Fever in pregnancy, while most often benign, can also signal a maternal or obstetric emergency and may accompany sepsis. Caroline Charlier, MD, infectious disease specialist at Cochin Port Royal Hospital in Paris, France, a major teaching hospital in the AP-HP network, presented a seven-step management algorithm based on the latest literature at the Pari(s) Santé Femmes 2025 Congress, a French national women’s health meeting.

Complete Clinical Exam Is Essential

Charlier noted that although there is no single consensus definition of fever, the most commonly used is a core (tympanic or rectal) temperature ≥ 38 °C, confirmed on two measurements 30 minutes apart. According to the two largest studies on the topic, published in 2021 and 2002, fever affects 14%-18.5% of pregnant women and is most often caused by seasonal viral infections or an arboviral infection.

Every episode should be medically evaluated with a complete clinical exam, taking into account the epidemiologic and obstetric context, recent travel, recent vaccination, and consumption of a food subject to a listeria recall. “If no cause is identified this way, the workup should include at minimum three pairs of aerobic/anaerobic blood cultures from a single venipuncture (total volume 40-60 mL), a vaginal swab with bacteriologic culture, and a urinalysis with urine culture,” she said.

Limit the ‘Holes in the Net’

She then outlined a seven-step algorithm. “These steps may seem heavy, but they help limit — or even avoid — too many holes in the net.”

Step 1: Determine whether there is a maternal emergency due to sepsis or septic shock (most often linked to intrauterine infections or endometritis, followed by pyelonephritis and respiratory infections).

This is rare (4-10 per 10,000 live births) and accounts for only 8% of maternal deaths. But in such cases, “deaths result from diagnostic or therapeutic errors in 80%-96% of cases,” Charlier said. Scores used to identify sepsis (systolic blood pressure ≤ 100 mm Hg, respiratory rate ≥ 22 breaths/min, or confusion) are not validated in pregnancy, creating a risk for over- or underdiagnosis. Delays in management quickly increase morbidity and mortality.

Step 2: Assess for an obstetric emergency. Signs of intrauterine infection include a temperature ≥ 38 °C without another obvious cause, plus two of the following: fetal tachycardia, uterine pain or spontaneous labor, and purulent amniotic fluid at the cervical os. In this scenario, induce delivery and start antibiotics.

Step 3: Look for another maternal infection — bacterial, viral, or parasitic — requiring specific treatment and follow-up. Charlier cited arboviral infections, particularly dengue (more severe in pregnancy); malaria (severe malaria is even more severe in pregnancy), underscoring the need to check for recent travel to malaria-endemic areas; as well as pneumonia, pyelonephritis, influenza, measles, varicella, and appendicitis.

Reassess at 48 Hours

Step 4: Search for hematogenous maternal-fetal infections under the acronym TORSCH: toxoplasmosis and other infections (eg, measles and Zika virus), rubella, syphilis, cytomegalovirus, herpesviruses — with particular attention to measles, which persists and is reemerging in France, and to syphilis, for which clusters are also reappearing.

In English-language literature, this group is often referred to as “TORCH” infections.

Step 5: Look for a benign cause (eg, nasopharyngitis or viral gastroenteritis).

Step 6: If fever is “isolated,” consider listeriosis. Caution: “Even if a blood culture (the only possible test before delivery) and preemptive amoxicillin are necessary, the latter should be continued regardless of the blood culture result — unless an alternative diagnosis is made — because blood culture is negative in 45% of proven maternal-neonatal listeriosis cases,” she said, adding that joint French Language Society for Infectious Diseases/French National College of Gynecologists and Obstetricians (French societies for infectious diseases and ob/gyn, respectively) recommendations on amoxicillin dosing in this setting are expected in 2026.

Step 7: Reassess at 48 hours. In a prospective multicenter study of 104 febrile pregnant women admitted to the emergency department, Charlier’s team identified an alternative diagnosis in 74% of cases.

She concluded by listing antibiotics to prioritize during pregnancy (beta-lactams, fosfomycin, nitrofurantoin, macrolides, and streptogramins); those requiring caution: glycopeptides (theoretical ototoxicity and nephrotoxicity and placental transfer), ciprofloxacin (the only quinolone allowed during pregnancy for urinary tract infection), trimethoprim (teratogenic between gestational weeks 1 and 10 and should always be combined with folic acid), gentamicin and amikacin (short courses only), and sulfonamides; and those to avoid: chloramphenicol (risk for gray baby syndrome), tetracycline (chelates calcium ions and causes yellow staining of deciduous teeth), colistin (because of renal toxicity), and streptomycin and kanamycin (due to fetal cochleovestibular toxicity).

Charlier reported having no conflicts of interest.

This story was translated from Medscape’s French edition.