PBL B11 W2

Question 1

Pre-eclampsia

Answer 1

Hypertension after 20 weeks gestation and is characterised by hypertension of at least 140/90 and proteinuria during pregnancy.

Question 2

Cause of pre-eclampsia

Answer 2

There is abnormal development of the placenta, where the trophoblasts are dysfunctional in their capacity for invasion of the myometrium which means spiral arteries maintain their muscular walls so blood flow through the spiral arteries is limited leading to placental hypoxia that causes endothelial damage. This occurs due to maternal immune system being active.

Question 3

Features of pre-eclampsia in maternal body

Answer 3

Inflammation; increased natural killer cells and Th1 promote development of autoantibodies which reduces angiogenesis and worsens oxidative stress, causing poor utero-placental perfusion. Maternal vasoconstriction occurs which causes high BP and hypoxia. The endothelial damage drives platelet consumption and reduces platelet count and hypoxia causes elevation of liver enzymes.

Question 4

Risk factors for pre-eclampsia

Answer 4

First pregnancy
High BMI
Maternal age over 40
Multiple pregnancy
Pre-existing conditions
Long interval between pregnancy
It can develop to eclampsia and cause seizures because of cerebral oedema.

Question 5

When is labour induced?

Answer 5

Labour is induced when pregnancy is beyond 42 weeks gestation, preeclampsia, gestational diabetes, twins or IUGR.

Question 6

When should labour induction be avoided?

Answer 6

It should be avoided with breech pregnancy, previous C-Section or placenta covers the cervix.

Question 7

What pain relief is available in labour?

Answer 7

Laughing gas/nitric oxide: partial agonist at opioid receptors

Injection of opiate and local anaesthetic in the epidural space at the level of L4

Opiate such as pethidine injected intramuscularly

Question 8

Which medications induce labour?

Answer 8

Oxytocin causes contraction of uterine smooth muscle

Prostaglandin causes cervical effacement which promotes dilation

Question 9

What are the types of femake pelvis?

Answer 9

Gynaecoid, android, platypelloid and anthropoid.

Question 10

What are the segments of the foetal skull?

Answer 10

Vault: contains parietal bone and portions of the temporal, frontal and occiptal

Face

Base

Question 11

What is the latent phase of labour?

Answer 11

Latent phase is the onset of contractions with cervical effacement and cervical shortening and cervical dilation at 3-4cm. It is faster in primiparous women.

Question 12

What is Stage 1 of labour?

Answer 12

The longest stage in labour with regular contractions and fully dilated at 10cm as the foetal head descends. Moulding occurs of the foetal cranial bones due to compression of maternal pelvis, with localised oedema swelling as foetal head presents.

Question 13

What is Stage 2 of labour?

Answer 13

Active and passive contractions for propulsion of the foetus.

Question 14

What is Stage 3 of labour?

Answer 14

Delivery of baby and placenta no more than 30 minutes later. Synthetic oxytocin and controlled cord contraction is used to speed up this stage. Delivery of the placenta creates open vascular beds that causes excessive bleeding, which must be prevented via uterine contractions around blood vessels to prevent post-partum haemorrhage.

Question 15

What is controlled cord traction?

Answer 15

-> controlled cord traction is pulling the umbilical cord to encourage placenta separation from the uterus.

Question 16

What is the role of the umbilical vein?

Answer 16

Umbilical vein transports oxygenated blood to the foetus in the right atria. A portion of blood meant to enter the right atria is transported to the inferior vena cava by the ductus venosus to be directed to the foetal vein and the liver.

Question 17

What is the role of the umbilical artery?

Answer 17

2 are contained in the umbilical cord which transport waste and deoxygenated blood from the foetus to the placenta.

Question 18

What is IUGR?

Answer 18

Intrauterine growth retardation is when the foetal size is below the expected standard for gestational age, typically in the 10th centile where 90% of foetuses of the same gestational age are larger. This is determined by measuring the symphysis-fundal height or a pre-natal ultrasound.

Question 19

How is IUGR classified?

Answer 19

Symmetrical IUGR: head and brain are small along with the rest of the foetal body.

Asymmetrical IUGR: Head and brain are expected size, but foetal body is disproportionally smaller because of vasodilation of vessels supplying vital organs, leading to foetal kidney failure. This is associated with uteroplacental insufficiency.

