[Analysis on the sex ratios at birth for deliveries in hospitals in China from 1987 to 1992].
OBJECTIVE
To estimate the sex ratios at birth (SRB) for livebirths in hospitals in China.


METHODS
Data were collected by the birth defects monitoring network. The livebirths with gestation of 28 weeks or over delivered in hospitals of 30 provinces, municipalities and autonomous regions all over the country from 1987 to 1992 were analyzed and used for calculating the SRB.


RESULTS
The high male bias in SRB was observed in the data from most areas, and there was an upward trend of SRB, especially in rural areas. The SRB for livebirths in the hospitals of urban areas was normal from 1987 to 1989, and rose to 108.9 in 1992. The SRB for rural areas was high and was 109.9 in 1987, and rose to 111.8 in 1992. The SRB for livebirths given by the mothers under 20 years of age and coming from lower educational background was higher than that for others. The SRB for higher parities was even higher.


CONCLUSIONS
The SRB in China is high; this is possibly related to sex-preference. Under-reporting of female neonates and "missing females" are not the main causes of the rising SRB.
Wang
Y
Y
National Center for Birth Defects Monitoring, WCUMS, Chengdu 610041, China.
Liang
J
J
Wu
Y
Y
Zhu
J
J
Miao
L
L
Zhou
G
G
Dai
L
L
D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D012744:Sex Ratio