Factors influencing participation in obstetrics by obstetrician-gynecologists.
OBJECTIVE
To examine factors affecting participation in obstetrics among obstetrician-gynecologists and changes in participation over time.


METHODS
Using physician billings from Ontario, Canada, from 1992/1993 to 2001/2002, we examined the impact of physician age, gender, practice location, and years of practice on participation in obstetrics with multiple logistic regression and repeated measures analyses. We also examined differences in practice patterns between obstetrics providers and nonproviders using linear and log-linear regressions.


RESULTS
Obstetrics participation declined with age, from 96% among physicians under age 35, to 34% among those aged 65 and over (2001/2002 figures). Regressions demonstrated a lower likelihood of performing obstetrics in successive years (odds ratio [OR] 0.95 per year; 95% confidence interval [CI] 0.93, 0.98) and among physicians who were older (OR 0.91 per year of age; 95% CI 0.90, 0.93), female (OR 0.57; 95% CI 0.36, 0.91), and practicing in cities with medical schools (OR 0.58; 95% CI 0.44, 0.78). The crude obstetrics participation rate dropped from 82% to 77%, from 1992/1993 to 2001/2002. The physician age-sex-adjusted participation rate dropped from 80% in 1992/1993 to 77% in 2001/2002. Obstetrics providers had almost double the annual billings of nonproviders ($364,000 verus $187,000; P <.001), but more on-call days worked (105 versus 13; P <.001). Nonproviders of obstetrics derived more of their billings from outpatient visits, psychotherapy, and diagnostic tests. The likelihood of an obstetrics nonprovider resuming obstetrics was 1.1% per year.


CONCLUSIONS
The proportion of obstetrician-gynecologists practicing obstetrics declined modestly in the last decade, partly because of more female physicians in the workforce who were less likely to practice obstetrics. Planners should consider these trends when estimating how many obstetrician-gynecologists to train to meet future societal needs.


METHODS
II-2
Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, Suite G-106, Toronto, Ontario M4N 3M5, Canada. ben@ices.on.ca
Benjamin T B
BT
Chan
Janice
J
Willett
D000328:Adult; D000367:Age Factors; D000368:Aged; D002321:Career Choice; D005249:Fees and Charges; D005260:Female; D006176:Gynecology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009774:Obstetrics; D009864:Ontario; D010818:Practice Patterns, Physicians'; D012737:Sex Factors; D013997:Time Factors; D016526:Workload