Antenatal Flashcards
What is gestational diabetes
Reduced insulin sensitivity ( carbohydrate intolerance) during pregnancy which may or may not resolve after birth
Give 5 RFs for gestational diabetes
- Previous gestational diabetes
- Previous macrosomic baby (≥ 4.5kg)
- BMI > 30
- black Caribbean, Middle Eastern and South Asian origin
- Polyhydramnios
- First gen FHx of diabetes
What is the screening test of choice for gestational diabetes
oral glucose tolerance test
What time of day should an Oral Glucose Tolerance Test (OGTT) be performed?
In the morning after a fast (patient can drink plain water).
When should individuals with risk factors for gestational diabetes be screened?
With an oral glucose tolerance test (OGTT) at 24–28 weeks gestation
When do women with a history of previous gestational diabetes have an OGTT?
as soon as possible after the booking clinic and subsequently at 24-28 weeks
Describe the oral glucose tolerance test
- patient drinks a 75g glucose drink at the start
- blood sugar level is measured before the sugar drink (fasting) and then at 2 hours
What are the diagnostic thresholds on an OGTT for gestational diabetes
- fasting glucose >= 5.6mmol/L
- 2 hour glucose >= 7.8mmol/L
How is gestational diabetes managed
- joint diabetes and antenatal clinics
- education - self monitoring of glucose, exercise, diet
- Fasting glucose <7 mmol/l: trial of diet and exercise for 1-2 weeks
- fasting glucose >7 mmol/l: start insulin ± metformin
- Fasting glucose >6 mmol/l plus macrosomia (or other Cx): start insulin ± metformin
How is gestational diabetes managed in a woman with a fasting glucose <7mmol/L
- trial of exercise for 1-2w
- if glucose targets not met within 1-2w then start metformin
- if glucose targets still not met, add short acting insulin
What medication is suggested for women who decline insulin or cannot tolerate metformin in the management of gestational diabetes?
Glibenclamide - sulfonylurea
How is gestational diabetes followed up postnatally
test fasting glucose at 6 weeks
How are pregnant women with pre-existing diabetes managed
- folic acid 5 mg/day from pre-conception to 12 weeks gestation
- retinopathy screening
- stop oral hypoglycaemic agents, apart from metformin, and commence insulin
- planned delivery between 37 and 38+6 w
- tight glycaemic control
What are the self-monitoring blood sugar targets for pregnant women with gestational and pre-existing diabetes?
- Fasting: 5.3 mmol/l
- 1 hour post-meal: 7.8 mmol/l
- 2 hours post-meal: 6.4 mmol/l
- Avoid levels of 4 mmol/l or below.
What are the risks to babies of mothers with diabetes?
- Neonatal hypoglycaemia
- Polycythaemia (raised haemoglobin)
- Jaundice (raised bilirubin)
- Congenital heart disease
- macrosomia -> birth trauma
When are women routinely screened for anaemia during pregnancy?
At the booking clinic and again at 28 weeks gestation
What causes anaemia in pregnancy
During pregnancy, the plasma volume increases. This results in a reduction in the haemoglobin concentration. The blood is diluted due to the higher plasma volume.
What are the normal ranges for haemoglobin during pregnancy
- Booking bloods: > 110 g/l
- 28 weeks gestation: > 105 g/l
- Post partum: > 100 g/l
What screening for haemoglobinopathy is offered to women at the booking clinic?
- Thalassaemia screening for all women.
- Sickle cell disease screening for women at higher risk.
