title: Influenza 2014-2015 among pregnant Japanese women: primiparous vs multiparous women.
abstract: This study was performed to determine whether multiparous pregnant women are prone to influenza. A questionnaire survey was conducted at 19 centres located throughout Japan, targeting all 6,694 postpartum women within 7 days after birth before leaving the hospital. All women gave birth during the study period between March 1, 2015, and July 31, 2015. Data regarding vaccination and influenza infection in or after October 2014, age, previous experience of childbirth, and number and ages of cohabitants were collected. Seventy-eight percent (n = 51,97) of women given questionnaires responded. Of these, 2,661 (51 %) and 364 (7.0 %) women reported having been vaccinated and having contracted influenza respectively. Multiparous women had a higher risk of influenza regardless of vaccination status (8.9 % [121/1362] vs 5.7 % [74/1299], relative risk [95 % confidence interval], 1.80 [1.36 to 2.38] for vaccinated and 9.3 % [112/1198] vs 4.3 % [57/1328], 2.18 [1.60 to 2.97] for unvaccinated women) compared to primiparous women. The risk of influenza increased with increasing number of cohabitants: 4.8 % (100/2089), 7.5 %, (121/1618), 9.0 %, (71/785), and 10.4 % (58/557) for women with 1, 2, 3, and ≥4 cohabitants respectively. Family size is a risk factor for influenza infection in pregnancy.
authors: Department of Obstetrics and Gynecology, Hokkaido University Graduate School of Medicine, N15W7, Kita-ku, Sapporo, 060-8638, Japan. taka0197@med.hokudai.ac.jp.
authors: T
authors: T
authors: Yamada
authors: Department of Obstetrics and Gynecology, Fukuda Hospital, Kumamoto, 860-0004, Japan.
authors: S
authors: S
authors: Kawakami
authors: Department of Obstetrics and Gynecology, Fukuda Hospital, Kumamoto, 860-0004, Japan.
authors: Y
authors: Y
authors: Yoshida
authors: Department of Maternal Fetal Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, Izumi, 594-1101, Japan.
authors: H
authors: H
authors: Kawamura
authors: Department of Maternal Fetal Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, Izumi, 594-1101, Japan.
authors: S
authors: S
authors: Ohta
authors: Department of Obstetrics and Gynecology, Faculty of Medicine, University of Tsukuba, Tsukuba, 305-8576, Japan.
authors: K
authors: K
authors: Abe
authors: Department of Obstetrics and Gynecology, Faculty of Medicine, University of Tsukuba, Tsukuba, 305-8576, Japan.
authors: H
authors: H
authors: Hamada
authors: Department of Obstetrics and Gynecology, Showa University Northern Yokohama Hospital, Yokohama, 224-0032, Japan.
authors: S
authors: S
authors: Dohi
authors: Department of Obstetrics and Gynecology, Showa University Northern Yokohama Hospital, Yokohama, 224-0032, Japan.
authors: K
authors: K
authors: Ichizuka
authors: Department of Obstetrics and Gynecology, Showa University Hospital, Tokyo, 142-8666, Japan.
authors: H
authors: H
authors: Takita
authors: Department of Obstetrics and Gynecology, Jichi Medical University, Shimotsuke, 329-0498, Japan.
authors: Y
authors: Y
authors: Baba
authors: Department of Obstetrics and Gynecology, Jichi Medical University, Shimotsuke, 329-0498, Japan.
authors: S
authors: S
authors: Matsubara
authors: Department of Obstetrics and Gynecology, Kitasato University Hospital, Sagamihara, 252-0375, Japan.
authors: J
authors: J
authors: Mochizuki
authors: Department of Obstetrics and Gynecology, Kitasato University Hospital, Sagamihara, 252-0375, Japan.
authors: N
authors: N
authors: Unno
authors: Department of Obstetrics and Gynecology, Mie Chuo Medical Center, Tsu, 514-1101, Japan.
authors: Y
authors: Y
authors: Maegawa
authors: Department of Obstetrics and Gynecology, Mie Chuo Medical Center, Tsu, 514-1101, Japan.