Question 20

What are the implications of IUGR?

Answer 20

IUGR means there is an increased risk that the baby will have neurological issues, abnormal blood count, low blood sugar and higher risk of pre-term birth so greater infection susceptibility. Foetus will have low blood calcium levels and low energy store so risk of hypothermia. Foetal kidney produces amniotic fluid in later pregnancy, therefore IUGR causes oligohydroamniosis (low amniotic fluid.) The hypoxia causes foetal acidaemia and risk of asphyxia during labour.

Question 21

What are the causes of IUGR?

Answer 21

Foetal infection with cytomegalovirus, measles or toxoplasmosis

Multiple pregnancy

Chromosomal/structural abnormality

Placental insufficiency

Question 22

How does placental insufficiency cause IUGR?

Answer 22

Not enough maternal blood supplied to the embryo for nutrients needed for development. This means the foetus has lower stores of free fatty acids and glycogen, inducing hypoglycaemia and lower subcutaneous fat.
Low oxygen uptake induces EPO production and leads to foetal polycythaemia, directing blood flow to the vital organs away from the developing liver and bones. There is reduced foetal kidney function SO volume of amniotic fluid.

Question 23

Why does placental insufficiency occur in IUGR?

Answer 23

low pre-pregnancy weight

Single umbilical artery for delivery of foetal blood to placenta

Monochorionic placenta that causes uneven blood flow/multiple pregnancy

Pre-eclampsia which leads to abnormal blood vessel development

diabetes or chronic autoimmune disease

smoking and drinking during pregnancy

daily vigorous exercise

Foetal infection

Question 24

What is an episiotomy?

Answer 24

Incision into the perineum and posterior vaginal wall during the 2nd stage of labour

Question 25

Where is milk produced in the breast?

Answer 25

Milk is produced in the mammary glands of the breast. These are modified versions of apocrine sweat glands that are larger

Question 26

How are the breast lobes separated?

Answer 26

separated by fibromuscular stroma called Cooper’s ligaments. These are continuous ligaments with the skin which are important for supporting the breasts and attaching the breast to the pectoralis fascia.

Question 27

What is the level of the breasts anatomically and nerve innervation?

Answer 27

Breast is innervated by the 4th to 6th thoracic intercostal nerve which control smooth muscle of blood supply and the muscles. It is at the level of ribs 2-6 and lies between sternum to mid-axillary line.

Question 28

What is the first stage of lactogenesis?

Answer 28

18 weeks post gestation, rise in progesterone induces production of colostrum. This is nutrient rich milk which contains many immunoglobins.

Question 29

What is the second stage of lactogenesis?

Answer 29

Post birth approximately 32-96 hours, there is copious milk production due to drop in oestrogen and increase in prolactin.

Question 30

What is the third stage of lactogenesis?

Answer 30

Maintenance of milk production via prolactin delivery initially. It is then maintained by suckling.

Question 31

Prolactin receptor theory

Answer 31

Activation of nipple mechanoreceptors decreases dopamine and induces prolactin release from lactotroph region in the anterior hypophysis which acts on lactocytes in the mammary gland for production of milk. Milk is produced by glandular cells during pregnancy and stored until interaction via touch receptors on nipple induces oxytocin release from the posterior pituitary gland that causes myoepithelial cells to contract and release of milk from the nipple. Oxytocin inhibits dopamine release.

Question 32

Why is breastfeeding beneficial for mother?

Answer 32

beneficial for losing weight post birth and shrinking of the uterus.

Question 33

Issues with bottlefeeding?

Answer 33

Highly processed and can cause GI issues and lead to enterocolitis and increases the risk of immune hypersensitivity such as eczema due to no transfer of antibodies. It requires sterilisation. Formula fed babies eat less often because it is difficult to digest formula milk.

Question 34

Cause of infective mastitis?

Answer 34

commonly caused by staphylcoccus aureus, and occassionally E.Coli and streptococci or epididermis. It causes rigor, redness, continuous pain even during breastfeeding and nipple discharge containing pus or blood. Infective mastitis is transmitted via pathogens on baby’s mouth, or break in the skin such as a nipple piercing.