Vaginal birth after Caesarean section: an Australian multicentre study. VBAC Study Group.

Area of Science:

• Obstetrics and Gynecology
• Maternal-Fetal Medicine
• Reproductive Health

Background:

• Vaginal birth after Caesarean section (VBAC) is a significant consideration in modern obstetrics.
• Understanding the risks and outcomes associated with VBAC, particularly uterine rupture, is crucial for patient counseling and clinical practice.

Purpose of the Study:

• To investigate the rates of VBAC, uterine rupture incidence, and associated maternal and infant outcomes.
• To compare outcomes of uterine rupture in women with previous Caesarean sections versus unscarred uteri.

Main Methods:

• Retrospective analysis of medical records from 11 major Australian obstetric hospitals over a 5-year period (July 1992 - June 1997).
• Inclusion of data from 234,015 total deliveries, focusing on the 21,452 women with prior Caesarean sections.

Main Results:

• VBAC was attempted in 25.3% of women with prior Caesarean sections.
• A total of 62 significant uterine ruptures occurred, with no maternal deaths.
• Perinatal mortality associated with rupture was 25%, and 25% of cases required hysterectomy.
• The uterine rupture rate for women attempting VBAC was estimated at 0.3%, with a 0.05% perinatal death rate and 0.05% hysterectomy rate.

Conclusions:

• VBAC rates in Australia are increasing but remain lower than international benchmarks.
• Uterine rupture during VBAC is associated with serious adverse outcomes, but its incidence is low.
• Rupture during a trial of labour appears to have better outcomes compared to rupture of an unscarred uterus.