authors: M
authors: M
authors: Maeda
authors: Department of Obstetrics and Gynecology, Sapporo Toho Hospital, Sapporo, 065-0017, Japan.
authors: E
authors: E
authors: Inubashiri
authors: Department of Obstetrics and Gynecology, Sapporo Toho Hospital, Sapporo, 065-0017, Japan.
authors: N
authors: N
authors: Akutagawa
authors: Shirota Obstetrical and Gynecological Hospital, Zama, 252-0011, Japan.
authors: T
authors: T
authors: Kubo
authors: Shirota Obstetrical and Gynecological Hospital, Zama, 252-0011, Japan.
authors: T
authors: T
authors: Shirota
authors: Department of Obstetrics and Gynecology, JCHO Hokkaido Hospital, Sapporo, 062-8618, Japan.
authors: Y
authors: Y
authors: Oda
authors: Department of Obstetrics and Gynecology, JCHO Hokkaido Hospital, Sapporo, 062-8618, Japan.
authors: T
authors: T
authors: Yamada
authors: Department of Obstetrics and Gynecology, Nippon Medical School Tama-Nagayama Hospital, Tokyo, 206-8512, Japan.
authors: E
authors: E
authors: Yamagishi
authors: Department of Obstetrics and Gynecology, Nippon Medical School Tama-Nagayama Hospital, Tokyo, 206-8512, Japan.
authors: A
authors: A
authors: Nakai
authors: Department of Obstetrics and Gynecology, Nagasaki University Hospital, Nagasaki, 852-8102, Japan.
authors: N
authors: N
authors: Fuchi
authors: Department of Obstetrics and Gynecology, Nagasaki University Hospital, Nagasaki, 852-8102, Japan.
authors: H
authors: H
authors: Masuzaki
authors: Department of Obstetrics and Gynecology, Hiroshima University Hospital, Hiroshima, 734-0037, Japan.
authors: S
authors: S
authors: Urabe
authors: Department of Obstetrics and Gynecology, Hiroshima University Hospital, Hiroshima, 734-0037, Japan.
authors: Y
authors: Y
authors: Kudo
authors: General Women's Medical and Health Science Center, Rakuwakai Otowa Hospital, Kyoto, 607-8062, Japan.
authors: M
authors: M
authors: Nomizo
authors: General Women's Medical and Health Science Center, Rakuwakai Otowa Hospital, Kyoto, 607-8062, Japan.
authors: N
authors: N
authors: Sagawa
authors: Department of Obstetrics and Gynecology, Kagoshima City Hospital, Kagoshima, 892-0846, Japan.
authors: T
authors: T
authors: Maeda
authors: Department of Obstetrics and Gynecology, Kagoshima City Hospital, Kagoshima, 892-0846, Japan.
authors: M
authors: M
authors: Kamitomo
authors: Department of Obstetrics and Gynecology, Hakodate Central General Hospital, Hakodate, 040-0011, Japan.
authors: K
authors: K
authors: Kawabata
authors: Department of Obstetrics and Gynecology, Hakodate Central General Hospital, Hakodate, 040-0011, Japan.
authors: S
authors: S
authors: Kataoka
authors: Department of Obstetrics and Gynecology, University of Toyama, Toyama, 930-0194, Japan.
authors: A
authors: A
authors: Shiozaki
authors: Department of Obstetrics and Gynecology, University of Toyama, Toyama, 930-0194, Japan.
authors: S
authors: S
authors: Saito
authors: Department of Obstetrics and Gynecology, Showa University Hospital, Tokyo, 142-8666, Japan.
authors: A
authors: A
authors: Sekizawa
authors: Department of Obstetrics and Gynecology, Hokkaido University Graduate School of Medicine, N15W7, Kita-ku, Sapporo, 060-8638, Japan.
authors: H
authors: H
authors: Minakami
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007251:Influenza, Human / Q000453:epidemiology*; D007564:Japan / Q000453:epidemiology; D008875:Middle Aged; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology*; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055815:Young Adult