Norovirus Infections and Pregnancy
Noroviruses are small, RNA viruses that do not appear to readily cross the placenta or directly affect the baby. These infections are often called ‘stomach flu’ and are also often mistaken for ‘food poisoning.’ They are usually accompanied by headaches, low-grade fever (less than that typically seen with the flu), chills, lethargy (tiredness), weakness, and muscle aches. The course of infection is usually limited to 2-3 days, but the nausea, vomiting (more common in children) and diarrhea (more common in adults) can result in dehydration and electrolyte imbalances very quickly. The latter are where our pregnant women get into trouble. With dehydration and electrolyte imbalances, pregnant women are at increased risk for preterm labor and for developing urinary tract infections (which may also contribute to preterm labor).
Noroviruses are spread by the ‘fecal-oral route’ in contaminated water and foods and can be passed directly between individuals. Onset of symptoms usually occurs within 24-48 hours after exposure. They are the source of very rapid and widespread outbreaks in close quarters such as schools, daycare centers, nursing homes, restaurants, hotels, and cruise ships and this is what has often led to the mistaken accusation of ‘food poisoning’ in those situations. Common contaminated sources of infection are raw or undercooked shellfish, swimming pools and lakes, wells and municipal water supplies, ice machines, and ill individuals who handle food sources. There are several different strains of Noroviruses and despite the fact that individuals develop ‘immunity’ to the viruses, the immunity often is not permanent and reinfection with the same or different strains readily occurs. Noroviruses are believed to cause about 300 deaths per year in the U.S., but these serious complications usually occur in very young children and elderly and debilitated individuals.
If you are pregnant and develop symptoms related to viral gastroenteritis, you should let your provider know. If you have a low-grade fever and if you are able to ‘keep up with your fluids’ during the acute phase of the illness, it is unlikely that you will develop serious complications related to the pregnancy. If you cannot keep up with the fluids, develop a high fever, begin having contractions or other symptoms of a more serious problem, let your provider know about these immediately. If you have a sick child at home with a Norovirus infection, wash your hands frequently, but don’t be surprised if you join them in their misery despite your best efforts. And when you feel well again, come back and visit me here!