Give 3 maternal complications of sickle cell in a pregnant woman
- crisis
- thrombosis
- pre-eclampsia
Give 2 fetal complications of sickle cell in their mother
- intrauterine growth retardation
- increased perinatal mortality
How is sickle cell managed in pregnancy
- folic acid 5mg
- aspirin
- penicillin V
- LMWH
In a pregnant woman with hypertension, which 3 antihypertensive medications should be stopped due to teratogenicity
- ACE inhibitors (e.g. ramipril)
- Angiotensin receptor blockers (e.g. losartan)
- Thiazide and thiazide-like diuretics (e.g. indapamide)
Give 3 antihypertensive drugs that are safe to use in pregnant women with existing hypertension
- Labetalol (a beta-blocker )
- Calcium channel blockers (e.g. nifedipine)
- Alpha-blockers (e.g. doxazosin)
Give some RFs of VTE in pregnancy and state their risk level
- Prev VTE - high
- thrombophilia - high/med
- prolonged hospitalisation - med
- co-morbidities - med
- surgery - med
- age >35
- BMI >30
- Parity >3
- smoking
- multiple pregnancy
- gross varicose veins
- immobility
- current pre-eclampsia
- FHx
When should VTE prophylaxis be initiated in pregnant women
- From 28 weeks till 6w postnatal if there are three RFs
- From the first trimester to 6 weeks postnatal if there are four or more risk factors
- if there’s a single high/ medium risk factor - as above
What is the pharmacological prophylaxis for VTE in pregnancy
Low molecular weight heparin (LMWH) unless contraindicated.
Eg. enoxaparin, dalteparin and tinzaparin
What is the protocol for VTE prophylaxis during and after labour?
Prophylaxis is temporarily stopped when the woman goes into labor and can be started immediately after delivery (except with PPH, spinal anaesthesia, and epidurals.
What is the recommendation for anticoagulation treatment if a DVT is diagnosed shortly before delivery?
Continue anticoagulation treatment for at least 3 months.
What are the options for mechanical VTE prophylaxis in pregnant women with contraindications to LMWH?
- Intermittent pneumatic compression (equipment that inflates and deflates to massage the legs).
- Anti-embolic compression stockings.
What is intrahepatic cholestasis of pregnancy
characterised by the reduced outflow of bile acids from the liver in a pregnant woman
(aka obstetric cholestasis)
When does obstetric cholestasis typically present?
Later in pregnancy, particularly in the third trimester.
Give 3 features of obstetric cholestasis
- pruritis - typically worse on palms, soles and abdomen
- jaundice (uncommon)
- excoriations without a rash
What fetal complication is associated with obstetric cholestasis?
increased risk of stillbirth.
How is obstetric cholestasis investigated
- LFTs - abnormally raised
- raised bile acids
How is obstetric cholestasis managed
- topical emollients - soothe skin
- antihistamine (e.g. chlorphenamine) - help sleep
- monitoring LFTs and bile acids
- ursodeoxycholic acid - reduce severity of pruritis
- vitamin k supplements
- induction of labour at 37-38w if [bile acids] >100micromol/L
Define gravidity
the total number of pregnancies a woman has had
Define parity
the number of times the woman has given birth after 24 weeks gestation, regardless of whether the fetus was alive or stillborn
Define gestational age
refers to the duration of the pregnancy starting from the date of the last menstrual period
What are the 3 trimesters of pregnancy
- first - from the start of pregnancy until 12 weeks gestation
- second trimester - from 13 weeks until 26 weeks gestation
- third trimester - from 27 weeks gestation until birth
At what gestation do fetal movements typically start
20 weeks
In pregnancy, what is the dating scan and when should it be done
- ultrasound to determine accurate gestational age using crown-rump length, also detects multiple pregnancies
- between 10 and 13+6 weeks
What is the basic antenatal schedule recommended for women with uncomplicated pregnancies
- 16w - discuss results of booking blood tests and screening of chromosomal abnormalities
- 18 - 20+6w - anomaly scan
- 25, 28, 31, 34, 36, 38, 40 and 41w
- scans at 25, 31 and 40 weeks are only done for nulliparous women
What are the key assessments and discussions during routine antenatal appointments?
- Discuss plans for the remainder of the pregnancy and delivery
- Symphysis–fundal height measurement from 24 weeks onwards
- Fetal presentation assessment from 36 weeks onwards
- Blood pressure
- Urine dip
Name conditions that all pregnant women are offered screening for
- anaemia
- HIV, Hep B
- syphilis
- rhesus status and blood group
- fetal anomalies
- down’s syndrome
- rubella immunity
- thalassaemia
Name a haemoglobinopathy screened for in high risk pregnant women
sickle cell disease
What is the advice on vitamin supplementation in pregnant women
- folic acid 400mcg from before conception till 12w
- avoid vitamin A as can be teratogenic in high doses
- 10mcg Vit D daily
What conditions are risk assessed in women during antenatal appointments, and what plans are made for high-risk conditions?
