What are the specific nutritional needs during pregnancy?

This article completes the series of articles on nutritional needs:

• Nutritional needs in adults
• Nutritional needs in seniors
• Nutritional needs during breastfeeding

To review the previous concepts, feel free to consult them.

Pregnancy brings about numerous changes in a woman's body, as adaptations occur to allow for fetal development. This leads to a shift in nutritional needs. These changes are critical for an optimal pregnancy and normal fetal development. Indeed, certain deficiencies during pregnancy can lead to malformations or developmental abnormalities.

A few reminders about nutritional needs

Definition of nutritional needs

Nutritional needs are defined as:

" the average amount of nutrients needed daily to ensure the development of the body, the renewal of tissues, the maintenance of good physical and mental health, and physical activity in accordance with one's living conditions ."

Nutritional references

In France, ANSES , through its expert committees and EFSA recommendations , defines nutritional reference values. This leads to the establishment of several concepts:

The average nutritional requirement or NRV

Defined as “ the average requirement within the population, as estimated from individual intake data in relation to a nutritional adequacy criterion in experimental studies ”.

The nutritional reference intake for the population or RNI

Defined as “ the intake which in theory covers the needs of almost the entire population considered (97.5% in most cases), as estimated from experimental data ”.

The satisfactory contribution or AS

Defined as “ the average intake of a population or subgroup for which nutritional status is considered satisfactory ”.

When the BNM and the RNP cannot be estimated correctly or are considered insufficient, the AS is retained as the nutritional reference.

The upper safety limit or LSS

In addition to these concepts, there are safety values ​​for certain nutrients, these are the upper safety limits or USLs.

The LSS is defined as “ the maximum chronic daily intake of a vitamin or mineral considered unlikely to present a risk of adverse health effects for the entire population ”.

What are the specific energy needs during pregnancy?

Pregnancy leads to changes in metabolism; the body adapts to pregnancy, and the needs of the fetus and its development are added to the needs of its mother.

During pregnancy, energy needs change. This change can be simplified by dividing it into trimesters. Each trimester of pregnancy, energy needs increase; they are therefore slightly higher than normal at the beginning of pregnancy and significantly higher at the end (of course, this change doesn't happen overnight, but this division allows for a clear distinction). As a reminder, energy requirements are 1800 to 2200 kcal per day (7536 to 9211 kJ per day) for women.

Thus, we observe an increase in the energy requirement of:

• + 70 kcal per day on average in the first trimester

• + 260 kcal per day on average in the second trimester

• + 500 kcal per day on average in the last quarter

To meet this need, nothing complicated, you just need to eat more, paying attention to the proportion of different nutrients.

During pregnancy, body mass increases. This increase averages 13 kg, with a weight gain of 1 kg/month during the first trimester, then 500 g/month thereafter. Particular attention should be paid to cases of insufficient or excessive weight gain. In all cases, regular medical monitoring allows for tracking progress.

What are the macronutrient requirements during pregnancy?

The proportions of the different macronutrients are maintained during pregnancy and the recommendations are the same as for the general adult population:

• 35 to 40% of energy intake should come from lipids (pay attention to omega-3 intake: consume oily fish)

• 10 to 27% of energy intake should come from protein . In the 3rd trimester, this range increases to 12-27% .

• Approximately 50% of energy intake should come from carbohydrates . Note that it is preferable to choose complex carbohydrates with a low glycemic index; simple sugars with a high glycemic index are not recommended.

Water requirements are also increased and a minimum intake of 2.3L per day is recommended.

What are the vitamin and micronutrient requirements during pregnancy?

During pregnancy, the need for vitamins and micronutrients increases. For some, special attention must be paid to ensure normal fetal development.

Folate (vitamin B9) intake is important before and during pregnancy

Folate is essential during fetal development, particularly during the first trimester of pregnancy. A deficiency can lead to neural tube defects, resulting in spina bifida.

To prevent spina bifida, vitamin B9 supplementation is recommended at a dose of 400µg/day starting 28 days before conception and continuing until the end of the 4th month (approximately 12 weeks of amenorrhea).

The needs that require attention

During pregnancy, the need for vitamins A, C and D, iron, calcium and iodine is increased or of particular importance.

Special attention should be paid to iron intake in individuals with low ferritin levels or anemia. There is a risk of iron deficiency anemia. Iron deficiency anemia is correlated with low birth weight, an increased risk of prematurity, and increased perinatal mortality. Only in these cases is iron supplementation recommended (50 mg of elemental iron per day).

To ensure proper brain development, iodine needs must be met (without excess), the sufficient intake is set at 200 µg/day with an upper safety limit of 600 µg/day.

Calcium intake should be at least 1000 mg/day and is met by consuming 3 to 4 dairy products.

Nutritional reference intake of vitamins and minerals during pregnancy

Nutrients whose needs differ from those of adult women are shown in orange.

Foods to avoid and precautions to take during pregnancy

Avoid the risks of listeriosis and toxoplasmosis

To avoid the risk of food contamination and the development of an infection that could jeopardize the pregnancy, you should avoid consuming:

• Raw or undercooked meats

• Non-sterilized deli meat products in jars (e.g., canned pâté like Henaf pâté: yes, "sliced" pâté: no)

• Raw milk

• Raw milk cheeses, except those with a pressed and cooked paste (e.g., Emmental)

• Cheeses with a washed or bloomy rind (e.g., Munster and Camembert types respectively)

• Pre-grated cheeses

• Raw eggs

• Raw seafood

Limit or eliminate the consumption of risky foods

You should avoid consuming:

• Too much soy: 1 food per day max, to limit the consumption of phytoestrogens.

• Energy drinks

• Goitrogenic foods

• Too much liver, and prioritize vegetables

We must refrain from consuming:

• Alcohol, which is particularly toxic during fetal development

• Tobacco

Sources

National Nutrition and Health Program (PNNS)

ANSES

EFSA

Nutrition - 2021, Elsevier

ANSES: Update of the PNNS dietary guidelines for pregnant or breastfeeding women

EatMove

CERIN: Nutritional reference intake during pregnancy and breastfeeding