Obstetrics: Antenatal

Question 1

What is obstetric cholestasis - how does it present, what are the risks and how is it managed?

Answer 1

The impaired flow of bile during pregnancy causes a build up of bile sats which can deposit in the skin and cause itching. The build up of bile salts can be detrimental to foetal wellbeing and the normal management is to induce labour at 37 weeks. Ursodeoxycholic acid is widely used as it vitamin K supplements.

Question 2

What physiological changes occur in the cardiovascular system during pregnancy?

Answer 2

1. Stroke volume increases by 30%
2. Heart rate increases by 15%
3. Cardiac output increases by 40%
4. Diastolic BP is lowered in the first and second trimester and returns to normal by term
5. Enlarged uterus may interfere with venous return which causes ankle oedema, supine hypotension and varicose veins.

Question 3

What physiological changes occur in the respiratory system during pregnancy?

Answer 3

1. Pulmonary ventilation increases by 40%
2. Tidal volume increases from 500ml to 700ml
3. Oxygen requirements increase by 20%
   4.

Question 4

What physiological changes occur in the haematological system during pregnancy?

Answer 4

1. Maternal blood volume increases by 30% - red cells up by 20% but plasma up by 50% so the haemoglobin levels fall.
2. Rise in coagulation due to rise in fibrinogen and factors VII, VIII and X.
3. Platelet count falls
4. WCC and ESR rise

Question 5

What bloods are done at the booking visit?

Answer 5

FBC
Blood group and antibodies 
Hepatitis B 
HIV
Rubella 
VDRL
Random blood glucose

Question 6

What is the normal schedule of midwife antenatal care?

Answer 6

Booking visit at 8 - 12 weeks 
Dating USS and 11 - 12 weeks 
Anomaly scan at 20 weeks 
Monthly visits until 28 weeks 
Anti D (if required) at 28 and 34 weeks 
Fortnightly visits 28 - 36 weeks 
Weekly visits 37 weeks until delivery

Question 7

What examinations/investigations are done at every antenatal visit?

Answer 7

Blood pressure
Urinalysis
Fetal heart

Question 8

When would essential hypertension present in pregnancy compared to gestational hypertension?

Answer 8

Essential - Before 20 weeks

Gestational - After 20 weeks

Question 9

What three anti - hypertensive are safe to be used in pregnancy?

Answer 9

1. Labetalol
2. Methyldopa
3. Nifedipine (usually only if monotherapy fails)

Question 10

What medications are used if a women presents with severe hypertension in pregnancy?

Answer 10

Labetalol (oral or IV)
Hydralazine (IV)
Nifedipine

Question 11

What extra screening do women with diabetes get in pregnancy?

Answer 11

Detailed USS at 28, 32 and 36 weeks with extended cardiac views
Retinal screening every trimester

Question 12

What BM and HBA1C should you be aiming for in pregnancy?

Answer 12

BM 4 - 6

HBA1C less than 6%

Question 13

What clotting factors increase in pregnancy?

Answer 13

VII, VIII, X and fibrinogen

Question 14

What investigation do you do for a suspected DVT in pregnancy?

Answer 14

Duplex US of lower limb

Question 15

What is the management for a suspected/confirmed PE is pregnancy?

Answer 15

Low molecular weight heparin
Continued until 3 months after delivery or 6 months after treatment (whichever is longer) Heparin in stopped during labour

Question 16

How do you manage hypothyroid in labour?

Answer 16

Increase levothyroxine by 25 - 50mcg in first trimester. Repeat TFTs every trimester

Question 17

Does hyperthyroid get better or worse in pregnancy?

Answer 17

Worse in the first trimester due to HCG

Improvement in the second and third trimester

Question 18

What is acute fatty liver of pregnancy?

Answer 18

A rare and life threatening complication of pregnancy that occurs in the third trimester or immediate period after delivery. It presents with nausea, vomiting, anorexia and abdominal pain. Jaundice and fever may also occur.
AST and ALT are raised as is bilirubin. There is also a high WCC and this can progress to DIC due to fat deposit in the microvasculature.

Treatment is to correct the fluid balance, electrolyte abnormaliites and DIC. It almost always requires a C section as the mother and fetus are both likely to be in distress

Question 19

What do you do to the thyroxine dose during pregnancy?

Answer 19

Increase levothyroxine by 25 - 50mcg in first trimester

Repeat TFTs every trimester

Question 20

What happens to hyperthyroid during pregnancy?

Answer 20

Gets worse due to HCG in the first trimester.
Improves in the second and third trimesters
TFTs every trimester