The safety of oseltamivir in pregnancy: an updated review of post-marketing data

Clinical Effectiveness and Safety of Antivirals for Influenza in Pregnancy

Seasonal influenza epidemics result in substantial health care burden annually. Early initiation of antiviral treatment of influenza has been shown to reduce the risk of complications and duration of illness. Pregnant and postpartum women may be at increased risk for influenza-associated complications; however, pregnant women have been generally excluded from clinical trials of antiviral treatment of influenza. In this review, we summarize the available evidence on the clinical effectiveness and safety of antiviral treatment of pregnant women with influenza. Observational data show a reduction of severe outcomes when pregnant and postpartum women are treated with oseltamivir and other neuraminidase inhibitors without increased risk of adverse maternal, fetal, or neonatal outcomes. Due to lack of safety and efficacy data for baloxavir treatment of pregnant and postpartum women, baloxavir is currently not recommended for use in these populations.

SARS-CoV-2 in the context of past coronaviruses epidemics: Consideration for prenatal care

Since December 2019, the novel SARS-CoV-2 outbreak has resulted in millions of cases and more than 200 000 deaths worldwide. The clinical course among nonpregnant women has been described, but data about potential risks for women and their fetus remain scarce. The SARS and MERS epidemics were responsible for miscarriages, adverse fetal and neonatal outcomes, and maternal deaths. For COVID-19 infection, only nine cases of maternal death have been reported as of 22 April 2020, and pregnant women seem to develop the same clinical presentation as the general population. However, severe maternal cases, as well as prematurity, fetal distress, and stillbirth among newborns have been reported. The SARS-CoV-2 pandemic greatly impacts prenatal management and surveillance and raise the need for clear unanimous guidelines. In this narrative review, we describe the current knowledge about coronaviruses (SARS, MERS, and SARS-CoV-2) risks and consequences on pregnancies, and we summarize available current candidate therapeutic options for pregnant women. Finally, we compare current guidance proposed by The Royal College of Obstetricians and Gynaecologists, The American College of Obstetricians and Gynecologists, and the World Health Organization to give an overview of prenatal management which should be utilized until future data appear.

Oseltamivir use in pregnancy: Risk of birth defects, preterm delivery, and small for gestational age infants

BACKGROUND

Influenza infection during pregnancy increases risks for adverse outcomes for both mother and fetus. For this reason, treatment for infection or postexposure prophylaxis with a neuraminidase inhibitor, such as oseltamivir, may be needed.

METHODS

Between 2009 and 2017, the Organization of Teratology Information Specialists (OTIS) MotherToBaby Pregnancy Studies enrolled pregnant women in the United States and Canada who were or were not treated with oseltamivir in a prospective cohort study. Data were collected on major birth defects, spontaneous abortion, preterm delivery, and small for gestational age birth size. Crude relative risks (RRs) or hazard ratios (HRs) were estimated together with 95% confidence intervals (CIs) for these outcomes.

RESULTS

There were 716 subjects available for analysis; 112 were exposed to oseltamivir sometime in pregnancy and 604 were unexposed. 2/30 (6.7%) first-trimester-exposed pregnancies resulted in a fetus or infant with one or more major birth defects compared to 48/604 (7.9%) in the unexposed cohort (RR 0.84, 95% CI 0.19, 2.80). There were no spontaneous abortions reported. Risk of preterm delivery was not elevated in exposed versus comparison women (HR 0.65, 95% CI 0.26, 1.63). RRs for small for gestational age infants on weight, length, and head circumference following oseltamivir exposure anytime in pregnancy ranged from 0.70 to 1.30 with all 95% CIs including 1.

CONCLUSION

We found no evidence of increased risks with oseltamivir for any of the outcomes evaluated. While numbers are small, these data are reassuring for pregnant women who need to be treated for infection or for postexposure prophylaxis.

Oseltamivir exposure in pregnancy and the risk of specific birth defects

BACKGROUND

Influenza during pregnancy contributes to maternal morbidity and mortality. Neuraminidase inhibitors, including oseltamivir, are recommended for treating women with influenza during pregnancy.

METHODS

Data from the Slone Birth Defects Study from 2009 to 2015 were used to investigate associations between oseltamivir and specific birth defects. We classified exposures according to timing in pregnancy and examined 52 and 16 defects with early and potential late pregnancy etiology, respectively; we calculated crude odds ratios (ORs) and 95% confidence intervals (CIs) for defects with three or more exposures.

RESULTS

Among 8,379 cases and 4,190 nonmalformed controls, we identified 79 and 42 oseltamivir exposures, respectively. The majority of defects had no exposures. ORs were elevated for several defects, but the CI excluded the null only for intestinal malrotation (OR: 10.7 [1.8, 45.2]; three exposures).

CONCLUSIONS

Largely null findings for specific defects are reassuring. The association with intestinal malrotation, while unstable, warrants further investigation.

Oseltamivir in pregnancy and birth outcomes

Background

Prenatal exposure to influenza or fever is associated with risk of congenital malformations. Oseltamivir is used to treat influenza and to provide post-exposure prophylaxis. We examined the association between oseltamivir use during pregnancy and birth outcomes.

