Purpose:  Cesarean delivery is the most frequently performed major surgery in the United States. Anthropometric variation amongst different ethnic groups suggests that it may be the shape and configuration of the fetal head in relation to the maternal pelvis, not size alone, that contributes to the common diagnosis of "failure to progress" and ultimately cesarean birth. Because there are many different racial and ethnic combinations of biologic parents in the US, it is conceivable that the c-section rate may be higher in the US than in countries where there is less ethnic variation between partners.  The purpose of this study is to explore the impact of same and different ethnicities of biological parents and their contribution to rate of cesarean births.

Method and Sample:  A retrospective, secondary data analysis of selected variables extracted from Texas Department of Health birth certificate records for the three-year period from 1999 through 2001. The study sample was derived from all births occurring in Texas (n=1,091,237) during the three-year study period.

Findings:  Cesarean birth occurred more frequently amongst mixed-ethnicity partners than parents of the same racial or ethnic background.  When both biologic parents are from the same racial group, the rate of operative birth is 14 to 17%.  Various combinations of ethnicities result in cesarean-section rates from 0 to 100 %.  White and Black races are usually not differentiated by ethnicity or country of ancestry.  Subgroups of the Asian population, however, are specified on Texas birth certificate records and statistically significant differences can be observed in cesarean delivery rates for parents from different ethnic backgrounds.

Implications:  Identification of additional factors in diagnosing fetal head versus maternal pelvis incongruency enables health care providers to anticipate at-risk patients prior to the onset of labor.  Further research is needed to determine the clinical usefulness of the cephalic index.