Antenatal care Flashcards
Aim of fetal anatomy scans
To optimise ANC by providing accurate diagnostic information
Indications for earlier scans (before routine anomaly scan)
Abnormal first trimester scan
Parent with congenital anomaly
Prev fetal anomaly
Teratogenic drugs
High risk first trimester screening
Consanguinity
Two inconclusive NIPS
When would a single repeat scan be done
Done if optimal images not seen by 26/40
Can be due to:
- increased BMI
- large fibroids
- abdominal scarring
- suboptimal fetal position
* if second USS doesn’t give clear images, should be referred for fetal med review
NB things to be noted on anomaly scan
Fetal biometry: BPD, HC, AC, FL. Discrepancy >10-14/7, rescan in 2/52
Amniotic fluid: DVP <2= oligo, >8 - poly
Number of pregnancies
Placenta location including leading edge
Cardiac function
Placental cord insertion
Definition and management of low-lying placenta
<20mm from os
Repeat USS at 34/40
If low-lying and > PAS –> fetal med reivew
Risk factors for vasa praevia
Velamentous cord insertion
Placenta dysmorphology
Low lying or bilobed placenta
Multiple pregnancy
IVF
When to give prophylactic progesterone
Hx of spontaneous PTL <34/40
Pregnancy loss from 16/40
Cx length </= 25mm on TVUS from 16-24/40
When to stop PV progesterone
34/40
When to do cerclage
Cx <25mm
PPROM in prev pregnancy
Hx cervical trauma
Dx and mx PPROM
Spec +/- amniosure
Erythromycin 250mg QDSx 10/7
Screen for infection - FBC, CRP, VS, MSU
CTG
When NOT to do cerclage
infection
Active PVB
Uterine ctx
When to consider cerclage
Between 16-24/40
Dilated cx + unruptured membranes
Management of PTL with intact membranes
Suspected labour </=29+6
- tocolysis
- maternal corticosteroids
At 30+
- TVUS for cx length
— >15mm: unlikely PTB
— < 15mm: tocolysis and steroids
Use of fetal fibronectin
Likelihood of birth within 48 hours
+= tocolysis and steroids
Considerations for tocolytics
Consider:
- suspected/ dx labour
- gestational age
- likely benefit of corticosteroids
- NICU availability
Consider nifedipine 24 - 33+6 if intact membranes and suspected PTL
Oxytocin receptor antagonists if nifedipine contraindicated
When to give maternal corticosteroids
Offer 24 - 35+6
Consider single repeat dose if <34/40
- already had corticosteroids > 7/7 ago AND
- very high risk birth
Do not give more than 2 doses for PT babies
When to use MgSO4 in PTL
23 - 23+6 and delivery within 24 hours
Offer from 24 - 29+6 if established PTL or planned PTB within 24 hours
Consider from 30 - 33+6 if established PTL or planned PTB within 24 hours
Dosing of MgSO4
4g IV bolus over 5 minutes then 1g/hr until birth or for 34 hours
* if oliguric or renal failure, monitor Mg
Invasive fetal monitoring in PTL
Do not use FSE <34/40
Can use FSE if 34+0 - 36+6
Do not use FBS < 34/40
High risk patients for PTL
Prev PTL
Prev cone biopsy, multiple LLETZ procedures
Prev fully dilated section
Short cx/ open cx at anatomy scan
Mid trimester ROM
Third trimester ROM
Incidence of PPROM
2% pregnancies
40% of PTL
PPROM complications leading to NND
Prematurity
Sepsis
Pulmonary hypoplasia
Signs of chorioamnionitis
Maternal tachy
Pyrexia
Leucocytosis
Uterine tenderness
Malodourous PV discharge
Fetal tachy
Labs: raised WCC, CRP
Ix in PPROM
SSE +/- amniosure to dx/ confirm
Weekly FBC and HVS
Fetal monitoring
USS
Home monitoring can be considered after 72 hours observation
- twice daily temp checks
Management of PPROM
Erythromycin 250mg QDS x 10/7
Steroids if 24-34/40
If chorio suspected- broad spectrum IV ab to cover GBS, E coli, listeria, anaerobes
- co-amox not recommended d/t risk of NEC
- Delivery
Consider delivery after 34/40, no later than 36+6
- increased risk of chorio
- decreased risk of resp problems
Risk factors for PAS
