Diseases in and of pregnancy Flashcards
What is oligohydramnios?
Amniotic fluid less than expected for gestational age
What is polyhydramnios?
Amniotic fluid greater than expected for gestational age
What is the combination of intrauterine growth restriction and polyhydramnios suggestive of?
Trisomy 18 (Edwards syndrome)
What strain of GBS is carried by up to 20% of women vaginally?
Streptococcus agalactiae
What are 3 foetal risks of GBS?
- Preterm labour
- Rupture of membranes
- Neonatal infection
What is the nuchal translucency test?
Done during 11-14w USS
Measures the subcutaneous area between the skin and cervical spine of the foetus in the sagittal section
Nuchal translucency increases when fluid accumulates in the area e.g. in Down Syndrome
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What tests are done around week 12 to screen for Down Syndrome?
Nuchal translucency (USS)
bHCG (elevated)
PAPP-A (decreased)
What is PAPP-A?
Pregnancy-associated protein A
A serum protein mainly synthesised by the placenta and therefore increases in pregnancy
Decreased in conditions involving chromosomal aberration
Why is hepatitis B screened for in pregnancy?
High rate of perinatal transmission
If an infant is infected the risk of chronic hepatitis is 90%
When in pregnancy is chorionic villus sampling (CVS) performed?
10-13 weeks
From when in pregnancy can amniocentesis be performed?
From the 15th week of pregnancy onwards
What is the risk of miscarriage with CVS?
1%
0.5% for amniocentesis
What is the definition of a spontaneous abortion/miscarriage?
Loss of pregnancy before 20 weeks’ gestation
What is the definition of a stillbirth?
Loss of pregnancy after 20 weeks’ gestation
What is a threatened abortion and is the cervical os closed or dilated?
Vaginal bleeding has occurred and the cervical os is closed, but the diagnostic criteria for spontaneous abortion has not been met
What is an inevitable abortion? Is the cervical os open or closed?
The patient has vaginal bleeding and visible/palpable products of conception
The internal cervical os is open
What is an missed abortion? Is the cervical os open or closed
Abortion in which the products of conception are not expelled spontaneously from the uterus. Symptoms of early pregnancy e.g. nausea, breast tenderness, disappear
The cervical os is closed
What is an incomplete abortion? Is the cervical os open or closed
Products of conception within the cervical canal or uterus
Open cervical os
What is a complete abortion? Is the cervical os open or closed?
Products of conception are entirely out of the uterus and cervix
The cervical os is closed, the uterus is small and well-contracted, vaginal bleeding and pain may be mild or resolved
How is a threatened abortion managed?
Expectant
(symptoms will resolve or progress to inevitable, incomplete or complete abortion)
What is a grade 1 perineal tear?
Laceration of the vaginal mucosa or perineal skin only
What is a grade 2 perineal tear?
Laceration involving the perineal muscles
What is a grade 3 perineal tear?
Laceration involving the anal sphincter muscles
What is a grade 4 perineal tear?
Laceration extending through the anal epithelium resulting in a communication of the vaginal and anal epithelium
What is the quantitiative definition of oligohydramnios?
Amniotic fluid index (AFI) < 5cm
What is the quantitiative definition of polyhydramnios?
Amniotic fluid index (AFI) > 25cm
What are 3 causes of a higher than expected hCG?
- Molar pregnancy
- Twins
- Choriocarcinoma
- Embryonic carcinoma
What are 2 causes of a lower than expected hCG?
- Ectopic pregnancy
- Threatened abortion
- Missed abortion
What is the most common cause of abnormal hCG?
Inaccurate dating
What is the intrapartum treatment for GBS positive mothers?
IV penicillin or ampicillin
When is GBS screened for in pregnancy?
35-37 weeks
GBS carriage fluctuates so colonisation is screened close to term
What is the treatment of intrahepatic cholestasis of pregnancy?
Ursdeoxycholic acid (a bile acid; symptomatic relief and may improve foetal outcomes)
Delivery at 37 weeks
What is the major function of human chorionic somatomammotropin (human placental lactogen)?
Increases maternal insulin resistance
What is the definition of gestational hypertension?
