Birth outcomes among women exposed to neuraminidase inhibitors during pregnancy

Management of influenza - updated Swedish guidelines for antiviral treatment

Influenza causes seasonal epidemics of respiratory infection in all parts of the world. Manifestations of influenza range from mild upper to severe lower respiratory tract infection. Medical risk groups are defined by factors predisposing for development of severe disease and are recommended annual vaccination as a protective measure. The previous Swedish treatment guidelines for influenza were issued in 2011, and a review of current evidence was deemed relevant. An important reason to revisit the guidelines is the recent approval of a novel drug for influenza treatment, baloxavir. Updated Swedish evidence-based guidelines created by a group of experts from various research areas, for the management of influenza are presented here. The work has been made in collaboration with the Public Health Agency of Sweden and the Swedish Reference Group for AntiViral therapy (RAV). The updated guidelines include guidelines for diagnostics, treatment and prophylaxis in special groups, including management of pregnant women and children with influenza. A new section about infection control has been added. Pharmacological treatment is covered in detail with regards to indication and dosage. Additionally, drug resistance and environmental aspects are discussed.

Neonatal outcomes after neuraminidase inhibitor use during pregnancy: A meta-analysis of cohort studies

AIM

Influenza infection poses a severe threat to pregnant mothers, and antiviral treatment is recommended. However, the safety of neuraminidase-inhibitor antiviral medications during pregnancy has not been well described.

METHODS

A systematic review and meta-analysis were performed to evaluate the adverse neonatal outcomes associated with exposure to neuraminidase inhibitors during pregnancy. The PubMed, Embase and Cochrane Library databases were searched to identify potential studies for inclusion.

RESULTS

Nine cohort studies that estimated adverse neonatal outcomes associated with exposure to neuraminidase-inhibitor medication during pregnancy were included. Exposure to a neuraminidase inhibitor during pregnancy was not associated with an increased risk of congenital malformation (odds ratio [OR] 0.9, 95% confidence interval [CI] 0.72-1.12, P = .341), low Apgar score (OR 0.96, 95% CI 0.77-1.2, P = .733) or preterm birth (OR 0.99, 95% CI 0.89-1.09, P = .771) compared with no exposure. However, exposure to a neuraminidase inhibitor was associated with a reduced risk of low birth weight (OR 0.79, 95% CI 0.68-0.92, P = .002) and giving birth to a small-for-gestational-age infant (OR 0.78, 95% CI 0.69-0.88, P < .001). Further analyses limited to oseltamivir exposure were consistent with the overall results.

CONCLUSION

Exposure to neuraminidase-inhibitor medication during pregnancy does not appear to be associated with adverse neonatal outcomes. We recommend further studies to investigate this association, which will help clinicians determine whether to prescribe a neuraminidase inhibitor during pregnancy.

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.

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.

H1N1 Infection in Pregnancy; A Retrospective Study of Feto-Maternal Outcome and Impact of the Timing of Antiviral Therapy

Background and Objective

H1N1 infection carries an increased risk in pregnancy. Our aim was to study the feto-maternal outcome and the effect of early initiation of therapy.

Methods

This is a retrospective descriptive study. Confirmed infected cases were included. Maternal age, parity, gestational age at diagnosis, presenting symptoms, the time between presentation and starting therapy, ICU admission, and maternal and perinatal outcome were evaluated.

Results

Nineteen confirmed patients were included. Most patients are 31 years old or more. Multiparous patients were 73.68%, and 57.89% were in the third trimester. Most of our patients presented with cough, fever, and chills. Two patients were admitted to the ICU. One of them was a case of maternal mortality. 42.10% of patients were started on therapy only one day after the clinical onset of symptoms. 26.31% delivered before 37 completed weeks. 73.68% delivered beyond term. Around one third delivered vaginally. 45% of babies weighed more than 3 kg. Four babies weighed less than 2 kg. Ninety percent had APGAR scores more than 8 at 1 and 5 minutes after delivery. Twenty-five percent were admitted to the NICU with no neonatal mortalities.