Prev CS (7x inc risk)
Increased risk with more CS (67% w 4+ CS)
Uterine surgery - myomectomy, D&C
AMA
ART
Placenta praevia and CS
Maternal morbidity assoc w. PAS
MOH
Median loss >2000ml
80% require RCC
Incidence of PAS
1 in 2000 pregnancies
Diagnosis of PAS
Clear documentation of placenta site at anatomy scan if prev CS
Suspicious features –> US by fetal medicine
Standardised reporting for PAS ultrasound features
MRI for suspicious USS
2D grayscale features suspicious for PAS
Loss of clear zone - loss/ irregularity of hypoechoeic plane in myometrium under placental bed
Abnormal placenta lacunae
Bladder wall interruption
Myometrial thinning - myometrium overlying placenta <1mm or undetectable
Placental bulge - deviation of uterine serosa away from expected plane
Focal exophytic mass - placental tissue breaking through serosa and extending beyond it
2D colour doppler features of PAS
Uterovesical hypervascularity
Subplacental hypervascularity
Bridging vessels - often perpendicular to myometrium, extend from placenta across myometrium and beyond serosa
Placental lacunae feeder vessels
3D USS +/- doppler features of PAS
Complex irregular arrangement of numerous placental vessels, exhibiting tortuous courses and varying calibres
Antenatal care of PAS
MDT: fetal med, anaestetics, surgeon w expertise in complex pelvic surgeries (onco-gynae)
? PAS <24/40 - review at 24/40
? PAS > 24/40 - review within 7/7
Outpatient ANC for PAS
Suitable for PAS with no bleeding
Clearly documented delivery plan in chart
Routine FBC
Small risk of FGR - US for growth at 28, 32 and 34/40
Physio referral
Antenatal eduction
Delivery considerations in PAS
If recurrent APH, admit until delivery, XM available
Delivery at 34 - 36+6 (individualised)
Consent with senior
Decision for hyst vs conservative: MDT decision; consider woman’s preference, severity and surgical expertise
IR on case-case basis
Aortic balloon
Postnatal considerations in PAS
VTE
Fe 6/52 if anaemic antenatally
Physio
PNMH
Debrief at 6/52
Specimen for pathology to be reported as per FIGO
Final histo r/v at MDT
Risk factors for placenta praevia
Prev CS (incr w number of CS)
sTOP
Multiple pregnancy
AMA
Smoking
ART
Deficient endometrium: MROP, endo, curettage, fibroids
Diagnosis placenta praevia
low lying: <20mm from internal os on TV or TA USS after 16/40
Covering os = praevia
Complications of placenta praevia
Maternal:
- anaemia
- infection
- mat shock
- coagulopathy
- incr hospital stay
- psych trauma
- blood transfusion
Fetal:
- hypoxia
- SGA/ IUGR
- prematurity (SOL/ iatrogenic)
- fetal death
DDx APH
Abruption
Praevia
Vasa praevia
Ca cxS
Screening for placenta praevia
Placental localisation at anomaly scan
Low-lying at anomaly –> rpt at 32/40
Still low-lying at 32/40 –> TVUS at 36/40 if no PVB
Ix if ? praevia
SSE
USS: placenta location, FH
FMH: Kleihauer
CTG
Management placenta praevia if active bleeding
MDT
Admit, consider d/c if no bleeding for >48 hours
IV access, bloods, G+XM, coag +. fibrinogen
USS
SSE
Dexa if <34/40
MgSO4 if <32/40
+/- antiD
Delivery of placenta praevia
Hx bleeding: 34- 36+6
No bleeding: 36 - 37
Deliver in unit w onsite transfusion service
Senior obs and anaesthetics present
Rapid infusion and warming devices available
Consider vertical skin +/- uterine. if transverse lie to avoid placenta, esp <28/40
Placenta praevia grades
Minor:
- 1. Low lying, not reaching os
- 2. reaches os, doesn’t cover
Major:
- 3. Covers int os asymmetrically
- 4. Covers internal os symmetrically
Teratogenic drugs
TERATOWA
T- Thalidomide, Tobacco
E- Epileptic meds (valproate, phenytoin)
R - Retinoids (vit A, tretinoin, isotretinoin)
A- ACE inibitors, ARBs
T- The third element, lithium
O- oral contraceptives, hormones
W- Warfarin
A- Alcohol
