How much weight should I gain during pregnancy? Recommendations

By (embryologist), (embryologist), (embryologist), (embryologist) and (biochemist).
Last Update: 06/30/2022

Weight gain during pregnancy is a common concern for the expectant mother. The pregnant woman feels a great responsibility, since she knows that the baby depends on her to obtain all the nutrients necessary for its development.

However, it is not necessary for the pregnant woman to double the amount of food she eats. This could lead to excessive weight gain during pregnancy, which is not recommended for her or the baby. However, it is also not advisable to gain too little weight during pregnancy.

Therefore, for a healthy pregnancy, weight gain should be monitored, but without obsessing about it. Pregnant women should ideally eat a varied and balanced diet, with plenty of fruits and vegetables and avoiding unhealthy foods such as processed foods.

Total weight gain in pregnancy

The weight a pregnant woman should gain is related to her body mass index (BMI) before the pregnancy. To calculate BMI (weight/height2), the woman should multiply her height in meters by her height (also in meters) and record the result. Subsequently, by dividing your weight in kilograms by the number noted, you will obtain your BMI.

In this way, depending on the calculated pregestational BMI, we can see if the pregnant woman shoud put on more or less kilos, or pounds, during pregnancy.

  • BMI less than 18.5: with low body weight, a total weight gain in pregnancy of 12.5-18 kilos (27 - 40 pounds) is recommended.
  • BMI between 18.5 and 24.9: with a normal weight, the kilos or gained with pregnancy should be between 11.5 and 16 (25 - 35 pounds).
  • BMI between 25 and 29.9: if overweight, weight gain during pregnancy should be between 7 and 11.5 kilos (15 and 25 pounds).
  • BMI greater than 30: if pregnancy begins with obesity, weight gain should be between 5 and 9 kilos (11 and 20 lb).

However, to avoid possible complications, it will always be the specialist who monitors the pregnant woman's weight.

Total weight gain in a twin pregnancy

If the pregnancy is a twin pregnancy, it is obvious that the pregnant woman will have to put on more weight. Depending on your pre-pregnancy BMI, this weight gain will be:

  • BMI between 18.5 and 24.9: it is recommended to put on between 16.8 to 24.5 kilos (20 - 54 pounds).
  • BMI between 25 and 29.9: if the pregnant woman is overweight, weight gain should be between 14.1 and 22.7 kilos (31 to 50 pounds).
  • BMI greater than 30: with obesity, the weight gained should be controlled to be between 11 and 19.1 kilograms (24 - 42 lbs).

As you can see, the recommended weight gain in a twin pregnancy is considerably higher than in the case of single baby.

Weight gain in each trimester of pregnancy

Although it is common to hear that during pregnancy you should gain one kilo per month, the total weight gained by a pregnant woman is not acquired uniformly throughout pregnancy. Weight gain varies according to the trimester of woman's pregnancy:

First trimester
during the first trimester of pregnancy, the pregnant woman may gain little or no more than a kilo or two of weight ( a total of 2 lb 3 oz - 4lb 6 oz). Fetal size is still small and, in addition, it is common that many women do not have an increased appetite due to morning sickness.
Second trimester
in the second trimester, the pregnant woman will put on an additional 6-6.5 kilos (13 - 14 lbs 5 oz).
Third trimester
during the third trimester, the pregnant woman will gain another 5-6 kilos (11 - 13 pounds).

Therefore, during the second and third trimester, the expectant mother will gain an average of half a kilo per week (just over 1 lb per week). However, this weight gain is slightly higher in the second trimester than in the third.

Why do we gain so much weight during pregnancy?

One of the doubts that may arise during pregnancy is why so much weight is gained, if the baby at birth weighs only about 3.5 kilos (7 lbs 11 oz). However, it should be noted that the pounds gained are also distributed in other tissues and structures that contribute to gestational weight gain, approximately, in the following way:

  • Placenta: about 700 g (1 lb 8 oz).
  • Uterus: 1 kilo (2 lb 3 oz).
  • Amniotic fluid: 800 g (1 lb 12 oz).
  • Breasts: 400 g (14 oz).
  • Blood: 1.5 kg (3 lb 5 oz).
  • Fat deposits: about 3.5 kilos ( 7lb 11 oz).
  • Extravascular fluid: 1.5 kg (3 lb 5 oz).

This also explains why much of the weight gained during pregnancy will be lost at the time of delivery.


The main recommendation that a pregnant woman should keep in mind to control weight gain with pregnancy is to eat a varied and balanced diet that provides all the necessary nutrients for her and the baby, from healthy foods. As such, it is better to avoid excess sugars and fried foods and opt for baking, roasting or steaming.

If necessary, the pregnant woman can consult a nutritionist to help her develop a diet that includes all the nutrients she needs at this special time.

In addition, it is equally important to do exercise adapted to pregnancy, such as Pilates or simply, walking (unless contraindicated by a specialist).

It is also essential that the expectant mother attends all gestational check-ups and respects the directions given to her by her gynecologist, since they are the one who knows the particular situation of the pregnant woman best.

Finally, it should be noted that in order to keep a more accurate control of the weight gained during pregnancy, it is best to always weigh yourself on the same scales and, for example, at the same time of day, ideally when you get up.

