O&G: Antenatal care Flashcards
pregnancy timeline
definition of Gestational Age
the duration of the pregnancy starting from the date of the last menstrual period
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definition of Gravida
the total number of pregnancies a woman has had
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definition of para
the number of times the woman has given birth after 24w gestation, regardless of whether the fetus was alive or stillborn
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G4P3
a pregnant woman with 3 previous pregnancies
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a non pregnancy woman with a previous birth of healthy twins
G1P1
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A non-pregnant woman with a previous miscarriage
G1 P0 +1
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A non-pregnant woman with a previous stillbirth (after 24 weeks gestation)
G1P1
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when is the 1st trimester
from the start of pregnancy until 12w gestation
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when is the 2nd trimester
13-26w gestation
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when is the 3rd trimester
from 27w - birth
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when do fetal movements start
from around 20w until birth
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when is the Booking clinic and what is its purpose
before 10w
offer a baseline assessment and plan the pregnancy
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when is the Dating scan
between 10 and 13+6
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what is the purpose of the dating scan
- an accurate gestational age is calculated from the crown rump length (CRL)
- and multiple pregnancies are identified
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when is first antenatal appointment and whats its purpose
16w
discuss results + plan future appointments
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when is the anomaly scan
between 18 and 20+6 weeks
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what is the purpose of the anomaly scan
an US to identify anomalies such as heart conditions
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when are the antenatal appointments and what are they for
25, 28, 31, 34, 36, 38, 40, 41 and 42 weeks
monitor the pregnancy and discuss future plans
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what is covered at each antenatal appointment
- plans for remainder of the pregnancy + delivery
- symphysis-fundal height: from 24w on
- fetal presentation: from 36w on
- urine dipstick for protein for pre-eclampsia
- blood pressure for pre-eclampsia
- urine for M+C for asymptomatic bacteriuria
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what vaccines are offered to all pregnant women
- Whooping cough (pertussis) from 16w gestation
- Influenza (flu) when available in autumn or winter
pregnancy timeline
what vaccines are avoided in pregnancy
live vaccines such as the MMR
Placenta praevia
definition
when the placenta is over the internal cervical os
Placenta praevia
definition of a low-lying placenta
when the placenta is within 20mm of the internal cervical os
3 causes of antepartum haemorrhage
placenta praevia
placental abruption
vasa praevia
Placenta praevia
risks
- antepartum haemorrhage
- emergency caesarean section
- emergency hysterectomy
- maternal anaemia + transfusions
- preterm birth and low birth weight
- stillbirth
Placenta praevia
Grade 1 or Minor praevia
placenta is in the lower uterus but not reaching the internal cervical os
Placenta praevia
grade 2 or marginal praevia
the placenta is reaching, but not covering the internal cervical os
Placenta praevia
grade 3 or partial praevia
the placenta is partially covering the internal cervical os
Placenta praevia
grade 4 or complete praevia
the placenta is completely covering the internal cervical os
Placenta praevia
the grading system is outdates, what 2 descriptions are now used
low-lying placenta
placenta praevia
Placenta praevia
RFs (6)
- previous caesarean sections
- previous placenta praevia
- older maternal age
- maternal smoking
- structural uterine abnormalities (e.g. fibroids)
- assisted reproduction (e.g. IVF)
Placenta praevia
dx
the 20w anomaly scan is used to assess the position of the placenta and diagnose placenta praevia
Placenta praevia
presentation
- many are asymptomatic
- painless vaginal bleeding in pregnancy (antepartum haemorrhage)
