title: Outcomes of infants exposed to oseltamivir or zanamivir in utero during pandemic (H1N1) 2009.
abstract: OBJECTIVE
  To assess adverse fetal outcomes and short-term prognoses of infants exposed to oseltamivir or zanamivir in utero during pandemic (H1N1) 2009 in Japan.
  
  
  METHODS
  Case series study. We asked the 2611 obstetric facilities in Japan that are members of the Japan Society of Obstetrics and Gynecology to participate, and data were provided from 157 facilities. We evaluated the numbers of pregnancy complications and neonatal abnormalities.
  
  
  RESULTS
  We evaluated 624 infants born to 619 women given oseltamivir and 50 infants born to 50 women given zanamivir. Of patients given oseltamivir before gestational week 22, 3 experienced miscarriage and 1 experienced induced abortion. The overall rate of congenital malformations was 2.1% (14/670). In infants exposed during the first trimester, the rate of malformations was 1.3% (2/156) with oseltamivir and 0.0% (0/15) with zanamivir, although in infants exposed during the second and third trimesters, this rate was 2.6% (12/464) with oseltamivir and 0.0% (0/35) with zanamivir. Increased rates of miscarriage in women given antiviral drugs before gestational week 22 (0.9% [3/322]), preterm delivery in women given antiviral drugs before gestational week 37 (5.5% [33/600]), stillbirth (0% [0/670]), neonatal death (0.15% [1/670]), birthweight <2500 g (8.7% [58/670]), small-for-gestational-age infants (8.4% [56/670]), necrotizing enterocolitis (0.0%), intraventricular hemorrhage (0.0%), seizures (0.15% [1/670]), and other transient abnormalities in the neonatal period (4.3% [29/670]) were not observed in those exposed to antiviral drugs before the corresponding episodes or complications.
  
  
  CONCLUSIONS
  Short-term prognoses of infants exposed to oseltamivir or zanamivir in utero were not adversely affected.
authors.affiliation: Department of Obstetrics and Gynecology, University of Toyama, Toyama, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Saito
authors.forename: Hisanori
authors.initials: H
authors.lastname: Minakami
authors.forename: Akihito
authors.initials: A
authors.lastname: Nakai
authors.forename: Nobuya
authors.initials: N
authors.lastname: Unno
authors.forename: Takahiko
authors.initials: T
authors.lastname: Kubo
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Yoshimura
mesh_terms: D000014:Abnormalities, Drug-Induced / Q000453:epidemiology*; D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000188:drug therapy*; D053139:Oseltamivir / Q000009:adverse effects*; D058873:Pandemics; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy*; D011256:Pregnancy Outcome; D011446:Prospective Studies; D013997:Time Factors; D053243:Zanamivir / Q000009:adverse effects*
chemical_list: D000998:Antiviral Agents; D053139:Oseltamivir; D053243:Zanamivir
keywords: antiviral drugs; case series study; fetal outcome; pregnancy complication