Temporal trends in perinatal mortality and cerebral palsy: A regional population-based study in southern Japan.
OBJECTIVE
The prevalence of cerebral palsy (CP) has not decreased in developed countries over the past 30 years. We examined gestational age-specific trends in the prevalence of CP.


METHODS
This unselected, population-based study was conducted in Miyazaki prefecture, Japan (10,000 deliveries annually), where 102,999 deliveries were registered between 2001 and 2010. Of these, 312 were stillbirths (⩾22 weeks of gestation), 126 were neonatal deaths (<28 days of birth), and 214 infants were determined to be at risk of CP at peer-review conferences. Survival and neurological damage were compared for two 5-year periods, 2001-2005 and 2006-2010, and infants were classified according to gestational ages.


RESULTS
Stillbirths and neonatal deaths decreased significantly during both periods. Likewise, the number of registered high-risk cases of CP decreased by 30.2%, from 126 to 88 cases. After excluding congenital anomalies, the corrected CP prevalence was 1.5 per 1000 (78/51,889) and 1.3 per 1000 (67/51,110), for the two periods, which was not a significant difference. The number of extremely preterm infants (22-25 weeks) did not change over the 10-year period, whereas that of moderately preterm infants (26-36 weeks) increased, and that of term infants significantly decreased (p<0.01). In term infants, asphyxia decreased from 18 to 7 cases (p<0.05).


CONCLUSIONS
Perinatal deaths and CP decreased in prevalence during both 5-year periods, and the CP prevalence was 2.1 per 1000 births. Furthermore, fewer term infants were at high risk for CP mainly because of the reduced prevalence of asphyxia.
Department of Obstetrics and Gynecology and Perinatal Center, Faculty of Medicine, University of Miyazaki, Japan. Electronic address: yuki_kodama@med.miyazaki-u.ac.jp.
Yuki
Y
Kodama
Department of Obstetrics and Gynecology and Perinatal Center, Faculty of Medicine, University of Miyazaki, Japan.
Hiroshi
H
Sameshima
Department of Obstetrics and Gynecology and Perinatal Center, Faculty of Medicine, University of Miyazaki, Japan.
Tsuyomu
T
Ikenoue
D002547:Cerebral Palsy / Q000453:epidemiology* / Q000401:mortality*; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D007564:Japan; D054238:Perinatal Mortality; D015995:Prevalence
Asphyxia; Cerebral palsy; Perinatal mortality; Periventricular leukomalacia; Population-based study