Session 6

Question 1

1. Where is hCG is released from? When does it peak?
2. What is the function of hCG (human chorionic gonadotrophin)
3. What other two hormones is important in maintaining pregancing

Answer 1

1. syncytiotrophoblasts 10 weeks gestation
2. Mimics LH prevent degeneration of CL
3. Oestrogen and especially progesterone

Question 2

1. When does the placenta develop?
2. Early development there is focus on ensuring development of the?

Answer 2

1. 2nd week
2. Placenta & fetal membranes

Question 3

1. What is the fate of the embryonic spaces (3)

Answer 3

1. • The yolk sac disappears

• The amniotic sac enlarges
• The chorionic sac is occupied by the expanding amniotic sac

Question 4

Answer 4

Question 5

1. In early embryonic development, the establishment of the ? takes precedent, why?
2. What trophoblastic layer develops into the placenta?
3. By the end of the second week, the conceptus has fully implanted & a fibrin clot has formed at the implantation site. The embryo (the bilaminar disc) is surrounded by two cavities in the amniotic cavity and the definitive yolk sac; this is suspended in the chorionic cavity by the connecting stalk.

As the embryo develops what changes occur to these sacs & why

Answer 5

1. placenta to ensure the adequate support for the pregnancy
2. cytotrophoblast & syncytiotrophoblast
3. The yolk sac disappears to form the primitive gut tube and the amniotic sac enlarges to surround the embryo. Soon, the chorionic sac is occupied completely by the expanding amniotic sac and a potential space forms between the amnion and chorionic membrane.
   As a consequence, the placenta forms as a specialisation of the chorionic membrane.

Question 6

What does implantation achieve? (3) state the diffrent villi and give a brief description of each.

Answer 6

Allows exchange

• anchor the placenta
• establish maternal blood flow within the placenta

Question 7

During implantation the placenta forms a mass of villi. Explain what the different villi contain.

Answer 7

– primary villi: early finger-like projections of trophoblast

– secondary villi: invasion of mesenchyme into core

– tertiary villi: invasion of mesenchyme core by fetal vessels

(placental membrane progressively thins)

Question 8

Implantation defects (4)

ashermans syndrome -> adhesions -> oligomenorrhea -> pain menstration

cervical stenosis -> oligomenorrhea

Fitz-hugh-Curtis -> due to PID -> RUQ pain -> perihepatic adhesions (liver and diaphragm) -> causes peritonitis

Answer 8

Implantation in the wrong place
– Ectopic pregnancy
– Placenta praevia

Incomplete invasion
– placental insufficiency
– pre-eclampsia

Question 9

1. What three things can cause shoulder pain
2. What is an ectopic pregnancy? Symptoms
3. What is placental praevia

Answer 9

1. Gallstones, ectopic pregnancy, heart attack
2. implantation at site other than uterine body (commonly Fallopian tube)
   - can be peritoneal or ovarian

Symptoms;

• shoulder tip pian + iliac fossa pain
• uterine bleeding
  3. - implantation in the lower uterine segment/ cervical opening
• can cause haemorrhage in pregnancy
• can require C-section delivery
• bleeding in third trimester

Question 10

1. What controls invasion in implantation?
2. How does invasion differ in ectopic pregnancies?
3. What aspect is the image showing?

Answer 10

1. endometrium -> decidua (presence of a conceptus)
2. No decidua
3. Fetal

Question 11

Answer 11

Question 12

1. State the structure of the chorionic villus
2. What will these villi be in contact with?
3. Other than villi for exchange what other villi are present?
4. From the tips of large anchoring cytotrophoblast cells spill out into the endometrium creating a shell and also contribute to the remodelling the walls of maternal spiral arterioles. Hence these cells are now technically outermost but are not involved in transport and/or exchange. The chorionic plate is the “base” of the placental disc (i.e. roots of the tree) and is composed of the trophoblastic part and the mesoderm part.

