Week 12 of Pregnancy
Learn about your baby's development and what to expect at 12 weeks pregnant.
Baby's Size This Week
Baby Development at Week 12
- ● Your baby is about 5.4 cm from crown to rump and weighs around 14g — roughly the size of a plum.
- ● The kidneys are beginning to produce urine, which will become the primary component of amniotic fluid from now on.
- ● Reflexes are developing rapidly — your baby can now open and close fingers, curl toes, and make coordinated sucking movements.
- ● The intestines that were growing in the umbilical cord are moving back into the abdominal cavity as space increases.
- ● Vocal cords are forming in the larynx, and the pituitary gland at the base of the brain is producing hormones.
- ● Sex organs are becoming more distinct as differentiation accelerates, though sex is still difficult to confirm on ultrasound.
Your Body at Week 12
- ● Morning sickness typically begins to fade by the end of week 12 for most women as hCG levels stabilize.
- ● The risk of miscarriage drops significantly after 12 weeks with a confirmed heartbeat — to about 2-3%.
- ● Your uterus has grown enough to begin rising above the pelvic bone, and a small baby bump may be newly visible.
- ● Heartburn may begin as the growing uterus pushes on the stomach and progesterone relaxes the esophageal sphincter.
- ● Skin changes like darkening of freckles, moles, and the linea nigra (line from navel to pubic bone) may appear.
- ● Appetite begins to return as nausea subsides, making it easier to focus on a nutritious, balanced diet.
Week 12 Checklist
- ☐ Complete first-trimester screening (nuchal translucency ultrasound and combined blood tests) if recommended.
- ☐ Consider sharing your pregnancy news with family, friends, and your employer now that risk is significantly lower.
- ☐ Update your diet to include iron-rich foods (lean meat, spinach, lentils) as blood volume continues to increase.
- ☐ Discuss any genetic testing results with your provider and plan for follow-up if needed.
- ☐ Begin shopping for maternity clothes as your regular wardrobe starts to feel tight around the waist.
- ☐ Schedule your second-trimester anatomy scan (typically between weeks 18-22) before spots fill up.
Frequently Asked Questions
What does the 12-week ultrasound show?
The 12-week ultrasound (often part of nuchal translucency screening) confirms gestational age and due date, measures the fluid at the back of baby's neck (NT measurement), checks for a heartbeat, evaluates the placenta location, counts the number of babies, and can show basic anatomy. You may see your baby moving, stretching, and even hiccupping.
Is the risk of miscarriage lower after 12 weeks?
Yes, significantly. About 80% of miscarriages occur in the first trimester, and after 12 weeks with a confirmed heartbeat, the risk drops to about 2-3%. This is why many couples choose to announce their pregnancy after the 12-week milestone. However, it is a personal choice, and some prefer to share earlier or later.
When should I tell my employer I'm pregnant?
There is no legal requirement to tell your employer at a specific time, though many women choose to share around 12-14 weeks. Consider your workplace culture, any needed accommodations, and your comfort level. You may want to tell your direct supervisor first, then HR. Research your company's maternity leave policy and your rights under applicable laws before the conversation.
Why am I getting heartburn already?
Heartburn during pregnancy is caused by progesterone relaxing the valve between the stomach and esophagus, allowing stomach acid to flow upward. As the uterus grows, it also pushes on the stomach. To manage it: eat smaller, more frequent meals; avoid spicy, fatty, and acidic foods; do not lie down immediately after eating; and elevate your head while sleeping. Ask your provider about safe antacids.
What is the chorionic villus sampling (CVS) test and who needs it?
CVS is a diagnostic prenatal test performed between weeks 10-13 that involves taking a small sample of placental tissue to test for chromosomal abnormalities and genetic disorders with high accuracy. Unlike NIPT (a screening test), CVS provides a definitive diagnosis. It is offered to women with abnormal NIPT results, those over 35, those with a family history of genetic disorders, or those who have had a previously affected pregnancy. It carries a small miscarriage risk of approximately 0.5-1%.
Track Your Exact Pregnancy Week
Use our free Pregnancy Week Tracker to find out exactly how far along you are based on your last menstrual period or due date.
Track My Pregnancy →Sources
- ACOG
- WHO Fetal Growth Charts
- Mayo Clinic
Medical disclaimer: This content is for informational purposes only and is not intended as medical advice. Always consult a qualified healthcare provider for guidance specific to your pregnancy.