Introduction
Cesarean delivery (CD) is one of the most common surgeries worldwide, performed on one in four pregnant women in the UK (according to the NHS website) and up to four in five women in other regions of the world.1 The rate of subsequent vaginal birth after Cesarean section (VBAC) is low, and estimated to be 13.3% in the United States,2 and only 52.2 percent will attempt VBAC for their second birth in the UK.3 The implications of repeat CD on morbidity are profound and include higher rates of blood transfusions, surgical injuries and hysterectomies, with increased rates of complications as the number of CD increases.4,5Therefore, many healthcare organizations try to increase VBAC rates. When consulting a woman regarding the mode of delivery, the risks and benefits of trial of labour after Cesarean (TOLAC) should be discussed, as well.6 Each woman should be advised according to her own obstetric and demographic characteristics, as well as her personal risk-factors for uterine rupture.7 Known risk-factors, such as previous arrest of descent, vertical uterine scar, etc. are well-established but infection of surgical site in the first CD is a possible risk-factor that has not been investigated in depth. The few studies that have been published are small and most did not isolate the type of infection as an independent risk factor.8Currently, previous peripartum infections are not included into consultations regarding the preferred mode of delivery after a CD.
Peripartum infections may influence scar tissue healing and consequently affect uterine scar strength and ability to remain intact during subsequent pregnancies and deliveries. They include chorioamnionitis during labour, postpartum endometritis and other surgical site infections. Surgical site infection tends to occur within 30 days of the operation9 and may affect superficial or deep tissues. Pathogens commonly associated with obstetrical infections are Gram-negative bacilli, enterococci, Group B streptococci and anaerobes.10
It is well-established that surgical scar infection is a risk-factor for impaired healing.11 The pathogens interfere with leukocyte function and angiogenesis. Free radicals and cytotoxic enzymes are released from neutrophils,12,13 which may interfere with the healing process and leave the scar weaker and more vulnerable. Although it is not commonly considered a risk-factor for uterine rupture during labour, a surgical scar with previous surgical site infection (SSI) may have a higher tendency to rupture during a subsequent trial of labour.
The objective of this study was to investigate whether peripartum infection in the first CD is an independent risk-factor for uterine rupture in a subsequent delivery.