Note: In 2003 states started to implement the 2003 revision of the U.S. Standard Certificate of Live Birth. Comparisons of some method of delivery data should be made with caution. See detailed description below.
Delivery Method rates are calculated for total cesarean sections, primary cesarean sections, vaginal births after cesarean sections (VBAC), and repeat cesarean sections.
The total cesarean section rate is calculated as the number of births delivered by cesarean section divided by the total number of live births less the not-stated values for delivery method, multiplied by 100.
The primary cesarean section rate is calculated as the number of women having a first cesarean delivery divided by the number of live births to women who have never had a cesarean delivery, multiplied by 100. The denominator for this rate excludes those with method of delivery classified as repeat cesarean, vaginal birth after previous cesarean, or method not stated.
The VBAC rate is calculated as the number of VBAC deliveries resulting in a live birth divided by the sum of VBAC and repeat cesarean deliveries, multiplied by 100.
The repeat cesarean section rate is calculated as the number of repeat cesarean deliveries resulting in a live birth divided by the sum of VBAC and repeat cesarean deliveries, multiplied by 100.
Impact of Birth Certificate Revision
The transition from the 1989 revision of the U.S. Standard Certificate of Live Birth to the 2003 revision has some implications on tracking rates of primary and repeat cesarean sections and VBAC deliveries in the United States.(1) The method of delivery item on the 2003 revision specifically asks if the mother had a previous cesarean section delivery under the "Risk Factors for Pregnancy" section of the birth certificate. In past revisions this information was indicated by a checkbox for VBAC under the method of delivery section. As a result of this modification, rates of VBAC and primary cesarean delivery from the 2003 revision are not comparable to data collected using earlier birth certificate revisions. Specifically, under the 2003 revision, rates of VBAC deliveries and primary cesarean section deliveries are slightly higher than expected, and repeat cesarean section deliveries (not shown on the PeriStats web site) are slightly lower. Total cesarean section and vaginal delivery rates are not impacted.
The state implementation of the 2003 revision also impacts U.S. and state temporal trends. While some states began using the revised birth certificate in 2003, the schedule for implementation varies by state. Therefore, starting in 2003, total U.S. rates of VBAC and primary cesarean deliveries are not reported due to data incompatibilities between states. Furthermore, some states have implemented the 2003 revision mid-year, and in these cases data for that year are not shown. In 2007 not all births in Michigan are reported based on the 2003 revision, and data are not shown for that year. Additionally, New York state started using the 2003 revised birth certificate in 2004 and New York City implemented in 2008. New York state VBAC and primary cesarean delivery rates exclude New York City from 2004 to 2007. Data for New York City can be found separately under city/county data.
On the PeriStats web site, graph bars displaying VBAC and primary cesarean delivery data based on the 2003 revision are shown in red instead of the standard blue color. Tables indicate the change with an asterisk (*). At the U.S. level VBAC and primary cesarean delivery rates for the total revised states are provided below the graph for the most recent year available. In addition, the functionality that allows you to make comparisons between regions has been removed from the VBAC and primary cesarean delivery section of the web site. To date the following states on the PeriStats web site have implemented the 2003 revision:
Beginning with the 2011 data year, the National Center for Health Statistics no longer includes unrevised data for primary and repeat cesarean sections and VBAC on the data file.
- 2003: PA, WA
- 2004: FL (mid-year), ID, KY, NH (mid-year), NY (excluding New York City), SC, TN
- 2005: KS, NE, PR, TX, VT (mid-year)
- 2006: CA (partially), DE, ND, OH, SD, WY
- 2007: CO, GA (mid-year), IN, IA, MI (partially)
- 2008: MT, NM, New York City, OR
- 2009: DC (mid-year), NV (mid-year), OK (mid-year), PR, UT
- 2010: IL, LA (mid-year), MD, MO, NC (mid-year)
- 2011: MA (mid-year), MN (mid-year), WI
This section of the web site will be updated as additional states implement the 2003 U.S. Standard Certificate of Live Birth.
- Martin JA, Hamilton BE, Sutton PD, et al. Births: Final data for 2003. National vital statistics reports; vol 54 no 2. Hyattsville, MD: National Center for Health Statistics. 2005.