Pregnancy Week 4: Symptoms, Tests and Baby Size
Pregnancy week 4 is one of the most exciting (and most confusing) ones: you’ve probably just noticed a missed period or you’re starting to feel a few strange things, and your whole body is telling you something big is happening. Let me explain what goes on this week, when to take the test and which symptoms are most common ❤️.
What is pregnancy week 4?
Pregnancy weeks are counted from the first day of your last menstrual period (your LMP), not from conception. That means in pregnancy week 4 you’re about 2 weeks past fertilisation, and it’s exactly the time when the embryo reaches the uterus and implants in its wall.
It’s the earliest stage of pregnancy, within the first trimester. In fact, most women don’t know they’re pregnant yet: the missed period usually appears at the end of this week or the next.
When can I take a pregnancy test?
This is the big question, and the answer has a catch. Your body starts producing the hCG hormone (the one tests detect) as soon as the embryo implants, around week 4. But the levels are still very low.
My advice is clear: wait until the first day of your missed period. If you test too early, you can get a false negative and an unnecessary disappointment. If you want to get ahead, blood tests (beta-hCG) can detect a pregnancy earlier, from about 10-12 days after conception.
And if you don’t want to wait with a box in your hands, you can take our free online pregnancy test to get some guidance from your symptoms. And if you fancy a bit of fun, try your luck with our fun fingerprint game — it’s just a game, not a real test. To know exactly how many weeks you are, use the how many weeks pregnant am I guide.
Which symptoms are normal in week 4?
Every pregnancy is different, and many women feel absolutely nothing in week 4. But if you’re paying attention, these are the most typical signs:
- A missed period: the most reliable sign (and the one that brought you here).
- Tender or swollen breasts: one of the first symptoms, caused by rising progesterone.
- Unexplained tiredness: your body is working at full speed, even if it doesn’t show.
- Light implantation bleeding: a few pink or brown drops around day 21-24 of your cycle. Not everyone has it.
- Frequent urination and some mild cramps in the lower belly, similar to period cramps.
- Mood swings and greater sensitivity to smells.
Feeling bloated or having period-like twinges? It’s completely normal: your uterus is starting to expand. If the pain is strong or one-sided and worries you, mention it to your doctor.
How big is the baby in week 4?
The embryo in week 4 measures about 1 to 2 millimetres: the size of a poppy seed. It’s still a group of cells getting organised, but the ones that will become the placenta and the baby himself are already taking shape.
During this week the gestational sac forms, which is what the gynaecologist will be able to see on an ultrasound soon (usually from week 5-6). So even though nothing is visible now, there’s a lot going on inside.
Tips for week 4
- Start (or keep taking) your folic acid if you haven’t already. It’s essential for your baby’s neural tube development, and I tell you all about it in my article on folic acid in pregnancy.
- Look after your diet and avoid alcohol and tobacco from now on.
- Don’t obsess over symptoms: feeling nothing is also normal.
- Book an appointment with your gynaecologist for the first check-up. The first ultrasound is usually done between week 6 and 8.
- If you haven’t yet, you can calculate your estimated due date with the gestogram, although the most reliable one will come from your doctor.
Frequently asked questions
Is it normal to have no symptoms in week 4?
Yes, absolutely. Many women feel nothing in these early weeks and the pregnancy progresses perfectly. The absence of symptoms doesn’t mean something is wrong.
Can I take a test in week 4?
You can, but it’s better to wait for the first day of your missed period. In week 4 the hCG levels are still low and the risk of a false negative is high. If it’s negative but you still have symptoms or a missed period, repeat the test a few days later.
Is implantation bleeding normal?
Yes. A few pink or brown drops around week 4 are normal and shouldn’t be confused with a period: they’re usually lighter and shorter. If the bleeding is heavy, consult your doctor.
How big is the baby in week 4?
The embryo measures between 1 and 2 millimetres, about the size of a poppy seed. The baby’s shape isn’t distinguishable on an ultrasound yet.
When can a pregnancy be seen on an ultrasound?
The gestational sac usually shows up from week 5-6, and the embryo’s heartbeat around week 6-7. The first recommended ultrasound is usually between week 6 and 8.
Remember this article is for information only. If you have any questions about your health or think you might be pregnant, consult your doctor. He or she can guide you with the right tests and support you in this very special moment ❤️.