- Rhesus negative (book anti-D prophylaxis)
- Gestational diabetes (book oral glucose tolerance test)
- Fetal growth restriction (book additional growth scans)
- VTE (provide prophylactic LMWH if high risk)
- Pre-eclampsia (provide aspirin if high risk)
What is the standard screening test for down’s syndrome antenatally
- combined test
when should the combined test be done when screening for down’s syndrome
between 11 - 13+6 weeks
Describe how the combined test is done
- ultrasound to measure nuchal translucency
maternal blood test to measure: - Beta‑human chorionic gonadotrophin (beta-HCG)
- Pregnancy‑associated plasma protein‑A (PAPPA)
What results would suggest down’s syndrome on the combined test
- high bHCG
- low Pregnancy‑associated plasma protein‑A (PAPPA)
- nuchal translucency thickness > 6mm
What screening test is done for down’s syndrome if the woman books too late for the combined test.
quadruple test done between 14-20w
What is measured in the quadruple screening test in regards to chromosomal abnormalities and what results would indicate down syndrome
- bHCG (high)
- alpha-fetoprotein (low in trisomy 21)
- inhibin (high in trisomy 21)
- oestriol (low)
Screening tests provide a risk score for the fetus having down-syndrome. What score is considered high risk
1 in 150 chance or less (eg 1 in 100)
What is offered to pregnant women with a high risk score after down-syndrome screening
- non-invasive prenatal screening test (NIPT)
- diagnostic tests: amniocentesis (after 15w) or chorionic villus sampling (before 15w)
Give 2 examples of neural tube defects
- spina bifida
- anencephaly (incompatible with life)
What protein is raised in a fetus with a neural tube defect
alpha-fetoprotein
Give 3 RFs for congenital heart anomalies
mother with:
* congenital heart disease
* diabetes
* antiepileptic meds
What is exomphalos
abdominal contents protrude through the anterior abdominal wall but are covered in an amniotic sac formed by amniotic membrane and peritoneum
Give 2 conditions associated with exomphalos
- down’s syndrome
- cardiac and kidney malformations
How is exomphalos managed
- C-section due to risk of sac rupture
- staged repair
What is gastroschisis
congenital defect characterised by free loops of bowel in the amniotic cavity
How is gastroschisis managed
postnatal surgery within 4 hours of birth
What is the most important antigen of the rhesus system
D antigen
Explain how rhesus incompatibility in pregnancy can be an issue
- if a Rh -ve mother has a Rh +ve child a leak of fetal red blood cells may occur
- this causes anti-D IgG antibodies to form in mother as she has become sensitised to rhesus-D antigens
- in later pregnancies these antibodies can cross placenta and cause haemolysis in rhesus +ve fetus
- this is haemolytic disease of the newborn
How is rhesus incompatibility in pregnancy managed
- test for D antibodies in all Rh -ve mothers at booking
- prevention of sensitisation (prophylaxis): IM anti-D to non-sensitised rhesus -ve mothers at 28w (or 28 + 34w)
What situations in pregnancy necessitate the administration of Anti-D immunoglobulin as soon as possible
- delivery of Rh +ve infant
- antepartum haemorrhage
- amniocentesis, chorionic villus sampling, fetal blood sampling
- abdominal trauma
- miscarriage if gestation is > 12 weeks
- ectopic if managed surgically
- any termination of pregnancy
anti-D within 72h
What tests should be done to assess rhesus incompatibility and sensitisation
- all babies born to Rh -ve mother should have cord blood taken at delivery for FBC, blood group & direct Coombs test
- Coombs test: direct antiglobulin, will demonstrate antibodies on RBCs of baby
- Kleihauer test (>20w) : add acid to maternal blood, fetal cells are resistant and persist while mothers Hb is destroyed. calculate remaining cells
What is the purpose of the Kleilhauer test
checks how much fetal blood has passed into the mother’s blood during a sensitisation event
What are dizygotic twins
non-identical
* develop from fertilisation of two different oocytes by two different sperms at the same time
What are monozygotic twins
identical twins
* from mitotic division of a single zygote
Are dizygotic or monozygotic twins more common?