Onset after 20 weeks gestation
SBP > 140
DBP > 90
On two separate occasions at least 4 hours apart
What is the definition of pre-eclampsia?
Gestational hypertension with
- proteinuria
- renal insufficiency
- thrombocytopenia
- evidence of liver damage
- pulmonary oedema
- cerebral oedema
What is HELLP syndrome?
A life-threatening form of pre-eclampsia
H = haemolysis
EL = elevated liver enzymes
LP = low platelets
What are 3 teratogenic effects of ACE inhibitors?
- Altered kidney development
- Neonatal renal failure
- Pulmonary hyperplasia
- Foetal growth retardation
What is alloimmunisation?
An immune response to foreign antigens after exposure to genetically different cells or tissues
e.g. pregnancy, transplant, transfusion
What condition is characterised by hyperthryoidism in the first trimester which spontaneously resolves?
hCG-mediated hyperthyroidism
hCG acts on the maternal thyroid
Which drugs are used for hyperthyroidism in pregnancy?
Propylthiouracil until 16 weeks
Carbimazole may be taken after 16 weeks
What is postpartum lymphocytic thyroiditis?
Autoimmune thyroiditis within a year of birth
Hyperthyroidism → hypothyroidism → recovery
How is hypothyroidism in pregnancy treated?
Levothyroxine
What are the adverse effects of cocaine use during pregnancy?
Vasoconstriction
→ placental abruption
→ preterm birth
→ low birth weight
→ small for gestational age
How is foetal anaemia assesed?
Blood flow through the middle cerebral artery on US
What are the sonographic features of hydrops?
Ascites, pleural and pleural effusions (rims of echolucent fluid inside the abdominal wall, chest and heart)
Skin oedema (subcutaneous tissue thickness on chest or scalp > 5mm) - late sign
May also be associated with polyhydramnios and placental oedema
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When do pregnant women have an OGTT?
Weeks 26-28
What fasting plasma glucose is diagnostic of GDM?
5.1 mmol/L or greater
What 1-hour glucose following 75g oral load is diagnostic of GDM?
10.0 or greater
What 2-hour glucose following 75g oral load is diagnostic of GDM?
8.5 or greater
What is hydrops fetalis?
Abnormal fluid accumulation in two or more foetal compartments
(ascites, pleural effusion, pericardial effusion, skin oedema)
May also be associated with polyhydramnios and placenta oedema
What is the most common cause of recurrent miscarriages in the second trimester?
Bicornate uterus, resulting from incomplete fusion of the paramesonephric ducts during uterine development
Name 3 conditions that predispose a women to preeclampsia or eclampsia
- Hypertension
- Chronic renal disease
- Diabetes
What is thought to be the initial insult that leads to increased vascular tone in preeclampsia?
Poor dilation of the spiral arteries → placental insufficiency → increased vascular tone
If a foetal anomaly has caused polyhydramnios, what process is likely failing to occur?
Swallowing of amniotic fluid
Name two congenital conditions associated with polyhydramnios
Oesophageal or dueodenal atresia
Anecephaly
If a foetal anomaly has caused oligohydramnios, what process is likely failing to occur?
Decreased urine excretion
Name two congenital conditions associated with oligohydramnios
- Bilateral renal agenesis (no urinary tract)
- Posterior urethral valves (obstructed urinary excretion)
What is the Potter sequence?
Oligohydramnios → decreased amniotic fluid ingestion → pulmonary hypoplasia (severe neonatal respiratory insufficiency) → death
What are the main DDx for RUQ pain in pregnancy?
- Gallstones
- Severe preeclampsia/HELLP
- Acute fatty liver
Which anticoagulant is preferred for thromboprophylaxis during pregnancy?
LMHW
Clexane/enoxaparin
What is the second most common clinical feature of pre-eclampsia, following hypertension?
Proteinuria
List 8 clinical features of pre-eclampsia
- Protienuria
- Elevated creatinine
- Oliguria
- Raised transaminases
- Epigastric/RUQ pain
- Convulsions
- Hyper-reflexia with sustained clonus
- Headache
- Visual disturbances (blurring, photopsia, scotoma, cortical blindness)
- Stroke
- Pulmonary oedema
What is the definition of gestational hypertension?
