Acute Appendicitis in Pregnancy: A Single-Center Retrospective Cohort Study

Abstract

Introduction

During pregnancy, acute appendicitis is responsible for about two-thirds of nontraumatic surgical emergencies. The aim of this study was to investigate whether the group of pregnant patients differs from the group of the normal population in perioperative features and whether surgery during pregnancy affects its further course.

Methods

We retrospectively analyzed a cohort of 1,054 patients who underwent surgery for signs of acute appendicitis. The cohort included 16 pregnant patients (1.5%), 6 patients (37.5%) in the first trimester, 10 patients (62.5%) in the second. Perioperative features of the groups were compared, and postoperative course of pregnancy was followed.

Results

We discovered that pregnant patients had a higher ratio of negative appendectomies (25% vs. 5.3%, p = 0.010) and shorter operating time (40 min vs. 51 min, p = 0.013).

Conclusion

Based on our data, acute appendectomy in pregnancy is associated with a higher rate of negative appendectomy and shorter operating time. Due to the small number of pregnant patients in the group and the occurrence of only one first trimester miscarriage of unknown etiology, it is not possible to clearly draw conclusion about the impact of acute appendectomy on the further course of pregnancy and further investigation is needed.

Introduction

Acute appendicitis is the most common cause of acute abdomen leading to acute surgery, and its prevalence in the general population is approximately 5.7–50 per 100,000 inhabitants per year with significant geographic differences and a peak between 10 and 30 years [1]. During pregnancy, appendicitis occurs in approximately 1 in every 181–1,700 pregnancies, with the highest rates observed in the second trimester. It is responsible for about two-thirds of nontraumatic surgical emergencies during pregnancy [2].

Diagnosing appendicitis in pregnant women is particularly challenging. Common symptoms such as nausea, vomiting, and abdominal pain may overlap with those typical of pregnancy. An appendectomy, performed to treat appendicitis, is among the most common surgical procedures during pregnancy and represents about 25% of all non-obstetric surgeries performed on pregnant women. Surgery during pregnancy is not only a surgical challenge but also a highly sensitive issue in society. Every non-obstetric surgery performed during pregnancy carries an increased risk of preterm labor or miscarriage, adverse obstetric outcomes, a higher likelihood of cesarean delivery, and prolonged hospital stay. Additionally, there is an elevated risk of antepartum hemorrhage, preeclampsia/eclampsia, and gestational diabetes [3]. The aim of this study was to investigate whether the group of pregnant patients differs from the group of the normal population in the choice of surgical approach, postoperative complications, timeliness of diagnosis, or frequency of complicated appendicitis and whether surgery during pregnancy affected its further course.

Methods

We conducted a retrospective analysis of patients undergoing surgery for suspicion of acute appendicitis at the Department of Surgery of the University Hospital Královské Vinohrady in Prague between January 2015 and April 2020. The diagnosis of acute appendicitis was established on medical history, symptoms, physical and imaging examination, basic laboratory tests (blood counts, biochemistry profile, C-reactive protein, and coagulation parameters). Ultrasound and/or CT scans were used as imaging methods.

Study enrolled 1,054 patients who underwent surgery for signs of acute appendicitis, and there were 16 pregnant patients in the group. The following data were recorded: sex, age, body mass index, length of hospital stay, length of surgery, surgical approach, surgical and histopathological findings, 30-day postoperative complications, 30-day mortality, duration of symptoms, comorbidities. In the group of pregnant patients, it was also followed up: week of pregnancy at the time of surgery, postoperative complications during pregnancy, termination of pregnancy (delivery and type of delivery, abortion), maturity, and postpartum adaptation of newborn.

The surgical approach was chosen by the attending surgeon and was based on several factors. Diagnosis of appendicitis or other pathological findings was confirmed by histopathological examination. All patients received a prophylactic dose of antibiotics (aminopenicillins as the first choice). Only patients with complicated appendicitis received antibiotics therapeutically according to the result of microbial culture. Clavien-Dindo (CD) classification was used to grade postoperative complications. The duration of clinical symptoms was defined as the time from symptom onset to surgery.

Statistical analyses were performed to compare group of common population with the group of pregnant patients using R version 4.2.2 [4] and RStudio 2024.09.0 [5]. Continuous data are expressed as means and standard deviations or medians with 25th and 75th percentiles (interquartile range) according to the normality of the distribution. Binary and categorical data are expressed as counts and percentages. Wilcoxon rank-sum test was used to compare continuous parameters. Categorical parameters were compared using Pearson chi-square test or Fisher’s exact test as appropriate. p values <0.05 were considered statistically significant.

