Acute appendicitis (appendicitis) is the most common surgical disease in pregnant and is a risk factor for a healthy pregnancy (1). Moreover it causes an important diagnostic problem. The incidence is estimated at between 1 in 1400 to 1 in 1600 pregnancies (2-5). According to the statistics it occurs slightly more often in the second trimester of pregnancy (2-5) and is most common in patients between 20 and 30 years of age (6).

Diagnosis of appendicitis in pregnancy is associated with many difficulties at the stage of history taking and physical examination. Physiological pregnancy as well as complicated one are associated with many symptoms which are common with appendicitis, such as nausea, vomiting or eating disorders.

Other diagnostic difficulty may be caused by the location of pain. Patognomical location of pain in appendicitis in the right lower quadrant of the abdomen in typical cases during the pregnancy may not be present, because of the uterus enlargement and in turn intestine displacement especially after the fifth month of pregnancy (7-9). However, the pain in the right lower quadrant of the abdomen is reported to be a constant symptom of appendicitis (3, 10). Pain located in the lumbar region and laterally may be associated with appendicitis located behind ceacum, but also with urolithiasis or inflammation of the urinary tract. Anatomically, the right side is particularly predisposed to purulent urinary tract infections because the pressure on the right ureter caused by right sided flexure of the uterus and hormone-dependent decrease in motility of the ureters (11). These two phenomena contribute to urine retention and bacteriuria found in the urine analysis (12).

Many patients have no evidence of fever, white blood cell count is also not reliable as in the course of pregnancy it physiologically grows (13).

At the management of a pregnant patient there is a risk associated on one hand with too late diagnosis with the possibility of perforation, on the other hand with appendectomy in the absence of appendicitis (so-called “negative appendectomy”) (13). In the past, principle aggressive approach and fast qualification for surgery were practiced because it was thought that the risk of negative appendectomy is much smaller for the mother and fetus than restraining from the intervention. Thus, in the current literature, the index of negative appendectomies is as high as 50% (8, 9). A careful analysis of the problem shows that 30% of negative appendectomies ended with miscarriage or preterm birth (14).

However, appendicitis in pregnancy – also treated surgically – carries the risk of perinatal complications. Perinatal complications are observed at a level from 10 to 20% of patients. Fortunately mortality in the present time is at a very low level (11, 12, 15-31).

There is no single treatment protocol recommended and followed by all the medical centers. The most important is the conclusion that the delay in diagnosis definitely worsens the prognosis (32). In recent literature reviews (32) complicated appendicitis was significantly more often associated with miscarriage comparing to the appendicitis without perforation (12.1 vs 3.4%, P = 0.0027).

For each acute abdominal pain in pregnancy diagnosis should always lead toward confirmation or exclusion of appendicitis (33). It is important to also remember to exclude potentially fatal pathologies associated with pregnancy such as placenta abruption or uterine rupture (34). Diagnosis should be based on accurate history taking, physical examination, laboratory tests (peripheral blood morphology, urinalysis, liver profile: AST, ALT, also amylase, lipase). These studies are not enough to confirm the diagnosis of appendicitis but they may exclude other acute abdominal diseases (such as: acute pancreatitis, cholestasis of pregnant, urinary tract infection etc.). CRP level is generally above normal, but may remain within the limits (19, 20) – it does not constitute a patognomic parameter for appendicitis (as it does in the case of non-pregnant patients).

Additionally the standard practice is to perform an ultrasound imaging of the abdominal cavity and the fetus. Please note that an ultrasound in such conditions is extremely difficult. Although in some US studies, the sensitivity of abdominal ultrasound in the detection of appendicitis in children and adults was 98% (but usually is at a level of 86%) and a specificity of 81% (35), be aware that this method is very dependent on the person performing the study. In the presence of pregnancy related changes in the anatomical relations in the peritoneal cavity and the uterus itself, it is very difficult to make correct interpretation and appropriate diagnostic evaluation – hence the rate of positive tests is significantly reduced.

In case of a negative ultrasound (even 97% of appendicitis is not visualized) in cases of doubt should be considered an additional tomography (CT) and/or resonance imaging (MRI) of the abdomen (36). MRI (performed without a solution gadolinium) is of sensitivity of 80 to 86% and specificity of 97 to 99% (37). If MRI is not available it is recommended to perform a CT scan of the abdomen and pelvis with the lowest possible dose of radiation – that is less than 5 rad (standard dose of radiation used in the pelvic imaging is 1 to 5 rads, depending on local protocols) (38, 39).

Comparison of the methods for diagnostic imaging in appendicitis (40-43) (tab. 1 and fig. 1).

Complications of appendicitis in pregnancy:

1. typical for appendicitis:

– perforation of the appendix,

– abscess/periappendical infiltration,

– acute peritonitis,

– wound infection,

– systemic septic complications,

– ileus,

– pneumonia;

2. associated with pregnancy:

– premature contractions,

– premature birth,

– low birth weight of the baby,

– intrauterine fetal death (44).

Algorithm for the management of pregnant patients with suspected appendicitis (13) (fig. 2).