New-onset hypertension wihtout maternal or foetal signs of pre-eclampsia after 20 weeks gestation
What are 5 maternal complications of pre-eclampsia?
- Placental abruption
- DIC
- HELLP syndrome
- Ascites
- Pulmonary oedema
- Acute renal failure
- Liver rupture
- ICH
- Eclampsia
What are two foetal complications of pre-eclampsia?
- Growth restriction
- Death
List 5 risk factors for pre-eclampsia
- Family history of pre-eclampsia
- Pre-eclampsia in a previous pregnancy
- Late maternal age
- 1st pregnancy
- New partner
- Multiple gestation
- Chronic hypertension
- Chronic renal disease
- GDM
- Thrombophilia
Why do mothers with pre-eclampsia have hyper-reflexia with clonus?
Vascular dysfunction → cerebral damage → damage of UMNs → loss on LMN inhibition
Why do women with pre-eclampsia have weight gain, oedema, crackles, papilloedema?
Endothelial dysfunction → increased vascular permeability
Why do patients with pre-eclampsia have RUQ pain?
Endothelial dysfunction → vasoconstriction → hepatic venous congestion → liver enlargement → stretching of the liver capsule
Why can women with pre-eclampsia have an AKI?
Endothelial dysfunction → arterial vasoconstriction → afferent arteriole vasoconstriction → decreased GFR
Why can oligohydramnios be a feature of pre-eclampsia?
Decreased placental perfusion → decreased foetal blood flow → redistribution of blood from the kidneys towards more vital organs
What signs warrant the use of magnesium sulfate prophylactically in women with pre-eclampsia?
Hyperreflexia/clonus
Severe headache
Visual changes
Severe preeclampsia (DBP > 110, proteinuria >300mg, thrombocytopenia)
What is a velamentous cord insertion?
Abnormal cord insertion into the chorioamniotic membranes, resulting in exposed vessels only surrounded by foetal membranes in the absence of protective Wharton’s jelly
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What are the glycaemic targets for GDM?
Fasting: < 5.0 mmol/L
2 hours post-prandial: < 6.7 mmol/L
HbA1c: < 6%
What is the Kleihauer-Betke test?
Blood test used to measure the amount of foetal haemoglobin transferred from a foetus to a mother’s bloodsteam
Usually performed in Rh-negative mothers to determine the required dose of anti-D
What dosages of anti-D are used?
625 IU
250 IU is only used for a 1st trimester sensitising event
What are the most common congenital abnormalities associated with diabetes in pregnancy?
- Cardiac (2/3) e.g. TGA, VSD, PDA
- Ancephaly and spina bifida
Highest risk in women with previous diabetes and poor glycaemic control at conception
- Flexion contracture of the limbs*
- Vertebral abnormalities*
- Cleft palate*
How is varicella zoster exposure in non-immune women managed in pregnancy?
Zoster immunoglobulin
How should a pregnant woman infected with varicella zoster be managed?
<24 hours since onset of rash: oral acyclovir
>24 hours: no treatment, monitor
What is alloimmunisation?
An immune response to foreign antigens after exposure to genetically different cells or tissues
What are the risks to the recipient twin in twin-twin transfusion syndrome?
Polycythemia
Polyhydraminos (if diamniotic)
What are the risks to the donor twin in twin-twin transfusion syndrome?
Anaemia
Growth retardation
Oligohydramnios (if diamniotic)
What drug is used to treat UTIs in pregnancy?
Cephalexin
What laboratory investigations should be done for a woman who presents with antepartum haemorrhage?
FBC
Coagulation screen
Group and save, crossmatch
Rhesus and Kleihauer if positive
UEC, LFT
What is the Kleihauer test?
Examining the blood film of the mother to look for fetal blood cells and hence determine whether there has been feto-maternal haemorrhage (as seen with placental abruption)
Foetal cells are less susceptible to acidic solutions
What are the clinical features of placenta praevia?
