The study revealed that the optimal weight gain for women would give them a balanced risk of having a very small or very large baby.
There is a strong link between the weight of the mother and the baby: very underweight mothers tend to have smaller babies -- called small for gestational age (SGA) babies -- and morbidly obese mothers tend to have more large for gestational age (LGA) babies.
According to the study, published in the journal Heliyon, although the current recommendations are correct for women with a normal BMI, they are not correct for underweight or obese women.
Thus, a woman with a body mass index (BMI) of 17 should gain about 22 kg instead of the recommended 12.5-18 kg.
An obese woman with a BMI of 32 should gain 3.6 kg instead of the recommended 5-9 kg. And a very obese woman with a BMI of 40 should actually lose 6 kg.
"While our results show the recommendations are fine for women in the normal weight range, we have shown they are not ideal for very underweight and very overweight women."
Robillard and the team carried out a 16.5-year observational study. They recorded the pre-pregnancy BMI, weight gain, and weight of the baby of 52,092 women who gave birth at full term.
Current recommendations should be changed for underweight and very obese women, the researchers said.
"The results of our research provide a solution to the conundrum affecting the 135 million pregnancies per year on this planet," Robillard said.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)