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Pregnancy

Pregnancy Week 12: End of the First Trimester

Babysential TeamMarch 27, 20265 min read
pregnancy week 12end of first trimestermiscarriage riskpregnancy milestone
Pregnancy Week 12: End of the First Trimester

Congratulations, you have reached the end of the first trimester. This is a significant milestone. The risk of miscarriage drops to about 2% after a healthy 12-week scan. Many people choose this moment to share their pregnancy news with family and friends. Use our Due Date Calculator to track your timeline.

Key Takeaways

  • At 12 weeks, your baby is about 5.5 cm long (the size of a plum) and weighs roughly 14 grams
  • Miscarriage risk drops to approximately 2% after a healthy 12-week scan — a major milestone
  • The placenta is now fully functional and takes over hormone production from the ovaries
  • The intestines, which grew temporarily outside the body, have moved back inside the abdomen
  • Morning sickness typically begins to fade after this week as energy starts to return

Your Baby This Week

Size: Plum (about 5.5 cm, or 2.1 inches)

Weight: About 14 grams

  • Reflexes: The fetus can now respond to touch. If you poke your belly, the fetus will move away, though you cannot feel it yet.
  • Face: Fully formed with a profile visible on ultrasound. Eyelids are fused shut and will remain closed until around week 26.
  • Digestive system: The intestines, which temporarily grew outside the body into the umbilical cord, have now moved back inside the abdomen.
  • Bone marrow: Starting to produce white blood cells
  • Vocal cords: Forming in the larynx
  • Placenta: Fully functional and taking over hormone production from the ovary

Track your baby's growth with our Milestone Tracker.

Your Body

  • Morning sickness typically begins to fade after this week
  • Energy returning as the placenta takes over hormone production
  • Small baby bump may start to appear, especially if this is not your first pregnancy
  • Reduced breast tenderness for some
  • Linea nigra: A dark line may appear down the center of your abdomen

Your uterus has risen above the pelvic bone, and your provider can now feel it by pressing on your lower abdomen.

What to Do This Week

  • Decide when and how to share the news. Many people feel ready now that the highest-risk period has passed.
  • Review your 12-week scan results with your provider. This ultrasound confirms the due date, checks for twins, and assesses fetal anatomy. See our Prenatal Testing & NIPT Guide for a full breakdown of first trimester screening.
  • Start thinking about prenatal classes. Popular ones fill up quickly. Options include hospital-based classes, Lamaze, hypnobirthing, and online courses.

Common Questions

How much should I have gained by now?

Weight gain in the first trimester is typically modest: 0.5 to 2 kg (1 to 4.5 pounds). Some people lose weight due to morning sickness, which is fine as long as you are staying hydrated and keeping some food down. Your provider will track your weight at each visit.

When will I start showing?

First-time parents often start showing between weeks 12 and 16. If you have been pregnant before, the abdominal muscles are more relaxed, so you may show earlier. Body type, uterus position, and whether you are carrying multiples all play a role.

FAQ

What happens at 12 weeks pregnant?

At 12 weeks, the first trimester ends. The fetus has all major organs in place. The placenta becomes fully functional, vocal cords begin forming in the larynx, and the intestines complete their move back inside the abdomen. The 12-week scan confirms your due date and checks fetal anatomy.

Is 12 weeks a safe milestone in pregnancy?

Yes. After a healthy 12-week ultrasound, the risk of miscarriage drops to around 2%, down from about 10-15% in the early weeks. This is why many people choose week 12 to share their pregnancy news publicly.

What does the 12-week scan check?

The 12-week scan (or dating scan) confirms the gestational age, checks for twins, and assesses early fetal anatomy including the brain, spine, and limbs. Combined with blood tests, it screens for chromosomal conditions such as Down syndrome (trisomy 21).

How much weight should I have gained by 12 weeks?

Weight gain in the first trimester is typically modest: 0.5 to 2 kg (1 to 4.5 pounds). Some people lose weight due to morning sickness, which is normal as long as you stay hydrated. Most weight gain happens in the second and third trimesters.

Can I travel after 12 weeks pregnant?

The second trimester (starting at 13 weeks) is generally the safest and most comfortable time to travel. Most airlines allow flying until 36 weeks, though policies vary. Always check with your airline and carry your prenatal records.

Sources

🔧 Helpful Tools

Sources & Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider for personalized guidance regarding your or your child's health.

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