dizygotic
What are dichrorionic diamniotic (DCDA) twin pregnancies
two separate placentas and two separate amniotics sacs
What are monochrionic diamniotic (MCDA) twin pregnancies
shared placenta but separate amniotic sacs
(most common)
What are monochorionic monoamniotic (MCMA) twin pregnancies
shared placenta and single amniotic sac
Give 4 predisposing factors for dizygotic twin pregnancies
- previous twins
- IVF
- FHx
- increasing maternal age
Give 3 maternal complications of multiple pregnancies
- anaemia
- gestational HTN
- postpartum haemorrhage
Give 5 fetal complications of multiple pregnancies
- miscarriage
- prematurity
- twin-twin transfusion syndrome
- fetal growth restriction
- congenital abnormalities
Explain twin-twin transfusion syndrome
- occurs when the fetuses share a placenta
- caused by unequal blood distribution through vascular anastomosis of the shared placenta
What are the effects of twin-twin transfusion syndrome on the ‘donor’
- volume depleted
- oligohydramnios
- growth restriction
- anaemic
What are the effects of twin-twin transfusion syndrome on the ‘recipient’
- fluid overloaded
- polyhydramnios
- heart failure
- polycythaemia
How is twin-twin transfusion syndrome managed
laser ablation of interconnecting vessels
How are multiple pregnancies managed antenatally
- FBC at booking, 20w and 28w
- 2 weekly scans from 16w for monochorionic twins
- 4 weekly scans from 20w for dichorionic twins
When is delivery advised in different types of multiple pregnancies
- 37 - 37+6w for uncomplicated dichorionic diamniotic twins
- 36 - 36+6w for uncomplicated monochorionic diamniotic twin
- 32+0 - 33+6 weeks for uncomplicated monochorionic monoamniotic twins
- before 35+6w for triplets
What are the delivery options for diamniotic twins
- vaginal delivery if the first baby has a cephalic presentation
- may need emergency csection to deliver the second twin after vaginal birth of the first twin
- elective caesarean if the first twin is not cephalic at the time of planned birth
What are the delivery options for monoamniotics twins
elective Csection between 32 - 33+6w
What is a breech presentation
when the presenting part of the fetus is the legs and bottom
State and define the 3 types of breech presentation
- extended (frank) breech - both hips flexed and knees fully extended
- footling breech - one or both feet present below the buttocks
- Flexed (complete) breech - both legs flexed at the hips and knees
What is the most common breech presentation
Extended/frank breech - 70%
Give 4 RFs for breech presentations
- prematurity
- fetal abnormality
- placenta praevia
- pelvic tumours/ deformaties
How are breech presentations managed
- <36w - no intervention as baby may turn spontaneously
- > 37w - External cephalic version.offer at 36 if nulliparous
- If ECV fails then choice between planned vaginal delivery and elective caesarean
What are the benefits of an elective caesarean compared to a vaginal delivery when delivering a breech baby
caesarean carries a reduced perinatal mortalitiy and early neonatal morbidity
Describe how external cephalic version is done
- tocolysis to relax uterus - SC terbutaline
- attempt to turn fetus using pressure applied on abdomen
- performed under ultrasound guidance
- Anti-D prophylaxis given to rhesus-D negative women
Give 5 contraindications to external cephalic version
- if vaginal delivery is contraindicated
- ruptured membranes
- multiple pregnancy
- antepartum haemorrhage
- compromised fetus
What is fetal lie
the relationship of the fetus to the long axis of the uterus
What are the 3 types of fetal lie
- longitudinal (mc) - cephalic or breech
- transverse lie - head in one flank
- oblique - head in one iliac fossa
Give 4 risk factors for abnormal fetal lie
- polyhydramnios
- high parity
- multiple pregnancy
- fibroids and other pelvic tumours
Give 3 complications of abnormal fetal lie
- pre-term rupture of membranes
- cord-prolapse
- uterine rupture if obstruction neglected
How are transverse and oblique lie managed
- <36w - no action required unless in labour