bleeding usually occurs later around 36w
Placenta praevia
mnx of a low-lying placenta or placenta praevia if diagnosed early
repeat TVUS at 32 and 36w
Placenta praevia
mnx of low-lying placenta or placenta praevia
corticosteroids given between 34 and 35+6 w
planned caesarean considered between 36 and 37w
Placenta praevia
why is delivery planned early
to reduce the risk of spontaneous labour and bleeding
Placenta praevia
when may emergency caesarean section be required
with premature labour or antenatal bleeding
Placenta praevia
what is the main complication
haemorrhage before, during and after delivery
Placenta praevia
what urgent mnx may be required after a haemorrhage
- Emergency caesarean section
- Blood transfusions
- Intrauterine balloon tamponade
- Uterine artery occlusion
- Emergency hysterectomy
Vasa praevia
what is it
a condition where the fetal vessels are within the fetal membranes (chorioamniotic membranes) and travel across the internal cervical os
Vasa praevia
what do the fetal vessels consist of
2 umbilical arteries
1 umbilical vein
Vasa praevia
what does the fetal membrane surround
the amniotic cavity and developing fetus
Vasa praevia
what does the umbilical cord contain
the fetal vessels:
2 umbilical arteries
1 umbilical vein
Wharton’s jelly
Vasa praevia
what is Wharton’s jelly
a layer of soft connective tissue that surrounds the blood vessels in the umbilical cord, offering protection
Vasa praevia
when can the fetal vessels be exposed, outside the protection of the umbilical cord or placenta
- Velamentous umbilical cord: umbilical cord inserts into the chorioamniotic membranes and the fetal vessels travel unprotected through the membranes before joining the placenta
- an accessory lobe of the placenta (aka succenturiate lobe) is connected by fetal vessels that travel through the chorioamniotic membranes between the placental lobes
Vasa praevia
what can exposed vessels leads to
prone to bleeding esp when membranes are ruptures during labour and at birth –> fetal blood loss + death
Vasa praevia
what is Type 1
the fetal vessels are exposed as a velamentous umbilical cord
Vasa praevia
what is Type 2
the fetal vessels are exposed as they travel to an accessory placental lobe
Vasa praevia
RFs
- low lying placenta
- IVF pregnancy
- Multiple pregnancy
Vasa praevia
dx
US during pregnancy
but may present with bleeding
Vasa praevia
asymptomatic mnx
- corticosteroids, given from 32w gestation to mature the fetal lung
- elective caesarean section planned for 34-36w
Vasa praevia
mnx if antepartum haemorrhage occurs
emergency caesarean section is required to deliver the fetus before death occurs
Vasa praevia
after stillbirth or unexplained fetal compromise during deliver, why is the placenta examined
for evidence of vasa praevia as a possible cause
Placental Abruption
what is it
when the placenta separates from the wall of the uterus during pregnancy
the site of the attachment can bleed extensively after the placenta separates
a significant cause of antepartum haemorrhage
Placental Abruption
RFs
- Previous placental abruption
- Pre-eclampsia
- Bleeding early in pregnancy
- Trauma (consider domestic violence)
- Multiple pregnancy
- Fetal growth restriction
- Multigravida
- Increased maternal age
- Smoking
- Cocaine or amphetamine use
Placental Abruption
presentation (5)
- Sudden onset severe abdominal pain that is continuous
- Vaginal bleeding (antepartum haemorrhage)
- Shock (hypotension and tachycardia)
- Abnormalities on the CTG indicating fetal distress
- Characteristic “woody” abdomen on palpation, suggesting a large haemorrhage
Placental Abruption
what suggests a large haemorrhage
characteristic ‘woody’ abdo on palpation
Placental Abruption
how can the severity of antepartum haemorrhage be defined
- spotting
- minor haemorrhage
- major haemorrhage
- massive haemorrhage
Placental Abruption
what is spotting
spots of blood noticed on underwear
Placental Abruption
what is a minor haemorrhage
<50ml of blood loss
Placental Abruption
what is a major haemorrhage
50-1000ml blood loss
Placental Abruption
what is a massive haemorrhage
> 1000ml blood loss or signs of shock
Placental Abruption
what is a concealed abruption
where the cervical os remains closed
and any bleeding that occurs remains within the uterine cavity
the severity of bleeding can be significantly underestimated with it
Placental Abruption
dx
clinical diagnosis based on presentation
initial mnx steps with major or massive haemorrhages
- Urgent involvement of a senior obstetrician, midwife and anaesthetist
