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.

• 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.

• 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.

In pregnancies<12 weeks gestation, anti-D Ig prophylaxis is only indicated following ectopic pregnancy, molar pregnancy, therapeutic termination of pregnancy and in
cases of uterine bleeding where this is repeated, heavy
or associated with abdominal pain. The minimum dose should be 250 IU. A test for fetomaternal haemorrhage (FMH) is not required

Read about Intrapartum Care in VBAC-

https://obgresource.com/2021/12/10/intrapartum-care-in-vbac-2/

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.

• Anthracyline regimens are safe
• There are fewer data on taxanes, which should be reserved for high-risk (node-positive) or metastatic disease.
• Tamoxifen is not used until after delivery.
• Trastuzumab  is contraindicated during pregnancy.
• Haemopoietic growth factors (granulocyte colony stimulating factor) may be employed to ameliorate chemotherapy-induced neutropenia.

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.

A dose of 250 IU anti-D immunoglobulin should be sufficient to cover up to five adult therapeutic doses of D positive platelets given within a 6-week period.

In severely thrombocytopenic patients with platelet count of?30 × 10^9/L, anti-D Ig should be given subcutaneously, or IV.

• 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.

After collection, swabs should be placed in a non-nutrient transport medium, such as Amies or Stuart. Specimens should be transported and processed as soon as possible. If processing is delayed, specimens should be refrigerated. When testing for GBS, the lab should be specifically informed that the swab is for GBS testing.

- For pregnancies at more than 16 weeks of gestation the term low-lying placenta should be used when the placental edge is less than 20 mm from the internal os on transabdominal or transvaginal scanning (TVS).

If the distance between the internal os and the placental edge is 20 mm or more on TVS, the placental location should be recorded as normal and managed as per routine

• The term placenta praevia should be used when the placenta lies directly over the internal os.