4 weeks pregnant
At 4 weeks pregnant, your baby is about the size of a poppy seed: under 1 cm long and lighter than 1 g. A tiny ball of cells is settling into the lining of your womb. The placenta is beginning to form.
Your baby at 4 weeks
A tiny ball of cells is settling into the lining of your womb. The placenta is beginning to form.
| Size | About the size of a poppy seed |
|---|---|
| Length | under 1 cm crown to rump |
| Weight | under 1 g |
Around now the fertilised egg, called a blastocyst, finishes burrowing into the lining of your womb. Its outer cells start to form the placenta and begin making hCG, the hormone a pregnancy test picks up. The inner cells will become your baby. A tiny yolk sac forms too; it feeds the embryo until the placenta takes over later in the first trimester.
How far along are you at 4 weeks?
At 4 weeks pregnant you are in the first month of your pregnancy and the first trimester. You have about 36 weeks to go until your due date. Doctors count pregnancy from the first day of your last period, not from conception, so at 4 weeks your baby has been growing for about 2 weeks. Not sure of your dates? Use our due date calculator.
Your body at 4 weeks
You may notice a missed period, tender breasts and tiredness that hits hard. Take folic acid daily and book your first appointment.
Common symptoms at 4 weeks
Every pregnancy is different, and you may have some, all or none of these.
- A missed period. Often the first clue. If your cycle is irregular, it may take a little longer to notice.
- Light spotting. Some women have a little pink or brown spotting as the egg implants. It is lighter than a period and lasts a day or two.
- Sore, fuller breasts. Rising hormones make breasts tender and heavy, a lot like before a period.
- Tiredness. Progesterone can make you feel unusually sleepy, even this early.
- Mild cramps. A dull, period-like ache low down is common as the womb lining changes.
- Needing to wee more. Blood flow to your kidneys increases from early pregnancy.
Your checklist for week 4
- Take a home pregnancy test, ideally with your first wee of the morning when hCG is most concentrated.
- Take folic acid, 400 micrograms a day, until 12 weeks. Ask your doctor about a higher 5 mg dose if you have diabetes, a BMI over 30, take epilepsy medicine or have a family history of spina bifida.
- Take vitamin D, 10 micrograms (400 IU) a day. Low vitamin D is very common in the Gulf and South Asia, even with lots of sun.
- Stop smoking and alcohol, and check every medicine or supplement you take with a pharmacist or doctor.
- Call your clinic or GP to book your first pregnancy appointment.
Tip of the week: Watch your caffeine
Keep caffeine under 200 mg a day. A mug of instant coffee has about 100 mg, a mug of filter coffee about 140 mg and a mug of tea about 75 mg. Strong, long-brewed karak or doodh patti can be higher, so two small cups a day is a sensible limit. Energy drinks are best avoided altogether.
For your partner
She may feel exhausted long before anything shows.
- Take over cooking if smells bother her
- Keep the news private until she's ready
- Go with her to the first appointment
When to call your doctor at 4 weeks
Contact your doctor, midwife or maternity unit the same day if you have:
- Pain on one side of your lower tummy, pain in the tip of your shoulder, or feeling faint. These can be signs of an ectopic pregnancy, where the pregnancy grows outside the womb.
- Bleeding that is heavy, like a period, especially with cramping.
Call your doctor or hospital straight away for bleeding, severe pain, fluid leaking, severe headache or vision changes.
Questions about 4 weeks pregnant
Can a pregnancy test be positive at 4 weeks?
Yes. At 4 weeks you are around the day your period is due, and many home tests can detect hCG by then. If your test is negative but your period still hasn't come, test again in two or three days. hCG roughly doubles every two to three days in early pregnancy.
Is cramping normal at 4 weeks pregnant?
Mild, period-like cramping is common as the embryo implants and your womb starts to change. Cramping that is severe, one-sided, or comes with bleeding, shoulder pain or dizziness needs to be checked by a doctor straight away.
When will I have my first scan?
Most women have their first scan, the dating scan, between 11 and 14 weeks. You may be offered an earlier scan at 6 to 8 weeks if you have bleeding or pain, have had an ectopic pregnancy or miscarriage before, or conceived through IVF.