- 2 x grey cannula
- Bloods include FBC, UE, LFT and coagulation studies
- Crossmatch 4 units of blood
- Fluid and blood resuscitation as required
- CTG monitoring of the fetus
- Close monitoring of the mother
- emergency caesarean if mother unstable or fetal distress
Placental Abruption
what is required when bleeding occurs in Rhesus-D negative women
anti-D prophylaxis
Kleihauer test is used to quantify how much fetal blood is mixed with the maternal blood to determine the dose of anti-D required
Placental Abruption
what is there an increased risk of after delivery in women with placental abruption
postpartum haemorrhage
active mnx of the 3rd stage is recommended
Placenta Accreta
what is it
when the placenta implants deeper, through and past the endometrium,
making it difficult to separate the placenta after delivery
Placenta Accreta
what are the 3 layers to the uterine wall
- endometrium (inner layer)
- myometrium (middle)
- perimetrium (outer)
Placenta Accreta
what does the endometrium contain
connective tissue (stroma)
epithelial cells
blood vessels
Placenta Accreta
what does the myometrium contain
smooth muscle
Placenta Accreta
what does the perimetrium contain
a serous membrane similar to the peritoneum (aka serosa)
Placenta Accreta
why might the placenta embed past the endometrium
due to a defect in the endometrium:
- previous uterine surgery: C-section or curettage procedure
Placenta Accreta
why might it lead to a postpartum haemorrhage
the deep implantation makes it very difficult for the placenta to separate during delivery leading to extensive bleeding
Placenta Accreta
what is superficial placenta accreta
the placenta implants in the surface of the myometrium, but not beyond
Placenta Accreta
what is placenta increta
where the placenta attaches deeply into the myometrium
Placenta Accreta
what is placenta percreta
where the placenta invaded past the myometrium and perimetrium, potentially reaching other organs such as the bladder
Placenta Accreta
RFs (6)
- previous placenta accreta
- previous endometrial curettage procedures (e.g. for miscarriage or abortion)
- previous caesarean section
- multigravida
- increased maternal age
- low lying placenta or placenta praevia
Placenta Accreta
presentation
usually asymptomatic during pregnancy
can present with bleeding (antepartum haemorrhage) in the 3rd trimester
Placenta Accreta
dx
can be diagnosed on antenatal USS
or at birth when it becomes difficult to deliver the placenta
Placenta Accreta
mnx if diagnosed antenatally
plan delivery between 35 to 36+6w
give antenatal steroids
Placenta Accreta
what are the options during caesarean section
- hysterectomy: w/ placenta remaining in the uterus (recommended)
- Uterus preserving surgery: resection of part of the myometrium along with the placenta
- expectant mnx: leave the palcenta in place to be reabsorbed over time
Placenta Accreta
what risks come with expectant mnx
bleeding and infection
Placenta Accreta
if placenta accreta is seem when opening abdo for elective caesarean, what do you do
close abdo and delay delivery whilst specialist services are put in place
Placenta Accreta
if placenta accreta is discovered after delivery of the baby, what is recommended
hysterectomy
Breech Presentation
what is it
when the presenting part of the fetus is the legs and bottom
Breech Presentation
complete breech
legs are fully flexed at the hips and knees
Incomplete breech
one leg flexed at the hip and extended at the knee
Extended breech
aka frank breech
with both legs flexed at the hip and extended at the knee
Footling breech
with a foot is presenting through the cervix with the leg extended
Breech Presentation
mnx for babies that are breech before 36w
none as they often turn spontaneously
Breech Presentation
when is external cephalic version used in babies that are breech
After 36 weeks for nulliparous women
After 37 weeks in women that have given birth previously
Breech Presentation
mnx if the first baby in a twin pregnancy is breech
caesarean section
Breech Presentation
what is external cephalic version
a technique used to attempt to turn a fetus from the breech position to a cephalic position using pressure on the pregnant abdomen
Breech Presentation
what is given to women before ECV
Tocolysis with SC terbutaline to relax the uterus before the procedure
Rhesus-D negative women require anti-D prophylaxis
Breech Presentation
what is terbutaline
a beta-agonist similar to salbutamol.
It reduces the contractility of the myometrium, making it easier for the baby to turn.
