Interim Clinical Considerations for Pregnant People with Confirmed or Probable Oropouche Virus Disease

Manifestations and clinical management of pregnant people

The data on Oropouche disease manifestation in pregnancy are limited to a few case reports. It is not known if Oropouche virus infection is more severe during pregnancy. Signs and symptoms are expected to be the same for pregnant people as non-pregnant people (e.g., acute onset of fever, chills, headache, myalgia, arthralgia). At present, the clinical management of the acute illness for pregnant people is expected to be the same as non-pregnant people.

Impact on pregnancy and infants

Based on limited data from Brazil and Cuba, vertical transmission of Oropouche virus is possible. However, it is not known how frequent vertical transmission occurs during pregnancy and if the timing of Oropouche virus disease (Oropouche) during pregnancy increases the risk of an adverse outcome.

Case report descriptions

Multiple reports of fetal loss among people with Oropouche virus disease during early and late pregnancy have been reported to date. However, the risk of fetal loss after Oropouche virus infection is unclear. In multiple reports, Oropouche virus was detected in numerous fetal tissues, including brain, liver, kidneys, lungs, heart, spleen, cerebrospinal fluid, as well as the placenta and umbilical cord.

In a limited case series of infants with microcephaly in Brazil who were found to be positive for Oropouche virus by IgM or molecular testing, most of the gestational parents had experienced symptomatic illness during pregnancy, including in the first and second trimester. Prenatal imaging findings reported for these pregnancies included microcephaly, ventriculomegaly, thinning of the brain parenchyma, agenesis of the corpus callosum, hypoplasia of the cerebellum, presumed porencephalic cysts, polyhydramnios, and oligohydramnios.

Reported outcomes among the liveborn infants included low birth weight, hydrops, skull collapse or overlapping cranial sutures with redundant scalp folds, microcephaly, ventriculomegaly, talipes equinovarus (club foot), contractures, seizures, and neonatal death.

Fetal screening and monitoring considerations

Insufficient data are available to define the optimal timing of initial fetal ultrasound following Oropouche virus disease in a pregnant person. Similar to other viruses, for pregnant people with confirmed or probable Oropouche virus disease, serial fetal ultrasounds (every 4 weeks) should be considered to assess fetal anatomy and to monitor growth. Detailed fetal anatomy, with attention to neuroanatomy, may detect brain or associated structural abnormalities that might precede development of microcephaly.

In two reported cases for which additional details were reported, first trimester infection was associated with detection of abnormalities in the third trimester. In the absence of additional data, timing and frequency of ultrasounds can be individualized based on clinical judgement and patient circumstances; however, fetal findings may take time to manifest after infection.

The sensitivity and accuracy of prenatal ultrasound for detection of microcephaly and brain abnormalities depends on a range of factors. These can include timing of screening, severity of microcephaly, expertise of the person performing the ultrasound, and patient factors. Limited data in other congenital infections indicate that ultrasound abnormalities identified in the prenatal period correlate with reported structural abnormalities in neonates at birth, and Oropouche virus disease during pregnancy may follow this same trend. A consultation with a high-risk prenatal care provider or obstetrician with expertise in congenital infections should be considered, if available.

The role of amniocentesis for the detection of Oropouche genetic material or Oropouche virus disease is unknown. Amniocentesis has been used in the evaluation of other congenital infections. However, amniotic fluid testing is not currently available for Oropouche virus.

At present, there is no specific antiviral treatment or vaccine available for Oropouche virus disease or associated vertical transmission and potential congenital abnormalities.

Care team coordination

• Coordinate and arrange care for pregnancies with possible fetal abnormalities with pediatric and other infant providers before and during the time of delivery.
• Document the pregnant person's laboratory test results in delivery and newborn medical records and communicate with the pediatric provider to facilitate thorough infant evaluation and management.

References

1. Pan American Health Organization / World Health Organization. Epidemiological Alert: Oropouche in the Region of the Americas: vertical transmission event under investigation in Brazil, 17 July 2024. Washington, D.C.: PAHO/WHO; 2024.
2. Pan American Health Organization / World Health Organization. Epidemiological Alert: Oropouche in the Region of the Americas, 1 August 2024. Washington, D.C.: PAHO/WHO; 2024.
3. Pan American Health Organization / World Health Organization. Public Health Risk Assessment related to Oropouche Virus (OROV) in the Region of the Americas, 3 August 2024. Washington, D.C.: PAHO/WHO; 2024.
4. Brazil Ministry of Health. Nota Técnica Conjunta nº 135/2024-SVSA/SAPS/SAES/MS — Ministério da Saúde (www.gov.br) 14 August 2024.
5. Clinical Overview of Oropouche Virus Disease | Oropouche | CDC
6. Oropouche fever: Latin America on high alert for virus that can cause stillbirths | The BMJ
7. das Neves Martins, Fernanda Eduarda et al. Newborns with microcephaly in Brazil and potential vertical transmission of Oropouche virus: a case series. The Lancet Infectious Diseases, ePub. 15 Oct 2024.
8. Pan American Health Organization / World Health Organization. Epidemiological Update Oropouche in the Americas Region - 15 October 2024. Washington, D.C.: PAHO/WHO; 2024.