Second Trimester

Pregnancy Week 23

Your baby is about the size of a grapefruit 🍊lungs developing (but not ready).

Week 22Week 23 / 40Week 24
🍊

Size comparison

Grapefruit

Length

28.9 cm

Weight

501 g

Milestone

Lungs developing (but not ready)

About 17 weeks to go until your due date (week 40).

Baby's development at week 23

The lungs are producing surfactant — the substance that keeps air sacs inflated. The baby's face is fully formed. They sleep in regular cycles and may startle at loud noises.

Start thinking about birth preferences — a birth plan helps you communicate your wishes.

Common symptoms at week 23

Linea nigra prominentCarpal tunnel symptoms in someHot flushes

Eat more of

  • Omega-3 fatty acids (salmon, flaxseed)
  • Calcium & Vitamin D (cheese, eggs, sunlight)
  • Protein (chicken, legumes, eggs)
  • Iron + Vitamin C together for absorption
  • Magnesium-rich foods (nuts, seeds, dark chocolate)

Foods to avoid

  • Alcohol
  • Raw/smoked seafood
  • High-mercury fish
  • Unpasteurised cheeses (brie, camembert)
  • Processed meats (deli cuts, hot dogs)
  • Excess sugar

Medically reviewed by First OPD Medical Team. Last reviewed on .

Based on average milestones from World Health Organization (WHO), ACOG, NHS UK. Educational only — not a substitute for personalised medical advice.

Track every week with a free First OPD account

Save your personalised week, get your due date, and book gynaecologists near you.

Browse pregnancy week by week