Development of your baby

3rd Trimester


Week 27

The baby's heart rate is around 120 to 160 beats per minute, roughly twice the speed of yours. It can now open and close its eyes. The baby practices 'breathing' by inhaling and exhaling the amniotic fluid. There is now a very good chance of surviving if born prematurely, although problems with breathing and keeping warm would mean special care is necessary.

Throughout the 3rd Trimester, we can undertake ultrasound examination to monitor the growth of the baby (24 -34 wk Growth Scan).

28 weeks

The airways continue to develop and the baby moves regularly. Babies kick most vigorously before they reach 30 weeks gestation, as such activity helps their muscles develop but in later gestation the space becomes more restricted. Eyelashes have formed and the baby's eye-sight is improving. In addition, the baby continues to add layers of fat and has continued hair growth. It now weighs over 1Kg and is about 37cm long, head to heel (25cm crown to rump).

Week 29

The brain function is still developing, with the increasing number of neurons forming evermore connections. The lungs continue to mature in preparation for the first breath and in the eye, the pupil iris is now able to dilate. The baby's hearing is developed to such a degree that you may notice that your baby becomes startled by loud noises.

Week 30

Those Braxton-Hicks Contractions of your uterus can probably be felt by your baby; but don't worry about the baby being hurt, as the amniotic fluid cushions and protects it. The baby is now about 33cm long from its head to its bottom.

Week 31

The baby continues to lay down fat stores and will almost double in weight before birth. The creamy moisturising 'Vernix' and fine, downy 'Lanugos' body hair are starting to disappear and the lungs are producing, increasing amounts of 'Surfactant' that will help keep them to inflated after birth.

Week 32

The baby now exhibits rapid eye movements during sleep, just like you when you are dreaming. Maybe your baby is have dreams of their own. Your baby now measures around 40cm from its head to bottom and weighs about 2.25lb (nearly 5Kg). If born now, neonatal intensive care would still be necessary but every day sees the baby getting stronger.

Week 33

Your baby is now settling into its birth position, although there is still plenty of time for it to move around if not yet head down.

Week 34

Fluid is passing through your baby's kidneys and is recycled back into the amniotic fluid. To harden bones your baby is drawing on your calcium reserves, it is therefore important for you to eat plenty of calcium-rich foods. If born now, the baby would be classed as "late preterm". Healthy babies born at this stage usually do well following brief care in a neonatal care unit.

Week 35

There is now a rapid growth phase and may gain up to 227g (1/2lb) a week. Through the wall of your tummy the open eyes can differentiate between darkness and light. Because of the increasing size, your baby is now cramped and restricted inside the uterus, so fetal movements may decrease, but at the same time they may be stronger and more forceful.

Between 35 weeks and Term, we can undertake ultrasound examination to establish the lie of the baby with in the Uterus (35 -Term Presentation Scan).

Week 36

The hearing is increasingly acute, the nails are growing and your baby may be born with a full head of hair. The body weighs about 51/2lbs (2.5kg) and measures 46cm from head to bottom, with fat on its cheek and powerful sucking muscles contributing to the baby's full face.

Week 37

Technically, your baby is now considered full-term; finger and toenails are now complete, which means that your baby is considered clinically mature, though weight will continue to be gained about 28g a day. The baby has developed enough coordination to grasp with its fingers. If you're expecting a boy, his testicles will have descended from his abdomen into his scrotum.

Week 38

The movements are likely to be prods, knocks and shifts, and strong ones can take you by surprise when you're resting. The growth slows down in the last week or two, a sign that your baby is ready to be born; but it currently weighs nearly 3Kg and measures about 34cm from Crown to Rump.

Week 39

Some of your antibodies are passing through the placenta into the babies bloodstream to boost the immune system for six months while it matures. The umbilical Cord that joins baby to placenta may be up to 55cm in length and 2cm thick.  The bowel contains Meconium - a sticky, tar-like substance consisting of cells shed from the intestines, dead skin cells and lanugo hair, that will be excreted as the first poo soon after birth.

Week 40

Term. AT LAST!! Plump, mature and finally ready for life outside your womb. Now roughly 51cm long and 3300g (7lb 4 oz), though of course newborn babies vary greatly in size and weight.

But if your baby has other ideas, don't be overly concerned; only 5% of women deliver on their estimated due dates, and many pending mothers find themselves waiting up to 2 weeks after their due date for their baby to arrive.

 

 

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