4 weeks pregnant: when to test and who to see in Singapore

At 4 weeks pregnant, your baby is a ball of about a hundred cells. Some time in the second half of this week, about 12 days after fertilisation, it burrows into the lining of your womb, KKH's pregnancy planner explains. You've probably only just missed a period, so a home test may show a faint line, or nothing yet.

Nothing medical is due this week. You can test on the right day, keep up folic acid, and decide where your first antenatal visit will be. In Singapore that last choice decides whether your hospital care is subsidised, so sort it out before you book.

Why it says 4 weeks when you conceived 2 weeks ago

Pregnancy is counted from the first day of your last period. KKH's planner explains that week 1 starts on day 1 of that period and ovulation comes about two weeks later, so by the time your period is late you're already counted as about 4 weeks pregnant. Your due date is 40 weeks from that first day. Our due date calculator does the sum, and your dating scan can correct the date later if your baby measures differently.

Your baby at 4 weeks

Right now the pregnancy is a blastocyst, a ball of about a hundred cells. Before your body even registers the pregnancy, the blastocyst hatches out of the egg's outer covering, floats in the womb for several days, then burrows in, usually near the roof of the womb.

Once it's in, the cells split into two groups. One group becomes the placenta and the other becomes the embryo. The burrowing cells also start making hCG, the hormone a pregnancy test looks for. KKH says hCG roughly doubles every 36 to 48 hours in a normal pregnancy, which is why a test that's negative today can turn positive a few days later.

When a home test works best

KKH's advice is to test on the first day after your missed period, using the first urine of the morning, when hCG is most concentrated after the night. You can test as early as 6 days after ovulation, but the level may still be too low to show. If the test is negative and your period still hasn't come, test again in a few days. Our guide to when to take a pregnancy test covers false negatives, and early signs of pregnancy lists what else you might notice.

Symptoms are vague this early. KKH lists tiredness, light-headedness and light bleeding, sometimes with cramps, much like the days before a period.

What's due in Singapore this week

• Keep taking folic acid. KKH recommends it from the time you start trying until you're 12 weeks pregnant, because it lowers the risk of defects such as spina bifida. Our prenatal vitamins guide compares what's on the shelf.
• Choose public or private care. KKH says that if you think you're pregnant, you can contact a polyclinic, a family clinic or KKH to arrange a first appointment. MOH gives specialist outpatient subsidies to Singapore citizens and PRs referred by a polyclinic or a CHAS GP clinic, up to 70% for citizens and 25% for PRs. A private gynae can be booked directly; how to choose a gynae and the delivery cost calculator help you weigh the two.
• Stop smoking and drinking if you haven't already. KKH says there is no known safe amount of alcohol in pregnancy.

There's nothing to tell your employer yet. MOM's notice rule applies to the leave itself: at least 4 weeks before your Government-Paid Maternity Leave starts. The later weeks of this series cover it.

When to call the hospital now

KKH says light bleeding at this stage is usually harmless, but it can also be a sign of miscarriage or an ectopic pregnancy, so get advice if you're unsure. Get seen the same day for:

• bleeding with cramps or tummy pain
• severe pain low in your tummy
• dizziness or feeling faint
• chest pain or shortness of breath

KKH's Urgent O&G Centre, at Basement 1 of the Women's Tower, takes walk-ins 24 hours a day for early pregnancy problems such as pain and bleeding. Under 16 weeks, if the bleeding is minimal or the pain is mild, its Early Pregnancy Assessment Unit can see you the same or next working day by appointment. If you're booked with another hospital, call its O&G clinic or go to its emergency department.

Frequently asked questions

Can I be 4 weeks pregnant and get a negative test?

Yes. hCG can still be too low for a home kit at 4 weeks. KKH suggests testing from the first day after a missed period with your first morning urine. A blood test at a clinic is more accurate and measures the actual level.

4 weeks pregnant is how many months?

About one month, counted from the first day of your last period. KKH's planner marks the 2-month point at week 8.

Do I need to see a doctor at 4 weeks pregnant?

Not urgently, unless you have pain or bleeding. KKH says some doctors like to see you at 7 to 8 weeks, and HealthHub says the dating scan can be done anytime from week 6 to 12. Booking now gets you a slot in that window.

Is cramping normal at 4 weeks pregnant?

Light bleeding with some cramping can happen and is usually harmless, KKH says. Severe pain, or bleeding that keeps going, needs to be checked the same day.

Week by week. Next week: 5 weeks pregnant. Every week from 4 to 40: pregnancy week by week.