The results of this systematic review and meta-analysis suggest that laparoscopic appendicectomy in pregnancy results in an almost twofold significantly higher risk of fetal loss compared with open appendicectomy. No significant differences were observed between groups in preterm delivery, birth weight, Apgar score, wound infection after surgery or duration of operation.
The higher risk of fetal loss after laparoscopic compared with open appendicectomy needs to be addressed in the era of laparoscopic surgery, and has been discussed in many reports of the relative safety of laparoscopy in pregnancy10, 13, 37
. However, this finding was largely dominated by the study of McGory and colleagues12
, which had largest sample size and greatest power in detection of an association. After exclusion of this study from the pooled analysis, there was no effect of laparoscopic appendicectomy on fetal loss.
The major consideration in laparoscopic appendicectomy in pregnancy is the effect of increased intra-abdominal pressure and fetal acidosis during carbon dioxide pneumoperitoneum. Increasing abdominal pressure from the pneumoperitoneum can lead to decreased venous return, especially in women with impaired cardiac output38
, and result in maternal hypotension and hypoxia39
. In addition, it has been reported that carbon dioxide is also absorbed across the peritoneum, which leads to fetal acidosis40
. However, this is in contrast the findings of another study that reported no substantial adverse effect on the fetus when the maximum pneumoperitoneal pressure was as high as 10–12 mmHg and the duration less than 30 min41
Although not statistically significant, the present results suggest that there may be an increased risk of preterm delivery in those undergoing laparoscopic appendicectomy compared with open appendicectomy. It is likely that this analysis did not have sufficient statistical power to detect a significant difference, given that a sample size of 749 would be required in each group to detect a RR of 1·44.
Although the mean operating time was 5·88 min longer in the laparoscopic group, this was not statistically significant. The length of hospital stay was approximately half a day shorter after laparoscopic compared with the open appendicectomy, but this result depends heavily on one outlier study and cannot be considered robust. This requires further investigation for health service use planning, but a shorter hospital stay after a laparoscopic appendicectomy might not be advantageous clinically because of the need to monitor the patient for the adverse events noted above.
This meta-analysis quantified the effects of laparoscopic and open appendicectomy on pregnancy and surgical outcomes. A previous review did not pool data and most included studies were non-comparative, with only one group21
. The present review included the most relevant pregnancy and surgical outcomes.
One major limitation is that all studies included in the pooled analysis were observational, and summary data published within each article were included in the review. Many other factors (such as patient age, duration of pregnancy, weight gain, complicated appendicitis, surgeon's skill, clinical setting) may affect the outcomes following appendicectomy, and confounding bias cannot be ruled out as the studies were not randomized. To adjust for confounding bias, individual patient data would be required from each study. There were no available data on complicated appendicitis (perforated and gangrenous) and it was not possible to assess whether the effects of laparoscopic appendicectomy on fetal loss were confounded by complicated appendicitis. Agreement between the present results and a meta-analysis of randomized trials or a subsequent large-scale trial is needed to confirm the present findings42
. Given that pregnant women are subject to human-subject protection in clinical studies, it will be difficult to conduct a randomized trial. However, the authors believe that the direction of bias is probably conservative: those with more co-morbidity and who are considered high risk are likely to undergo open appendicectomy, making the laparoscopic approach look spuriously superior. The increased risk of fetal loss seen here is therefore likely to be an underestimate. It was not possible to identify a statistically significant difference for preterm delivery and infection owing to the limited number of studies available for pooling. Finally, as the severity of appendicitis was not reported consistently in the pooled studies, a subgroup analysis to identify specific subgroups of women who might benefit from, or be harmed by, laparoscopic appendicectomy was not possible.