Pregnancy Requires Major Changes in the Quality of the Diet for Nutritional Adequacy: Simulations in the French and the United States Populations

Abstract

Background: Maternal nutrition is critical to the health of both mother and offspring, but there is a paucity of data on the nutritional adequacy of diets during pregnancy.

Objective: Our objective was to identify to what extent pregnancy reduces the nutritional adequacy of the expecting mother's diet and if this nutritional gap can be resolved by simple quantitative or qualitative changes in the diet.

Materials and methods: We evaluated the observed overall nutritional adequacy of diets of French and American women of childbearing age participating in ENNS (n = 344) and NHANES (n = 563) using the probabilistic approach of the PANDiet system, resulting in a 100-point score. Then, we simulated the changes in the PANDiet scores of women of childbearing age who would remain on their diet during pregnancy. Finally, by either increasing the quantity of consumed foods or using eleven snacks recommended during pregnancy, we simulated the effect of a 150-kcal increase in the energy intake of French women.

Results: Observed PANDiet scores were equal to 59.3 ± 7.0 and 58.8 ± 9.3 points respectively in France and in the US. Simulation of pregnancy for women of childbearing age led to a decrease in nutritional adequacy for key nutrients during pregnancy and resulted in reducing PANDiet scores by 3.3 ± 0.1 and 3.7 ± 0.1 points in France and in the US. Simulated 150-kcal increases in energy intake proved to be only partially effective in filling the gap both when the quantity of food consumed was increased and when recommended snacks were used.

Conclusions: The decrease in nutritional adequacy induced by pregnancy cannot be addressed by simply following generic dietary guidelines.

Fig 1. Distribution of observed PANDiet scores and simulated-pregnancy PANDiet scores, Adequacy sub-scores and Moderation sub-scores for French women of childbearing age from the ENNS survey (left panel) and US women of childbearing age from the NHANES survey 2009–2010 (right panel).

Each bar represents n = 344 for the French sample and n = 563 for the US sample. The light grey bars represent the observed PANDiet score and sub-scores. The dark grey bars represent the simulated-pregnancy PANDiet score and sub-scores. The middle line in the box plots shows the median, the bottom and top of the box are the 25th and 75th percentiles and the ends of the whiskers represent the 5th and 95th percentiles. Differences between observed and simulated-pregnancy PANDiet scores, Adequacy sub-scores and Moderation sub-scores were assessed with a mixed model: * P<0.05

Fig 2. Probabilities of adequacy composing PANDiet scores for the five vitamins and minerals for which the probability of adequacy was lowered the most when simulating the changes in the nutritional requirements in the first trimester of pregnancy in the French sample (left panel) and in the US sample (right panel).

Each bar represents n = 344 for the French sample and n = 563 for the US sample. The light grey bars represent probabilities of adequacy for nutrient intakes composing the observed PANDiet score. The dark grey bars represent probabilities of adequacy for nutrient intakes composing the simulated-pregnancy PANDiet score. The middle line in the box plots shows the median, the bottom and top of the box are the 25th and 75th percentiles and the ends of the whiskers represent the 5th and 95th percentiles. Differences between observed and simulated-pregnancy probabilities of adequacy for nutrients were assessed with a mixed model after a Box-Cox transformation: * P<0.05.