4. Obstetrics p108-111 (Maternal Disorders in Pregnancy)

Question 1

Incompetent cervix (2)

Answer 1

Shortened cervix, associated with high risk of premature delivery.
Endocervical canal <2.5cm in length.

Question 2

Hydronephrosis (2)

Answer 2

Occurs in 80% of pregnancy due to mechanical compression of ureters.
More often right sided (dextrorotation of pregnant uterus).

Question 3

Fibroids (3)

Answer 3

Tend to grow in early pregnancy due to elevated oestrogen.
Progesterone will have opposite effect, inhibiting growth later in pregnancy.
Stretching of uterus may affect arterial blood supply and promote infarcts and cystic degeneration.

Question 4

Uterine rupture (3)

Answer 4

Commonest in 3rd trimester at site of prior C-section.
Other risk factors: Unicornate uterus, prior uterine curettage, trapped uterus (persistent retroflexion from adhesions) and interstitial implantation

Question 5

HELLP syndrome (3)

Answer 5

Haemolysis, Elevated Liver enzymes, Low Platelets.
Most severe form of pre-eclampsia, favours young primigravid women in their third trimester.
20-40% end up with DIC.
Seen as subcapsular hepatic haematoma in pregnant or recently pregnant woman.

Question 6

Peripartum cardiomyopathy (3)

Answer 6

Dilated cardiomyopathy, seen in last month of pregnancy to 5 months post-partum.
Cardiac MRI findings include global depressed function, and non-vascular territory subepicardial late enhancement - corresponding to cellular lymphocyte infiltration

Question 7

Sheehan syndrome (4)

Answer 7

Pituitary apoplexy, seen in post partum female suffering from large volume haemorrhage.
Pituitary grows during pregnancy, and hypotensive episode can cause ischaemia.
MR appearance depends on time period, acutely is usually T1 bright.
Ring enhancement of an empty sella is a late look.

Question 8

Ovarian vein thrombophlebitis (3)

Answer 8

Cause of post partum fever, risk factors include C-section and endometritis.
RIght side is affected 5x more than the left.
Enlarged ovary with thrombosed adjacent ovarian vein

Question 9

Retained products of conception (5)

Answer 9

Typical clinical story of continued bleeding after delivery (or induced abortion). Commonest appearance is echogenic mass within uterine cavity.
Varied presence or absence of flow.
Irregular thickening of the endometrium with some reflective structures and shadowing, representing foetal parts.
Can also be considered if endometrial thickness is >5mm following D&C.
Associated with medical termination, second trimester miscarriage and placenta accreta

Question 10

Endometritis (3)

Answer 10

Inflammation or infection of endometrium.
Hx will be fever, uterine tenderness and C-section (prolonged labour).
US will show thickened, heterogenous endometrium without fluid or air.

Question 11

Placentation terminlogy (4)

Answer 11

Monozygotic twins (identical),
Dizygotic twins (not identical).
Dizygotics are always dichorionic and diamniotic.
Monozygotic have more varied placenta, depending on timing of fertilized ovum splitting (before 8 days = diamniotic, after = mono).
Late splitting after 13 days can cause conjoined twin.
Later split = worse outcomes.

Question 12

Monochorionic vs dichorionic (5)

Answer 12

Membrane thickness
- Thick = easy to see (1-2mm), thin = hard to see.
- Thick suggests 4 laters = dichorionic
Twin peak sign
- Beak like tongue between 2 membranes of a dichorionic diamniotic fetus.
- Excludes monochorionic foetus.
T-sign: Absence of twin peak sign. No chorion between membrane layers. Suggests monochorionic.

Question 13

Twin growth (3)

Answer 13

Normal growth charts in first and second trimester (not third).
Femur length tends to work best for aging twins in later pregnancy.
More than 15% difference in foetal weight or abdominal circumference is considered significant

Question 14

Twin-twin transfusion (4)

Answer 14

Occurs in monochorionic, when vascular communication exists in the placenta.
End up with one larger twin taking all the blood and nutrients.
Larger twin ends up doing worse, getting hydrops and more mortality.
Unequal fluid in amniotic sacs with donor twin having severe oligohydramnios and sometimes “stuck to the wall” of the uterus.
Larger twin floats freely in the polyhydramniotic sac.
Donor twin also has high resistance umbilical artery spectrum.

Question 15

Twin reversed arterial perfusion syndrome (4)

Answer 15

Intraplacental shunting resulting in a “pump” twin, who pumps blood to the other twin. Other twin ill not develop a heart and referred to as an acardiac twin.
Acardiac twin ends up with deformed upper body, whilst pump twin usually does OK.
If acardiac twin is >70% of foetal weight of co-twin, the strain usually kills the pump twin.
Can show as doppler with umbilical artery flow towards the acardiac twin, or vein flow away from acardiac twin

Question 16

One dead twin (2)

Answer 16

Bigger problem for surviving twin if it occurs later in pregnancy.
Foetal papryaceous is a pressed flat dead foetus

Question 17

Twin-twin embolisation syndrome (3)

Answer 17

Embolysed necrotic dead baby being transferred to living foetus.
Can result in DIC, tissue ischaemia and infarct.
Can only occur in monochorionic pregnancy.

Question 18

Things that grow during pregnancy (4)

Answer 18

Babies.
Splenic artery aneurysms.
Renal AMLs.
Fibroids.