Results

A total of 16 pregnant patients (1.5%) underwent surgery for acute appendicitis in the study, 6 patients (37.5%) were in the first trimester of pregnancy, and 10 patients (62.5%) were in the second. No patient in the third trimester was included in this study. In all patients, the pregnancy has proceeded physiologically so far.

Basic demographic data show a statistically significant difference between the two groups (group 1 of common population, 1,038 patients, 98.5%, and group 2 of pregnant patients, 16 patients, 1.5%) in gender distribution (52.2% of women in group 1 vs. 100% of women in group 2, p < 0.001) and the presence of comorbidities (28.9% in group 1 vs. 0% in group 2, p = 0.009). The average age of patients in group 2 was younger (30 vs. 39 years, p = 0.072), and the average BMI value was also lower (22.1 vs. 25.1, p = 0.006), but the differences did not show statistical significance.

Overall, more patients underwent open (61.6%) versus laparoscopic appendectomy (LA) (38.4%). Conversion to open surgery occurred only in group 1 in 40 cases (3.9% vs. 0%, p > 0.9). A higher percentage of open appendectomies (OAs) was performed in the pregnant group (81.2% vs. 61.3%, p = 0.1). LA was more common in the general population group (38.7% vs. 18.8%, p = 0.1). The average operating time was significantly shorter in group 2 (40 vs. 51 min, p = 0.013). Except for the operating time, no statistically significant difference was found. The above data are shown in Table 1.

Table 1.

Surgical outcomes

	Group 1: common population (n = 1,038)	Group 2: pregnant patients (n = 16)	p value
OA	636 (61.3%)	13 (81.2%)	0.1
LA	402 (38.7%)	3 (18.8%)	0.1
C	40 (3.9%)	0 (0%)	>0.9
Operating time, min	51	40	0.013

OA, open appendectomy; LA, laparoscopic appendectomy; C, conversion.

The most common finding in both groups was phlegmonous appendix (52.4% in group 1 vs. 37.5% in group 2, p = 0.2). In the group 1, the order was followed by gangrenous (19.5%), catarrhal (16.2%), perforated appendix (11.5%), and normal appendix (0.4%). In the group 2, the order was as follows: catarrhal (37.5%), gangrenous (12.5%), and with equal frequency, normal and perforated appendix (both in 1 patient, 6.25%). Complicated appendicitis appeared more often in the group of the common population (31% vs. 18.75%, p = 0.4). A statistically significant difference was found only in the proportion of catarrhal appendicitis (16.2% vs. 37.5%, p = 0.036). Results are shown together with a histological result in Table 2.

Table 2.

Surgical findings and histological results

	Group 1: common population (n = 1,038)	Group 2: pregnant patients (n = 16)	p value
Normal appendix	4 (0.4%)	1 (6.25%)	0.074
Catarrhal inflammation	169 (16.2%)	6 (37.5%)	0.036
Phlegmonous inflammation	544 (52.4%)	6 (37.5%)	0.2
Gangrenous inflammation	202 (19.5%)	2 (12.5%)	0.8
Gangrenous with perforation	119 (11.5%)	1 (6.25%)	>0.9
Complicated appendicitisa	321 (31.0%)	3 (18.75%)	0.4
Normal appendix	55.0 (5.3%)	4.0 (25.0%)	0.010
Acute appendicitis	917.0 (88.3%)	10.0 (62.5%)	0.008
Chronic appendicitis	43.0 (4.1%)	1.0 (6.25%)	0.5
Appendiceal tumor	23.0 (2.2%)	1.0 (6.25%)	0.3

^aGangrenous inflammation and perforations.

Abovementioned macroscopically normal appendix was later histopathologically evaluated as NET, G1, pT1a. In the group 1, a total of 23 appendiceal tumors (2.2% vs. 6.25%, p = 0.3) were histologically confirmed.

Acute appendicitis was histopathologically verified with a statistically significant difference in a total of 88.3% of patients in the group 1 and 62.5% of patients in the group 2 (p = 0.008), and chronic appendicitis was confirmed in 4.2% of group 1 patients and in 6.25% of group 2 patients (p = 0.5). Appendix without pathological changes was verified significantly more often in the group 2, in 25% (vs. 5.3% in the group 1, p = 0.01). Results are shown along with the surgical findings in Table 2.

