Comparison with existing literature
To our knowledge, this is the first systematic review performed according to the PRISMA methodology regarding this subject. It provides new information that can be used to counsel pregnant patients with a medical history of surgically corrected anorectal malformation. A recent literature study on this matter concluded that a cesarean section is preferable in patients with a cloacal repair, as these patients all have undergone some type of extensive correction of the perineal body and vagina [
6]. It is assumed that these patients have an increased risk of damage to these structures during vaginal delivery because scar tissue does not stretch as well as healthy tissue. The authors based their conclusion on their review comprising 13 different studies. However, only two studies reported results of vaginal delivery [
6]. In line with our finding, they also state that there is a paucity of evidence-based data.
In our systematic review only five articles were eligible for inclusion. All studies were of low-quality due to the study design with consequent methodological flaws. As our interest was vaginal delivery in patients with a corrected ARM we did not report the outcomes after a cesarean section which led to the exclusion of 21 articles. Only Appiah et al. and Kawaguchi et al. were included because vaginal delivery was attempted before performing a cesarean section. [
18,
19]. Appiah et al. shows the importance of screening for gynecological malformations in female patients with a history of anorectal malformation: anatomical abnormalities may be present and might affect the choice of delivery method [
18,
24]. Therefore, screening for gynecological malformations, e.g. with ultrasound, is recommended in patients with an ARM in their medical history. Collaboration between pediatric surgery and gynecology is essential in order to deliver optimal care in these patients [
24].
Most clinicians consider cloacal malformations as complex anorectal malformations requiring extensive surgery at young age. These patients might be prone to damage to their birth canal and pelvic floor by extensive stretching during vaginal delivery possibly resulting in ruptures. Therefore, in most patients, a cesarean section is advised. In other types of anorectal malformations recommendations regarding mode of delivery are not specifically made. Another possible reason for the relatively high number of cesarean sections in patients with a history of ARM may be due to cultural differences. In general, more cesarean sections are conducted in Latin America and the Caribbean region [
25].
Currently, the decision to perform a cesarean section in our population is based on expert opinion, the severity of the condition of the regarding patient and the experience of the obstetrician and pediatric surgeon. Any consensus based on the current literature is lacking at the time of writing this study.
One must bear in mind that a cesarean section can also be a potential harmful procedure for both mother and child. For example, the incidence of postoperative ileus after cesarean section is approximately 12% [
26]. In addition, there is a higher risk of postpartum sepsis and subsequent admittance to the ICU, especially in case of an emergency cesarean section. [
25,
26]. Subsequent cesarean sections and an uterus rupture in the medical history can result in even higher risks. Kramer et al. found a 47% increase in abnormal placentation and a 40% increase in placental abruption [
27]. The number of placenta accretes directly correlates with the number of previous cesarean sections. [
27]. For 1–5 cesarean sections in the past medical history the percentages are respectively 3%, 11%, 40%, 61% and 67.1% [
27]. Patients with a surgically corrected cloaca most likely underwent additional procedures like a bladder augmentation [
6]. These procedures address caution when performing a cesarean section due to the risk of iatrogenic damage. However, the risk of bleeding in a planned cesarean section is lower in comparison to a planned vaginal birth (respectively 1.1% and 6.0%) [
26].
Apart from adverse effects on the mother, a cesarean section can have disadvantages for the child as well. The lungs of a newborn should be cleared rapidly to allow gas exchange for a smooth transition to air breathing in order to prevent respiratory morbidity. Tefera et al. performed a systematic review and meta-analysis on the risk of neonatal respiratory morbidity in elective cesarean section vs vaginal delivery. Children born by elective cesarean section experienced significantly more respiratory problems compared to vaginal delivery [
28].
As a result of the mentioned arguments a vaginal delivery is preferred over a cesarean section in the Netherlands. A thorough risk assessment must be performed considering the wellbeing of both mother and child. This issue deserves further international attention, particularly for women with a history of ARM.
Approximately 2.4% of healthy women will develop obstetrical anal sphincter injuries (OASI) as a result of vaginal delivery [
29]. Recent studies show that tearing of the perineum is a risk factor for developing urinary incontinence, fecal incontinence and dyspareunia [
29,
30]. Although patients are at risk for these complications and the numbers are low, Iwai et al. and Peña et al. showed that a vaginal delivery is possible without complications in patients with an anorectal malformation. Additional research is needed to provide a recommendation about the mode of delivery in pregnant women with a history of anorectal malformations.
Strengths and limitations
This systematic review included five studies of poor quality mainly due to the methodology (i.e. case series). Large heterogeneity in these series therefore existed regarding patient selection and outcome definitions. Although in most studies general statements regarding complications of vaginal delivery were made, only two studies explicitly described them [
15,
18]. The secondary outcomes of this study were absent in most of these studies and therefore no conclusions could be drawn regarding this subject. Secondly, due to the small sample size and poor-quality data, no general recommendation can be made. As mentioned above selection bias is present in most studies included in this study. In many cases it was unclear why the decision was made to deliver vaginally. Additionally, selection bias/indication bias due to cultural differences as stated above could be of importance. Although we performed an extensive literature search, it was decided not to search for unpublished data or grey literature. Therefore, we could have missed some articles. Lastly, pilot was conducted to ensure inter-rater reliability.