Pregnancy and Botulism

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Botulism is a condition that is caused by a toxin called botulinum toxin, produced by a bacterial species called Clostridium botulinum and that causes paralysis. Exposure to botulinum toxin can come from ingesting contaminated food, especially homemade foods that have been canned or preserved incorrectly. Exposure also can come from the presence of C. botulinum spores in a wound or in the intestines. Additionally, botulinum toxin is given as a treatment (Botox) for certain conditions, such as migraine and for wrinkles. Rare cases of Botox overdoses also can cause botulism, but most botulism comes from contaminated food and from spores in wounds. In the United States, this comes to approximately 100 to 150 cases of botulism occur each year, of which just a fraction occurs in pregnant women.

Symptoms of paralysis from botulism can include visual problems (including double vision and blurry vision) and trouble keeping the eyes open, difficulty swallowing and speaking, facial muscle weakness, shortness of breath (dyspnea), and dry mouth. Symptoms of food-borne botulism typically begin 12 to 36 hours after ingestion of the contaminated food, whereas wound botulism can take several days to develop. In either case, paralysis can advance to the point of preventing the person from being able to breathe, in which case the condition will be fatal unless the person is put onto mechanical ventilation. Usually, respiratory failure does not develop until after the other symptoms have begun, but occasionally, failure of the respiratory system has been among the first symptoms. In cases of maternal botulism, the baby’s life is in danger, firstly because the mother’s life is in danger. Due to the small number of cases, it is not possible to know all possible effect on the baby, but the medical literature reports that 6 of the 17 women with botulism have delivered preterm infants.

Diagnosis of botulism begins with physical examination with emphasis on the neurological exam, looking for muscle weakness and paralysis. Signs of paralysis include weakness in the voice and droopy eyelids. Doctors also will ask about your recent history with respect to food consumption that may have been contaminated with botulinum toxin and will examine wounds that may have been contaminated with C. botulinum. Doctors need to pay close attention to examining for signs of difficulties related to the cranial nerves, which are twelve nerves on each side of the body that carry information between the brain and other areas, mostly in the head and neck, without involving the spinal cord. Despite knowledge of the clinical picture of botulism and how it progresses, the medical literature has documented a number of cases of botulism that have been misdiagnosed. Misdiagnosis or delayed diagnosis can have a profoundly negative effect on survival. Neurological conditions that may be confused with botulism include myasthenia gravis and Guillain-Barré syndrome. Some researchers suggest that doctors should maintain a particularly high level of suspicion for botulism when it comes to women who are pregnant or in the postpartum period, not because the disease is common, but due to the fact that such women may be more susceptible than others and possibly experience a more extreme type of botulism. Suspicion of botulism will initiate a process that will lead to laboratory testing of potential sources of contamination, which may involve government agencies, such as local public health departments.

Botulism can be treated with an injection of botulism antitoxin. The antitoxin consists of antibodies or parts of antibodies that attach to the botulinum toxin and block its effects. In cases of wound botulism, antibiotics can be given as an additional treatment to confront any C. botulinum that may still be growing in the wound and producing toxin. Antibiotics are not useful in food-borne botulism, because the toxin has all come from the food that the person has ingested and no more toxin is being produced. Generally, a pregnant woman suffering from botulism would be admitted into the intensive care unit and put on mechanical ventilation.

As for issues surrounding nursing mothers, there have not been enough cases of post-partum botulism for researchers to study the question of antitoxin and breast milk. Nevertheless, it is not likely that the antitoxin would harm a nursing infant even it does pass into breast milk. As for the botulinum toxin itself, researchers do not think that it enters breast milk.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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