There are three stages of pregnancy. These are the first, second and third trimesters. The first trimester runs from week one to week fourteen, the second covers weeks 15 – 26, then the
third trimester is weeks 27 – 40.
We will explain week by week what is happening and the changes you can expect in part 2 of this 3 part series:
Week 15: The baby’s neck is now defined, with the head now resting on the neck rather than the shoulders. The hair pattern of the baby will be defined by the 102nd day of the pregnancy your baby will now be able to turn its head, open its mouth, kick, press its lips together and turn its feet.
Week 16: This week the baby’s toe nails will start to grow. The muscles will be growing stronger and the neck and head are growing straighter. As the uterus starts moving upwards you may start showing more, but this does mean less pressure on your bladder, making you feel like urinating less.
Week 17: Your baby will be working on more reflexes this week; blinking, sucking, and swallowing. Development is carrying on with all the existing structures. Through the course of this month your baby’s weight will increase 6 times.
Week 18: By mid week your baby’s eyes and ears will now be in the right places. The finger tips and toes will develop pads, and toe and finger prints will start to develop later in the week.
Myelinization, a process of coating the nerves with a fatty substance called myelin which speeds up nerve cell transmission and insulates nerves, will start happening this week. Also by the second day of this week meconium (faecal waste) will start developing in the baby’s bowels.
Week 19: A creamy looking substance that covers the baby’s body, vernix coseosa, will start to form. This protects the baby and its developing glands and sensory cells. If you’re having a baby girl primitive egg cells are now developed in the ovaries, in fact females are born with all the eggs their ovaries will ever have.
Week 20: Most of the major development has now taken place, and the danger zone of the first three months is now over. Your baby will be waking and sleeping, just as newborns do. Also the formation of fine scalp hair and eyebrows will begin.
Week 21: Your body is replacing the amniotic fluid very three hours at this stage of your pregnancy. Baby’s leg and arm movements increase as the muscles and bones become stronger. By the end of the week a stethoscope will be able to detect the baby’s heart beat.
Week 22: If the baby is a boy, the testes will start to move from the pelvic area into the scrotum. The hair on the head and eyebrows is now visible as white and short.
Week 23: The bones in the middle ear start hardening making the conduction of sound possible. The baby will start to gain some considerable weight between now and next month. The size of the baby’s body will start to get into proportion though the head will remain larger than the rest of the body.
Week 24: The skin of your baby is wrinkled, but will smooth out as fat is deposited. Also by the end of this week the baby’s heart beat is so strong it is some times possible to hear it by placing an ear on your stomach.
Week 25: Baby’s skin is now turning a reddish/pink as capillaries start to develop. The nostrils will now start to open, as they have been plugged unto now. The lungs will start developing blood vessels and the finger and toe nails will now be covering half the nail bed.
Week 26: with the nostrils now open, muscular breathing will start. By the end of the week the lungs will be secreting surfactant, a substance which prevents the lung tissue sticking together.
Also with the formation of blood vessels in the lungs, they will now also be developing air sacks. Brain wave activity starts this week for auditory and visual activity.
Next month we will have the 3rd Trimester.
This article is courtesy of Beverley Brooke, of Pregnancy week by week