Hantavirus in Pregnancy: A Rare but High-Stakes Diagnosis Obstetricians Should Not Miss
Highlights
Hantavirus infection is uncommon in pregnancy, but maternal deterioration can be rapid once respiratory symptoms begin.
No effective antiviral therapy is established; management is largely supportive, often requiring intensive care and advanced respiratory support.
Exposure and travel history are central to diagnosis, especially in patients with rodent contact or residence/travel in endemic areas.
Although no published cases of Andes hantavirus infection in pregnancy were identified in the reviewed literature, lessons from other hantavirus infections and nonpregnant Andes cases are clinically informative.
Clinical background and why this matters
Hantaviruses are zoonotic viruses transmitted primarily through exposure to infected rodent excreta, including urine, droppings, and saliva. Human infection can produce two major syndromes: hantavirus pulmonary syndrome (HPS), more commonly reported in the Americas, and hemorrhagic fever with renal syndrome (HFRS), more commonly reported in Europe and Asia. The Andes hantavirus (ANDV), identified in South America, is particularly concerning because it can spread person-to-person in addition to rodent-to-human transmission.
For obstetric clinicians, the concern is not just infection itself, but the speed with which patients may worsen after the onset of respiratory compromise. Pregnant patients may initially present with nonspecific symptoms such as fever, myalgias, headache, malaise, or gastrointestinal complaints, which can be mistaken for influenza, COVID-19, pyelonephritis, or preeclampsia-related symptoms. When shortness of breath develops, clinical decline can be abrupt and severe. This creates a narrow window for recognition and escalation of care.
The recent cluster of severe respiratory illness caused by ANDV infection underscores that obstetricians, maternal-fetal medicine specialists, emergency clinicians, and intensivists should be aware of hantavirus as a rare but critical differential diagnosis during pregnancy.
Article scope and approach
The cited article by Rasmussen and colleagues is a narrative clinical review published in Obstetrics & Gynecology. The authors summarized English-language reports indexed in PubMed describing hantavirus infection in pregnancy. Importantly, they did not identify published cases of ANDV infection during pregnancy, so their recommendations are inferential rather than based on pregnancy-specific ANDV case series. Instead, the review integrates evidence from other hantavirus infections in pregnancy and from ANDV infections among nonpregnant individuals to inform obstetric practice.
This type of evidence synthesis is appropriate for a rare disease with sparse pregnancy data. However, it also means the conclusions must be interpreted cautiously: the risk estimates, maternal-fetal outcomes, and best management strategies are not defined by comparative trials, and much of the guidance is extrapolated from case reports and general critical care principles.
What the published literature suggests
The clinical literature on hantavirus in pregnancy is limited, but several practical themes emerge. First, diagnosis is often delayed because the early illness is nonspecific. Second, once cardiopulmonary manifestations appear, progression may be swift, with pulmonary edema, hypoxemia, and shock requiring intensive care. Third, maternal survival depends heavily on early recognition and supportive management rather than pathogen-specific therapy. Fourth, fetal risk is driven primarily by maternal illness severity, hypoxemia, hemodynamic instability, and the risk of preterm delivery associated with critical maternal illness.
Reports of other hantavirus infections in pregnancy have described variable outcomes, including maternal recovery and fetal loss, but the small number of cases prevents reliable estimation of obstetric risk. Because of this uncertainty, clinicians should maintain a low threshold to involve maternal-fetal medicine, infectious diseases, critical care, and neonatology when hantavirus is considered.
ANDV adds an additional layer of concern because person-to-person transmission has been documented. That feature is unusual among hantaviruses and has implications for infection control, household contact assessment, and exposure tracing. In pregnancy, these considerations are especially important in clinical settings that care for symptomatic patients before the diagnosis is established.
Recognition at the bedside: when to suspect hantavirus
The most important clinical message from the review is that exposure history is central. Obstetricians should ask specifically about recent travel to endemic regions, occupational or recreational exposure to rodents, cleaning of rodent-infested spaces, camping, farm work, and household contact with rodents or their droppings. In the case of ANDV, clinicians should also consider potential contact with a symptomatic person from an affected area.
Symptoms that should raise suspicion include fever, severe myalgia, headache, abdominal pain, vomiting, diarrhea, and rapid onset of cough or dyspnea. Laboratory abnormalities may include thrombocytopenia, hemoconcentration, leukocytosis, and evidence of capillary leak or organ dysfunction. In severe cases, chest imaging may show bilateral pulmonary infiltrates or pulmonary edema, and the patient may deteriorate into respiratory failure and shock.
