Validating a Term BMI using Mode of Delivery
Validating a “Term BMI” using Mode of Delivery, Estimated Blood Loss, and Neonatal Weight Diana Garretto, MD & Erin Stevens, MD State University of New York at Stony Brook University Medical Center Department of Obstetrics, Gynecology, & Reproductive Medicine Background Results Among non-pregnant women age 20 -39, 25% of them are overweight and 28% are obese, and 6% have a BMI >= to 40. Issues begin with pre-conception with infertility etc to antepartum issues including GDM and anomalies through intrapartum problems. Postpartum issues include increased risk for venous thrombosis, etc. Based on the IOM guidelines, a patient would be considered underweight if the BMI at term was <23. 5, normal weight if the BMI at term was 23. 5 -29. 9, overweight if the BMI at term was 30 -33. 5 and obese if the BMI at term was >33. 5. These were used as the “Term BMI” categories. Objective To validate using a “Term BMI” instead of pre -pregnancy BMI to evaluate for risk of blood loss, LGA fetus, and cesarean section on day of delivery. A single institution retrospective chart review was then performed of patients who delivered at term (>=37 weeks) from July 2009 to January 2010 was performed to validate the use of a Term BMI. Data included height, prepregnancy weight, maternal delivery weight, mode of delivery, neonatal weight, and estimated blood loss. Table 1 C-Section Rate Term Normal Weight 27. 79% 28. 64% Overweight 31. 87% 28. 93% Obese 42. 27% 40. 5% P-value 0. 0026 0. 0033 EBL Mean Pre-pregnancy EBL Mean Term Normal weight 589 573 Overweight 636 627 Obese 727 731 P-value 0. 0002 <0. 0001 BMI Table 2 Conclusions Using the “Term BMI” at the time of delivery may be an easier and more accurate way to objectively assess risks of obesity at term than pre-pregnancy weight or BMI alone. The “Term BMI” allows calculation of a woman’s BMI the actual day of delivery and can help to predict complications associated with delivery including mode of delivery, neonatal weight, and estimated blood loss. C-Section Rate Pre-pregnancy BMI 1, 031 patients met inclusion criteria. The data was analyzed using the Jonckheere-Terpstra Test. There was a significant increase in risk of cesarean section with increasing BMI in both the pre-pregnancy and Term BMI groups (Table 1). There was also a significant increase in estimated blood loss (Table 2) and neonatal weight (Table 3) with increasing BMI in both the pre-pregnancy and Term BMI groups. Study Design In non-pregnant populations, underweight is a BMI <18. 5, normal weight is a BMI 18. 5 -24. 9, overweight is a BMI 25 -29. 9, and obese is a BMI>30. The “Term BMI” was calculated by adding the respective IOM weight gain recommendations of each category to each pregnancy at term. . Tables Neonatal weight Mean Pre-pregnancy Neonatal weight Mean Term Normal weight 3405 3366 Overweight 3420 3436 Obese 3466 3510 P-value 0. 0168 <0. 0001 BMI Table 3
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