Third Trimester

Your changing body and your growing baby

Baby’s development

Week 27-30

  • Your baby measures about 42.5cm from head to toe, and weighs about 1.2kg
  • The baby can distinguish bright sunlight or artificial light through the uterine wall Baby is performing fewer acrobatics as conditions in the womb become more cramped, but it can still do a lot of kicking and stretching

Week 31

  • Your baby measures about 43cm from head to toe and weighs about 1.3kg
  • Baby is getting more body fat which helps it to control its own body temperature
  • The eyebrows and eyelashes are fully developed
  • The hair on the head is getting thicker
  • The head and body are now proportioned like a newborn’s
  • The hands are now fully formed and the fingernails are growing

Week 32

  • Your baby measures about 45.7 cm long from head to toe and weighs about 1.5kg
  • Rather than hearing vibrations, baby’s nerve endings in his ears are connected now and can hear distinct sounds, like familiar voices and music. This is a good time to start reading to your baby

Week 33

  • Your baby measures about 49cm from head to toe and weighs about 2.3kg
  • The baby will gain more than half its birth weight in the next seven weeks
  • Baby begins to move less now as it runs out of room and curls up with it’s knees bent, chin resting on chest and arms and legs crossed- The classical foetal position.

Week 34

  • Your baby measures about 50 cm from head to toe and weighs about 2.3kg
  • Baby is probably settling into the head-down position, although it might not be final. The organs are almost fully mature, except for lungs, and the skin is pink instead of red
  • The fingernails reach the ends of the fingers, but the toenails are not yet fully grown Baby might have lots of hair on it’s head
  • Movements are less frequent as things get more cramped

Week 35

  • Your baby measures about 51.5cm from head to toe and weighs more than 2.5 kg
  • The lungs are almost fully developed
  • The baby still doesn’t have enough fat deposits beneath its skin to be able to regulate its own temperature, so lots of fattening up to do in the few remaining weeks

Week 36

  • Your baby measures about 52.5cm from head to toe and weighs about 2.7kg
  • The baby may engage (or drop) into the pelvis
  • Most babies have settled into a head-down position, if yours isn’t see ‘Helping baby find an easy birth position ‘
  • The brain has been developing at a fast pace, and your baby will be practicing blinking.

Week 37

  • Your baby is about 53cm from head to toe and weighs almost 2.9kg
  • Baby is fattening up every day
  • The skin is getting pinker and losing its wrinkly appearance
  • Baby’s head is usually engaged in the pelvis by now (or the baby has ‘dropped’). This allows you to breathe a little easier.

Week 38

  • Your baby is about 53cm head to toe and weighs about 3kg
  • Most of the baby’s downy hair, lanugo, and whitish coating, vernix, is disappearing Your baby is getting antibodies from you to protect against illness, getting ready for the outside world
  • Baby’s growth is slowing, but fat cells under skin are still depositing for life on the outside
  • You are almost ready for birth, your baby would do well if labour begins any time from now

Week 39

  • Your baby is about 54.6cm long from head to toe and weighs a little more than 3.1kg
  • The toenails and fingernails have grown to tips of toes and fingers
  • Muscles of your baby’s arms and legs are strong, and it will be practicing lung movements

Week 40

  • Your baby’s length is about 54.6 cm from head to toe and it weighs about 3.4kg, boys often tend to weigh a little more than girls.
  • Reflexes are coordinated so the baby can blink, close it’s eyes, turn the head, hold things and respond to sounds, light and touch.
  • More lanugo falls out, but some may remain at birth on shoulders, folds of skin and backs of ears.
  • Your baby could be here any time now.

What’s happening to Mum?

  • In the third trimester, some women become increasingly uncomfortable as their due date nears
  • As the baby grows in size and crowds the abdominal cavity, some mothers have difficulty taking deep breaths or getting comfortable at night for sleep
  • You may notice that you feel hot and have a higher skin temperature as the baby radiates body heat
  • You may need to urinate all the time (it’s back) due to the pressure the baby puts on the bladder
  • Your blood pressure may decrease as the baby presses on the main vein that returns blood to the heart
  • You may notice swelling of the ankles, hands, and face, see your care provider if this is excessive
  • You may notice hairier arms, legs, and face due to hormone stimulation of hair follicles.
  • Your hair may also feel courser.
  • Leg cramps can become more frequent.
  • Braxton-hicks contractions may begin to occur at irregular intervals in preparation for childbirth
  • Stretch marks may appear on the abdomen, breast, thighs, and buttocks
  • Colostrum may begin to leak from the nipples
  • Dry, itchy skin may persist, particularly on the abdomen, as the skin continues to grow and stretch, you may even feel yourself getting stretch marks , ouch!
  • Your libido may change, most decline but some increase
  • Dark patches of skin on the face may become more noticeable
  • You may notice a white vaginal discharge which may contain more mucous than usual
  • In the final week or days before birth you may notice pre-labour signs, see pre-labour to learn about this

See ‘Natural Help For The Discomforts Of Pregnancy‘ for safe and effective natural therapies and self help techniques to help you through this time