FAQs from users

How many kilos should a woman gain during pregnancy?

By Andrea Rodrigo B.Sc., M.Sc. (embryologist).

There is no exact weight gain, each woman's body is different, and each pregnancy is a unique situation and cannot be generalized.

In order to tell a woman how many kilos she should gain during pregnancy, specialized nutritionists must take into account different factors, such as the woman's weight before becoming pregnant, possible fluid retention and the type of food eaten during the nine months of pregnancy.

How much weight does a pregnant woman put on in the first trimester?

By Silvia Azaña Gutiérrez B.Sc., M.Sc. (embryologist).

In the first trimester of pregnancy, some pregnant women hardly gain any weight, while others may gain about 2 kg ( 4lb 6 oz).

The typical nausea of the first trimester and the small size of the baby mean that the weight that the pregnant woman gains in these first weeks of pregnancy is not very much.

Therefore, not putting on much weight in the first trimester of pregnancy may be normal. However, if you have any doubts or concerns, it is always best to consult a specialist.

Is it normal to gain 17 kilos during pregnancy?

By Silvia Azaña Gutiérrez B.Sc., M.Sc. (embryologist).

Gaining 17 kilograms during pregnancy is within the recommended range if the pregnant woman was underweight when she became pregnant, that is, if her pre-pregnancy BMI was less than 18.5. In this case, it is recommended that the pregnant woman gain between 12.5 and 18 kg.

However, if the pregnant woman was normally overweight (BMI 18.5-24.9), the recommended range of kilos to be gained during pregnancy is 11.5 to 16 kg.

Similarly, if the woman was overweight (BMI 25-29.9), it is recommended that she put on between 7 and 11.5 kg during pregnancy and, if she was obese (BMI over 30), only 5-9 kg.

How much weight should I gain during pregnancy?

By Silvia Azaña Gutiérrez B.Sc., M.Sc. (embryologist).

There is no maximum weight limit that can be applied to all pregnant women. The recommended gestational weight gain will depend on the woman's body mass index (BMI) at the time of becoming pregnant.

Thus, an underweight woman should gain more weight during pregnancy than a woman with a high BMI (overweight or obese).

In the case of a woman with an adequate weight (BMI between 18.5 and 24.9), she should gain between 11.5 and 16 kilos (25 - 35 lb) during pregnancy.

However, it should be taken into account that the recommended weight gain will be higher in the case of twin or multiple gestation.

When does the pregnant belly start to show?

By Sarai Arrones BSc, MSc (embryologist).

Tummy growth usually starts to become noticeable around the fifth month of pregnancy, when the bottom of the uterus reaches the level of the navel. However, it may be noticed earlier or later depending on the woman's age, her constitution and whether it is her first pregnancy. If you have been a mother before, the muscles of your abdominal walls have already been stretched and the belly will be visible earlier.

If you are interested in knowing what vitamins you should take during pregnancy, we recommend you visit this link: What vitamins should be taken during pregnancy?

If you are in the first month of pregnancy and want more information, you can read the following article: First month of pregnancy: first symptoms and care for the mother

We make a great effort to provide you with the highest quality information.

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FAQs from users: 'How many kilos should a woman gain during pregnancy?', 'How much weight does a pregnant woman put on in the first trimester?', 'Is it normal to gain 17 kilos during pregnancy?', 'How much weight should I gain during pregnancy?' and 'When does the pregnant belly start to show?'.

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Authors and contributors

 Andrea Rodrigo
Andrea Rodrigo
B.Sc., M.Sc.
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia along with the Valencian Infertility Institute (IVI). Postgraduate course in Medical Genetics. More information about Andrea Rodrigo
 Cristina Mestre Ferrer
Cristina Mestre Ferrer
B.Sc., M.Sc.
Bachelor's Degree in Biological Sciences, Genetics & Human Reproduction from the University of Valencia (UV). Master's Degree in Biotechnology of Human Assisted Reproduction from the UV and the Valencian Infertility Institute (IVI). Embryologist at IVI Barcelona. More information about Cristina Mestre Ferrer
 Sarai Arrones
Sarai Arrones
BSc, MSc
Bachelor's Degree in Biomedicine and Biomedical Sciences from the University of Valencia (UV). Master's Degree in Biotechnology of Human Assisted Reproduction from the UV and the Valencian Infertility Institute (IVI). Specialist Training Course of gamete, embryo, and animal tissue cryopreservation. Embryologist specializing in the field of Assisted Procreation. More information about Sarai Arrones
 Silvia Azaña Gutiérrez
Silvia Azaña Gutiérrez
B.Sc., M.Sc.
Graduate in Health Biology from the University of Alcalá and specialized in Clinical Genetics from the same university. Master in Assisted Reproduction by the University of Valencia in collaboration with IVI clinics. More information about Silvia Azaña Gutiérrez
License: 3435-CV
Adapted into english by:
 Michelle Lorraine Embleton
Michelle Lorraine Embleton
B.Sc. Ph.D.
PhD in Biochemistry, University of Bristol, UK, specialising in DNA : protein intereactions. BSc honours degree in Molecular Biology, Univerisity of Bristol. Translation and editing of scientific and medical literature.
More information about Michelle Lorraine Embleton

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