Obstetrics Flashcards
When is the booking visit?
approx 10wks gestation
How do you calculate EDD?
LMP + 7/7 + 9/12
When is the dating scan?
approx 12 wks
What is tested for in ‘booking bloods’?
- blood group and rhesus status
- FBC (for anaemia)
- haemoglobinopathies
- HIV
- hepatitis B
- syphilis
When is the anomaly scan performed?
approx 20wks
What is rhesus prophylaxis?
Given to all women who are rhesus negative
Prevents maternal antibodies attacking fetal blood
Cell free DNA or anti-D treatment
How many antenatal visits do the average nulliparous and mutliparous women recieve?
Multiparous - 8
Nulliparous - 10
What maternal factors effect fetal growth?
genetic: height, weight, parity, ethnic group
environmental: social class, nutrition, altitude, comorbidity
How do you assess fetal growth?
Symphysis-fundal height
USS
What measurments are taken in a growth scan?
biparietal diameter
head circumference
abdominal circumference
femur length
How do you assess placental function?
Doppler studies to assess blood flow in fetal arteries
What day in menstrual cycle does implantation occur?
23
Where does fertilisation occur?
fallopian tube
What are the effects of raised progesterone in pregnancy on the cardiovascular system?
increased CO (HR and SV both increased) BP decreases (fom decreased SVR)
What are the effects of raised progesterone in pregnancy on the respiratory system?
increased resp rate
What are the effects of raised progesterone in pregnancy on the uterine quiescence?
‘relaxation’
uterus doesn’t contract until the end of pregnancy
What are the effects of raised progesterone in pregnancy on the immune system?
weakened to prevent attack on baby (foreign body!)
makes UTIs and thrush v common
What are the effects of raised progesterone in pregnancy on the GI system?
progesterone is a muscle relaxant therefore –> constipation
How quickly does the fetus grow before 12wks?
Doubles in size every week until week 12
When does fetal heart activity begin?
6-7wks
When do fetal limb buds form?
8wks
What antenatal screening is offered?
fetal anomalies
infectious disease (HIV, hep B, syphilis)
haemoglobiopathies
rhesus negative
What is the ‘combined screening’?
opt-in test offered at early pregnancy scan
measures nuchal tranluscency and maternal blood test for PAPPA and HCG
results show only ‘probability of increased risk’
If the combined screening returns a ‘higher risk’ result, what can be offered to the mother?
- chorionic villous sampling (from 11wks)
- amniocentesis (from 15wks)
What is the risk of miscarriage with CVS and amniocentesis?
1% for both
Should a HIV diagnosis be written in a mother’s notes?
NO
confidential
Should a diagnosis of hepatitis B be written in a mother’s notes?
YES
clear documentation necessary as notifiable disase
What intervention is necessary in a pregnant women with a new diagnosis of hepatitis B?
- refer to hepatology
- new born vaccines (5 doses)
- household contact testing
What intervention is necessary in a pregnant women with a new diagnosis of syphilis?
- refer to GUM for abx
- need full treatment at least 4wks before delivery to prevent transmission
- partner tracing
Which of the following tests are opt-in or opt-out?
- HIV
- Hepatitis B
- syphilis
- haemoglobinopathies
- combined screening
HIV: opt-out Hep B: opt-out syphilis: opt-out Haemoglobinopathies: opt-out combined screening: opt-in
Why do pregnant women get carpal tunnel?
Due to signifiacnt oedema, causes compression on median nerve in wrist
In which trimester are women likely to suffer from haemorroids?
3rd trimester
Why do pregnant women get varicose veins?
progesterone relaxes vasculature and fetal mass effects pelvic venous return
How do urinary symptoms vary from 1st to 3rd trimester?
1st: frequency from increased glomerular filtration rate
3rd: stress incontinence from pressure on pelvic floor
Why is constipation common in pregnancy?
reduced gastric motility (mediated by progesterone)
What hormone is thought to be responsible for ‘morning sickness’ and when does it normally resolve?
HCG
resolves by week 16-20
What is hyperemesis gravidarum?
excessive sickness and vomitting - warranting hospital admission
persisten intractable vomiting, can’t keep down fluids, weight loss and severe dehydratioin
What is the treatment for hyperemesis gravidarum?
admit for oral fluids if can’t keep down (saline or Hartmann’s)
daily U&Es - replace K+ as necessary
NBM for 24hrs
antiemetics (promethazine or cyclizine)
What is SGA?
‘small for gestational age’ - born with weight less than 10th centile
How do you distinguish between a baby who is constitutionally small and one who has IUGR?
IUGR: head sparing, growth slows and plateaus
CS: always small but increasing size normally and otherwise healthy
What factors affect the placental transfer of nutrients (therefore are RFs for IUGR)?
Severe anaemia
low pre-pregnancy weight
substance abuse
What factors affect placental implantation and vascultaure (therefore are RFs for IUGR)?
pre-eclampsia autoimmune disease thrombophilias renal disease DM HTN
What are the major RFs for IUGR?
maternal age >40 smoker cocaine use daily vigorous exercise previous SGA baby previous still birth chronic HTN DM with vascular disease renal impairment antiphospholipid syndrome
What factors can make measuring symphysis-fundal height inaccurate?
high BMI
large fibroids
multiple pregnancy
If a patients SFH measures small, what is done next?