Answer 12

1. One umbilical vein, two umbilical arteries
2. maternal blood (uteroplacental circulation)

syncytiotrophoblastic

3. Anchoring villi: cross the intervillous space and attach directly to the maternal uterine decidia (uterine lining (endometrium) during a pregnancy, which forms the maternal part of the placenta).

4.

Question 13

1. Who has spiral arteries?

Answer 13

1. The mother

Question 14

1. Why are the arteries spiral?
2. What do the arteries supply?
3. Explain how the placenta changes?

Answer 14

1. Low resistance vascular beds = high flow
2. intervillous space
3. Image

Question 15

What is the umbilical cord composed of?

Answer 15

• Two umbilical arteries
– Deoxygenated blood from fetus to placenta

• One umbilical vein
– Oxygenated blood from placenta to fetus

Question 16

Describe the role of the placenta as an endocrine organ supporting pregnancy LO

Hormones produced by the placenta are:

Human Chorionic Gonadotrophin (hCG)

1. When is it produce during pregnancy?
2. Why is it produced?
3. What is it produced by?
4. Clinical significance?

Answer 16

1. first 2 months of pregnancy
2. supports the secretory function of corpus luteum (continue production of progesterone & oestrogen?)
3. Syncytiotrophoblast
4. • excreted in maternal urine therefore used as the basis for pregnancy testing
   • trophoblast disease
   – molar pregnancy (hydatidiform mole)
   – choriocarcinoma

Question 17

Explain the factors influencing the passive diffusion of substances across the placenta LO

1. Name the placental steroid hormones

What week does it start releasing hormones?

2. Which placental hormones influence maternal metabolism? Explain how.
3. Which molecules pass by simple diffusion?
4. Facilitated diffusion

Answer 17

1. progesterone & oestrogen,

placental production takes over from corpus luteum by the 11th week

2. Progesterone - increased appetite
   * *hCS / hPL** - increases glucose availability to fetus
3. • water • electrolytes • urea & uric acid • gases
4. glucose transport

Question 18

Identify the major substances which are actively transported across the placenta LO

1. Where are AT transporters expressed?
2. What is actively transported?
3. – amino acids
   – iron
   – vitamins

Answer 18

1. syncytiotrophoblast

Question 19

Explain the function of the placenta as a provider of passive maternal immunity to the neonate LO

Answer 19

receptor-mediated process/ endocytosis

IgG only (concentrations exceed those in maternal circulation)

Question 20

State how gasses, urea, FFAs, glucose, aa & IgG transport across the membrane

Answer 20

Question 21

Name 5 harmful substances that can pass the placenta

Answer 21

• thalidomide
– Limb defects (Destroyed small blood vessels in the developing limbs)

• Alcohol
– FAS and ARND (Can SS via diffusion Complete alcohol syndrome)

• therapeutic drugs
– Anti-epileptic drugs – Warfarin – ACE inhibitors

• drugs of abuse
– Dependency in the fetus and newborn

• smoking

Question 22

What points of embryogenesis is the embryo susceptible?

Answer 22

• Pre-embryonic
– lethal effects

• Embryonic
– ++ sensitive
– narrow windows for some systems

• Fetal
– +/- sensitive

• After embryonic period, risk of structural defects very low
– Except CNS

Question 23

Define direct & indirect maternal causes of death

Answer 23

Question 24

Which one is a more common cause of death direct or indirect?

Answer 24

Indirect -> 75% of maternal deaths have a pre-existing medical condition

• Diabetes (prevent fetal deaths and macrosomn\ia )
• Cardiac disease
• Neurological conditions- epilepsy- rv meds
• Essential hypertension (BP tablets suitable for pregnancy - labetalol, nifedipine (SR)or methyl dopa (a2 agonist) Ace Inh and statins contraindicated
• Rheumatological conditions (ensure not on cytotoxic medication e.g. methotrexate)
• Respiratory disease- CF weight gain, use inhaler if asthmatic
• Previous spinal surgery (further imaging?)
• Bariatric surgery (avoid pregnancy for 12-18 months, GTT, 5mg folic acid, Vitamin D)
• HIV (Discuss starting HAART, mode of delivery, breast feeding contraindicated; antiretrovirals and postnatal testing in infant)

Question 25

At around 8 - 12 weeks since conception pregnant women need to book an appointment. What must be checked?