Pre-eclampsia
what is it
HTN in pregnancy with end-organ dysfunction
notably with proteinuria
Pre-eclampsia
how many weeks gestation does it occur
after 20w, when the spiral arteries of the placenta form abnormally
leading to high vascular resistance in these vessels
Pre-eclampsia
what can it lead to if untreated
- maternal organ damage
- FGR
- seizures
- early labour
- death
Pre-eclampsia
triad features
- hypertension
- proteinuria
- oedema
Pre-eclampsia
define chronic HTN
high BP that exists before 20w gestation and is longstanding
not caused by dysfunction in the placenta and is not classed as pre-eclampsia
Pre-eclampsia
define pregancy induced HTN or gestational HTN
HTN occurring after 20w gestation
without proteinuria
Pre-eclampsia
define eclampsia
when seizures occur as a result of pre-eclampsia
Pre-eclampsia
pathophysiology
- high vascular resistance in the spiral arteries
- poor perfusion of the placenta
- causes oxidative stress in the placenta
- and release of inflammatory chemicals into the systemic circulation
- leading to systemic inflammation and impaired endothelial function in the blood vessels
Pre-eclampsia
high-risk factors (5)
- pre-existing HTN
- previous HTN in pregnancy
- existing autoimmune condition
- diabetes
- CKD
Pre-eclampsia
moderate-risk factors (6)
- > 40yrs
- BMI>35
- > 10 yrs since previous pregnancy
- multiple pregnancy
- first pregnancy
- FH of pre-eclampsia
Pre-eclampsia
why are women offered aspirin
as prophylaxis against pre-eclampsia
Pre-eclampsia
when are women offered aspirin
from 12w gestation until birth if they have :
- 1 high-risk factor
or
- > 1 moderate-risk factor
Pre-eclampsia
symptoms
- headache
- visual disturbance / blurriness
- N+V
- upper abdo or epigastric pain (liver swelling)
- oedema
- reduced urine output
- brisk reflexes
Pre-eclampsia
NICE diagnosis
BP >140/>90
plus any of:
- proteinuria
- organ dysfunction
- placental dysfunction
Pre-eclampsia
examples of organ dysfunction
- raised Cr
- raised LFTs
- seizures
- thrombocytopenia
- haemolytic anaemia
Pre-eclampsia
example of placental dysfunction
fetal growth restriction
abnormal Doppler studies
Pre-eclampsia
how can proteinuria be quantified
Urine protein:creatinine ratio (> 30mg/mmol is significant)
Urine albumin:creatinine ratio (>8mg/mmol is significant)
Pre-eclampsia
what test should be used between 20-35w gestation to rule out pre-eclampsia
placental growth factor (PlGF)
Pre-eclampsia
what is placental growth factor
a protein released by the placenta that functions to stimulate the development of new blood vessels
Pre-eclampsia
what are the levels of placental growth factor in pre-eclampsia
low
Pre-eclampsia
mnx of gestational HTN (without proteinuria)
- aim for BP< 135/85
- weekly urine dipstick
weekly blood tests - monitor fetal growth by serial growth scans
- placental growth factor testing on one occasion
Pre-eclampsia
at what BP should you admit a woman with gestational HTN
> 160/110
Pre-eclampsia
what scoring system is used to determine whether to admit the woman with Pre-eclampsia
fullPIERS or PREP-S
Pre-eclampsia
monitoring for pre-eclamptic women
- BP monitoring every 48h
- fortnightly US monitoring
Pre-eclampsia
1st line medical mnx
labetalol
Pre-eclampsia
2nd line medical mnx
nifedipine (modified-release)
Pre-eclampsia
3rd line medical mnx
methyldopa (stop within 2d of birth)
Pre-eclampsia
what may be used as an antihypertensive in critical care in severe pre-eclampsia or eclampsia
IV hydralazine
fluid restriction
Pre-eclampsia
what is given during labour and in the 24h afterwards to prevent seizures
IV magnesium sulphate
Pre-eclampsia
after delivery, what medical mnx should be used
one or a combination of:
1st line: enalapril
1st line in black pts: nifedipine
3rd line: labetalol or atenolol
Pre-eclampsia
mnx of eclampsia
IV magnesium sulphate
Pre-eclampsia
what is HELLP syndrome
a combination of features that occurs as a complication of pre-eclampsia and eclampsia
Haemolysis
Elevated Liver enzymes
Low Platelets
Obstetric Cholestasis
aka?
intrahepatic cholestasis of pregnancy.
Obstetric Cholestasis
what does chole- mean
relates to the bile and bile ducts.
Obstetric Cholestasis
what does stasis refer to
inactivity
Obstetric Cholestasis
what is it characterised by
the reduced outflow of bile acids from the liver
Obstetric Cholestasis
how is this condition resolved
after the delivery of the baby
Obstetric Cholestasis
when does it develop in pregnancy
late (after 28w)
Obstetric Cholestasis
cause?
thought to be a result of increased oestrogen and progesterone levels
Obstetric Cholestasis
RFs
seems to be a genetic component
more common in women of South Asian ethnicity
Obstetric Cholestasis
where do bile acids come from
produced in the liver from the breakdown of cholesterol
Obstetric Cholestasis
where do bile acids flow
from the liver
to the hepatic ducts
past the gallbladder
out the bile duct
to the intestines
Obstetric Cholestasis
what causes the classic symptom of pruritis
outflow of bile acids is reduced, causing them to build up in the blood
resulting in itch
Obstetric Cholestasis
what does it increase the risk of
stillbirth