Methods

This was a nationwide registry-based prevalence study with individual level data linkage, in a setting of universal health care access. We included all recorded pregnancies in Denmark in 2002–2013, and used data from population registries to examine associations between dispensings for oseltamivir during pregnancy (first trimester, second/third trimester, none) and congenital malformations, foetal death, preterm birth, foetal growth, and low 5-min Apgar score. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were computed using propensity score matching.

Results

The study included 946,176 pregnancies. Of these, 449 had first-trimester exposure and 1449 had second/third-trimester exposure to oseltamivir. Adjusted ORs following first-trimester exposure were 0.94 (95% CI 0.49 to 1.83) for any major congenital malformation and 1.75 (95% CI 0.51 to 5.98) for congenital heart defects, based on 7 exposed cases. The association with congenital heart defects was present for etiologically implausible exposure periods and for known safe exposures. There was no evidence of an association between prenatal exposure to oseltamivir and any of the other birth outcomes assessed.

Conclusions

The study does not provide evidence of risk associated with oseltamivir treatment additional to that associated with influenza infection.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3423-z) contains supplementary material, which is available to authorized users.

A Review of Antiviral and Antifungal Use and Safety during Pregnancy

Antiviral and antifungal use in pregnancy presents challenges because of the paucity of clinical and safety data for many agents in these classes. If untreated, viral and fungal infections can have deleterious effects on both maternal and fetal health. Understanding the use and risks of these medications in pregnancy is vital to provide appropriate care. This article reviews the current literature for the use of antiviral and antifungals, the pharmacokinetics of these agents, and their safety in pregnancy.

[Influenza and pregnancy]

Influenza is a respiratory disease caused by influenza viruses. The virus is responsible for pandemics by emergence of new viral strains, then for seasonal flu by antigenic drift. Seasonal flu is more frequent and severe in pregnant women, with increased risk of pneumonia and increased risk of hospitalization (but no increased death reported). Pandemic flu is more severe in pregnant women, with increased risk of pneumonia and increased mortality. Influenza vaccination is recommended for all women who are or will be pregnant (in any trimester) during influenza season. After closed contact with a flu case or in case of symptoms compatible with flu, early oseltamivir-based treatment (prophylactic in the first situation, curative in the latter one) is recommended, at any term of pregnancy. The occurrence of flu symptoms in a pregnant woman requires medical evaluation to confirm the diagnosis or identify any alternative infection requiring appropriate therapy like listeriosis, chorioamniotitis, pyelonephritis or viral primo-infection.

Rates and effectiveness of antiviral use among hospitalized influenza patients

The influenza virus is currently a global public health problem. There are several thousand cases of classic and newly emerging atypical influenza virus infections around the world annually. Prevention, early diagnosis and treatment are the keys to managing influenza outbreaks. Some influenza treatments have proven to be more useful than others. A standard antiviral drug has been developed and is recommended for the management of hospitalized influenza patients. This article briefly outlines the rates and effectiveness of antiviral use among hospitalized influenza patients. It also discusses some important considerations regarding controversial issues and future perspectives on antiviral use for the management of hospitalized influenza patients.

Influenza vaccination during pregnancy and its usefulness to mothers and their young infants

The current approach to protecting pregnant women from influenza infection and serious influenza-related complications is vaccination. It is, therefore, critical to evaluate the vaccine's safety, immunogenicity, and protection efficacy during pregnancy. However, because it is affected by previous influenza vaccination or infection, the efficacy of the seasonal trivalent inactivated influenza vaccine is difficult to evaluate in pregnant women. The A/H1N1pdm pandemic in 2009 provided us with the opportunity to evaluate the immunogenicity of the influenza vaccine unaffected by previous vaccinations or infections. Vaccination with inactivated influenza virus during pregnancy elicited neutralizing antibody titers that were sufficient and comparable to those of naturally infected individuals. Furthermore, post-pandemic surveys provided a wealth of definitive information on vaccine efficacy and safety. In addition, transplacental transfer of antibodies following vaccination protected newborn infants against influenza infection. With reports showing the effectiveness of influenza vaccine during pregnancy, it is suggested that influenza vaccination benefits both mothers and their young infants.

Maternal immune activation and abnormal brain development across CNS disorders

Epidemiological studies have shown a clear association between maternal infection and schizophrenia or autism in the progeny. Animal models have revealed maternal immune activation (mIA) to be a profound risk factor for neurochemical and behavioural abnormalities in the offspring. Microglial priming has been proposed as a major consequence of mIA, and represents a critical link in a causal chain that leads to the wide spectrum of neuronal dysfunctions and behavioural phenotypes observed in the juvenile, adult or aged offspring. Such diversity of phenotypic outcomes in the mIA model are mirrored by recent clinical evidence suggesting that infectious exposure during pregnancy is also associated with epilepsy and, to a lesser extent, cerebral palsy in children. Preclinical research also suggests that mIA might precipitate the development of Alzheimer and Parkinson diseases. Here, we summarize and critically review the emerging evidence that mIA is a shared environmental risk factor across CNS disorders that varies as a function of interactions between genetic and additional environmental factors. We also review ongoing clinical trials targeting immune pathways affected by mIA that may play a part in disease manifestation. In addition, future directions and outstanding questions are discussed, including potential symptomatic, disease-modifying and preventive treatment strategies.