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Pediatric Congress 2019 Current Pediatric Research | ISSN: 0971-9032 | Volume 23
Page 16
July 25-26, 2019 | Amsterdam, Netherlands
OF EXCELLENCE
IN INTERNATIONAL
MEETINGS
YEARS
International Conference on
PEDIATRICS AND NEONATOLOGY
THE EFFECT OF BIRTHWEIGHT DISCORDANCE
ON INFANT MORTALITY RATES AMONG ZYGOTIC
TWINS IN JAPAN, 1995-2008
I nfant mortality rates (IMRs) of monozygotic (MZ) and dizygotic (DZ) twins were
estimated using vital statistics from Japan during 1995 to 2008. Using the same
data, author reported that mortality risk factors were maternal ages of <20 years
and gestational ages of up to 35 weeks. In the present study, 128, 236 MZ and
180, 920 DZ twins were used as denominators to compute IMRs in zygotic twins.
Numbers of infant deaths were 1,858 MZ and 1,620 DZ twins. Birth weight discor-
dance (BWD) levels were classified into seven groups from <5% to 30%≥. Fig. 1
shows the relationship between IMRs and BWD levels. The lowest IMR was 7.5 per
1000 live births at 5−9% in MZ and 6.7 at <5% in DZ twins. IMRs were significant-
ly higher in MZ than DZ twins except two BWD levels from 5%−9% to 10−14%.
The lowest IMR in MZ twins was significantly increased after 10−14%. The lowest
IMR in DZ twins was 6.7 at <5% and significantly increased at 10−14% and after
25−29%. As for gestational age (GA) <28 weeks, the ratios of the highest vs the
lowest IMRs were 2.2 (376.2/173.6) for MZ and 1.3 (275.2/207.2) for DZ twins. As
for 28weeks≤GA, the corresponding ratios were 13.8 (53.7/3.9) vs 9.1 (29.1/3.2) re-
spectively. Namely, under GA 28 weeks, a risk factor of BWDwas not a main factor.
Yoko Imaizumi, Curr Pediatr Res 2019, Volume 23
Yoko Imaizumi has received her Doctor of Sci-
ence (PhD) from Hiroshima University. Her under
graduated major was Math. She worked at Na-
tional Institute of Radiological Science at Division
of Genetics for nine years and worked two years
at Population Genetic Laboratory at University of
Hawaii, USA. She worked for 27 years at National
Institute of Population Studies, Ministry of Health
andWelfare. She moved to Hyogo University as a
Professor. She is now an Invited Professor at the
Center for Twin Research, Osaka University. She
has published over 100 papers in English and has
been serving as an Editorial Board Member of
journals for twin research and human genetics.
Yoko Imaizumi
Osaka University, Japan
BIOGRAPHY
0
10
20
30
40
50
60
70
80
90
<5 5-9 10-14 15-19 20-24 25-29 30-
Infant mortality rate per 1000 live
twins
Birth weight discordance (%)
Fig 1. Relationship between infant mortality rate
and birth weight discordnce in Japan, 1995-2008
MZ twins
DZ twins