Coding Obesity in Pregnancy
If a patient has a diagnosis of obesity (BMI ≥ 30) O99.21__ (obesity complicating pregnancy, childbirth and the puerperium) is an accepted indication for a detailed fetal anatomy survey (CPT 76811) according to published guidelines. To determine BMI in a pregnancy affected by obesity, we recommend utilizing the pre-gravid height/weight to calculate this value. If pre-gravid BMI is not available, it is advised that the physician calculate the BMI at the first pregnancy encounter in their office.
Example #1:
A 29 year old G2P1 presents at 8 week ob visit, and her height/weight obtained calculates a BMI of 29 kg/m2. When the patient returns for ob visit in the 2nd trimester, it is noted she has gained 40 pounds. Her height/weight now calculates a BMI of 35 kg/m2. How would you code the 2nd visit?
In this case, the code for excessive weight gain in pregnancy (O26.0__) would be used. ICD-10 code O99.21__ for obesity complicating pregnancy would not be assigned, because the diagnosis of obesity was not present until the subsequent visit. If a fetal anatomy ultrasound was performed in the 2nd trimester, 76805 would be billed, rather than 76811, since O26.0__ is not an indication for 76811.
Example #2:
Prenatal records are unavailable for the patient, who presents at 18 weeks to your office for fetal anatomy ultrasound. As no records are available, you obtain a height & weight to calculate her BMI in your office. The BMI is calculated to be 44kg/m2.
ICD-10 code O99.212 (obesity complicating pregnancy, second trimester) should be used, along with E66.01 (E66.xx series to identify type of obesity). Given BMI > 30, performance of a detailed anatomy ultrasound (76811) would be appropriate. The ICD-10 code for BMI (Z68.1-Z68.45) should NOT be assigned in pregnancy. Chapter 21 of the ICD-10 Official Guidelines for Coding and Reporting states: Do not assign BMI codes during pregnancy.