• No screening test is entirely accurate.
• 17% to 25% of women who have a positive swab at 35–37 weeks of gestation will be GBS negative at delivery.
•  5% to 7% of women who are GBS negative at 35–37 weeks of gestation will be GBS positive at delivery.
• Many of the babies who are severely affected from GBS infection are born prematurely, before the suggested time for screening.

• If the history suggests that the reaction described is not likely to be allergic in nature then penicillin should be given.
• If the history suggests an allergy to beta-lactams, but one that is not severe(i.e. no anaphylaxis, angioedema, respiratory distress or urticaria), then a cephalosporin can be administered.
• If the allergy to beta-lactams is severe then intravenous vancomycin is recommended.

Antenatal treatment for vaginal or rectal colonisation does not reduce the likelihood of GBS colonisation at the time of delivery and so is not indicated in this situation.

IAP should be offered to GBS-colonised women

The recommended dose is - 3 g intravenous benzylpenicillin be given as soon as possible after the onset of labour  and 1.5 g 4 hourly until delivery.
The first dose should be given at least 4 hours prior to delivery.

Successful VBAC is more likely among women with previous caesarean for
fetal malpresentation (84%) compared with women with previous caesarean for either labour dystocia (64%) or fetal distress (73%) indications.

Up to 10% of women scheduled for ERCS go into labour before
39+0 weeks. Therefore it is good practice to to discuss and document a plan for delivery if labour starts prior to the scheduled date.

Previous vaginal delivery, particularly previous VBAC, is the single best predictor of successful VBAC and is associated with a planned VBAC success rate of 85–90%.

Previous vaginal delivery is also independently associated
with a reduced risk of uterine rupture.

• The timing of delivery should be tailored to the patient.
• If history of vaginal bleeding/ other risk factors for preterm delivery- consider ‘Late preterm delivery’- 34+0 to 36 +6 weeks.
• If uncomplicated placenta previa- Consider between 36+ 0 and 37+0.

This is GBS bacteruria. GBS bacteriuria is associated with a higher risk of chorioamnionitis and neonatal disease. Women with GBS bacteriuria should be offered IAP.

Women with GBS urinary tract infection (growth of greater than 10^5 cfu/ml) during pregnancy should receive appropriate treatment at the time of diagnosis as well as IAP. 

Planned VBAC is associated with an approximately 1 in 200 (0.5%)
risk of uterine rupture

Bonus info- There is at least one more condition in which the delivery should be delayed for some time after appearance of the condition- Chickenpox ! In varicella rash- planned delivery should normally be avoided for at least 7 days after the onset of the maternal rash to allow for the passive transfer of antibodies from mother to child.

If the placenta is thought to be low lying (less than 20 mm from the internal os) or praevia
(covering the os) at the routine fetal anomaly scan, a follow-up ultrasound examination
including a TVS is recommended at 32 weeks of gestation to diagnose persistent low-lying
placenta and/or placenta praevia.

Use of TVS- to accurately see the placental edge. Also, cervical length is a predictor of antepartum bleeding and emergency preterm caesarean section in placenta praevia. Women with a cervical length of less than 31 mm have a 16 times higher risk of emergency
caesarean section due to massive haemorrhage.