Conclusions

H1N1 influenza A infection in pregnancy is associated with adverse maternal and perinatal outcomes. Medical and public awareness, low threshold for testing suspected pregnant patients, very early initiation of antiviral therapy, and a multidisciplinary approach in our series decreased the overall adverse effects of this infection.

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.

Neuraminidase inhibitors during pregnancy and risk of adverse neonatal outcomes and congenital malformations: population based European register study

Objective To evaluate the possible effects of exposure to neuraminidase inhibitors during embryo-fetal life with respect to adverse neonatal outcomes and congenital malformations.Design Population based multinational observational cohort study and meta-analysis.Setting National registers covering information on maternal healthcare, births, and prescriptions in Denmark, Norway, and Sweden and the EFEMERIS database from the Haute-Garonne district in France.Participants All women together with their singleton infants born between 1 January 2008 and 31 December 2010. Only infants born at 154 days of gestation or later were included. Infants were defined as exposed if the women filled a prescription during pregnancy for either of the two neuraminidase inhibitors oseltamivir or zanamivir.Main outcomes Low birth weight, low Apgar score, preterm birth, small for gestational age birth, stillbirth, neonatal mortality, neonatal morbidity, and congenital malformations. Crude and adjusted hazard ratios of preterm birth were estimated using Cox regression models. Crude and adjusted odds ratios for other outcomes were estimated by logistic regression models.Results The study included 5824 (0.8%) exposed women and their infants and 692 232 who were not exposed. Exposure to neuraminidase inhibitors in utero was not associated with increased risks of any of the investigated neonatal outcomes, including low birth weight (adjusted odds ratio 0.77, 95% confidence interval 0.65 to 0.91), low Apgar score (adjusted odds ratio 0.87, 0.67 to 1.14), preterm birth (adjusted hazard ratio 0.97, 0.86 to 1.10), small for gestational age birth (adjusted odds ratio 0.72, 0.59 to 0.87), stillbirth (adjusted odds ratio 0.81, 0.51 to 1.30), neonatal mortality (adjusted odds ratio 1.13, 0.56 to 2.28), and neonatal morbidity (adjusted odds ratio 0.92, 0.86 to 1.00). No increased risk of congenital malformations overall associated with maternal exposure was observed during the first trimester (adjusted odds ratio 1.06, 0.77 to 1.48). Similarly, no significantly increased risks of any of the outcomes were observed in an analysis restricted to oseltamivir alone.Conclusions This large multinational register study found no increased risks of adverse neonatal outcomes or congenital malformations associated with exposure to neuraminidase inhibitors during embryo-fetal life. The results support previously reported findings that the use of neuraminidase inhibitors is not associated with increased risks of adverse fetal or neonatal outcomes.

Influenza virus infection in pregnancy: a review

BACKGROUND

Influenza virus infection is very common and a significant cause of morbidity and mortality in specific populations like pregnant women. Following the 2009 pandemic, several reports on the effects of influenza virus infection on maternal health and pregnancy outcome have been published. Also the safety and efficacy of antiviral treatment and vaccination of pregnant women have been studied. In this review, we have analyzed and summarized these data.

OBJECTIVE

To provide information on the influence of influenza virus infection during pregnancy on maternal health and pregnancy outcome and on the effect of treatment and vaccination.

DATA SOURCES

We have searched Medline, Embase and the Cochrane Library. We used influenza, influenz*, pregnancy and pregnan* as search terms.

STUDY SELECTION

In total, 294 reports were reviewed and judged according to the STROBE guidelines or CONSORT statement. In all, 100 studies, published between 1961 and 2015, were included.

RESULTS

Compared to the general population, pregnant women are more often hospitalized and admitted to an intensive care unit due to influenza virus infection. For hospitalized patients, increased rates of preterm birth and fetal/neonatal death are reported. Early treatment with oseltamivir is associated with a reduced risk of severe disease. Vaccination of pregnant women is safe and reduces maternal and neonatal morbidity.

