Article Figures & Data
Figures
- Figure 1.
Receiver operator characteristic (ROC) curve of sensitivity of percentage change in body mass index (BMI) of ≥25% vs specificity.
Tables
Characteristic Normal Weight (n=157) Macrosomic (n=29) PValue P values based on t test (for means) or χ2 test (for proportions). Age, mean y (SD) 26.6 (5.1) 25.9 (4.6) .527 Age, n (%) .378 <25 y 64 (40.8) 12 (41.4) 25–29 y 55 (35.0) 11 (37.9) 30–34 y 24 (15.3) 6 (20.7) ≥35 y 14 (8.9) 0 (0) Race, n (%) .274 White 86 (54.8) 19 (65.5) Black 44 (28.0) 4 (13.8) Other 27 (17.2) 6 (20.7) Parity, n (%) .414 0 68 (43.3) 11 (37.9) 1 51 (32.5) 13 (44.8) 2+ 38 (24.2) 5 (17.2) Gravidity, n (%) .928 1 52 (33.1) 9 (31.0) 2 46 (29.3) 8 (27.6) 3+ 59 (37.6) 12 (41.4) BMI Initial (SD) 25.8 (5.09) 25.3 (5.43) .625 Final (SD) 30.6 (4.98) 33.9 (5.13) .001 % change 15.6 (6.44) 25.5 (6.59) <.001 Birth weight, g (SD) 3,332 (345) 4,244 (243) <.001 IOM Guidelines Macrosomic n Normal Weight n Total n BMI = body mass index; IOM = Institute of Medicine. P<.001. a Sensitivity=75%, specificity=100%, positive predictive value=100%, negative predictive value=98%. b Sensitivity=70%, specificity = 97%, positive predictive value = 78%, negative predictive value = 96%. c Sensitivity=100%, specificity = 84%, positive predictive value = 68%, negative predictive value = 100%. Weight gain less than IOM recommendationsa Change in BMI ≥25% 3 0 3 Change in BMI <25% 1 48 49 Total 4 48 52 Weight gain within IOM recommendationsb Change in BMI ≥25% 7 2 9 Change in BMI <25% 3 64 67 Total 10 66 76 Weight gain greater than IOM recommendationsc Change in BMI ≥25% 15 7 22 Change in BMI <25% 0 36 36 Total 15 42 58 Initial Body Mass Index IOM Recommended Weight Gain, lb From the Institute of Medicine.4 <19.8 (underweight) 28–40 19.8–26.0 (normal) 25–35 26.1–29.0 (overweight) 15–25 >29.0 (obese) At least 15
The Article in Brief
Percentage Change in Antenatal Body Mass Index as a Predictor of Neonatal Macrosomia
Chad A. Asplund , and colleagues
Background Macrosomia, a condition in which a fetus grows unusually large, affects between 3% and 15% of all pregnancies and can cause health problems for both infant and mother. This study examines whether a percentage change in the mother's body mass index, or BMI, (a measurement of body fat) during pregnancy predicts macrosomia.
What This Study Found During pregnancy, an increase in the mother's BMI of 25% or more is highly predictive of macrosomia, regardless of her initial BMI or absolute weight gain.
Implications
- This is the first published study showing that change in BMI during pregnancy is a sensitive predictor of fetal macrosomia, regardless of initial weight.
- This method of predicting macrosomia is easy to use without any special equipment or expert clinical skills and is more sensitive and specific than other methods.
- This method may allow clinicians to tailor pregnancy weight gain recommendations to women's individual needs.
