Birth by the Numbers Gene Declercq March, 2016 Is there a relationship between pre-pregnancy obesity and cesarean section Birth by the Numbers Gene Declercq March, 2016

Long Standing Concern with Maternal Obesity

Contemporary Categorization of Obesity BirthByTheNumbers.org

BMI & Obesity Categories Category Person 5’4” <18.5 Underweight < 110 lbs 18.5 – 24.9 Normal Weight 110-144 25.0 – 29.9 Overweight 145-174 30.0 – 34.9 Obese I 175-204 35.0 – 39.9 Obese II 205-235 40+ Obese III 235+ BirthByTheNumbers.org

Trends in U.S. Obesity over Time

Obesity Trends* Among U.S. Adults BRFSS, 1985 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14%

Obesity Trends* Among U.S. Adults BRFSS, 1986 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14%

Obesity Trends* Among U.S. Adults BRFSS, 1987 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14%

Obesity Trends* Among U.S. Adults BRFSS, 1988 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14%

Obesity Trends* Among U.S. Adults BRFSS, 1989 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14%

Obesity Trends* Among U.S. Adults BRFSS, 1990 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14%

Obesity Trends* Among U.S. Adults BRFSS, 1991 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19%

Obesity Trends* Among U.S. Adults BRFSS, 1992 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19%

Obesity Trends* Among U.S. Adults BRFSS, 1993 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19%

Obesity Trends* Among U.S. Adults BRFSS, 1994 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19%

Obesity Trends* Among U.S. Adults BRFSS, 1995 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19%

Obesity Trends* Among U.S. Adults BRFSS, 1996 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19%

Obesity Trends* Among U.S. Adults BRFSS, 1997 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% ≥20%

Obesity Trends* Among U.S. Adults BRFSS, 1998 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% ≥20%

Obesity Trends* Among U.S. Adults BRFSS, 1999 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% ≥20%

Obesity Trends* Among U.S. Adults BRFSS, 2000 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% ≥20%

Obesity Trends* Among U.S. Adults BRFSS, 2001 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% ≥25%

Obesity Trends* Among U.S. Adults BRFSS, 2002 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% ≥25%

Obesity Trends* Among U.S. Adults BRFSS, 2003 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% ≥25%

Obesity Trends* Among U.S. Adults BRFSS, 2004 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% ≥25%

Obesity Trends* Among U.S. Adults BRFSS, 2005 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

Obesity Trends* Among U.S. Adults BRFSS, 2006 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

Obesity Trends* Among U.S. Adults BRFSS, 2007 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

Obesity Trends* Among U.S. Adults BRFSS, 2008 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

Obesity Trends* Among U.S. Adults BRFSS, 2009 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

Obesity Trends* Among U.S. Adults BRFSS, 2010 (*BMI ≥30, or ~ 30 lbs. overweight for 5’ 4” person) Why do maps stop in 2010? No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

Trends in Obesity, US Adult Women, 1988-2012 Source: NHANES surveys BirthByTheNumbers.org

Prepregnancy Obesity, U.S. (sort of)* 2003, 2006, 2009, 2011*, 2013* While there is justifiable concern with the health consequences of obesity overall and in pregnancy, maternal prepregnancy obesity has also levelled off in recent years. Sources: 2003-2009 -- S. Fisher. Is obesity still increasing among pregnant women? Preventive Medicine 2013; 56: 372-378; 2011 & 2013 – CDC VitalStats. * Based on different combinations of states in 2011 & 2013 BirthByTheNumbers.org

Term, Singleton, Vertex (TSV) , No prior Cesarean Term – 37 + weeks gestation Singleton – no twins Vertex – no breech births No prior cesarean BirthByTheNumbers.org

BMI categories for Term, Singleton, Vertex births to mothers w/ no prior cesarean: 38 states & DC, 2012 Characteristic of mother Under-weight Normal weight Overweight and obese Total Over-weight Total Obese Obese I Obese II Obese III (BMI<18.5) (BMI 18.5-24.9) (BMI 25+) (BMI 25.0-29.9) (BMI 30+) (BMI 30.0-34.9) (BMI 35.0-39.9) (BMI ≥40.0) (N=88,638) (N= 1,066,630) 1,002,074) (N=542,296) (N=459,778) (N=266,872) (N=118,111) (N=74,795) All 4.1 49.4 46.4 25.1 21.3 12.4 5.5 3.5 Race and Hispanic origin Hispanic 3.1 44.4 52.5 29.1 23.4 14.7 5.6 3.0 Non-Hispanic White 4.0 52.3 43.7 23.9 19.8 11.3 5.2 3.3 Black 3.7 38.7 57.6 27.1 30.5 16.1 8.0 6.3 AIAN 37.1 59.8 27.3 32.5 17.7 9.1 5.7 Asian 9.5 66.9 23.5 17.5 6.1 4.7 1.0 0.3 BirthByTheNumbers.org

Prepregnancy Obesity also related to: Being born in the U.S. (23%) rather than foreign born (15%) Being on private insurance (25%) rather than Medicaid (19%) Having only a high school education (25%) compared to a graduate degree (12%) BirthByTheNumbers.org

Also related to how many kids you’ve had: Obesity by Live Birth Order, 2013 BirthByTheNumbers.org

How is BMI related to the likelihood of a cesarean? BirthByTheNumbers.org

Unadjusted Primary Cesarean Rate TSV births to mothers with no prior cesarean: 38 states and DC, 2012 Cesarean rates vary dramatically by obesity categories. Source: CDC VitalStats, 2013. BirthByTheNumbers.org

CS Rates for TSV mothers by BMI and Race/Ethnicity BirthByTheNumbers.org

Overall relationship adjusted for: maternal age, race/ethnicity, education, trimester prenatal care began, nativity (US or foreign-born), method of payment for the delivery, pre-pregnancy and gestational diabetes and hypertension. BirthByTheNumbers.org

Adjusted~ risk ratios^ for CS by BMI, TSV Adjusted~ risk ratios^ for CS by BMI, TSV* Mothers w/ no Prior CS, 38 states, 2012 ~ Adjusted for maternal age, race/ethnicity, education, trimester prenatal care began, nativity (US or foreign-born), method of payment for the delivery, and pre-pregnancy and gestational diabetes and hypertension. ^ “Normal weight” (BMI 18.5-24.9) was the reference group; Error Bars represent 95% Confidence Intervals. *Singleton, vertex, 37-41 weeks of gestational age. LBO = live birth order BirthByTheNumbers.org

Conclusion BMI retains a significant impact on the likelihood of a CS, even after controlling for socio-demographic and medical risks Robust relationship that was consistent across different analyses of subgroups (e.g. mothers without diabetes or hypertension) What about outcomes? Future Birth by the Numbers video BirthByTheNumbers.org

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