Painless antepartum haemorrhage
What would you expect to find on digital examination of a woman with antepartum haemorrhage caused by placenta praevia?
YOU MUST NEVER DO A DIGITAL EXAMINATION OF A WOMAN WITH SUSPECTED PLACENTA PRAEVIA AS THIS CAN PROVOKE MASSIVE BLEEDING
What would you expect to find on abdominal examination of a woman with antepartum haemorrhage caused by placenta praevia?
Soft, non tender uterus
Cephalic presentation not engaged
What are the risk factors for developing placental abruption?
Hypertension
Preeclampsia/eclampsia
Abdominal trauma
Cocaine/smoking
Previous abruption
Young/old maternal age
On abdominal palpation of a patient with placental abruption, what would you expect to find?
Tender and firm uterus
What test would confirm that blood loss is fetal and therefore possibly as a result of vasa praevia?
Kleihauer test - this must only be done if the CTG is normal as otherwise delivery should not be delayed.
What is circumvallate placenta?
A type of placental disease in which the fetal membranes (chorion and amnion) “double back” on the fetal side around the edge of the placenta.
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Does not affect placental function
What are the risk factors for placenta accreta?
Prior damage to the endometrium e.g., ablation, D&C
Previous cesarean section
If using hydralazine IV as an antihypertensive in a pregnant woman, what must you give before administering the drug?
Bolus of fluid as can cause rapid hypotension
What % of patients with eclampsia have their seizures postnatally?
40% occur within 48 hours of delivery
What is the MoA of methyldopa?
Alpha agonist
Prevents vasoconstriction
What is the MoA of labetalol?
Alpha and beta blocker
When in pregnancy is the risk of seizures at its highest?
Labour and the 24 hours following delivery. Epileptics women are advised against having home births.
What are the guidelines surrounding breast feeding and anti-epileptic medications?
Breast feeding is considered safe in epileptic mothers taking medications.
How should hyperthyroidism be treated while the mother is breastfeeding?
Carbimazole
What is the role of vitamin K in obstetric cholestasis?
Give when prothrombin time is prolonged
What are the risk factors for acute fatty liver of pregnancy?
Prior history
Multiple gestation
Pre-eclampsia/HELLP
Male fetal sex
Low BMI
How do we treat people with acute fatty liver of pregnancy?
Stabilisation
Correction of hypoglycaemia and coagulopathy
Delivery
When in pregnancy does acute fatty liver of pregnancy occur?
Third trimester
What are the complications of acute fatty liver of pregnancy?
Acute liver failure
Acute renal failure
Encephalopathy
Fetal and maternal death (10%)
What makes pregnancy a pro-thrombotic state?
Increase in certain clotting factors
Increase in fibrinogen levels
Decrease in fibrinolytic activity
Decrease in protein S and antithrombin
Increased venous stasis in lower limbs (left more than right)
At what point will pregnant women be screened for HIV?
At booking appointment
When does puerperal psychosis usually start?
2-3 weeks postnatally
Are anti-psychotic medications safe in pregnancy and breastfeeding?
Data is limited but optimistic
Use the lowest dose of a single antipsychotic
What congenital abnormality is associated with Lithium use in bipolar mothers?
Cardiac defects
When in pregnancy do women tend to be affected by nausea and vomiting in pregnancy (NVP)?
Onset: 4-7/40
Peak: 9/40
Resolution: 20/40
How do you manage hyperemesis gravidarum?
- H1 antagonists e.g., promethazine/doxylamine
- Phenothiazines e.g., prochlorperazine
- Metoclopramide
- Ondansetron
Ginger, fluids
How are VTEs in pregnancy treated?
LMWH
Continue for the remainder of pregnancy and at least 6 weeks postnatally
What is the loading dose for magnesium sulfate
4g (will be in 8mL)
How is hyperemesis gravidarum diagnosed?
- > 5% prepregnancy weight loss
- Dehydration
- Electrolyte imbalance
What happens to urea in pre-eclampsia?
Elevated
Afferent arteriolar vasoconstriction
What is the apt test?
