Week 12
Your baby’s first reflexes begin
Your baby's the size of a plum, and you're nearing the end of the first trimester.
Baby's size this week
About the size of
a lime
- Length
- 2.13 in (5.4 cm)
- Weight
- 14 g
About the size of a plum, with tiny reflexes starting to form.
Sophie reads you this week
A short note, out loud·1:07
What to expect in week 12
Your baby’s reflexes are kicking in. Tiny fingers curl and toes wiggle, though you won’t feel it yet. Their facial muscles are practicing movements, and they’re swallowing amniotic fluid, an early step in digestion.
Your body’s adjusting. The placenta is fully functional now, taking over hormone production to support your pregnancy. This shift can ease some early symptoms, like nausea, though fatigue might linger.
- Eyelids forming. Those tiny eyes are now covered by eyelids, which will stay shut for a while longer.
- Vocal cords developing. Your baby’s voice box is taking shape, though you won’t hear those cries for months.
- Bone marrow at work. It’s starting to produce white blood cells, a big step for your baby’s immune system.
You might feel a shift. For many, week 12 marks the start of the ‘honeymoon phase’ of pregnancy. Energy levels may rise, and the constant nausea could ease up, but everyone’s timeline is different.
Things to be aware of this week
Round ligament pain. As your uterus grows, you might feel a sharp tug or ache low in your belly. It’s normal, but mention it to your provider if it’s severe or persistent.
Skin changes. Hormones can make your skin act up, think dryness, oiliness, or even a pregnancy glow. Gentle skincare and moisturizer can help.
- Talk to your provider. If you notice any spotting, severe cramping, or unusual discharge, let them know right away.
- Heartburn starts. Your growing uterus can push stomach acid upward. Small, frequent meals and avoiding spicy food might help.
What might happen this week
Your first-trimester screening. If you haven’t already, this is the week many providers schedule a combined ultrasound and blood test to check for chromosomal abnormalities.
NT scan. Between weeks 11 and 14, you might have a nuchal translucency scan. This ultrasound measures the fluid at the back of your baby’s neck to assess risk for certain genetic conditions.
Every pregnancy is unique. Trust your instincts and ask questions.
- Schedule your NT scan
- Start thinking about prenatal vitamins with iron
- Discuss any symptoms with your provider
