The diagnosis of acute appendicitis in the pregnant patient can be particularly challenging, as nausea, anorexia, and abdominal pain may be symptoms of both appendicitis and normal pregnancy. In addition, the gravid uterus can displace the abdominal viscera, shifting the location of the appendix from the right lower quadrant. Appendicitis affects 1 in every 1,400 pregnancies, an incidence similar to that of the nonpregnant female population.It can occur in any trimester, with perhaps a slight increase in frequency during the second trimester. Perforation is more common in the third trimester, however, and results from a longer duration from the onset of symptoms to operation. The differential diagnosis of appendicitis includes not only the conditions possible in nonpregnant women, but also certain conditions specific to pregnancy: ectopic pregnancy, chorioamnionitis, preterm labor, placental abruption, and round ligament pain.
Appendicitis is the most common nonobstetric surgical disease of the abdomen during pregnancy. Pregnant women develop appendicitis with the same frequency as do nonpregnant women of the same age, and the cases are equally distributed through the three trimesters of pregnancy. By far the most common presentation is right lower quadrant pain and tenderness—the classic syndrome—but the enlarged uterus occasionally will have pushed the appendix into the right upper quadrant, which gives rise to pain in this location. Fever is less common than with appendicitis in the absence of pregnancy. Leukocytosis is typical, but it too may be absent. The main problem is to recognize the possibility of appendicitis and perform appendectomy promptly. Delay in operation runs a higher than usual risk of perforation and diffuse peritonitis, because omentum is less available to wall off the infection. The mother is in greater jeopardy of serious abdominal infection, and the fetus is more vulnerable to premature labor with complications. Laparoscopic appendectomy (specifically the pneumoperitoneum) is well tolerated by the mother and fetus, but the frequency of technical complications is higher than with the open approach. Appendectomy during pregnancy is often followed by preterm labor but rarely by preterm delivery. Early appendectomy has decreased the maternal death rate to under 0.5% and the fetal death rate to under 10% of appendicitis.