Week 13-27

Week 13

What’s happening this week

Your baby..

  • is about the size of an AirPod case 
  • measures about 7cm
  • weighs about 23 grams
  • all 20 teeth are formed
  • meconium (the baby’s first poo) is developing.

You…

  • are in the second trimester now!
  • are starting to feel pregnant
  • may want to spread the good news if you haven’t already.

The hormone changes of the early weeks begin to settle and your chances of miscarriage are now much lower.

Week 14

What’s happening this week

Your baby…

  • is about the size of a Tamagotchi
  • weighs about 43 grams
  •  is developing fine hair called “lanugo”, it is just on his face at this stage
  • genitals are fully developed (sometimes hard to detect on ultrasound)
  • the musculoskeletal system has matured and the nervous system begins to exercise some control over the body, blood vessels rapidly develop.

You…

  • your uterus is the size of a grapefruit
  • hormones cause changes to the skin – a line may begin to appear down the centre of your abdomen called “linea nigra” (it usually fades after birth)
  • may notice an increase in vaginal secretions/discharge.

Week 15

What’s happening this week

Your baby…

  • is about the size of a large kiwifruit
  • weighs about 70 grams
  • hands are ready to grasp and is able to kick against his walls – the amniotic sac
  • skin is so thin and translucent you can see the blood vessels through it
  • hair growth continues on the head and eyebrows – the scalp hair pattern is developing.

You…

  • some women talk about “baby brain”, that pregnancy causes them to be forgetful, clumsy and unable to concentrate.  Take it in your stride!
  • your heart is increasing its output to supply the baby with oxygen.

You could feel in an ‘in-between’ state around now – too large for your ordinary clothes, not ready for maternity clothes. 

 

Week 16

What’s happening this week

Your baby…

  • is about the size of a mixtape
  • weighs about 100 grams
  • can hold his head erect
  • has expressions on his face
  • limb movements are becoming more coordinated
  • empties his bladder every 40-45 minutes
  • all organs and structures have formed and a period of simple growth begins.

You…

  • may begin to feel your baby move (particularly if this isn’t your first baby)
  • some women experience headaches due to the changes in blood volume and vacular tone
  • may feel hungrier than usual.

If you have decided to have an amniocentesis, it may be done this week.

Week 17

What’s happening this week

Your baby…

  • is about the size of a L&P Can
  • weighs around 140g
  • loud noises outside may cause the baby to startle in utero There are no documented cases of hearing loss at birth associated with noise in utero.
  • is forming brown fat deposits under his skin (helps maintain body temperature when he is born)
  • may be grasping the umbilical cord from time to time.

You…

  • your uterus is halfway between your pubic bone and navel
  • you may notice some breast changes – veins may be visible and a possible increase in breast size, this is due to hormones preparing your breasts for milk production.

Week 18

What’s happening this week

Your baby…

  • is about as big as a large donut
  • weighs around 190 grams
  • ears move to their final position and stand out from the head
  • bones are continuing to ossify
  • a white waxy substance called vernix protects the baby which helps delicate skin from being chapped or scratched
  • pads on the fingers and toes are formed and fingerprints are developing.

You…

  • you may feel faint or dizzy if you stand up suddenly due to adjustments in your new circulatory patterns
  • may feel a little short of breath.

Week 19

What’s happening this week

Your baby…

  • an impressive week for growth – increasing to around 240 grams
  • now about the size of a taco
  • lanugo (fine hair) appears all over the baby’s body
  • eyelashes develop
  • permanent teeth buds are forming behind the already formed milk teeth buds
  • if you are having a girl her ovaries contain primitive egg cells.

You…

  • breasts begin secreting colostrum in preparation for nursing
  • may be bothered by varicose veins (caused by the enlarged uterus interfering with blood flow in the lower extremities).

As pregnancy progresses, you may feel hungrier. You may start thinking about those first few moments after your baby is born.

Week 20

What’s happening this week

Your baby…

  • your baby measures about 16cm (CRL)
  • is about the size of a game controller
  • weighs about 300 grams
  • hair and nail growth continue
  • following a regular schedule of sleeping turning, sucking and kicking and has settled upon a favourite position within the uterus (you may become aware of these wake/sleep cycles).

