Venomous bites during pregnancy: the black widow spider (Latrodectus Mactans)

The spider genus Latrodectus, commonly called “widow spider,” is found all over the world. Its venom contains α-latrotoxin, which leads to a massive presynaptic release of acetylcholine so, after a person has been bitten, crampy muscle spasms usually occur within an hour. There is a lack of information about spider bites and envenomation during pregnancy, so we performed a systematic review of the literature using the following MeSH-terms: “black widow spider pregnancy”; “black widow spider” AND “pregnancy”; “black widow spider pregnant”; “black widow spider AND pregnant”. The only restriction was the language: we included in the review articles in English, Italian, Spanish or French. The literature search yielded 26 results, but after the revision of the full texts, we identified 5 manuscripts to include in the review. They were American studies, published between 1979 and 2011. 28.25 years was the mean age of women when they were bitten, the gestational age ranged from 4 to 40 weeks, the left thigh, the right knee and the right breast were the most common sites of the bites. The most common symptoms were: spasms, local erythema, abdominal cramps, hypertension, anxiety, muscle rigidity. Patients were usually treated with benzodiazepines to allay the anxiety, with calcium gluconate, and in a limited number of cases (6.9%) with antivenin after a skin test to avoid anaphylactic reactions. No notable obstetric effects followed the bite: only in one case the authors described the onset of contractions and cervical dilatation which promptly arrested after treatment. Black widow spider bites have the potential to cause significant maternal morbidity and mortality. Acute risks to the fetus appear to be negligible in the short term if an appropriate therapy is promptly administered to the mother.