Your baby and your body

In the first few weeks of pregnancy, most changes happen inside your body. In the last stages of pregnancy, your pēpi (baby) will gain weight more quickly than before. you may start to feel uncomfortable as they get bigger. Learn about how your pēpi develops, and changes to your body.

Your growing pēpi


6 to 7 weeks

  • At 7 weeks your pēpi (baby) is about 8 mm long from head to bottom.
  • The brain is growing and the heart is beginning to beat.
  • Ears, eyes, arms and legs are also starting to grow.
  • Your pēpi will start to move, but you will not be able to feel it yet.

8 to 9 weeks

  • At 9 weeks your pēpi is about 17 mm long from head to bottom.
  • Your baby’s face is slowly forming and there are eyelids.
  • They have a mouth and a tongue.
  • Hands and feet, with ridges where the fingers and toes will be, are also beginning to grow.

10 to 12 weeks

  • By 12 weeks your pēpi is fully formed.
  • They have all their organs, muscles, limbs and bones and can kick and move.

13 to 14 weeks

By 14 weeks your pēpi can swallow and their fingerprints have formed.


17 to 20 weeks

  • Your pēpi is getting bigger and putting on weight.
  • Their heart is beating — much faster than yours.
  • They are moving and kicking.
  • If this is your first pregnancy, you may feel them move at about 20 weeks.

21 to 24 weeks

  • By 24 weeks your pēpi is about 30 cm long and weighs 600 g (or a little bit bigger than a pack of butter).
  • Their skin is thicker and less see-through (transparent) than before. But it is still wrinkled because there is no fat underneath.
  • They can hear voices and is moving strongly.
  • They start practising breathing and swallowing movements.

25 to 27 weeks

  • Your pēpi can recognise your voice.
  • They have a pattern of wake and sleep times.
  • Their eyes begin to open.
  • They start sucking their fingers and thumbs.

28 to 30 weeks

  • At 28 weeks your pēpi is over 38 cm long and is about 900 g in weight (nearly 2 packs of butter).
  • Your baby’s skin begins to develop a white, greasy covering (called vernix), which waterproofs the skin.
  • Baby’s movements can easily be felt at this stage.
  • By week 30 your pēpi is about 43 cm long and weighs about 1.3 kg.

30 to 32 weeks

  • Your baby’s eyes are open and they can see and hear.
  • They will not grow much more but will gain weight.
  • There is less room for them to move around.

33 to 36 weeks

  • Your pēpi may have a full head of hair.
  • They usually settle into a head-down position, and move down so that their head is in your pelvis.
  • Your baby’s lungs are almost fully grown.

37 to 40 weeks

  • Baby keeps gaining weight.
  • The downy hair and vernix coating are gone.
  • They may sit low in your pelvis.
  • By 40 weeks your pēpi is about 50 cm long and weighs over 3 kg. Remember though that all babies are different — they can be longer or shorter, bigger or smaller.
  • They are now fully developed and the lungs have matured, ready for birth.

41 to 42 weeks

Most babies are not born on their due dates — you may be waiting a little bit longer for them to arrive.


Your changing body


Weeks 14 to 30

As your baby grows, so does your belly. Usually by about 20 weeks you will need to start wearing loose or stretchy clothing. You may have:

  • a growing belly
  • breast changes and some drops of colostrum (the first early milk) present
  • aches and pains (low back pain is common)
  • practice tightenings of your uterus (Braxton Hicks contractions)
  • bleeding gums
  • a metallic taste in your mouth
  • skin, hair and nail changes
  • nose bleeds, a stronger sense of smell, colds and sinus problems
  • restless legs
  • swelling in legs, feet and hands
  • vaginal changes
  • a renewed interest in sex.

Week 30 onwards

In the last stages of your pregnancy, your pēpi will gain weight more quickly. You may start to feel uncomfortable as they get bigger.

You may have more aches and pains, or other problems, because of the extra weight you are carrying around. 

Common issues in pregnancy (internal link)


Weeks 0 to 14

During early pregnancy you may:

  • have no periods or lighter bleeding
  • notice breast and nipple changes
  • need to wee more than normal 
  • have bloating, cramps, and backache
  • have morning sickness
  • notice more saliva in your mouth than usual 
  • feel dizzy or faint 
  • feel tired
  • have headaches
  • have constipation and wind 
  • not have an interest in sex, or want to have sex more.

Changes to your mood

Your mood may change during pregnancy — this is normal. Talk to your midwife or doctor if you are worried about your changing body, or your mood.