How many kilos should you gain during pregnancy? Recommendations

By (embryologist), (embryologist), (embryologist) and (embryologist).
Last Update: 05/12/2022

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. Ideally, pregnant women should 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 pre-pregnancy body mass index(BMI). 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 entered, you will obtain the BMI. Thus, depending on the calculated pregestational BMI, it will be advisable for the pregnant woman to gain more or less kilos during pregnancy.

  • BMI less than 18.5: with low weight, a total weight gain in pregnancy of between 12.5-18 kilos is recommended.
  • BMI between 18.5 and 24.9: with a normal weight, the kilos gained with pregnancy should be between 11.5 and 16.
  • BMI between 25 and 29.9: if overweight, weight gain during pregnancy should be between 7 and 11.5 kilos.
  • BMI greater than 30: if pregnancy begins with obesity, weight gain should be between 5 and 9 kilos.

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

Total weight gain in a twin pregnancy

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

  • BMI between 18.5 and 24.9: it is recommended to gain from 16.8 to 24.5 kilos.
  • BMI between 25 and 29.9: if the pregnant woman is overweight, weight gain should be between 14.1 and 22.7 kilos.
  • BMI greater than 30: with obesity, weight gain should be controlled to be between 11 and 19.1 kilograms.

As can be seen, the recommended weight gain in a twin pregnancy is considerably higher than in the case of singleton gestation.

Weight gain in each trimester of pregnancy

Although it is common to hear that during pregnancy you should gain one kilo month by month, the total weight gained by a pregnant woman is not acquired uniformly throughout pregnancy. Weight gain varies according to the woman's trimester of 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. Fetal size is still small and, in addition, many women often do not have an increased appetite due to morning sickness.
Second trimester
in the second trimester, the pregnant woman will gain an additional 6-6.5 kilos.
Third trimester
during the third trimester, the pregnant woman will gain another 5-6 kilos.

Therefore, during the second and third trimester, the pregnant woman will gain an average of half a kilo 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 about why so much weight is gained, if the baby at birth weighs only about 3.5 kilos. However, it should be noted that the kilos gained are also distributed in other tissues and structures that contribute to gestational weight gain, approximately as follows:

  • Placenta: about 700 g.
  • Uterus: 1 kilo.
  • Amniotic fluid: 800 g.
  • Breast: 400 g.
  • Blood: 1.5 kilos
  • Fat deposits: about 3.5 kilos.
  • Extravascular fluid: 1.5 kilos

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. Therefore, it will be better to avoid excess sugars and fried foods and opt for baking, roasting or steaming.

If necessary, the pregnant woman can turn to 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).

On the other hand, it is essential that the pregnant woman attends all gestational check-ups and respects the indications given by her gynecologist, since he is the one who best knows the particular situation of the pregnant woman.

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

FAQs from users

How much weight should I gain during pregnancy?

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

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

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 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.

How much weight does a pregnant woman gain 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 kilos.

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 high.

Therefore, not gaining 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 kilos.

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.

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

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.

When does the pregnant belly start to show?

By Sarai Arrones BSc, MSc (embryologist).

Belly 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 given way and the belly will be visible earlier.

Suggested for you

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

On the other hand, 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 maternal care.

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

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FAQs from users: 'How much weight should I gain during pregnancy?', 'How much weight does a pregnant woman gain in the first trimester?', 'Is it normal to gain 17 kilos during pregnancy?', 'How many kilos should a woman 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

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