Women with major risk factors are referred for serial USS and umbilical artery Doppler
Women with minor risk factors referred for Doppler - if abnormal, then serial USS as well
What medications should be given in severe IUGR?
Progesterone to prevent pre-term birth
Maternal steroids in case of pre-term birth
What is macrosomia?
‘large for dates’
babies bown with a weight above the 90th centile
What are risk factors for macrosomia?
maternal diabetes Hx of fetal macrosomia maternal obesity excessive weight gain in pregnancy male infant overdue
What complications arise from fetal macrosomia?
Maternal:
- prolonged vaginal delivery time (higher risk of CS)
- uterine rupture (if previous CS
- difficult/traumatic birth
Fetal:
- hypoglycaemia after delivery
- childhood obesity
- increased risk of birth defects
- respiratory distress
When should women be aware of fetal movements?
from 20 wks
What does fetal movement indicate?
integrity of CNS and MSK system
What are the risks associated with reduced fetal movement?
IUGR, placental insufficiency, congenital malformation
What is a prolonged pregnancy?
pregnancy exceeding 42wks form first day of LMP
What risks to the mother are associated with prolonged pregnancy?
anxiety and psychological stress
increased need for intervention (IOL, operative delivery etc)
What risks to the fetus are associated with prolonged pregnancy?
- perinatal mortality
- meconium aspiration
- shoulder dystocia
- fetal distress in labour
- oligohydramnios
- neonatal hypothermia/hypoglycaemia/polycythaemia
- fetal post-maturity syndrome
What is the management of a prolonged pregnancy?
offer stretch and sweep from 41wks
offer IOL at 41-42wks
continuous fetal monitoring with CTG
What is PPROM?
preterm pre-labour rupture of membranes
What is PROM?
premature rupture of membranes (at term, but before onset of labour)
How do you diagnose ROM?
- pooling of amniotic fluid on speculum
- nitrazine/ferning staining
At what gestation can labour be induced?
34wks
For women with PROM and PPROM, what is their chance of spontaneous labour?
PPROM - 80% within 7days
PROM - 90% within 48hrs
How do you manage PPROM?
<34 wks
- aim for increased gestation
- monitor for signs of chorioamnionitis
- prophylactic erythromycin
- 2x12mg betametasone 24hrs apart
34-36wks
- monitor for signs of chorioamnionitis
- prophylactic erythromycin
- 2x12mg betametasone 24hrs apart
- IOL recommended
>36wks -monitor for signs of chorioamnionitis -clindamycin/penicillin during labour watch and wait for 24hrs (may labour spont) -IOL
What are the main complications associated with PPROM?
- chorioamnionitis
- oligohydramnios
- neonatal death
- placental abruption
- umbilical cord prolapse
What fetal risks are associated with IUGR?
- intrapartum fetal distress
- meconium aspiration
- emergency CS
- necrotising enterocoloitis
- hypoglycaemia and hypocalaemia
What social factors calss a pregnancy as high risk?
- teenage pregnancy
- maternal age >40
- high parity
- low interpregnancy interval
- alcohol intake
- substance misuse
- poor socioeconomic conditions
What obstetric history would cause the currecnt pregnancy to be classed as high risk?
CS preterm delivery recurrent miscarriage stillbirth GDM pre-eclampsia 3rd-4th deg tear
What Hx of the current pregnancy would class it as high risk?
multiple pregnancy SGA placenta previa GDM pre-eclampsia meconium stained liquor worrying CTG need for oxytocin lack of progress
What is the management of hypertension in pregnancy?
1st: labetalol (contraindicated in asthma)
2nd: nifedipine
NB do not use ACEi in pregnancy
What is the stage of cleavage for various types of twins?
DCDA: day 1-3
MCDA: day 4-8
MCMA: day 8-13
conjoined: day 13-15
What are the maternal complications associated with multiple pregnancy?
- hyperemesis gravidarum
- anaemia
- miscarriage
- preterm labour
- pre-eclampsia
- antepartum and postpartum haemorrhage
- postnatal depression
What are the fetal risks associated with multiple pregnancy?
- prematurity
- congenital abnormalities
- fetal growth restriction
- intrauterine death
How regularly do multiple pregnancies recieve growth scans?
DCDA - 4wkly from 16wks
MCDA/MD - 2wkly from 16 wks
When should multiple pregnanceis be delivered?
DCDA - 37-38wks
MCDA - 36wks
What is recurrent miscarriage?
3 or more consecutive miscarriages in 1st trimesters with same biological father
What are possible causes of recurrent miscarriage?
- antiphospholipid syndrome
- genetic factors
- fetal chromosomal anomalies
- anatomical abnormalities
- large fibroids
- thrombophilic disorder
- infection
- 35% have no known cause
How should recurrent miscarriage be investigated?
- parental blood karyotyping
- cytogenic analysis of products of conception
- thrombophilia screen
- antibody testing
What is mid-trimester loss?
Loss of pregnancy between 12 and 24wks
What are possible causes of mid-trimester loss?
chronic disease (DM, HTN, lupus, CKD)
infection
medications (misprostol, retinoids, methotrexate, NSAIDs)
PCOS