CONCLUSIONS

There is level 2b evidence that maternal health and pregnancy outcome can be severely affected by influenza virus infection. Antiviral treatment may diminish these effects and vaccination protects pregnant women and neonates from infection (level of evidence 2b and 1b, respectively).

Influenza and its treatment during pregnancy: A review

The influenza viral infection has dramatic effects during pregnancy on the mother and the fetus. We present a review article on the prevention and treatment recommendations of influenza infection in pregnant women, and the effects of antiviral medications on maternal-fetal outcomes. This viral infection not only leads to miscarriages, preterm deliveries and a high maternal mortality rate, but it also poses negative risks to the fetus including small-for-gestational age infants, and admissions to neonatal intensive care units. Vaccination is the most effective strategy for preventing influenza infection during pregnancy whereby can protect both maternal and fetal immunities. The safety profiles of antiviral drugs during pregnancy are limited. Available risk-benefit evidence has indicated that pregnant women with suspected or confirmed influenza should receive prompt antiviral therapy where these medications reduce the risk of complications among pregnant women, and attenuate the teratogenic effects of the influenza infection. Post-exposure prophylaxis is not recommended for most pregnant women, but it may be prescribed in pandemic settings, particularly to non-vaccinated women. Although some ex vivo models for pharmacokinetic studies have revealed that the transplacental transfer of oseltamivir to fetal circuits may occur, there is no evidence of adverse fetal outcomes as a result of most in utero exposures to neuraminidase inhibitors. Due to the large number of confounding variables, large, population-based studies are needed to assess the association between in utero oseltamivir exposure and fetal outcome.

Pregnancy outcomes of women exposed to laninamivir during pregnancy

Purpose

The purpose of this study is to assess pregnancy outcomes of women treated with a novel neuraminidase inhibitor, laninamivir, during pregnancy.

Methods

A retrospective review of pregnancy outcomes of 112 pregnant women who were given laninamivir for treatment of influenza was performed. Possible adverse events, including miscarriages, preterm birth, foetal malformation and any neonatal morbidity requiring treatment, were assessed.

Results

Seventeen, 39, 46 and 10 women were administered a single inhaled dose of 20 or 40 mg of laninamivir at gestational week (GW) 3–11, 12–21, 22–36 and 37 or more, respectively. One (1.8%) of 56 women with laninamivir at GW <22 experienced miscarriage at GW <12. The remaining 111 women gave birth to 111 viable infants but at preterm (GW <37) in nine (8.8%) of 102 women with laninamivir at GW <37. Three (2.7%) of the 111 newborns had malformations: forefoot varus deformity, foot polydactyly and cleft lip in one each born to a mother taking laninamivir at GW 6, 17 and 21, respectively. Five neonates (4.5%) were small for gestational age. Eleven (9.9%), five (4.5%) and no neonates required phototherapy for jaundice, transient respiratory supports for respiratory distress syndrome (n = 2) or transient tachypnoea of the newborn (n = 3), and glucose administration for hypoglycaemia, respectively.

Conclusions

Although this study included a small number of study women and no control women, the results suggested that maternal exposure to laninamivir did not increase the rate of adverse pregnancy and foetal outcomes.

