Second trimester · Source-backed weekly guide

Pregnancy week 13

Pregnancy week 13: a source-backed guide to development, possible body changes, useful next steps, and questions for your prenatal care team.

By BabyToBloom EditorialReviewed September 20, 2026
Expectant parent relaxing in a sunlit nursery

Development

What is developing around week 13

Around the 12-week source checkpoint, nerves and muscles are beginning to work together, the fetus can make a fist, and growth is shifting toward greater length and proportion.

Your body

Changes you may notice

Second-trimester changes may include a growing abdomen, back or pelvic discomfort, skin changes, tingling hands, and swelling. Sudden or extreme swelling, significant itching with other symptoms, or anything that feels wrong deserves prompt clinical guidance.

Symptoms vary widely. Absence, presence, or intensity of a symptom cannot confirm that a pregnancy is progressing normally.

This week’s focus

A practical next step

Notice how energy, nausea, appetite, and mood are changing without assuming there is one normal experience.

  • Notice how energy, nausea, appetite, and mood are changing without assuming there is one normal experience.
  • Keep appointments and follow the plan created with your prenatal care professional.
  • Save new symptoms and questions in one place so changes are easier to explain.

Prenatal visit

Questions worth bringing with you

  • What should I understand or prepare during pregnancy week 13?
  • Which symptoms should make me call you now rather than wait for my next appointment?
  • What tests, vaccines, medicines, or decisions are coming next in my care plan?
Build your appointment question list →

Sources

BabyToBloom uses authoritative public-health sources and identifies the source checkpoints behind developmental statements. Individual development and clinical schedules vary.

Guidance that moves with you.

Save your due date and priorities for a personalized weekly plan without entering the same information twice.

Personalize week 13
Pregnancy Week 13: Development, Changes & Questions | baby to bloom OS