The shorter hospital stay was in the pregnant group (average 3.6 days vs. 4.5 days, p = 0.4) with zero readmission (vs. 22 readmissions in group 1, 2.1%, p > 0.9). As well, uncomplicated postoperative course was more frequent in the group 2 (81.25% vs. 76.5%, p > 0.9). No statistically significant difference was noted in these parameters. In this group, there were 3 patients with complications, 2 patients had surgical site infection (CD I), and 1 patient had vaginal mycosis and wound seroma (CD II). In group 1, the complications were as follows: CD I 140 patients (13.5%), CD II 55 patients (5.3%), CD IIIA 5 patients (0.5%), CD IIIB 24 patients (2.3%), CD IVA 10 patients (1%), CD IVB 6 patients (0.6%), CD V 3 patients (0.3%). All 3 deaths occurred in elderly polymorbid patients with complicated appendicitis and peritonitis. The most common complication in this group was surgical site infection. Postoperative outcomes are listed in Table 3.

Table 3.

Postoperative outcomes

	Group 1: common population (n = 1,038)	Group 2: pregnant patients (n = 16)
Hospital length of staya	4.5	3.6	p = 0.4
Readmission	22 (2.1%)	0 (0%)	p > 0.9
Postoperative complicationsb			0 versus I–V: p > 0.9
0	795 (76.5%)	13 (81.25%)
I	140 (13.5%)	2 (12.5%)
II	55 (5.3%)	1 (6.25%)
IIIA	5 (0.5%)	0 (0%)
IIIB	24 (2.3%)	0 (0%)
IVA	10 (1.0%)	0 (0%)
IVB	6 (0.6%)	0 (0%)
V	3 (0.3%)	0 (0%)

^aAverage duration in days.

^bDefined by the CD classification.

The average duration of symptoms was shorter in the group 1 (2.1 days vs. 2.6 days, p = 0.5). No statistically significant difference was demonstrated.

In the group of pregnant patients, one spontaneous abortion (6.25%) occurred in the 8th week of pregnancy (surgery in the 6th week; the reason for the fetal loss was not investigated in detail). Furthermore, there was one artificial termination of pregnancy (6.25%) in the group due to the diagnosis of Edwards disease during the first trimester screening (termination 14 + 6, surgery in the 7th week of pregnancy). In 13 patients (81.25%), the pregnancy continued without complications and ended with the delivery of a healthy, mature newborn at term with good postpartum adaptation. One patient with twin pregnancy (6.25%) delivered prematurely at 34 + 2, and one of the newborn twins required oxygen temporarily. Out of a total of 14 births, 7 were spontaneous (50%), 1 spontaneous with subsequent vacuum extraction (7.14%), 1 induced (7.14%), 4 acute births by cesarean section (28.6%), 1 birth by planned cesarean section (7.14%). None of the indications for cesarean section were related to appendectomy. All these newborns are currently healthy children.

Discussion

In this retrospective observational study, we compared perioperative features of group of pregnant patients with group of common population in a cohort of patients who underwent acute appendectomies. We discovered that pregnant patients more often underwent an OA and had a higher ratio of negative appendectomies, shorter operating time and hospital stay, lower incidence of postoperative complications, lower rate of complicated appendicitis, and longer time from symptom onset to surgery. However, only a higher proportion of negative appendectomies and a shorter operating time in pregnant patients were statistically significant.

Demographic data show some significant differences between the two groups; in the group of the common population, there is a significantly higher incidence of comorbidities, which may bias the results especially of postoperative complications, which as stated they were more frequent in the group 1 without statistical significance, however. According to the available knowledge, differences in the sense of a different gender ratio should not play a role in the side of the postoperative results.

In this study, there is a generally high percentage of OAs compared to up-to-date recommendations. There could be several reasons for stated results: a less experienced younger surgeon performing the surgery, a conservative attending surgeon, several years old data compared to today, only slowly changing old workplace habits, and probably a number of other factors leading the attending surgeon to this decision. Given that a number of studies have shown the advantages and superiority of LA compared to open [1, 6], as well as for complicated appendicitis [7], today, there is certainly an effort to maximize laparoscopic performance, and the ratio of LAs is significantly higher.

Recommendations for a surgical approach for appendectomy in pregnant patients are more complex. Some authors reported that LA is safe in the first two trimesters only, and others found laparoscopic approach safe in any trimester [8]. The European Association for Endoscopic Surgery guidelines from 2022 recommends a laparoscopic approach in patients up to the 20th week of pregnancy, or if the fundus of the uterus is below the umbilicus. Indications for LA after 20 weeks of pregnancy fully depend on the surgeon’s experience and preference, and the pneumoperitoneum should be established in an open fashion [9].

In accordance with the introduction of this article, appendicitis was also most common in this group in the second trimester. Five patients (31.25%) were more than 20 weeks pregnant, and one (6.25%) was in the 20th week with twins, which certainly led to a more frequent choice of an open approach.

