A matched case-control study of preterm birth in one hospital in Beijing, China.

Background: Preterm birth is an unresolved global health issue. The etiologies of preterm birth are complex and multifactorial. To examine risk factors related to preterm birth, a matched case-control study was conducted in a hospital in Beijing, China where little data on preterm birth have been published in the scientific literature.

ART do not increase the risk of Y-chromosome microdeletion in 19 candidate genes at AZF regions.

Y-chromosome microdeletions (YCMs) have been found at a much higher rate in infertile men than fertile controls. A specific deletion in the azoospermia factor locus (AZF) at Yq11 is significantly associated with male infertility. Whether assisted reproductive technology (ART) increases the risk of YCM in ART-derived offspring remains unclear.

Risk factors for preterm birth in five Maternal and Child Health hospitals in Beijing.

Background: Preterm birth, the birth of an infant prior to 37 completed weeks of gestation, is the leading cause of perinatal morbidity and mortality. Preterm infants are at greater risk of respiratory, gastrointestinal and neurological diseases. Despite significant research in developed countries, little is known about the causes of preterm birth in many developing countries, especially China.

[Factor analysis of sexual behavior in migratory adolescent and choice of contraceptive measures].

Objective: To comprehend the young migrants' sexual behavior and contraceptive status, and to provide the scientific basis for the health education regarding sex and reproduction for the young migrants in cities.

Methods: An anonymous self-designed structured questionnaire was used to survey 4 389 young migrants in Beijing, Guangzhou and Ji'nan.

Results: In the study, 33.