11 weeks pregnant: your first trimester screening window

At 11 weeks pregnant your baby averages 4.1cm from crown to rump, KKH says, bigger than any Singapore coin. For many women the waves of nausea and vomiting should be coming to an end. If you've decided on first trimester screening, book it now: the scan window opens this week.

Your baby at 11 weeks

Your baby's body is straightening and the genitals are starting to develop. It's still too early to tell boy or girl. KKH says the sex is hard to see accurately until after 20 weeks, though a specialist may catch a glimpse earlier if it's a boy and the baby lies the right way.

Head growth slows compared with the body, the reverse of the past few weeks. KKH's planner notes that growth in length is fastest in months 3 to 5, and weight gain dominates the last two months.

First trimester screening: what happens

First trimester screening (FTS) has two parts, which a computer combines with your age to give a risk figure, KKH explains:

1. An ultrasound between 11 weeks and 13 weeks 6 days, while your baby measures 45 to 84mm. It measures the nuchal translucency, the fluid at the back of the neck, checks the nose bone, and looks for major structural problems such as heart defects. It's usually done through your tummy.
2. A blood test for two proteins, PAPP-A and hCG, done between 9 weeks and 13 weeks 6 days.

On its own, the nuchal translucency measurement picks up about 80% of babies with Down syndrome; with the blood test, about 90%. A result higher than 1 in 300 counts as increased risk. It's a chance, and only a diagnostic test can say for sure. KKH's example: of ten pregnancies with a 1 in 10 result, one baby has Down syndrome and nine don't. If your baby is under 45mm on the day, KKH gives you another scan date; if over 84mm, it discusses other screening.

If your result comes back high, the next step is a choice between NIPT and a diagnostic test, CVS or amniocentesis. Our 9 weeks pregnant guide compares all four.

Week 11 at a glance

Nausea easing means your appetite may come back. Our guide to eating well in pregnancy covers what to eat more of in Singapore.

Headaches: when to worry

Low-grade headaches can carry on through pregnancy, KKH says. Paracetamol is safe, along with plenty of water and enough sleep. See your doctor immediately if a headache keeps getting worse despite paracetamol, or comes with blurred vision, sluggish reflexes or feeling generally unwell.

Other reasons to go in today: bleeding, tummy pain, fluid leaking, chest pain, fainting or breathlessness.

At KKH, early pregnancy problems such as bleeding and tummy pain go to the Urgent O&G Centre, a 24-hour walk-in centre at Basement 1 of the Women's Tower. For minimal bleeding or mild pain under 16 weeks, KKH's Early Pregnancy Assessment Unit offers appointments the same or next working day. Booked elsewhere? Call that hospital's O&G clinic, or go to its emergency department after hours.

Frequently asked questions

Is first trimester screening painful?

The scan is usually done through your tummy, KKH says, and the blood test is an ordinary blood draw.

What does a 1 in 300 result mean?

KKH counts any result higher than 1 in 300 as increased risk. It means further testing is worth considering, not that your baby has Down syndrome.

11 weeks pregnant is how many months?

About two and three quarter months, counted from the first day of your last period.

When can I find out if it's a boy or a girl?

Usually at the anomaly scan around 18 to 20 weeks, HealthXchange says, though it isn't guaranteed.

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