In quality analysis of systematic reviews, seven of the eight included meta-analyses demonstrated a lower rate of preterm birth after LA compared to open, however reported that LA performed during pregnancy might be associated with higher rates of fetal loss [10]. In contrast, recent meta-analysis showed not statistically difference in fetal loss between open LA [11]. Due to the complexity of the issue of operations during pregnancy, a strongly individual approach is appropriate in these cases.

In this study, two cases of pregnancy loss were reported. One case was an artificial termination of pregnancy due to genetic causes, therefore certainly not related to surgery. In the second case, it was a miscarriage in the 8th week of pregnancy approximately 2 weeks after the appendectomy. Due to the very early stage of pregnancy, when it is known from studies that 15–20% of pregnancies end in miscarriage [12], the effect of the surgery cannot be assessed with certainty, but at the same time cannot be ruled out. One case of premature birth was recorded, but in a patient with a twin pregnancy. Given that approximately 60% of twins are born before the 37th week and 19.5% of twins are born before the 34th week [13], the operation took place at the 20th week of pregnancy and the patient gave birth at 34 + 2, more than 14 weeks after surgery; in this case, the effect of the surgery on premature birth is very questionable.

Although the appendectomy of pregnant patients could be technically more demanding due to the changed anatomical proportions, the operative time was significantly shorter in the pregnant group. The reason could be the higher rate of OAs and the choice of an experienced surgeon to perform the surgery. Some studies show that OA compared to LA is associated with a shorter operating time [14].

In agreement with other studies, a higher percentage of negative appendectomies was found in the group of pregnant patients (25%). Because delay in diagnosis of acute appendicitis in pregnancy is associated with a higher risk of complicated appendicitis, fetal loss, and postoperative complications, in case of uncertainty, early exploration is often performed. The rate of negative appendectomies varies between 11 and 50% [15, 16]. In accordance with a voluminous study of 7,000 cases, in case of diagnostic uncertainty and persistent difficulties, surgical exploration was preferred, because clinical observation compared to appendectomy leads to a higher number of adverse situations, such as the development of peritonitis and sepsis [17].

Postoperative complications in uncomplicated appendicitis are comparable in appendectomy in pregnant and nonpregnant patients [18]. Complicated appendicitis is associated with higher rate of postoperative complications and higher rate of pregnancy adverse events as premature labor or fetal loss [19]. In agreement with a prospective cohort study of pregnant patients with appendicitis [20], the frequency of complicated appendicitis was not higher in the group of pregnant patients, although the average duration of symptoms was half a day longer. In this study, the uncomplicated postoperative course was more common in the pregnant group, but with no statistical significance. This result may also be influenced by the demographic differences of the groups, such as higher age in the group 1 and a significantly higher proportion of patients with comorbidities, as well as an insignificant higher proportion of complicated appendicitis.

In contrast to another large retrospective analysis of women undergoing acute appendectomy [21], the hospital stay was almost a full day (0.9 days respectively) shorter in the pregnant group, but without statistical significance. The more frequent uncomplicated postoperative course, the smaller number of complicated appendicitis, and the fact that this is a group without comorbidities certainly had an influence here.

For forensic reasons, it is crucial to follow a complete protocol before each surgery to avoid potential legal consequences. Prior to any surgical procedure, fetal viability should be assessed, and the obstetrician should be informed about the planned surgery. After surgery, fetal viability should be reassessed using ultrasound, and this should be repeated daily. The patient should receive intravenous therapy with MgSO₄ to reduce uterine irritability, and adequate caloric intake should be ensured. A multidisciplinary approach is advantageous, benefiting both the patient and the fetus. Study was limited by the low number of pregnant patients and the related large difference in the number of patients in both groups, the different demographics of both groups, the generally high number of open surgeries and its retrospective design.

Conclusion

Based on our data, acute appendectomy in pregnancy is associated with a higher rate of negative appendectomy and shorter operating time. Due to the small number of pregnant patients in the group and the occurrence of only one first trimester miscarriage of unknown etiology, it is not possible to clearly draw conclusion about the impact of acute appendectomy on the further course of pregnancy and further investigation is needed.

Statement of Ethics

The retrospective analysis of collected data was approved by the ethical board of the University Hospital Královské Vinohrady (Approval No. EK-VP/09/0/2022). All patients gave informed consent. All data were anonymized.

Conflict of Interest Statement

The authors have no conflict of interest to declare.

Funding Sources

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Author Contributions

I.L.: writing manuscript, analyzing data, and collecting data. J.Z. and B.S.: writing manuscript. P.W.: data analysis. M.O.: designing study and reviewing manuscript.

Funding Statement

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data Availability Statement

The data that support the findings of this study are not publicly available due to their containing information that could compromise the privacy of participants and research institution.