Over-nutrition in pregnancy


Like not eating enough (under-nutrition) during pregnancy, eating too much (over-nutrition) can create health risks for both the pregnant woman and her developing foetus. Over-nutrition during pregnancy is common in developed countries. Some 43% of American women gain too much weight during pregnancy (compared to only 20% who do not gain enough weight).

Due to the increasing prevalence of obesity in developed countries, understanding the association between over-nutrition and poor pregnancy outcomes is of increasing importance. For example, in the US some 18-38% of pregnant women are obese and these women typically continue to over-consume during pregnancy, putting both their and their growing baby’s health at risk.

Health risks for mothers who are obese when they become pregnant

Over-nutrition during pregnancyMany women are obese when they become pregnant. Pre-pregnancy obesity is associated with an increased risk of:

Health risks for mothers who over-eat during pregnancy

Many women experience increased appetite during pregnancy. This occurs partly because their hormonal balance is altered, but also because the growing foetus removes food by-products from their blood. It is therefore also possible for women to consume too much during pregnancy and gain excessive weight.

Women who over-consume during pregnancy increase their risk of:

  • Obesity – women who gain excessive weight during pregnancy often fail to lose weight after childbirth and risk becoming overweight or obese, or increasing the severity of their condition if they are already obese;
  • Pre-eclampsia (a condition which occurs in late pregnancy and is characterised by high levels of protein in the urine, hypertension and excessive fluid in tissues);
  • Gestational diabetes;
  • Caesarian delivery;
  • Failure to initiate and early termination of breastfeeding.

Health risks for the baby


Image courtesy of Blausen Medical Communications. Contact Andrew Walbank.

Macrosomnia (foetal over-growth) can occur because a pregnant woman over-consumes, but also as a result of irregularities in the transfer of nutrients from the pregnant woman’s body to her foetus. For example, excessive transfer of glucose and other nutrients can occur in pregnant women with diabetes. As the nutrition a foetus receives in the womb programs the metabolic system to function later in life, over-nourished foetuses have an increased risk of obesity and associated metabolic conditions such as type 2 diabetes later in life. There is also evidence of an increased risk of the infant experiencing the following:

  • Polycythaemia (abnormally high red blood cell concentration);
  • Needing assisted respiration or having difficulty breathing following birth;
  • Hypoglycaemia (abnormally low blood sugar levels);
  • Seizures.

Health risks for the child in the long-term

Over-nutrition during pregnancyWhile further research is needed, current evidence also suggests that high birth weight as a result of maternal over-nutrition is associated with an increased risk of chronic health conditions later in life.

Type 2 diabetes mellitus

Infants born to women who over-consumed during pregnancy have an increased risk of developing type 2 diabetes mellitus later in life. In one study the risk of developing type 2 diabetes was associated with the mother eating too much overall or eating too much sugar during pregnancy.

Research in animals suggests that the increased risk of type 2 diabetes associated with over-consumption during pregnancy may be due to excessive fat intake (rather than excessive calorie intake). However, further studies in humans are needed to better understand the risk.

Cardiovascular disorders

Individuals born to women who over-consumed during pregnancy also have an increased risk of cardiovascular disorders. The association seems to be related to the amount of fat consumed during pregnancy. Studies which used pregnant laboratory animals have also shown associations between high-fat diets and cardiovascular disorders including hypertension, metabolic syndrome and endothelial (the system which regulates blood flow) dysfunction.

More information

Pregnancy For more information about pregnancy, including preconception advice, stages of pregnancy, investigations, complications, living with pregnancy and birth, see Pregnancy.
Nutrition For more information on nutrition, including information ontypes and composition of food, nutrition and people, conditions related to nutrition, and diets and recipes, as well as some useful videos and tools, see Nutrition.
Pregnancy planning For more information about pregnancy planning, including importance of nutrition before pregnancy, being under-weight, being overweight, tobacco exposure and alcohol consumption, see Pregnancy Planning (Preconception Advice).



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