Is there a relationship between maternal diet and birth weight for gestational age?

In a recent study published in the Nutrients Journal, researchers examined the dietary habits of 667 pregnant women living in Catania, Italy.

The study used the principal component (PC) clustering approach to determine the association between maternal diet and infant weight at gestational age.

Study: Effect of Maternal Nutritional Pattern on Birth Weight for Behavioral Age: Results from the MAMI-MED Cohort. Image Credit: G-StockStudio/


Gestational diabetes mellitus and inadequate gestational weight gain (GWG) are major threats to maternal-newborn well-being.

Adverse outcomes for the baby include low birth weight (LBW), births that are too large or small for gestational age (LGA and SGA), macrosomia, intrauterine growth restriction (IUGR), and preterm births (PTB ).

Maternal nutrition is one of the most important determinants of neonatal outcomes and can be modified for better neonatal growth and development.

However, data on the influence of maternal dietary patterns on birth weight are limited, and most previous studies that have examined the relationship have not considered gestational sex and infant age.

About the study

In this study, the researchers assessed the effects of maternal diet on infant birth outcomes.

The study included maternal-neonatal deaths from the MAMI-MED study, for which complete dietary, sociodemographic, and birth outcome data were obtained using questionnaires, including maternal educational attainment, employment status, smoking habits, and anthropometric data. Pre-pregnancy body mass index (BMI) was calculated using World Health Organization (WHO) criteria.

GWG was calculated by subtracting the self-documented pre-pregnancy body weight from the infant’s birth weight, and its adequacy was derived based on Institute of Medicine (IOM) guidelines. At delivery, data were collected on length of gestation, length of birth, and weight.

Study outcomes included preterm birth (PTB, spontaneous delivery before 37.0 weeks) and weight for gestational age. [LGA, SGA, or appropriate gestational age (AGA)] using sex-based reference tables.

Dietary habits in the previous 30.0 days were assessed using food frequency questionnaires (FFQs). Daily consumption was calculated based on portion size and frequency of intake. In addition, the total caloric consumption is predicted using the food intake database of the United States Department of Agriculture (USA), accessed on January 1, 2014, and adapted to the Italian food items.

The data were analyzed using a combination of principal component analysis (PCA) and clustering (primarily K-means and hierarchical clustering). Multiple logistic regression modeling was performed, and odds ratios (OR) were calculated.


Among the study participants, a median age of 31.0 years was observed; 51.0% were primiparous, 25.0% were highly educated, and 51.0% were employed. Among the participants, 91.0% did not smoke during pregnancy, and their median total calorie intake was 1,703.0 kcal. Pre-pregnancy BMI (median) was 23.0 kg/m2and 60.0% of the mothers had a normal body weight.

Based on the mean GWG of 12.0 kg, 39.0% of mothers documented reduced weight gain, and 29.0% documented excessive weight gain. The median value for the gestational week at the time of infant birth was 39.0, and the majority (94.0%) were normal term births.

Regarding birth size, median values ​​of 50.0 cm and 3.30 kg were found for birth length and weight, respectively, and 82%, 7.0%, and 11.0% of neonates were AGA, SGA, and LGA, respectively.

Two clusters representing different diets were identified. The first cluster (158 women) consisted mainly of plant-based foods (including raw and cooked vegetables, potatoes, soup, legumes, nuts, fruit, wholemeal bread, and rice), white meat, fish, eggs, margarine, butter, tea. , and coffee.

The second cluster (509 women) was characterized by Western dietary patterns and junk food (high-salt snacks, dips, fries, and sweets), milk, white bread, and olive and vegetable oils.

Regarding nutrients, women from the first cluster consumed more magnesium, folate, vitamin A, vitamin B6, and vitamin C, whereas women from the second cluster consumed more unsaturated and saturated fatty acids, vitamin B1, and calcium. Younger and less educated women followed a Western diet (second cluster).

The main predictors of small-for-gestational-age births were preference and employment status but not dietary compliance. Newborns of employed mothers had a lower chance of SGA than unemployed mothers (OR 0.4).

Conversely, SGA was more likely than those with ≥1.0 previous pregnancies (OR 2.7). Women in the second cluster showed greater odds of large-for-gestational-age (LGA) births than women in the first cluster (OR 2.2).

In addition, the odds of LGA increased by 11.0% per unit elevation in pre-gestational BMI (OR 1.1). Younger Italian women had worse diet quality, indicating that health consciousness improves with age.

Highly educated people tend to be better informed about the risk-benefit ratios of their diets, and therefore, education is the most important socio-demographic factor influencing dietary decision-making.


Overall, the results of the study highlighted the association between adherence to Western diets and the likelihood of LGA newborns.

Women who adhered to Western diets were 2.20-times more likely to have LGA than those who adhered to healthier plant-based diets after adjusting for covariates such as GWG and total caloric intake .

Furthermore, the odds of LGA increased with increasing BMI values. Additional research needs to investigate potential confounding and mediation by employment type, work hours, family income, and regular activities to add to the scientific literature and guide nutrition policymaking for pregnant women.

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