pregnancy week 13
13 weeks pregnant.
Welcome to the second trimester. Your baby has unique fingerprints and can already make tiny facial expressions.
Updated 29 July 2026 · Sources: NHS and ACOG
Your baby this week
Proportions are evening out — the head is now about a third of the body length. Skin is still translucent so blood vessels show through.
- Fingerprints form
- Second trimester begins
- Facial expressions practice
- Intestines move from cord to belly
What may be changing in your body
Energy returns for many people. You may start to show a small bump. Increased blood flow can give skin a glowing look (the 'pregnancy glow' is real).
The second-trimester lift
Many people cross into this trimester feeling dramatically better — more energy, less nausea, steadier moods. It is often called the honeymoon phase of pregnancy for good reason.
Increased discharge
Thin, milky discharge tends to increase through the second trimester and is protective. Only itching, soreness, a green tint or strong odour needs a doctor's opinion.
Round ligament pain
Sharp, brief pulling on one or both sides of the lower belly when you stand, twist or sneeze is the uterus's support ligaments stretching. Moving more slowly into position changes usually prevents it.
Visible bump emerging
The uterus is now above the pelvic brim and a genuine bump may be appearing. First pregnancies often stay subtle a few weeks longer.
Returning libido
With nausea fading and blood flow increased, many people find desire returns in the second trimester. Sex in a normal pregnancy is safe throughout.
Nosebleeds
Swollen, blood-rich nasal vessels burst more easily now. Lean forward and pinch the soft part of the nose for ten minutes; frequent heavy nosebleeds are worth mentioning at your next appointment.
Your week 13 checklist
- Book the anomaly (20-week) scan if your service has not scheduled it automatically
- Start researching antenatal classes and put your name down — spots fill early
- Establish a sleep set-up you can grow into: side-sleeping habit, extra pillows
- If you have not told work yet, plan the conversation — flexibility for appointments starts once they know
A useful partner move this week
As her energy returns, this trimester is your practical window: plan the bigger jobs like sorting the nursery room, researching prams, or booking a trip while travel is still comfortable. Sign yourselves up for antenatal classes together now rather than at week 28 when they are full. And if her libido returns, let intimacy find its way back naturally — reassurance that you find her attractive matters more than you might guess.
What comes next
Movement may be felt for the first time between weeks 16–22, called quickening. Each person feels it on a slightly different timeline.
Common questions
When does the second trimester officially start?
Definitions vary slightly, but most providers count the second trimester from the start of week 13 or 14 and running to the end of week 27. The exact boundary matters less than the pattern: for most people, this is the most comfortable stretch of pregnancy. Energy, appetite and mood commonly improve from here.
Is it safe to sleep on my back at 13 weeks?
At 13 weeks, yes — the uterus is not yet heavy enough to compress the major blood vessels that run behind it. The advice to settle on your side applies from around 28 weeks, when back-sleeping is linked to a small increase in stillbirth risk. Building the side-sleeping habit now, with a pillow between your knees, makes the later transition effortless.
Why do I feel pulling pains in my lower belly when I stand up?
That is almost certainly round ligament pain — the two ligaments anchoring the uterus stretch as it grows, and sudden movements tug them sharply. It is brief, one- or two-sided, and provoked by standing, twisting, coughing or laughing. Pain that is constant, severe, or paired with bleeding or fever is a different matter: call your midwife or doctor.
How many months is 13 weeks pregnant?
Pregnancy months do not divide evenly into weeks, so clinicians date pregnancy in weeks. At 13 weeks, you are in trimester one.