Answer 25

Question 26

Infections in pregnancy

Answer 26

Question 27

Draw a diagram showing the physiological changes in pregnancy

Question 28

What is preeclampsia

Answer 28

BP \> **140/90** \> **0.3 g**/save protein in a 24 hour urine collection \> 20 weeks gestestation will present Fibrosis of the uterine arteries (cannot dilate) -\> intrauterine growth restriction/death Reduced perfusion if the placenta -\> inflammatory markers are released Causes vasoconstriction due to endothelial dysfunction -\> hypertension Causes **oedema** -\> cerebral (eclampsia), lung, Causes vasospasm -\> kidneys (oligouria, proteinuria), retina (blurry), liver **RUQ pain** (inc liver enzymes) Damage to endothelial wall -\> thrombi

Question 29

How does our metabolism of glucose change during pregnancy?

Answer 29

There is a decrease in insulin sensitivity -\> more glucose in the blood to feed the fetus

Question 30

1. How does gestational diabetes occur? 2. Risk factors? 3. Complications?

Answer 30

1. Insulting resistance (image) 2. GTT if BMI\>30, family history of diabetes, PCOS, long term steroid use 3. fetal macrosomia, stillbirth, neonatal hypoglyceamla more glucose to fetus, pancreas produces more insulin, after laabour reduction in glucose, but still overactive pancreatic B-cells = hypoglycaemia

Question 31

How do we manage the mother?

Answer 31

Question 32

How do we manage the fetus?

Answer 32

Question 33

Management of patients with pre eclampsia State the high & low risk factors for pre eclampsia Symptoms that occur before an eclamptic episode include:

Answer 33

Low dose **aspirin** from 12 weeks (can be started up to 20 wk) continue until delivery (75mg od) severe headache problems with vision, such as blurring or flashing before the eyes severe pain just below the ribs vomiting sudden swelling of the face, hands or feet

Question 34

State how the clotting factors change during pregnancy

Answer 34

More coaguable

Question 35

State the risks for venous thromboembolism in pregnancy

Answer 35

* If **3 or more** current or persisting risk factors consider **AN prophylactic LMWH.** * If **2 or more** persisting risk factors should be considered for LMWH for **7 days PN** BMI \> **40kg/m2**, LMWH for **7** days **PN** **Emergency caesarean** section consider LMWH for **7** days **PN** Post elective caesarean section who have one or more additional risk factors (eg BMI\>35) consider LMWH for 7 days PN. Women with **VTE before** the current pregnancy should be offered **LMWH for 6 weeks following delivery.** In women who have additional **persistent** (lasting more than 7 days postpartum) **risk factors**, such as prolonged admission or wound infection, thromboprophylaxis should be extended for up to **6 weeks** or until the additional risk factors are no longer present.

Question 36

What is the effect of pregnancy on the CV, respiratory, urinary, metabolic & peripheral vascular system. State what changes are seen in each trimester.

Answer 36

Question 37

What changes are seen on an ECG of a pregnant woman

Answer 37

ECG changes that are physiological, not pathological, during pregnancy are: * atrial and ventricular ectopics * left shift in the QRS axis * small Q wave and inverted T wave in lead III * **ST segment depression and T wave inversion in the inferior and lateral leads.** * ST ELEVATION IS NOT NORMAL IN PREGNANCY- think MI

Question 38

If a patient is obese and pregnant how should we manage the patient What are obese pregnant women at risk of?

Answer 38

* Miscarriage, * Fetal congenital anomaly, * Thromboembolism * Gestational diabetes * Pre-eclampsia, * Dysfunctional labour, * Shoulder dystocia * Postpartum haemorrhage, * Wound infections * Stillbirth neonatal death * Higher caesarean section rate * Lower breastfeeding rate

Question 39

State which commonly used drugs should be avoided during pregnancy

Answer 39