pregnancy and foetal growth Flashcards
how do you determine the gestation of a foetus
- 40 weeks from last menstrual period
- 38 weeks from fertilisation
- estimation via length and ultrasound measurements of foetus
common physical signs of pregnancy
- cessation of menstruation
- morning sickness
- increased frequency of urination
- increased size of breasts
- fatigue
- darkening of areolae
what are the 2 foetal membranes
aminon
chorion
explain the vessels in the umbilical cords
1 umbilical vein = oxygenated
2 umbilical arteries = deoxygenated
explain the anatomy of the placental/blood interface
- maternal blood vessels drain into the blood lakes
- chorionic villi with blood vessels into the blood lakes
which organs in the foetus does the placenta essentially replace
lungs
kidneys
GIT
what is the function of hCG
rescues the corpus lutem –> survives until a stable placenta made
function of human placental lactogen
breast development
metabolic effects on mother
functions of oestrogen and progesterone during pregnancy
pregnancy maintenance
breast development
explain the feedback mechanism for labour
once rhythmic uterine contractions are initiated they are sustained by positive feedback by oxytocin and prostaglandins
what are some of the proposed triggers for labour onset
- CRH
- foetus stretching the cervix
- placental role
- oxytocin –> triggers prostaglandin release
which hormones cause the development of breast gland tissue during pregnancy
oestrogen
GH
cortisol
what change in the breasts occurs in late pregnancy and under what hormone
progesterone stimulates conversion of ducts to secretory epithelium
how is lactation inhibited during pregnancy
by prolactin-inhibiting hormone
what are the hormonal changes that occur after birth causing lactation
high prolactin and low oestrogen (due to placental removal)
how does suckling influence hormones
- inhibits PIH allowing prolactin to stimulate milk production for the next feed
- stimulates oxytocin to trigger myoepithelial cells for milk ejection for this feed
- inhibits GnRH and the ovarian cycle
what are the 3 major pregnancy complications
preterm labour
pre-eclampsia
IUGR
what is the definition of preterm labour
labour before 37 weeks gestation
what proportion of deliveries are preterm
5-8%
why is preterm labour bad
because it counts for 80% of perinatal mortality and morbidity
what is the eitology of preterm labour
- unknown
- role of infection
- premature rupture of membranes
- multiple pregnancy
- polyhydramnios
what is pre-eclampsia
high maternal blood pressure, causing proteinuria and generalised oedema
why is pre-eclampsia bad
can lead to eclapsia, placental dysfunction and IUGR
pre-eclampsia is common when
first pregnancy
