Table 4 Pregnancy and Influenza Multinational Epidemiologic Study Primary and Secondary Objectives and Outcomes

 Evaluate the effects of laboratory-confirmed influenza virus infection during pregnancy on pregnancy and perinatal outcomes.

• Relative risk of preterm birth (< 37 weeks gestation based on ultrasound performed at < 28 weeks gestation) among women with versus those without real- time reverse transcription polymerase chain reaction (RT-PCR)-confirmed influenza virus infection during pregnancy (P)

• Difference in mean gestational age at delivery or end of pregnancy among women with versus those without RT-PCR-confirmed influenza virus infection during pregnancy (P)

• Difference in mean birth weight among all infants and among term singleton infants born to women with versus those without RT-PCR-confirmed influenza virus infection during pregnancy (P)

 Estimate the incidences of any acute respiratory illness (ARI), febrile ARI, and laboratory-confirmed influenza during pregnancy.

• Episodes per 10,000 pregnant women months of observation of:

o RT-PCR-confirmed influenza (P)

o serologically-confirmed influenza (P)

o ARI (S)

o febrile ARI (S)

o any ARI-associated hospitalization (S)

o RT-PCR-confirmed influenza-associated hospitalization (S)

 Examine the clinical spectrum of illness due to influenza virus infection among pregnant women including duration and severity of illness.

• Frequency of illness signs and symptoms and duration of measured fever > 38.0 C among pregnant women with RT-PCR-confirmed influenza (P)

 Evaluate the effects of ARI and febrile ARI during pregnancy on pregnancy and perinatal outcomes among women in middle-income countries.

• Difference in mean gestational age at delivery or end of pregnancy among women with versus without any ARI or febrile ARI (as separate exposures) during pregnancy (S)

• Difference in mean birth weight among all infants and among term infants born to women with versus without any ARI or febrile ARI (as separate exposures) during pregnancy (S)

• Relative risk among women or infants of women with versus without any ARI or febrile ARI (as separate exposures) during pregnancy of

o spontaneous abortion (< 22 weeks gestation) (S)

o stillbirth (> = 22 weeks gestation) (S)

o maternal death during pregnancy or within 28 days of end of pregnancy (S)

o early neonatal death (at 0–6 days of life) (S)

o neonatal death (at 0–27 days of life) (S)

 Examine knowledge, attitudes, and practices (KAP) related to influenza and influenza vaccination among pregnant women in middle-income countries.

• Frequencies of KAP related to influenza virus infection during pregnancy and its impact on the mother and fetus

• Frequencies of KAP related to influenza vaccination during pregnancy, including safety and effectiveness of the vaccine for the mother and fetus

• Frequencies of trusted sources of information about influenza and influenza vaccination during pregnancy

• Association between KAP related to influenza and influenza vaccination and reported influenza vaccine receipt during the current pregnancy (at sites where influenza vaccines are available)

 Estimate the effectiveness of inactivated influenza vaccine to prevent laboratory-confirmed influenza among pregnant women at sites where influenza vaccine is used in pregnant women.

• Relative risk of influenza virus infection among women who received influenza vaccine during pregnancy compared to those who did not receive vaccine

 Compare the accuracy of last menstrual period (LMP) versus ultrasound at < 28 weeks gestation for pregnancy dating in the subset of women who recall their LMP.

• Mean difference in days between gestational age estimated from LMP compared to ultrasound at < 28 weeks gestation using ultrasound as the gold standard.