Risk management of seasonal influenza during pregnancy: current perspectives

Influenza poses unique risks to pregnant women, who are particularly susceptible to morbidity and mortality. Historically, pregnant women have been overrepresented among patients with severe illness and complications from influenza, and have been more likely to require hospitalization and intensive care unit admission. An increased risk of adverse outcomes is also present for fetuses/neonates born to women affected by influenza during pregnancy. These risks to mothers and babies have been observed during both nonpandemic and pandemic influenza seasons. During the H1N1 influenza pandemic of 2009-2010, pregnant women were more likely to be hospitalized or admitted to intensive care units, and were at higher risk of death compared to nonpregnant adults. Vaccination remains the most effective intervention to prevent severe illness, and antiviral medications are an important adjunct to ameliorate disease when it occurs. Unfortunately, despite national guidelines recommending universal vaccination for women who are pregnant during influenza season, actual vaccination rates do not achieve desired targets among pregnant women. Pregnant women are also sometimes reluctant to use antiviral medications during pregnancy. Some of the barriers to use of vaccines and medications during pregnancy are a lack of knowledge of recommendations and of safety data. By improving knowledge and understanding of influenza and vaccination recommendations, vaccine acceptance rates among pregnant women can be improved. Currently, the appropriate use of vaccination and antiviral medications is the best line of defense against influenza and its sequelae among pregnant women, and strategies to increase acceptance are crucial. This article will review the importance of influenza in pregnancy, and discuss vaccination and antiviral medications for pregnant women.

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

PURPOSE

Influenza infection places pregnant women at greater risk of morbidity and hospitalization. The use of oseltamivir to treat influenza increased markedly in all population groups during the A/H1N1pdm09 pandemic, including pregnant women. Given this increase in exposure, a reassessment of the safety of oseltamivir in pregnancy was conducted.

METHODS

The Roche Global Safety Database was searched for all exposures to oseltamivir during pregnancy in the 13 years up to 30 April 2012.

RESULTS

Of the 2926 maternal exposures to oseltamivir retrieved from the Safety Database, pregnancy outcomes were known for 2128 women. Most exposures (>90%) were reported during or after the pandemic. The incidence of adverse pregnancy outcomes in exposed women was: spontaneous abortions, 2.9% (61/2128); therapeutic abortions, 1.8% (39/2128); and pre-term deliveries, 4.2% (84 of 2000 live births), values which are lower than background rates in the general population (women with or without influenza). Fetal outcomes were known in 1875 of the 2926 exposures. For the 81 reported birth defect cases, 11 occurred during the sensitive period for the respective defects. A review of these and other case reports of birth defects did not suggest that they resulted from oseltamivir exposure.

CONCLUSIONS

The data reviewed in this article reinforce the findings of a previous review, suggesting that oseltamivir is unlikely to cause adverse pregnancy or fetal outcomes.

Safety of oseltamivir during pregnancy: a comparative study using the EFEMERIS database

OBJECTIVE

To compare pregnancy outcome between women exposed and unexposed to oseltamivir during pregnancy.

DESIGN

A comparative observational cohort study of women exposed to oseltamivir during pregnancy.

SETTING

A French prescription database (EFEMERIS) that includes data for pregnant women was used. EFEMERIS records prescribed and dispensed reimbursed drugs during pregnancy and pregnancy outcomes in Haute-Garonne, South West France.

POPULATION

Women who delivered from 1 July 2004 to 31 December 2010.

METHODS

The study compared exposed and unexposed pregnant women. Two women unexposed to oseltamivir were individually matched, by maternal age, month, and year of delivery, with one women exposed to oseltamivir. Multivariable conditional logistic regression and multivariable Cox proportional hazards regression were used to evaluate associations between each outcome and exposure to oseltamivir during pregnancy.

MAIN OUTCOME MEASURES

Pregnancy loss for any cause, preterm delivery, low birthweight, neonatal pathology, and congenital malformation.

RESULTS

A cohort of 337 (0.58% of women included in EFEMERIS) women exposed to oseltamivir were compared with 674 unexposed women. The risk for pregnancy loss (HR 1.52; 95% CI 0.80-2.91), for preterm birth (adjusted OR 0.64; 95% CI 0.31-1.27), and for neonatal pathology (adjusted OR 0.62; 95% CI 0.23-1.54) did not differ between exposed and unexposed groups. When exposure during organogenesis was considered, one case of congenital anomaly (2.0%) among 49 exposed women and one case (1.0%) among 99 unexposed women were observed (crude OR 2.00; 95% CI 0.13-32.00).

CONCLUSIONS

There was no significant association between adverse pregnancy outcomes and exposure to oseltamivir during pregnancy.

