M5 Antenatal Care Flashcards
What % of sections are elective vs emergency
Emergency 15% (14.8%)
Elective 10% (10.7%)
Risk of uterine rupture in planned VBAC
1 in 200 (0.5%)§
Success rate of planned VBAC
Up to 75%
Success rate of planned VBAC with previous vaginal birth
Up to 90%
Women with previous uterine rupture - what is risk of recurrent uterine rupture with vaginal birth?
5%
What is % risk of placenta praevia with
1 previous CS
2 previous CS
3 previous CS
1 previous CS - 1%
2 previous CS - 1.7%
3 previous CS - 2.8%
What % of women with placenta praevia also have a placenta accreta
1 previous CS
2 previous CS
5 previous CS
1 previous CS - up to 14%
2 previous CS - up to 40%
5 previous CS - up to 67%
VBAC after x2 previous CS
Success rate? %
Uterine rupture rate? %
Rate of hysterectomy? /10,000
Success - 71%
Uterine rupture - 1.36%
Rate of hysterectomy? 56/10,000
(compared to 19/10,000)
US myometrial thickness for uterine defect
positive predictive (mm)
negative predictive (mm)
positive predictive i.e. there is a uterine defect <2mm
negative predictive i.e. uterus okay 2.1-4mm
What % of women go into labour before ELCS?
10%
Risk of OASI in VBAC (%)
5%
Risk of instrumental in VBAC (%)
39%
Risk of maternal death with VBAC vs ELCS
VBAC 4 / 100,000
ELCS 13 / 100,000
Unclear whether statistically significant. Absolute risk low.
VBAC infant outcomes
Stillbirth
HIE
Perinatal death
Vs ELCS infant outcome
Perinatal death
VBAC
Stillbirth 10 / 10,000
HIE 8 / 10,000
Perinatal death 4/ 10,000
ELCS
Perinatal death 1/ 10,000
What % of uterine rupture cases need hysterectomy?
Up to 33%
What % of VBAC infant outcomes are due to uterine rupture in
HIE
Perinatal death
HIE - 33% due to uterine rupture
Perinatal death - 60% due to uterine rupture
Transient tachypnoea of newborn risk
VBAC
ELCS
VBAC - up to 3%
ELCS - up to 5%
IOL, no previous vaginal birth, BMI >30, prev CS for labour dystocia –> what % with all of these factors achieve VBAC
40%
VBAC success with reason for previous CS
malpresentation
fetal distress
labour dystocia
malpresentation - 84%
fetal distress - 73%
labour dystocia - 64%
What % of cases of uterine rupture have abnormal CTG
75%
Abnormal CTG most consistent finding
VBAC with IOL
What fold increased risk of:
EMCS
Uterine rupture
VBAC with IOL
EMCS - 1.5 fold
Uterine rupture - 3 fold
What dose of oxytocin increases the risk of uterine rupture in VBAC four fold
> 20 miliunits/minute
How much higher is risk of stillbirth after 39 weeks in women with previous caesarean
1.5 - 2 fold higher
Absolute risk
11 / 10,000
vs
5 / 10,000
What gestation should vasa praevia be delivered at?
ELCS at 34-36 weeks
(in asymptomatic women)
What % of women planning vaginal breech need an EMCS
40%
5 scenarios where vaginal breech higher risk:
-Footling breech
-Hyperextended neck
-EFW >3.8kg
-SGA EFW <10th centile
-Antenatal fetal compromise
Breech presentation occurs in what % of term deliveries?
Up to 4%
(and more preterm)
Risk of abnormally invasive placentation with
1 previous CS
4 previous CS
1 previous CS - 0.31%
4 previous CS - 2.33%
Figures from the VBAC green top p.12
What period of time allowed for passive second stage before Caesarean section recommended in breech?
If the breech is not visible within 2 hours of the passive second stage, caesarean section should be recommended.
Three reasons to expedite breech?
- Poor condition: tone/colour
- delay of more than 5 minutes from delivery of the buttocks to the head
- delay more than 3 minutes from the umbilicus to the head.
What % of vaginal breech deliveries have head entrapment?
14%
Where should incisions be made on cervix for head entrapment
2, 6, 10 o’clock
What % of pregnancies are complicated by PPROM
3%
What % of preterm births are associated with PPROM?
Up to 40%
What is the median latency after PPROM
Medial latency after PPROM is 7 days.
Tends to shorten as gestational age advances
What is the success rate of ECV (%)
50% success rate of ECV
What is the total fetal blood circulation at term?
80-100ml/kg
(therefore small bleed from vasa praevia = most of fetal blood circulation)
Risk ratio of perinatal death with vasa praevia
4.52
What are fetal survival rates with vasa praevia when
- diagnosed antenatally
- diagnosed intrapartum
- diagnosed antenatally 97%
- diagnosed intrapartum
44%
Eponymous name for painless vaginal bleeding
Benckiser’s haemorrhage
Definition of vasa paevia
A vessel running in the free placental membranes within 2 cm of the cervix
When should vasa praevia be diagnosed
At anomaly scan (18-24 weeks) -prenatal diagnosis most effective at this gestation.
+ reconfirmed during third trimester (30-32 weeks)
What are the prenatal detection rates of vasa praeiva (range)
53-100%
Name 5 risk factors for vasa praevia
placenta praevia (60%)
velamentous cord insertion (56%)
bilobed placenta,
succenturiate placental lobes,
assisted reproductive technology
Should twins be screened for vasa praevia?