You…

  • your belly button may poke out as your uterus presses upwards
  • the placenta reaches its largest size relative to the fetus, covering one-half of the uterine lining
  • 400mls of fluid now present in the amniotic sac
  • for some women fetal movements can still not be felt – they won’t be far away.

Week 21

What’s happening this week

Your baby…

  • is about the size of a wooden buzzy bee
  • the intestines are now able to absorb sugars from the amniotic fluid that is swallowed.  Most nourishment though is still from the placenta
  • until now the liver and spleen have been responsible for blood cell production, the bone marrow spaces now contribute to blood cell formation.

You…

  • may feel achey in the abdomen as the ligaments either side of the uterus stretch as the baby grows
  • can feel the top of your uterus in your abdomen – it may reach somewhere near your belly button by now
  • may notice some backache.

Week 22

What’s happening this week

Your baby…

  • measures about 19cm
  • can now hear your voice – if you talk, read or sing to your baby
  • the skeleton is developing rapidly as the bone forming cells increase their activity
  • taste buds have started to form on the tongue
  • fetus can feel touch as brain and nerve endings are forming
  • baby boy’s testes have begun to descend from the abdomen
  • baby girl’s uterus and ovaries are in place and vagina is developed.

You…

  • may find this an enjoyable time of pregnancy – the aches and pains are fading and you’re not too large to be uncomfortable
  • libido may be increased.

This is a good time to think ahead for what you’ll need for your baby – even if, like many mothers, you don’t want to start buying anything yet. If you are working, your progressing pregnancy may mean some adjustments at work.

Week 23

What’s happening this week

Your baby…

  • is about the size of a DSLR Camera
  • weighs about 450 – 500 grams
  • has the proportions of a newborn but is much thinner
  • has a wrinkled appearance
  • has eyes that are fully formed, though they have no colour yet, the eyelids begin to open and close.

You…

  • may experience “Braxton Hicks” contractions – irregular painless tightenings, they are not dangerous or harmful and thought to be ‘practice’ contractions for the real thing
  • may experience vivid dreams.

Your baby is gaining weight steadily now, and you may experience sudden food cravings. This week we offer some suggestions for easing long commutes for working women and tips for combating backache.

Week 24

What’s happening this week

Your baby…

  • is about the size of Mr Potato Head
  • weighs about 765 grams
  • has well-developed hearing and will be listening to your voice and the beat of your heart
  • has lungs that are preparing to breathe air rather than fluid
  • if your baby was born this week it may be possible he could survive (with expert medical care).

You…

  • the placenta becomes thicker rather than wider
  • nose bleeds can sometimes occur (due to nasal congestion and the increased blood volume)
  • may feel off balance and clumsy as your centre of gravity continues to shift
  • may need to see a dentist if your gums are giving your problems.

Week 25

What’s happening this week

Your baby…

  • is about the size of your Bountiful Your Pregnancy/Your Baby publications!
  • your LMC may be able to tell you which way your baby is lying by examining your abdomen.

You…

  • reflux or heartburn may be problematic due to the hormones of pregnancy relaxing the valve at the opening of the stomach
  • may notice your first stretch marks.

Week 26

What’s happening this week

Your baby…

  • is about the length of a Whittaker's block of chocolate
  • weighs about 900 grams
  • to a certain extent can now breathe, swallow and regulate her body temperature but still depends greatly on maternal support.

You…

  • people on the ‘outside’ may be able to share the baby’s movements and feel them too
  • sleeping may become uncomfortable, your LMC may suggest sleeping on your side
  • may notice darkening of the skin line down the centre of your abdomen (the linea nigra)
  • may have an ache in your wrists and hands as the carpal tunnel in your wrist swells during pregnancy and can pinch the nerves that run through it.

Week 27

What’s happening this week

Your baby…

  • is about the length of a whisk
  • measures about 25cm (CRL) – but if the legs were extended (they’re tucked up while inside you) could measure nearly 38cm long!
  • is going through a fast and furious phase of brain development
  • may begin to open eyes
  • may suck a finger or a thumb
  • a substance called surfactant forms in the lungs so they can function independently at birth.

You…

  • may feel your baby’s hiccups – sometimes it feels like they are in your bottom!
  • leg and muscle cramps may be annoying (particularly at night)
  • may be plagued by constipation.