12 weeks pregnant
First trimester about 2 months
At 12 weeks pregnant, your baby is about the size of a lime.
Baby this week
About 55mm. The fetus is now fully formed and looks recognizably human. Reflexes are developing and the face can make expressions. This is the end of the first trimester.
Did you know? By week 12, the fetus's kidneys are producing urine, which becomes part of the amniotic fluid — a cycle that continues for the rest of pregnancy.
What she may be feeling
- Nausea fading for most
- Energy returning
- Round ligament pain
- Increased appetite
- Visible bump
- Skin and hair changes
- Mild heartburn
- Leg cramps
Tips for her this week
- Congratulations on reaching the end of the first trimester — the hardest stretch is behind you.
- Nausea typically fades significantly this week for most people.
- Energy should start returning — enjoy it when it does.
- A nuchal translucency ultrasound may be done around now to screen for chromosomal conditions.
For partners
- The end of the first trimester is a major milestone — celebrate it meaningfully.
- Share the news widely if that's your plan — this is the traditional 'safe' announcement week.
- The risk of miscarriage drops to below 1% from here. Take a breath.
- Now is a great time to book a birthing class — they fill up months in advance.
Partner to-do list
- Make the pregnancy announcement — you've earned it
- Book a birthing class now (they fill up fast)
- Plan something special to celebrate the end of T1
- Look into baby gear: car seat, crib, monitor — research takes time
This week together
- Make the pregnancy announcement
- Book a birthing class
- Start the nursery planning in earnest
- Create a baby registry (or at least start a list)
When to call your doctor or midwife
Contact your care provider right away, or call emergency services, if she has:
- Heavy bleeding
- Severe cramping
- Fever
- Signs of UTI: painful urination, urgency, pressure
Trusted guidance: NHS: Pregnancy · NHS: Pregnancy complications · ACOG: Pregnancy · Pregnancy Info: Your pregnancy
Common questions
How big is the baby at 12 weeks?
At 12 weeks pregnant, your baby is about the size of a lime. About 55mm.
How many months is 12 weeks pregnant?
12 weeks pregnant is about 2 months, in the first trimester.
What can partners do at 12 weeks?
The end of the first trimester is a major milestone — celebrate it meaningfully. Share the news widely if that's your plan — this is the traditional 'safe' announcement week.