you’ve been charting your basal body temperature (your temperature at full rest) you may notice that it stays high.
- Increased sex drive is also an early sign of pregnancy.
- Some very sensitive home pregnancy tests may show up as positive if you test during this time.
ALSO READ:
How to Spot the Early Signs of Pregnancy
Have Symptoms But Pregnancy Test Is Negative? Here’s Why This Happens!
Brown Discharge During First Trimester: What’s Normal And What’s Not?
Pregnancy Care: Your Checklist for Weeks 1-3
- If you haven’t started on a prenatal vitamin already, now is a good time to begin.
- Also, give up smoking and alcohol, eat a healthy diet, and drink at least six to eight glasses of water a day.
- To ensure the healthy development of your yet-to-be conceived baby’s brain and spinal cord, start taking 400 micrograms of folic acid daily.
- You may want to cut down on your coffee intake, as caffeine can have a negative impact on fertility.
- It’s not too early to take prenatal vitamins that will provide essential nutrients for you and your baby. As soon as you suspect you’re pregnant, or if you are trying to conceive, ask your doctor if you can get started on prenatal vitamins. Make sure it contains iron, vitamin D, calcium, and folic acid to reduce your baby’s risk of certain birth defects.
- Check that your chickenpox and rubella vaccinations are up-to-date well in advance. If not, your doctor may advise you to get these vaccinations before you become pregnant.
- If you haven’t scheduled a preconception doctor’s appointment yet, now’s the time to do it. You will learn about some lifestyle, genetic, and environmental hazards that may have an impact on your fertility and baby.
- Until you’ve confirmed whether you’re pregnant or not, it’s best to steer clear of smoking, illegal drugs and alcohol, as well as strenuous exercises that may put your pregnancy and your baby at risk.
- Whether you are taking herbal, prescription, or over-the-counter medications, check with your doctor that they are safe to take during this period of trying to conceive and very early pregnancy.

Here at theAsianparent Singapore, it’s important for us to give information that is correct, significant, and timely. But this doesn’t serve as an alternative for medical advice or medical treatment. theAsianparent Singapore is not responsible for those that would choose to drink medicines based on information from our website. If you have any doubts, we recommend consulting your doctor for clearer information.
