14. Pregnancy and Birth

• Gestation (aka. Pregnancy):

  The time that the embryo or foetus is carried in the uterus (40 weeks)
• What is the average length of a developing child at the end of gestation?

  About 50 cm
• What is the average weight of a newborn at the end of gestation?

  3400 g
• How long does gestation typically last?

  About 280 days (or 40 weeks)
• What significant developments occur by the end of the first two months of embryonic life?

  The general body form of the infant has developed, and the basic plan of the organ systems is in place.
• What is the term used to refer to the developing baby after the first two months of embryonic life?

  Foetus
• At approximately how many weeks does the foetus reach a recognisable human form?

  8 weeks
• What are some key developments that occur during the third month of foetal development?

  Forelimbs well developed; eyelids closed; outer ear completed; bone marrow formed; blood cells formed in bone marrow; sex distinguishable.
• What happens to the foetus during the fourth month of development?

  Arms and hands are fully shaped; skeleton is completed; exercising of muscles is evident; ears stand out from the head.
• What significant changes occur in the foetus during the fifth month of development?

  Fine hair covers the body; gripping reflexes are developed; increased growth occurs.
• What developments occur during the sixth month of foetal development?

  Respiratory movements begin; digestive glands start to function; tooth buds become evident; eyebrows and eyelashes appear.
• What is the period of greatest growth for the foetus?

  Seventh month of development
• What happens during the eighth month of foetal development?

  Accumulation of fat beneath the skin occurs, and growth slows down.
• What key developments occur during the ninth month of foetal development?

  Eyes open; nose is well formed; sucking and grasping reflexes are apparent; fine body hair is shed.
• What is the most obvious physical change in a pregnant mother?

  The growing abdomen due to the growth of the uterus.
• What hormonal changes occur in a pregnant mother that affect her breasts?

  Pregnancy hormones result in the development of milk-secreting tissues, increasing the size of breasts.
• How does pregnancy affect a mother's blood volume and kidney function?

  Greater blood volume results in increased blood flow to the kidneys, which increases urine production.
• What emotional changes may occur in a pregnant mother?

  The emotional state may change due to hormonal changes and natural fears accompanying pregnancy.
• What is the process called by which the foetus is expelled from the mother’s body at the end of gestation?

  Birth or parturition
• What hormonal changes occur in preparation for birth?

  Relaxin causes ligaments of the pelvis to soften, and oxytocin increases the response of the uterus to stimuli and strengthens contractions.
• What happens to the foetus's position before labour begins?

  The foetus's head settles in the mother’s pelvis, and the cervix softens and shortens, likely beginning to open a little.
• What is the first stage of labour characterized by?

  It includes the time from the onset of labour until the cervix is fully dilated (10 cm) and usually lasts 8-9 hours for a first birth.
• What occurs during the dilation of the cervix in the first stage of labour?

  Waves of contractions travel from the upper part of the uterus downwards towards the cervix, shortening it and allowing the foetus deeper into the pelvis.
• What happens once the cervix is fully dilated?

  The uterus, cervix, and vagina form a single, curved passage known as the birth canal.
• What is the second stage of labour characterized by?

  It involves the delivery of the foetus and lasts from 20 minutes to 2 hours, usually beginning with the bursting of the amniotic membrane.
• How does the foetus move through the vagina during the second stage of labour?

  The foetus's head stretches the vagina, stimulating the woman to contract her abdominal muscles, pushing the foetus through the vagina.
• What happens to the foetus's head during delivery?

  The head turns to face towards the mother's back, and with each contraction, the foetus advances a small amount but retreats a little between contractions.
• What occurs once the head of the foetus emerges?

  The head turns sideways to face the mother’s hips, allowing the shoulders and the rest of the body to move more easily through the birth canal.
• What is the third stage of labour characterized by?


  It involves the expulsion of the placenta and outer membranes, known as the afterbirth, approximately 5 minutes after the baby is born.
• What happens to the umbilical cord after birth?

  The umbilical cord is clamped, tied in two places, and cut between the ties, causing the veins and arteries in the umbilical cord to contract.
• What is the afterbirth?


  The afterbirth refers to the placenta and outer membranes expelled from the uterus after the baby is born.
• How does foetal circulation change at birth?

  Foetal blood is carried to the placenta by two umbilical arteries to collect nutrients and remove wastes, returning to the foetus via the umbilical vein.
• What is the ductus venosus and its function?

  The ductus venosus is a blood vessel that allows about 30% of blood returning from the placenta to bypass the liver and flow into the inferior vena cava.
• Why does some blood bypass the liver in foetal circulation?

  Because the mother’s liver is serving the needs of the foetus.
• What happens to blood returning from the foetal heart?

  Blood enters the right atrium (RA) and can either flow to the lungs or bypass them through the ductus arteriosus.
• What is the ductus arteriosus?

  The ductus arteriosus is a vessel that bypasses the lungs, allowing blood in the pulmonary artery to flow directly to the aorta.
• What is the foramen ovale and its role in foetal circulation?

  The foramen ovale is an opening between the right and left atria that allows blood to flow directly from the right atrium to the left atrium, bypassing the lungs.
• What triggers the closure of the foramen ovale after birth?

  The commencement of breathing may trigger the closure of the foramen ovale.
• What is a hole in the heart?

  A hole in the heart refers to a defect in the septum that separates the heart's chambers, allowing blood to flow abnormally between them.
• How can maternal diet, infections, and drugs influence a developing foetus?

  They can affect the foetus's growth, development, and overall health.