Introduction:

Periconceptional maternal ultra-processed food (UPF) consumption impairs embryonic growth. Impacts of exposure to UPF on distinct components of fetal growth in late pregnancy are unknown.

Objective:

To investigate the influence of frequency of UPF consumption during pregnancy on fetal head circumference (HC), abdominal circumference (AC), and femur length (FL).

Methods:

This study included 417 live-born singleton pregnancies prospectively followed-up since the antenatal period in the MINA-Brazil Study (Maternal and Child Health and Nutrition in Acre, Brazil), with an available ultrasound scan at >24 gestational weeks. Frequency of food groups consumption in the previous month was categorized as no/monthly, weekly, or daily. Ultrasound scans were conducted at 27.8 (SD: 1.7) gestational weeks. HC, AC, and FL z-scores were calculated for gestational age using the INTERGROWTH-21st Project standards. Simultaneous-quantile regression models were fitted at the 10th, 50th, and 90th percentiles of the distribution of each ultrasound parameter according to UPF consumption, with adjustment for potential confounders.

Results:

Participants were aged on average 24.7 (SD: 6.5) years, 44.8% were primiparous, and 26.9% and 24.9%, respectively, had weekly and daily UPF consumption. Compared to no/ monthly intake, daily UPF consumption impaired HC across its distribution, with significant effect sizes varying from -0.24 to -0.40 z-score. Weekly UPF consumption decreased HC at the 90th percentile by -0.39 z-score (95% CI: -0.78, -0.01) and FL at the 50th percentile by -0.32 z-score (95% CI: -0.60, -0.04). No association was noted with AC.

Conclusion:

Frequency of UPF consumption was negatively associated with skeletal components of fetal growth in late pregnancy. Infant body composition may benefit from healthy food practices since pregnancy.