- > 37w - admit to hospital. ECV if membranes haven’t ruptured and women would like a vaginal delivery
- elective caesarian - patient choice or ECV failed/ CI
What is fetal hydrops
occurs when extra fluid accumulates in two or more fetal compartments
What is an unstable fetal lie
when a fetus’s position and presentation frequently change in late pregnancy, usually after 37 weeks
GIve 4 causes of fetal hydrops
- Immune: anaemia and haemolysis secondary to rhesus disease
- Non-immune:
- chromosomal abnormalities
- structural abnormalities (pleural effusion)
- cardiac abnormalities
- anaemia causing heart failure (parvovirus, fetal a-thalassaemia major)
How is obesity in pregnancy defined
BMI > 30 kg/m2
Give 5 maternal risks of obesity in pregnancy
- pre-eclampsia
- venous thromboembolism
- gestational diabetes
- postpartum haemorrhage
- wound infections
Give 5 risks to the fetus due to maternal obesity in pregnancy
- congenital anomaly
- perinatal mortality
- prematurity
- macrosomia
- stillbirth
How is obesity in pregnancy managed
- women avoid dieting and instead maintain weight during pregnancy due to malnutrition risk
- 5mg folic acid
- gestational diabetes screening
- BMI >40 - anaesthetic risk assessment and antenatal thromboprophylaxis
Define small for gestational age
a fetus that measures below the 10th centile for their gestational age
What 2 measurements on ultrasound are used to assess fetal size
- Estimated fetal weight (EFW)
- Fetal abdominal circumference (AC)
What are the two categories of causes for Small for Gestational Age
- Constitutionally small, matching the mother and others in the family, and growing appropriately on the growth chart
- Fetal growth restriction (FGR), aka intrauterine growth restriction (IUGR)
Define intrauterine growth restriction
when there is a small fetus (or a fetus that is not growing as expected) due to a pathology
What are the two categories of causes for intrauterine growth restriction?
- Placenta-mediated growth restriction.
- Non-placenta-mediated growth restriction
What conditions can lead to placenta-mediated fetal growth restriction
- Pre-eclampsia
- Maternal smoking
- Maternal alcohol/ drug use
- Anaemia
- Malnutrition
- Infection (e.g. CMV)
- Maternal health conditions (e.g. autoimmune)
What are some causes of non-placenta-mediated growth restriction in the fetus?
- Genetic abnormalities
- Structural abnormalities
- Fetal infection
- Errors of metabolism
Apart from small for gestational age, give 4 signs that indicate fetal growth restriction
- Reduced amniotic fluid volume
- Abnormal Doppler studies
- Reduced fetal movements
- Abnormal CTGs
Give 3 complications of fetal growth restriction
- stillbirth
- fetal distress
- preterm delivery
Give 5 RFs for small for gestational age
- heavy daily exercise
- smoking
- cocaine usage
- prev SGA baby or stillbirth
- multiple pregnancy
What parameters are monitored in a fetus at risk or with Small for Gestational Age (SGA) using serial ultrasound scans?
- Estimated fetal weight (EFW) and abdominal circumference (AC) to determine the growth velocity
- Umbilical arterial pulsatility index (UA-PI) to measure flow through the umbilical artery
- Amniotic fluid volume
How is intrauterine growth restriction managed
- serial growth scans
- early delivery by caesarean or induction if fetal compromise
What is placenta accreta
when the placenta implants deeper, to the myometrium instead of endometrium, making it difficult to separate the placenta after delivery of the baby
Give 2 RFs for placenta accreta
- previous caesarean section
- placenta praevia
What is the risk of placenta accreta
As the placenta does not properly separate during labour there is a risk of postpartum haemorrhage
Describe the 3 types of placenta accreta
- superficial accreta: placenta implants in the surface of the myometrium, but not beyond
- increta: placenta attaches deeply into the myometrium
- percreta: placenta invades past the myometrium and perimetrium, potentially reaching other organs such as the bladder
