Kazuo Hayakawa

Publications
  • Research Article
    Stillbirth Rates and Risk Factors for Stillbirths among Zygotic Twins in Japan, 1995-2008
    Author(s): Yoko Imaizumi and Kazuo HayakawaYoko Imaizumi and Kazuo Hayakawa

    We aimed to determine the Stillbirth Rates (SRs) for monozygotic (MZ) and dizygotic (DZ) twins, with the risk factors for stillbirth. SRs were estimated using Japanese vital statistics from 1995 to 2008. The SRs of zygotic twins significantly decreased during the period. The SR was the lowest at maternal age (MA) of 30-34 years for MZ (66) and DZ twins (18) and significantly higher at MA <20 years than the other MA groups for both zygosities. The SR was the lowest at Gestational Age (GA) of 37 weeks for MZ (5.7) and DZ twins (1.8). The SR was significantly higher for MZ than for DZ twins at each GA group except for those born at GA 39 and GA ≥ 40 weeks. The SR significantly decreased from 1995-1998 to 2004-2008 except GA ≥ 40 for both zygotic twins and 32-35 weeks for DZ twins. Incidences of preterm delivery increased from 1995 (43% for MZ and 38% for DZ twins) to 2008 (62% a.. View More»

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