Outcomes of infants exposed to oseltamivir or zanamivir in utero during pandemic (H1N1) 2009

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.

STUDY DESIGN

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.

CONCLUSION

Short-term prognoses of infants exposed to oseltamivir or zanamivir in utero were not adversely affected.

Infant outcomes among pregnant women who used oseltamivir for treatment of influenza during the H1N1 epidemic

OBJECTIVE

This study was undertaken to examine the association between maternal oseltamivir treatment for influenza and infant outcomes during the 2009 HINI influenza pandemic.

STUDY DESIGN

This was a retrospective cohort study using a population-based maternal newborn database including women who gave birth to a singleton infant in the Canadian province of Ontario from November 2009 through April 2010. Risks of small for gestational age (SGA) (10th percentile and 3rd percentile), preterm birth (<37 weeks of gestation), very preterm birth (<32 weeks of gestation), and 5-minute Apgar score <7 associated with maternal exposure to oseltamivir were analyzed by multivariable regression.

RESULTS

A total of 55,355 women with a singleton birth were included in this study. Among them, 1237 (2.2%) women received oseltamivir for treatment or prevention of influenza during pregnancy. Women who took oseltamivir during pregnancy were less likely to have a SGA infant based on the 10th percentile for growth (adjusted risk ratio, 0.77; 95% confidence interval, 0.60-0.98). No association between maternal use of oseltamivir with SGA on 3rd percentile, preterm birth, very preterm birth, and low Apgar score was observed.

CONCLUSION

There is no evidence of an association between maternal use of oseltamivir for influenza and early birth, low Apgar at birth, and poor fetal growth.

Influenza in pregnancy

Please cite this paper as: Memoli et al. (2012) Influenza in pregnancy. Influenza and Other Respiratory Viruses 00(00), 000–000.

The 2009 pandemic served as a strong reminder that influenza‐induced disease can have a great impact on certain at‐risk populations and that pregnant women are one such important population. The increased risk of fatal and severe disease in these women was appreciated more than 500 years ago, and during the last century, pregnant women and their newborns have continued to be greatly affected by both seasonal and pandemic influenza. In this review, we briefly discuss the data collected both before and after the 2009 pandemic as it relates to the impact of influenza on pregnant women and their fetuses/newborns, as well as risk variables, clinical features, clues to pathophysiologic mechanisms, and approaches to treatment and prevention.

Estrogen mediates innate and adaptive immune alterations to influenza infection in pregnant mice

Pregnancy is a leading risk factor for severe complications during an influenza virus infection. Women infected during their second and third trimesters are at increased risk for severe cardiopulmonary complications, premature delivery, and death. Here, we establish a murine model of aerosolized influenza infection during pregnancy. We find significantly altered innate antiviral responses in pregnant mice, including decreased levels of IFN-β, IL-1α, and IFN-γ at early time points of infection. We also find reduced cytotoxic T cell activity and delayed viral clearance. We further demonstrate that pregnancy levels of the estrogen 17-β-estradiol are able to induce key anti-inflammatory phenotypes in immune responses to the virus independently of other hormones or pregnancy-related stressors. We conclude that elevated estrogen levels result in an attenuated anti-viral immune response, and that pregnancy-associated morbidities occur in the context of this anti-inflammatory phenotype.

Antivirals and resistance: influenza virus

Influenza causes annual epidemics of respiratory viral infections are associated with significant morbidity and mortality. Influenza vaccines have been shown to reduce the risk of infection and mitigate against some of the virus' sequellae. Likewise, two classes of antivirals, the adamantanes (amantadine and rimantadine) and the neuraminidase inhibitors (laninamivir, oseltamivir, peramivir, and zanamivir) are currently approved for the prevention and treatment of influenza; several other classes of antivirals and immune modulators are also currently under investigation. One of the greatest challenges to our armamentarium of antivirals is the emergence of resistant mutants. In this paper, we will review the currently approved and investigational antiviral agents and the mechanisms of resistance that impact their activity.