Table 1

Summary statistics

VariablesObservationsMeanStandard Deviation
Panel A: Pregnancies
    Birth614,408    0.84      0.37
    Abortion614,408    0.13      0.33
    Miscarriage614,408      0.03      0.16
    Still birth614,408    0.004      0.060
Panel B: Births
    Male child298,615    0.53      0.50
    First birth298,615    0.59      0.49
    Second birth298,615    0.29      0.45
    Third (or higher order) birth298,615    0.12      0.33
    Urban299,933    0.28      0.45
    Han299,933    0.85      0.36
    Maternal education299,933    5.69      4.23
    Maternal age (at conception)299,933  26.38    7.39
    Household income (in 1992)294,1103,830.373,259.98
    Gestation (months)299,933    9.29      0.56
    No prenatal care299,933    0.49      0.50
    First trimester initial visit299,933    0.17      0.38
    Second trimester initial visit299,933    0.16      0.37
    Third trimester initial visit299,933    0.16      0.37
    Ultrasound (available in county)299,933    0.41      0.49

  • Note: Panel A contains pregnancies that started between January 1974 and June 1992. Panel B contains births for which the information on ultrasound is available. Both samples are from the Chinese Children Survey. Information on ultrasound access is collected by the authors.