First trimester
13 weeks pregnant
The last week of the first trimester under most conventions. The fetus is around the size of a peapod, and the hardest physical stretch is usually behind you.
Size of
lemon
Length
74 mm
Weight
23 g
Your baby at 13 weeks
Fingerprints have formed, unique already. The fetus is developing more coordinated movements and may be seen on a scan bringing a hand toward its face.
Vocal cords are complete. Bones in the skull and long bones continue hardening, and the head is becoming more proportionate to the body.
If the fetus is female, ovaries already contain the full complement of egg cells they will ever have — a detail many people find striking.
How you may be feeling
Energy typically continues improving. Appetite often returns properly, and many people find this the first week in a while that feels manageable.
The uterus is now large enough that a bump is commonly visible. Round ligament pain, a sharp pull low in the abdomen when changing position quickly, often starts around now.
Common symptoms around week 13
- Energy and appetite improving
- Round ligament pain with sudden movement
- Visible bump for many
- Continued increased discharge
- Occasional heartburn as hormones relax the valve at the top of the stomach
Appointments and tests around now
If you have not had combined screening and want it, this is near the end of the window. Discuss with your provider promptly rather than assuming it can be arranged later.
What is normal, and what varies
Round ligament pain is sharp and can be alarming the first time. It is typically brief, triggered by movement, and eases when you change position. Constant pain is a different thing and worth reporting.
Worth doing this week
Move more gradually
Round ligament pain is usually provoked by sudden changes of position. Rolling rather than twisting out of bed makes a surprising difference.
Use the energy window
The second trimester is when most people feel best. If there are appointments, travel, or preparations to get through, this is the stretch to do them in.
Keep up gentle activity
Walking, swimming and prenatal classes are commonly recommended. Check with your provider about anything higher-impact.
Looking ahead
Next week opens the second trimester, with steadier growth and generally fewer symptoms.
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.