Nurturing life Your reference in perinatal nutrition, from pregnancy to childhood

How to tell whether a pregnant woman should consult a nutritionist about her weight gain?

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By : Nurturing Life's Nutrition Team | Montreal Diet Dispensary
— Updated on :

Women who have any of these conditions would benefit from an evaluation by a nutritionist and to receive advice on weight gain and food choices during pregnancy:

  • A loss of 5-10% of their weight in the first trimester (12 weeks);

  • Weight loss during the 2nd and 3rd trimester;

  • Gaining more than 2 kg (4 pounds) in the first trimester;

  • Gaining less than 4.5 kg (10 pounds) at the 20th week;

  • Obesity (a body mass index greater than 30 kg/m2).


It is observed that there is a larger risk of disease and complications associated with being overweight (BMI of 30 and over), such as gestational diabetes and caesarean section. That is why, in 2009, the Institute of Medicine (IOM) decreased the total weight gain recommended to 5-9 kg for obese mothers with a BMI of 30 or more.


For different reasons than those related to obesity, thinness brings significant risk to the health of the mother and baby. In addition to low fat reserves, and therefore energy, very thin women have a lower blood volume. Consequently, the pregnant woman is at risk of premature delivery or having a low birth weight baby.


Pregnancy in women with eating disorders (such as anorexia, bulimia, etc.) or weight concerns requires close monitoring. These women are at risk of nutritional deficiencies even before conception. Moreover, their eating behavior may slow down their weight gain or cause excessive gain during pregnancy. These women should make sure to follow-up with a nutritionist.


Finally, women whose financial situation is precarious are at risk of inadequate weight gain because they do not always have access to good nutritious food in sufficient quantity.


Several services are available to help women experiencing one or many of the above-mentioned conditions:

  • For women with low income: the Montreal Diet Dispensary and the OLO program in CLSCs and community organizations.
  • For women with sufficient income: CLSCs, nutritionist in private practice (see the College of Dieticians – French only).


  • Institute of health economics. (2008). Alberta, Canada. Determinants and prevention of low birth weight: a synopsis of the evidence. Alberta : Institute of health economics.
  • Institute of Medicine (IOM) and the National research council of the national academies. (2009). Weight gain during pregnancy: Reexamining the guidelines. Washington DC : The National Academies.
  • Santé Canada. (2010). Ligne directrice sur la nutrition pendant la grossesse à l'intention des professionnels de la santé: gain de poids pendant la grossesse.
  • Société des obstétriciens et gynécologues du Canada. (2010). Directive clinique: Obésité et grossesse.


The Public Health Agency of Canada has contributed financially to the production of Nurturing Life.

The views expressed herein do not necessarily represent the official views of the Public Health Agency of Canada.