Mediterranean diet during pregnancy cuts small-for-gestational-age risk in babies

Mothers who keep a Mediterranean diet while pregnant are less likely to give birth to small-for-gestational age (SGA) infants, according to a recent study.

“[H]igh compliance with the Mediterranean diet pattern during pregnancy appears to be favourable for reducing the risk of SGA,” the researchers said, “suggesting that this diet pattern has a positive effect on foetal growth.

“These results should be taken into account during the implementation of nutritional intervention programmes, which should focus on a healthy diet like the Mediterranean diet for pregnant women to prevent nutritional deficiencies that might adversely impact the health of the baby,” they added.

The prospective analysis included 614 mother-child dyads. A food frequency questionnaire was used to assess maternal diets during pregnancy, which were given a relative Mediterranean diet score (rMedDiet), calculated based on the intake of nine food groups, including vegetables, fruits, fresh fish, and dairy. Outcomes were neonatal characteristics, including weight, height, SGA, and head circumference.

Mothers showed an average rMedDiet score of 9.8. Only 22 percent were highly adherent to a Mediterranean diet (score ≥12 points). These women tended to be older, had better educational backgrounds, and were of a higher social class. [Sci Rep 2022;12:13794]

Infants were born with a mean birth weight of 3,294.6 g and a mean length of 49.3 cm. Average head circumference was 34.5 cm. The prevalence rates of SGA assessed according to the respective parameters were 10.7 percent, 13.3 percent, and 16.8 percent. SGA was more common in boys than in girls.

Multivariable logistic regression analysis found that better adherence to the Mediterranean diet was protective of SGA regardless of the anthropometric measure used.

For instance, mothers in the highest tertile of adherence (rMedDiet score 12–18 points) were nearly 65 percent less likely to give birth to infants SGA for weight than comparators with low adherence (rMedDiet score 0–9; adjusted odds ratio [OR], 0.36, 95 percent confidence interval [CI], 0.16–0.79; p_trend=0.005).

Similarly, high adherence cut the likelihood of SGA for length and head circumference by more than 40 percent (adjusted OR, 0.57, 95 percent CI, 0.28–1.17; p_trend<0.013) and 60 percent (adjusted OR, 0.39, 95 percent CI, 0.18–0.86; p_trend=0.015), respectively.

Taking rMedDiet score as a continuous variable yielded generally similar results, with each 1-point increase resulting in significant reductions in the likelihood of SGA for weight (adjusted OR, 0.74, 95 percent CI, 0.64–0.85) and head circumference (adjusted OR, 0.82, 95 percent CI, 0.72–0.94). Such an effect for SGA for length was only of borderline significance.

Other notable predictors of SGA for weight were insufficient gestational weight gain (adjusted OR, 2.16, 95 percent CI, 1.14–4.09) and smoking (adjusted OR, 2.62, 95 percent CI, 1.44–4.78), both of which aggravated such risk by more than twofold. Smoking was also correlated with SGA for head circumference, increasing its likelihood by more than three times (adjusted OR, 3.64, 95 percent CI, 1.83–7.23).

Meanwhile, aside from adherence to a Mediterranean diet during pregnancy, none of the other potential predictors were found to be significantly associated with SGA for infant length.

“Our study adds to current knowledge regarding the influence of maternal diet on foetal growth and highlights the importance of promoting a healthy Mediterranean diet eating pattern early in pregnancy as an effective strategy for preventing SGA births,” the researchers said.