Hemoglobin alkaline denaturation test (Apt test)
- A foetal blood sample is mixed with an alkali
- If the mixture turns red to green-brown it contains foetal and maternal blood
What is the first sign of magnesium toxicity?
Loss deep tendon reflexes (followed by respiratory then cardiac arrest)
What is the antidote for magnesium sulfate?
Calcium gluconate
Name 10 risk factors on the maternity VTE score
- Personal history of VTE
- Thrombophilia
- Ovarian hyperstimulation syndrome
- Cancer
- Pre-existing diabetes with vascular complication
- Nephrotic syndrome
- BMI > 30
- Non-obstetric surgery in pregnancy
- Parity 4+
- Smoker
- Extensive varicose veins
- Current sepsis
- Prolonged restricted mobility
- Pre-eclampsia in current pregnancy
- Mulitple pregnancy
- Hyperemesis
- PPROM
- Abruption
- 1st degree relative with VTE
When are pregnant women at the greastest risk of VTE?
Postnatally
For which condition is smoking in pregnancy protective?
Pre-eclampsia
How is asymptomatic bacteruria/UTIs/pyelonephritis treated in pregnancy?
Cephalexin
OR
Amoxycillin + clavulanate
Can trimethoprim be used in pregnancy?
Avoid in the first trimester
Safe in 2nd and 3rd trimesters
What is the importance of good glycaemic control intrapartum?
Hyperglycaemia is associated with fetal acidosis and neonatal hypoglycaemia
What is the BP target in the management of pre-eclampsia?
140/90 +/- 10
Avoid hypotension
Are uterine contractions more characteristic of placental abruption or placenta previa?
Placental abruption
What proportion of pregnancies with maternal rubella infection result in fetal damage?
90%
+ the baby sheds the virus for 6-12 months after birth if it survives
How are children born to HBV +ve mothers treated?
Immunisation and immunoglobulins at birth
What is the significance of absent end-diastolic flow (AEDF) in an umbilical artery Doppler?
Indicates foetal vascular stress in mid/late pregnancy
Placental insufficiency → increased placental resistance → reduced diastolic flow
Associated with IUGR
In which leg are DVTs in pregnancy more common?
Left (75%)
How does maternal age affect Down Syndrome risk? specific numbers
20 - 1:1500
30 - 1:900
35 - 1:350
40 - 1:100
45 - 1:30
50 - 1:6
How are pregnancy women with antiphospholipid syndrome managed?
Aspirin and LMWH from conception
How is single deepest pocket interpreted?
Oligohydramnios - depth < 2cm
Normal - depth 2-8cm
Polyhydramnios - depth > 8cm
What are the antepartum risks of obesity?
Early pregnancy loss
Preterm birth (induced and spontaneous)
Gestational hypertension
Pre-eclampsia
Obstructive sleep apnoea
Thromboembolism
VTE
What are the neonatal risks of GDM?
RDS
Jaundice
Hypoglycaemia
Prematurity
Polycythemia
Macrosomia - shoulder dystocia, fratures, palsies, caesarean section, HIE
Hypocalcaemia
What are the teratogenic effects of trimethoprim?
Neural tube defects
Folic acid antagonist
What marker on the 2nd trimester quadruple screen is abnormal in neural tube defects?
Alpha feto protein
How are mothers with hepatitis B managed in pregnancy?
Tenofovir in the 3rd trimester
To prevent transmission intrapartum
What does a positive HBsAg suggest?
Hepatitis B surface antigen
Suggests active infection, acute or chronic
What does a positive anti-HBs suggest?
Hepatitis B surface antibody
Suggests life-long immunity, either resolved infection or vaccination
What does positive anti-HBc IgM suggest?
Current infection
Positive 4-8 months after infection
What does a positive anti-HBc IgG suggest?
Resolution of acute infection
OR chronic infection (does not confer immunity)
How do HBsAg levels change over time?
Positive: 2-10 weeks after infection
Negative: 4-6 months after infection (positive anti-HBc may be the only marker of acute infection)
Positive: > 6 months after infection (signals chronic infection)
What does HBeAg reflect?
Marker of viral replication
Marker of infectibility/transmission
What is a high risk first trimester screening result?
1:300