Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), which emerged in December 2019 in China, was identified to cause severe viral pneumonia [1]. The World Health Organization (WHO) named the disease as Coronavirus Disease 2019 (COVID-19) and on March 2020, declared it a pandemic [2]. Various drugs that are previously approved for other indications and have antiviral activity against SARS-CoV-2 in vitro or in observational studies were used empirically in COVID-19 treatment throughout the world, such as hydroxychloroquine [3], favipiravir [4,5], remdesivir [6], lopinavir, and ritonavir [7]. Early in the pandemic, favipiravir was used in outpatient and inpatient clinics with some special permissions and distributed to the patients by the filiation teams assigned by the Turkish Ministry of Health [8,9]. However, these drugs except remdesivir are later discontinued due to a lack of sufficient evidence or adverse effects, and treatment guidelines are revised and updated [10].

Favipiravir is an antiviral agent that inhibits the RNA polymerase enzyme, approved for the treatment of influenza in Japan and China [11]. In animal studies, favipiravir caused post-implantation fetal loss, decreased fetal and placental weight, unspecified abnormalities of the head, brain, heart, and tail, as well as unidentified cardiac and thymic abnormalities in mice and rats. Fetal edema and ascites occurred in all fetuses in an experiment with pregnant monkeys when favipiravir was given at a dose of 200 mg/kg/day, whereas cleft palate occurred in 2 of 5 fetuses [12]. However, human data are scarce and consist of only four case series (Table 1) with a total of 58 pregnancies exposed to favipiravir [13], [14], [15], [16].

This study aims to provide information about the outcomes of pregnant women who used favipiravir unaware of their pregnancy and consulted our medical pharmacology outpatient clinic. We report the data on prenatal drug exposure, pregnancy course and outcome, the variables about the infant's health, the pediatric examination results if available, and the general well-being of infants.