Abstract
Background Early pregnancy nutritional status can be associated with adverse birth outcomes such as small-for-gestational age (SGA) and low birth weight (LBW). BMI (Body Mass Index) and MUAC (Mid-upper arm circumference) are
easy to use assessments and are indicative of the pre-pregnancy nutritional status if obtained in the frst trimester. This
study primarily assesses the association of maternal nutritional status using BMI and MUAC with SGA in a communitybased cohort of Pakistani women. It also aims to determine the predictive ability of MUAC and BMI in predicting SGA.
Secondarily, we assessed the association between maternal nutrition and large for gestational age (LGA) and LBW.
Methods This study is a secondary analysis of an ongoing pregnancy cohort “Pregnancy Risk Infant Surveillance
and Measurement Alliance (PRISMA)“in Ibrahim Hyderi and Rehri Goth, Karachi. PRISMA participants who were
enrolled between January 2021 to August 2022 were included given they had a gestational age<14weeks confrmed
via ultrasound, MUAC and BMI measurements were available and birth weight was captured within 72hours. Multivariable logistic regression was used to determine an association between maternal nutritional status and SGA. The
PRISMA study was approved by the Aga Khan University Ethics Review Committee (2021–5920-15,518).
Results Of 926 women included in the analysis, 26.6% (n=247) had a low MUAC (<23 cm) while 18.4% (n=171) were
underweight (BMI<18.5 kg/m2). Nearly one third of low MUAC and underweight women delivered SGA infants (34.4
and 35.1% respectively). Underweight women and women with low MUAC had a statistically signifcant association
with SGA (Underweight: OR 1.49, 95% CI 1.1,2.4; Low MUAC-OR 1.64, 95% CI 1.2,2.3) as well as LBW (Underweight:
OR-1.63, 95% CI 1.1,2.4; Low MUAC-OR-1.63, 95% CI 1.2,2.3). ROC curves showed that MUAC and BMI had modest
predictability for SGA (AUC<0.7).
Conclusion Maternal nutritional status as indicated by BMI and MUAC are strongly associated with adverse pregnancy outcomes including SGA, LGA and LBW. Although MUAC and BMI are widely used to determine maternal
nutritional status, they have poor predictive ability for newborn size. Further research is needed to identify other
tools or a combination of tools to better predict adverse birth outcomes in resource-limited settings and plan
interventions.
