Third trimester

Pregnancy Week 42

A practical week 42 guide covering fetal development, symptoms, nutrition, prenatal tests, baby size comparison, and warning signs to discuss with your care team.

Week 42 ยท newborn size

Fetal development

Close follow-up is usually recommended after 41 weeks.

Baby size comparison

Around week 42, baby is roughly comparable to a newborn size. Estimated size: about 21.1 inches and 178 ounces, with natural variation.

Common symptoms

  • Energy, appetite, sleep, and digestion may change.
  • Some people notice cramps, bloating, skin changes, or back discomfort.
  • Symptoms vary widely, and absence of a symptom does not always mean a problem.

Tests and appointments

  • Weeks 40-42: Post-date monitoring and induction timing discussions if still pregnant.

Nutrition focus

  • Include protein, fiber-rich carbohydrates, colorful produce, and healthy fats.
  • Ask about iron, folic acid, iodine, vitamin D, choline, and omega-3 needs.
  • Follow local food-safety advice for fish, caffeine, unpasteurized foods, and supplements.

Warning signs

  • Call your care team for heavy bleeding, severe pain, fever, fainting, severe headache, vision changes, fluid leakage, or decreased fetal movement later in pregnancy.
  • Emergency symptoms should be handled urgently according to local medical guidance.

Medical disclaimer

This week-by-week pregnancy content is educational and does not replace care from a qualified healthcare professional.