Are early first trimester weights valid proxies for preconception weight?

• Published in: BMC pregnancy and childbirth Vol. 16; no. 1; p. 357
• Main Authors: Krukowski, Rebecca A, West, Delia S, DiCarlo, Marisha, Shankar, Kartik, Cleves, Mario A, Saylors, Marie E, Andres, Aline
• Format: Journal Article
• Language: English
• Published: England BioMed Central 21.11.2016
• Subjects: Adult; Agreements; Behavior modification; Body composition; Body Mass Index; Body Weight; Childrens health; Diabetes; Female; Gestational Age; Humans; Longitudinal Studies; Maternal & child health; National Academies of Science, Engineering, and Medicine (U.S.) Health and Medicine Division; Obesity; Overweight - complications; Overweight - diagnosis; Predictive Value of Tests; Pregnancy; Pregnancy Complications - diagnosis; Pregnancy Complications - etiology; Pregnancy Trimester, First - physiology; Prenatal Care - methods; Prenatal Diagnosis - methods; Risk Factors; United States; Weight Gain; Womens health; Obesity; Obstetrics; Preventive medicine
• ISSN: 1471-2393; 1471-2393
• DOI: 10.1186/s12884-016-1159-6

An accurate estimate of preconception weight is necessary for providing a gestational weight gain range based on the Institute of Medicine's guidelines; however, an accurate and proximal preconception weight is not available for most women. We examined the validity of first trimester weights for estimating preconception body mass index category. Under identical measurement conditions, preconception weight and two first trimester weights (i.e., 4-10 and 12 weeks gestation) were obtained (n = 43). The 4-10 week and the 12 week weight correctly classified 95 and 91% women, respectively. Mean weight changes were relatively small overall (M = 0.74 ± 1.99 kg at 4-10 weeks and M = 1.02 ± 2.46 at 12 weeks). There was a significant difference in mean weight gain by body mass index category at 4-10 weeks (-0.09 ± 1.86 kg for normal weight participants vs. 1.61 + 1.76 kg for overweight/obese participants, p = 0.01), but not at 12 weeks (0.53 ± 2.29 kg for normal weight participants vs. 1.54 ± 2.58 kg for overweight/obese participants). Assigning gestational weight gain guidelines based on an early first trimester weight resulted in 5-9% of women being misclassified depending on the gestational week the weight was obtained. Thus, most women are correctly classified based on a first trimester weight, particularly an early first trimester weight, although it is possible that modeling strategies could be developed to further improve estimates of preconception body mass index category. Clinicaltrials.gov # NCT01131117 , registered May 25, 2010.