These features can overlap with other pregnancy-associated emergencies. For example, thrombocytopenia and elevated liver enzymes may suggest preeclampsia or HELLP syndrome; pulmonary symptoms may suggest pulmonary embolism, viral pneumonia, or asthma exacerbation; and acute kidney injury may suggest sepsis or obstruction. A broad differential diagnosis is essential, but the exposure history can help direct testing and isolation decisions.
Management principles
There is no proven antiviral treatment for hantavirus infection. Therefore, management is supportive and should be initiated promptly when the diagnosis is suspected. In practice, this often means early hospital admission, frequent reassessment, oxygen supplementation, and readiness to escalate to intensive care. Patients with respiratory compromise may need noninvasive or invasive mechanical ventilation, vasopressors, careful fluid management, and close hemodynamic monitoring.
Because hantavirus can cause capillary leak and noncardiogenic pulmonary edema, fluid resuscitation must be individualized. Overly aggressive fluids may worsen respiratory failure, yet under-resuscitation may compromise placental perfusion and maternal organ function. This balance is particularly challenging in pregnancy and supports early ICU-level management in unstable patients.
Obstetric management should be individualized based on maternal status, gestational age, fetal condition, and the feasibility of maternal stabilization. In critical maternal illness, maternal resuscitation takes priority because maternal oxygenation and perfusion are the best predictors of fetal outcome. Continuous fetal monitoring may be appropriate in viable gestations if it will influence maternal management, but fetal intervention should not delay stabilization.
Delivery is not a treatment for hantavirus infection itself. If preterm delivery becomes necessary for maternal or fetal indications, the decision should be multidisciplinary and guided by the patient’s respiratory and hemodynamic status. Transfer to a tertiary center may be appropriate when advanced maternal care, ECMO-capable support, or high-level neonatal services are required.
Prevention and counseling
Prevention remains the most effective strategy. Patients should be counseled to avoid contact with rodents and their excreta, particularly during travel, farming, camping, cleaning of enclosed spaces, or work in structures with rodent infestation. Safe cleaning practices matter: areas contaminated by rodents should be ventilated, and droppings should be disinfected and cleaned using methods that minimize aerosolization.
For pregnant patients, prevention counseling is especially relevant because pregnancy may coincide with travel, family visits, or work in rural or high-exposure environments. Obstetric providers should include rodent exposure questions in travel counseling and in the evaluation of febrile respiratory illness when epidemiologically appropriate.
Where ANDV is a concern, infection control and contact tracing become even more important because person-to-person spread has been documented. Health care facilities should follow local public health guidance for isolation precautions and reporting when a case is suspected.
Expert commentary and limitations of the evidence
The review is valuable because it translates a rare infectious threat into actionable obstetric guidance. Its main strength is clinical relevance: it emphasizes recognition, risk assessment, and escalation rather than unsupported claims about drug therapy. However, the evidence base is inherently limited. The published literature consists mainly of case reports and small series, with heterogeneity across hantavirus species, geography, and clinical settings. As a result, prognosis in one hantavirus syndrome cannot be assumed to apply to another.
The lack of published ANDV pregnancy cases is a major gap. Without direct pregnancy data, clinicians must extrapolate from nonpregnant ANDV infection and from other hantavirus infections, which may differ in virulence, transmission patterns, and organ involvement. Future reports should standardize maternal illness severity, gestational age, fetal outcomes, timing of delivery, and neonatal follow-up to improve counseling and care.
Even with these uncertainties, the review reinforces a practical point: rare infections become clinically important when they are missed early. In obstetrics, where respiratory and febrile illnesses can evolve quickly and where maternal-fetal physiology complicates management, suspicion is often the difference between timely supportive care and catastrophic delay.
Conclusion
Hantavirus infection in pregnancy is rare, but it can be life-threatening, and ANDV deserves special attention because of its severity and potential for person-to-person transmission. Obstetricians should consider hantavirus in pregnant patients with compatible symptoms and relevant rodent or travel exposure, especially when respiratory symptoms develop. There is no proven specific therapy, so early recognition, supportive critical care, and prevention through exposure avoidance are the cornerstones of management. The key clinical lesson is simple: in the right epidemiologic context, a high index of suspicion can save lives.
Funding and clinicaltrials.gov
No funding source or clinical trial registration was reported in the cited review article.
References
Rasmussen SA, Meaney-Delman DM, Khan AS, Jamieson DJ. Hantavirus and Pregnancy: What Obstetricians Need to Know. Obstetrics and Gynecology. 2026-06-17. PMID: 42300128.
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