Trimester Weight Gain Pattern And The Adjoining Health Issues And Nutrient Requirements Accordingly

Pregnancy is the optimal time to intervene related to eating habits & physical activity to prevent excess weight gain.


Greata Sherene Robinson, Executive Nutritionist, Cloudnine Group Of Hospitals, Chennai

As soon as the pregnancy kit shows two lines, we get very conscious about what goes inside your tummy. We also get conscious about weight gain and in order to develop a healthy offspring we go devoid of junk and also make alterations in the diet. But it is equally important to prevent excess weight gain to achieve optimal pregnancy outcomes. In the current era, nearly 50% of women exceed their weight gain goals with overweight and obese women having the highest prevalence of excess weight gain.

Thus the health care provider measures the women’s height and weight at the prenatal visit to calculate body mass index (BMI) and then counsel women on gestational weight gain (GWG) goals. Inadequate weight gain can land up on low birth weight (LBW) of the baby, failure to initiate breast feeding. Excess weight gain can also cause issues like C – sec deliveries, post-partum weight retention, Large for gestational (LGA) age baby, macrosomia, obese child later in life. It can also cause complications in pregnancy like Gestational Diabetes (GDM), Gestational hypertension (G.HTN), etc.

Now let’s look at the normal weight gain pattern in pregnancy

BMI Range Category WEIGHT GAIN (Normal) WEIGHT GAIN (Twin gestation)
< 18.5 Kg/m2 Underweight 12 – 18 kgs  
18.5 – 22.9 Kg/m2 Normal 11.5 – 16 kgs 17 – 25 kgs
23 – 25 Kg/m2 Overweight 7 – 11.5 kgs 14 – 23 kgs
>25 Kg/m2 Obese 5 – 9 kgs 11 – 19 kgs


Pregnancy is the optimal time to intervene related to eating habits & physical activity to prevent excess weight gain. Gestational weight gain is comprised of so many factors such as water, placenta, uterus, amniotic fluid, maternal blood volume, mammary gland, maternal adipose tissue and finally the weight of the fetus. Products of conception (fetus, amniotic fluid, and placenta) usually contributes to 35% of the total gestational weight gain.

In a pregnancy a mother has to eat a minimum of 1500 calories and an additional 300 calories for the growing baby. This can be split as three main meals and two to three small meals in-between. Energy requirements increase in pregnancy by approximately 200,300, 400kcal/day in 1st, 2nd & 3rd trimester respectively but this will also depend on the BMI.

Let’s go trimester wise:

1st trimester (week 1 -12)

Here the weight gain depends on early placental development and expansion of maternal blood volume not fat deposits. The development of central nervous system also happens during this stage. The first trimester GWG is more reflective of maternal weight gain and adiposity deposition. So, remember to always keep the weight gain minimal for the first month. A weight gain of 0.5 kg to 2 kg is ideal during this trimester. Some may lose weight due to morning sickness and some may gain weight due to pregnancy cravings.

For pregnant mothers who are losing weight due to morning sickness or nausea it is important to work on nutrients to keep the balance. Thus a diet comprising of more proteins, healthy fats and complex carbohydrates with adequate water will work better. And also remember to start the day with dry cereal like bread, nuts, and ginger to control vomiting. Try to split small frequent bland meals throughout the day and just get the proteins right throughout the day.

For pregnant mothers who are gaining weight increasingly due to the pregnancy cravings, know if the craving is homemade or junk and try to keep them in moderation. Anything too much is not good for the growing fetus.

Remember that anything more or less than 5-10% of the pre pregnancy weight during the first trimester has to be addressed to the dietitian.

2nd trimester (week 13-28)

During this phase the weight gain should be gradual with 0.2 – 0.5 kg per week. The increase in the baby weight and the rapid growth of the baby will bring changes in the weight gain of the mother. As the baby grows the calorie and nutrient demands are really important in the second trimester and the meals have to be more balanced. Focus more on right proteins, healthy fats, and good source of iron, calcium and omega 3 fatty acids to be incorporated in the diet.

Always keep a check on blood sugars and blood pressure control during this trimester. The total weight gain of 4-5 kgs is ideal during this trimester. Progressive insulin resistance and maternal fat accumulation is common during this trimester which has to be addressed immediately.

3rd trimester (week 29-40)

The fetus gains the most weight during the third trimester and this is where the mother can sometime have heart burns to acidity issue. This is because the uterus is occupying the growing baby and the tummy gets smaller. Trying to incorporate small frequent meals with proper timings and work on bland easy digestible foods will make the mother better. Third trimester is the time when deep fried to spicy foods, outside foods are to be restricted. Concentrate more on healthy proteins, antioxidants from fruits and vegetables and adequate fluids throughout the day which will help with the proper weight gain. A weight of 4-5 kgs in this trimester will do depending on the pre pregnancy BMI. Excess weight gain can be marker for edema which in turn can cause pre-eclampsia & pre term delivery.

Take away points:

  • Specific individualized counselling has to be done if there is significant deviation from the weight gain/weight loss goals.
  • Nutritional intervention during each trimester helps us in achieving adequate maternal weight gain.
  • Eat twice as healthy but not twice the amount and ensure to stick to balanced diet.
  • Lifestyle changes like adhering to good dietary control and regular exercise will do wonders.
  • Track calories, weight and work more on a varied diet concentrating on the nutrients intake. Limit empty calories as much as possible and stick to whole foods.
  • Give more positive affirmations to acknowledge effort, values, skills and strength to help the pregnant mother do better.

Thus knowing the relationship between pre pregnancy BMI, Gestational weight gain and pregnancy outcomes helps us to design optimal interventions on weight gain pattern and to have a healthy mom & baby. It is okay to feel anxious when the scales go up and these extra pounds usually come off after the baby is delivered. Remember it took 9 months to put on weight so just wait a little while to lose it.






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