Multiple pregnancy, short cervix, part-time worker, steroid use, low educational level and male fetus are risk factors for preterm birth in Japan: a multicenter, prospective study.
OBJECTIVE
To examine the relationship between preterm birth and socioeconomic factors, past history, cervical length, cervical interleukin-8, bacterial vaginosis, underlying diseases, use of medication, employment status, sex of the fetus and multiple pregnancy.


METHODS
In a multicenter, prospective, observational study, 1810 Japanese women registering their future delivery were enrolled at 8⁺⁰ to 12⁺⁶ weeks of gestation. Data on cervical length and delivery were obtained from 1365 pregnant women. Multivariate logistic regression analysis was performed.


RESULTS
Short cervical length, steroid use, multiple pregnancy and male fetus were risk factors for preterm birth before 34 weeks of gestation. Multiple pregnancy, low educational level, short cervical length and part-timer were risk factors for preterm birth before 37 weeks of gestation.


CONCLUSIONS
Multiple pregnancy and cervical shortening at 20-24 weeks of gestation was a stronger risk factor for preterm birth. Any pregnant woman being part-time employee or low educational level, having a male fetus and requiring steroid treatment should be watched for the development of preterm birth.
Department of Obstetrics and Gynecology, University of Toyama, Toyama.
Arihiro
A
Shiozaki
Satoshi
S
Yoneda
Masao
M
Nakabayashi
Yoshiharu
Y
Takeda
Satoru
S
Takeda
Motoi
M
Sugimura
Koyo
K
Yoshida
Atsushi
A
Tajima
Mami
M
Manabe
Kozo
K
Akagi
Shoko
S
Nakagawa
Katsuhiko
K
Tada
Noriaki
N
Imafuku
Masanobu
M
Ogawa
Tomoya
T
Mizunoe
Naohiro
N
Kanayama
Hiroaki
H
Itoh
Shigeki
S
Minoura
Mitsuharu
M
Ogino
Shigeru
S
Saito
D000328:Adult; D054791:Cervical Length Measurement; D002584:Cervix Uteri / Q000000981:diagnostic imaging / Q000473:pathology*; D004522:Educational Status; D005260:Female; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008297:Male; D009929:Organ Size; D011247:Pregnancy; D011256:Pregnancy Outcome; D011272:Pregnancy, Multiple; D047928:Premature Birth / Q000139:chemically induced / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology; D015995:Prevalence; D012307:Risk Factors; D012727:Sex Characteristics; D012959:Socioeconomic Factors; D013256:Steroids / Q000009:adverse effects*; D014931:Women, Working
D013256:Steroids
cervical length; fetal sex; multiple pregnancy; part-time worker; steroid use