Monthly changes in head circumference by postnatal (left panel) and prenatal (right panel) intervention arms with the dashed lines representing the control group (IFA) and solid lines representing the intervention group (IFA + BEP).
Line graphs represent locally weighted scatterplot smoothing of observed values. Group differences were estimated using mixed-effects models with random intercepts for infant and random slopes for intervention time, with fixed effects including time spline variables with 6 knots, intervention group, and time × group interaction terms adjusted for allocation to the other intervention, clustering indicators (health center and randomization block), and a priori determined prognostic factors (maternal height, BMI, MUAC, hemoglobin, age and gestational age at inclusion, and parity). Group difference was tested by likelihood ratio test comparing a model with and without time × group interaction terms. BEP, balanced energy–protein supplement; BMI, body mass index; IFA, iron–folic acid; MUAC, mid-upper arm circumference.