title: Sex ratio of fetuses during the second trimester of gestation.
abstract: The authors have investigated the sex ratio of fetuses between the thirteenth and twenty-fourth menstrual weeks. The study material, consisting of 749 fetuses, was obtained through induced second trimester abortions. The sex ratio of the 749 specimens was 109. The ratio was 129 between the thirteenth and sixteenth weeks, 105.8 between the seventeenth and twentieth weeks, and 94 between the twenty-first and twenty-fourth weeks of pregnancy. The overall ratio was 112 among Caucasian and 107 among both Black and Central American populations.
mesh_terms: D000028:Abortion, Induced; D044383:Black People; D002489:Central America; D005260:Female; D005333:Fetus; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012744:Sex Ratio; D044465:White People