Epidemiologic aspects of shoulder dystocia-related neurological birth injuries.

PURPOSE: The first part of the study involved data collection for the detection of geographic variations and chronologic fluctuations in the rates of shoulder dystocia. The second part of the research evaluated head-to-body delivery times in cases of arrest of the shoulders at birth that had resulted in fetal damage during the last four decades in the USA.

METHODS: The study of geographic and chronologic changes in the rates of shoulder dystocia rested on reported statistics coming from the USA and 11 other countries. These data were obtained by computer search. Evaluation of head-to-body delivery times rested on 104 well-documented cases that resulted in permanent neonatal damage.

RESULTS: Literary reports of shoulder dystocia indicate that the incidence of shoulder dystocia has increased in the USA about fourfold since the middle of the twentieth century. No comparable trend has been reported from most other countries. Study of head-to-body delivery times revealed that more than two-thirds of all injured fetuses had been extracted from the birth canal within 2 minutes.

CONCLUSIONS: Incidents of shoulder dystocia began to escalate in the USA during the 1980s, shortly after the introduction of "active management" of the birthing process. This new technique replaced a conservative philosophy which had recommended abstinence from intervention on the part of the accoucheur. The authors consider the interventionist approach largely responsible for the exponential increase in the rates of shoulder dystocia in the USA. They recommend adherence to the traditional method of delivery on the part of obstetricians in Europe and elsewhere.