First trimester
12 weeks pregnant
A significant week. The fetus is around the size of a lime, miscarriage risk drops substantially, and for many people this is the point at which the pregnancy becomes public.
Size of
lime
Length
54 mm
Weight
14 g
Your baby at 12 weeks
Reflexes are developing. The fetus will curl its toes and open and close its fists, and may respond to pressure on the abdomen even though you cannot feel it.
Vocal cords are forming. The intestines, which developed partly inside the umbilical cord, move fully into the abdomen this week.
The kidneys are producing urine, and the fetus is swallowing and excreting amniotic fluid in a cycle that continues until birth.
How you may be feeling
Nausea has typically eased or resolved for most people by now, though a minority continue for considerably longer. Energy often improves noticeably.
The uterus has risen out of the pelvis and a bump may be starting to show, particularly by the end of the day. Many people find they are showing earlier than expected in second and later pregnancies.
Common symptoms around week 12
- Nausea resolving for most, and energy returning
- A visible bump beginning for some
- Dizziness, particularly on standing
- Increased vaginal discharge, which is normal if clear or milky and not itchy
- Headaches, which are common in pregnancy
Appointments and tests around now
The dating scan is typically offered around weeks 11 to 14 if not already done. This is the most accurate point for dating the pregnancy, and the date it gives takes precedence over any calculation from your last period.
What is normal, and what varies
There is no correct week to tell people. Many wait until after the 12-week scan, but telling earlier means having support if something goes wrong. It is entirely your decision.
Worth doing this week
Start sleeping on your side
Side-sleeping, particularly left, is generally recommended as pregnancy progresses. Building the habit now is easier than switching later when it matters more.
Get a maternity bra fitted
Breast size has usually changed substantially by now, and underwires can become uncomfortable as the ribcage expands.
Tell work when you are ready
Rights around leave and risk assessments usually depend on having notified your employer. Knowing your entitlements before the conversation helps.
Looking ahead
Next week begins the second trimester, widely regarded as the most comfortable stretch.
Nearby weeks
Not sure which week you are in? The week tracker works it out from the first day of your last period, and the due date calculator gives you an estimated due date.