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First Trimester (Weeks 1 - 13) Week 12 of 40
Fetal Size Comparison

Week 12 Size: Plum

About the size of a sweet plum.

Length 5.4 cm 2.1 inches
Weight 14 g 0.5 oz

Relative Visual Scale

Solid circle represents your baby's size. Dotted circle shows the full-term week 40 size threshold.

Inside The Womb

Baby's Development

The baby's reflexes are developing; they can open and close their hands and curl their toes. The kidneys are producing urine, and the bone marrow is starting to make white blood cells.

Weekly Milestones

  • Reflexes Develop
  • Uterus Rises from Pelvis
Maternal Health

Your Body & Symptoms

Your uterus is rising out of the pelvic cavity, relieving pressure on your bladder, which means fewer trips to the bathroom! You may start showing a small baby bump.

Common Symptoms this Week

Reduced morning sickness Fewer bathroom trips Headaches Dizziness Pregnancy glow

Doctor & Care Recommendations

  • Maintain a safe exercise routine; walking and swimming are excellent.
  • Start sleeping on your side (preferably left side) instead of your back.
  • Plan how you want to announce your pregnancy to friends and family.
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PregWeeks

CHECKLIST

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Prepare for labor with confidence. Our doctor-reviewed checklists ensure you don't forget any newborn or partner essentials in the hospital delivery room.

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Weekly Health Guides & Resources

Trimester Guide

First Trimester Guide

Read comprehensive clinical milestones, screening checklists, and developmental guidelines for this phase.

Explore Trimester →
Common Symptoms

Track & Relieve Symptoms

Learn why symptoms occur, home remedies, and clinical indicators for this week:

Pregnancy Nutrition

Food Safety Checklists

Verify safety statuses, listeria and mercury risks, and safe alternatives for:

Full Nutrition Guide →

Frequently Asked Questions: Week 12

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Evidence-Based Clinical Sources for Week 12

PregWeeks is dedicated to medical transparency. Every milestone, symptom tip, and fetal development guideline for Week 12 is sourced directly from clinical guidelines published by leading obstetric authorities. Read more about our editorial methodology on our Medical Sources page.

Nutrition During Pregnancy FAQ

ACOG

Patient and practitioner reference guidelines on prenatal nutritional intake, including essential vitamins, iron, calcium, and weight thresholds.

View Clinical Guideline

Early Pregnancy Loss (Practice Bulletin No. 200)

ACOG

Clinical guidelines on diagnostics, physical symptoms, and care options during early pregnancy challenges in the first trimester.

View Clinical Guideline

Food Safety for Pregnant Women

FDA / CDC

Standard warnings and food safety guidelines regarding Listeria, Salmonella, and mercury levels in seafood during gestation.

View Clinical Guideline
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🏥 Medical Disclaimer

PregWeeks is an educational planning tool and does not provide clinical diagnoses or medical advice. Always consult your obstetrician or healthcare professional for health concerns.