Latrodectus mactans (black widow spider) envenomation: an unusual cause for abdominal pain in pregnancy.

BACKGROUND: The differential diagnosis of abdominal pain in pregnancy is extensive. An important consideration in endemic areas is a bite by a black widow spider. CASE: A 30-year-old woman at 30 weeks' gestation presented with acute abdominal pain following an insect bite. We based the diagnosis on classic symptomatology in an area endemic for Latrodectus mactans. Treatment consisted of supportive therapy and observation. Symptoms resolved over 48 hours and did not recur. The patient delivered a healthy child at 40 weeks' gestation. CONCLUSION: In endemic areas, black widow spider envenomation should be part of the differential diagnosis of abdominal pain in pregnancy.