Pregnancy Week 15 – The Baby’s Progress

Pregnancy week 15 is where the hair follicles begin to spring into action as your baby’s body is now all in proportion. His eyelashes, along with the hint of faint eyebrows he had, will now develop further. If your baby is going to have dark coloring then his hair follicles will begin producing dark pigment. Around weeks 15-16 will also see the growth of Lanugo hair which is a very fine, downy hair that covers the entire body except for the palms of the hands and the soles of the feet. This is nature’s way of retaining human body heat where there is a lack of body fat. (Lanugo can also appear on an adult that is suffering from severe anorexia).


Pregnancy at 15 weeks shows the growth of Lanugo Hair

This minutely fine hair gently swirls against the body like little fingerprints on the skin. It will usually shed itself around the 8th month of pregnancy so a baby born with lanugo is usually a sign of prematurity. As this fine hair begins to shed itself into the amniotic fluid, it can actually be consumed orally by the baby and traces of this hair can usually be found in the baby’s first bowel movement (Meconium) when they are born.

Beneath his thin and transparent skin sees the development of a complex network of blood vessels knitting themselves together. As all of the connections between the brain, nervous system and muscles are now all joined together and the nerves have been coated in a protective layer of Myelin, he has a much more intricate range of movements and will show evidence of his co-ordination by sucking on his thumb. Scientists believe that the thumb he chooses to suck on is an indication of whether he will be left or right-handed in future.

Apart from his regular workouts of swimming, somersaulting and flexing within the womb, by pregnancy week 15 he will still be practising his breathing by hiccuping and taking amniotic fluid into his lungs. This may sound somewhat bizarre to us as we don’t associate the intake of fluid with breathing, lest it be said, that this primitive breathing technique is not the same as ours.

Your baby is not actually be ‘breathing’ yet as his lungs are still underdeveloped and he is still receiving his oxygen from the blood supplied by the placenta, via the umbilical cord, through his naval area and directly into his circulatory system, by-passing his lungs entirely. At this point he is merely ‘practising’ his reflex ability to breathe in the near future when he is born.

Your growing child will now be more or less half the length of a ruler and in pregnancy week 15 will measure around 4 ” (10.2cm) and weight approximately 2.65 oz (75 g).

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(See 15 Weeks Pregnant – The Mother’s Progress)

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