To assess obstetrician-gynecologists' judgments of gestational age of viability and earliest age of medical intervention for preterm delivery, and to associate these practice decisions with physician characteristics.
Questionnaires were mailed to 1193 members of the American College of Obstetricians and Gynecologists (ACOG).
The response rate was 59%. The majority of respondents considered 24 weeks the earliest age a fetus is potentially viable (57%) and at which they would routinely perform cesarean section for fetal distress (58%). Those respondents who judged viability as 23 weeks or less were more likely to have been in practice for a shorter period (p < 0.05), be a maternal-fetal medicine specialist (p < 0.005), and be from southern or central states (p < 0.005). Similarly, those respondents who would not intervene for fetal distress until 26 weeks gestation were more likely to have been in practice for longer (p < 0.01), to have performed fewer deliveries (p < 0.05), to be in solo practice (p < 0.01), and not to be a maternal-fetal medicine specialist (p < 0.01); males and females did not differ when controlling for age (p = 0.552).
Obstetrician-gynecologists' judgment of viability threshold is consistent with standard estimates of 24 weeks. Viability judgment and reported earliest age for routine intervention both differ by physician characteristics.