Parturition
Preterm labour and complications
o Complications occur in 6-10% of deliveries in the developed world
Little change in rate in the last 30 years
o Very low birthweight infants (<1500g) have major problems
o Preterm babies have 85% survival rate due to improved neonatal care
25% have motor impairment
30% have hearing and visual impairment
40-60% have special educational needs
o Preterm birth increases chance of long-term chronic lung and heart disease
and diabetes
They also have increased admission to hospital for acute illness
o We need to understand regulation of labour due to the severity of preterm
birth
Foetuses are programmed for later life in utero
Safe motherhood
o Half a million maternal deaths per annum
o 300 million mothers have short- and long-term morbidity
o Higher chance of death in developing and poorest parts of the world due to:
Limited health care, particularly in rural areas
Lack of trained birth attendants
o Lifetime risk of maternal death:
Developed world- 1/2500
Developing world- 1/60
Poorest areas- 1/16
War zones- 1/7
o These figures show that everyone who is having a baby is at risk of death, but
that there is a higher chance in poorer areas
o Very basic training and drugs make a huge difference
Regulation of labour in sheep
o There are hormonal changes in sheep that trigger the initiation of labour
Firstly, foetal cortisol begins to increase 8 days before delivery
There is a separation between foetal and maternal blood that
stops maternal cortisol passing into the foetus
o 11βHSD breaks down cortisol so it doesn’t enter the foetus
Foetal cortisol levels can be a representation of foetal brain
development
Secondly, there is a drop in maternal progesterone about 5 days before
delivery
Progesterone is essential for maintenance of pregnancy
, It is secreted firstly by the corpus luteum, then by the placenta
Progesterone is involved in immune suppression
o Also maintains uterine quiescence and suppresses
myometrial activity
Progesterone receptor agonist (RU486)- an antigesterone
o RU486 binds to progesterone receptors
o Prevents progesterone signalling and induces labour
o The foetal anterior pituitary is stimulated to secrete ACTH
There is an increase in ACTH levels before labour occurs
A non-functional HPA axis can lead to brain defects such as creating a
one-eyed lamb
Without the HPA axis driving an increase in ACTH, labour does not occur
Occurs because ACTH is not present to increase cortisol levels
Lambs on the left were delivered at 230 days (about 80 days late)
Lambs on the right were normal
o Trophoblast steroidogenesis
Preterm labour and complications
o Complications occur in 6-10% of deliveries in the developed world
Little change in rate in the last 30 years
o Very low birthweight infants (<1500g) have major problems
o Preterm babies have 85% survival rate due to improved neonatal care
25% have motor impairment
30% have hearing and visual impairment
40-60% have special educational needs
o Preterm birth increases chance of long-term chronic lung and heart disease
and diabetes
They also have increased admission to hospital for acute illness
o We need to understand regulation of labour due to the severity of preterm
birth
Foetuses are programmed for later life in utero
Safe motherhood
o Half a million maternal deaths per annum
o 300 million mothers have short- and long-term morbidity
o Higher chance of death in developing and poorest parts of the world due to:
Limited health care, particularly in rural areas
Lack of trained birth attendants
o Lifetime risk of maternal death:
Developed world- 1/2500
Developing world- 1/60
Poorest areas- 1/16
War zones- 1/7
o These figures show that everyone who is having a baby is at risk of death, but
that there is a higher chance in poorer areas
o Very basic training and drugs make a huge difference
Regulation of labour in sheep
o There are hormonal changes in sheep that trigger the initiation of labour
Firstly, foetal cortisol begins to increase 8 days before delivery
There is a separation between foetal and maternal blood that
stops maternal cortisol passing into the foetus
o 11βHSD breaks down cortisol so it doesn’t enter the foetus
Foetal cortisol levels can be a representation of foetal brain
development
Secondly, there is a drop in maternal progesterone about 5 days before
delivery
Progesterone is essential for maintenance of pregnancy
, It is secreted firstly by the corpus luteum, then by the placenta
Progesterone is involved in immune suppression
o Also maintains uterine quiescence and suppresses
myometrial activity
Progesterone receptor agonist (RU486)- an antigesterone
o RU486 binds to progesterone receptors
o Prevents progesterone signalling and induces labour
o The foetal anterior pituitary is stimulated to secrete ACTH
There is an increase in ACTH levels before labour occurs
A non-functional HPA axis can lead to brain defects such as creating a
one-eyed lamb
Without the HPA axis driving an increase in ACTH, labour does not occur
Occurs because ACTH is not present to increase cortisol levels
Lambs on the left were delivered at 230 days (about 80 days late)
Lambs on the right were normal
o Trophoblast steroidogenesis
