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Healthy Weight Gain During Pregnancy

By Valerie Lorenz

Pregnancy is a critical period in the human life course that influences the health and wellbeing of both you and your baby. It is an opportune time to adopt a healthy lifestyle to ensure a healthy weight gain during pregnancy.

The majority of pregnant women in Australia report not knowing their recommended weight gain and that they never or rarely receive advice from a health professional regarding healthy weight gain. In another study, pregnant women were more likely to gain weight consistent with recommendations if they receive such advice from a healthcare provider, while an absence of advice is associated with weight gain outside of the recommendations.

The amount of weight gained during pregnancy can affect the immediate and future health of you and your baby. If you do not gain enough weight, you are at risk of preterm birth and having babies with low birth weight. If you are overweight or obese or gain too much weight during pregnancy, you are at risk of high blood pressure, gestational diabetes, caesarean delivery, miscarriage, obstetric interventions and having a large baby. Your baby is at risk of being obese, requiring medical attention post delivery and developing hypoglycemia, which is low blood sugar levels. It is therefore important for you to maintain a healthy weight gain during pregnancy.

The weight you should aim to gain during pregnancy depends on what your weight and body mass index was before you became pregnant. Body mass index or BMI is an attempt to quantify the amount of tissue mass (muscle, fat, and bone) in an individual, and then categorize that person as underweight, normal weight, overweight, or obese based on that value. Your body mass index is calculated by taking your weight in kilograms and dividing it by your height in metres squared. BMI is the number used to work out the recommended weight range for you.

BMI =      weight (kg)
              [Height (m)]2


Sally is 175cm tall and her pre-pregnancy weight is 65kg

Her BMI is 65/(1.75×1.75) = 21 kg/m2

If you are not sure how to calculate your BMI, ask your health care professional to help you calculate it or you can visit the following websites that calculate it for you.

There are currently no specific Australian recommendations regarding appropriate weight gain during pregnancy. The Institute of Medicine however provides recommended weight gain ranges based on pre-pregnancy BMI and are suitable for those in developed countries. These recommended guidelines balance the severity and long-term consequences of adverse maternal and infant outcomes.


If your pre-pregnancy BMI was…



You should gain…


Less than 18.5 kg/m2 (under weight)

18.5 to 24.9 kg/m2 (normal)

25 to 29.9 kg/m2 (over weight)

Above 30 kg/m2 (obese)


12.5 to 18 kg

11.5 to 16 kg

7 to 11.5 kg

5 to 9 kg



If we go back to Sally’s BMI of 21, you can see that she should gain between 11.5 and 16 kilograms.

As well as having an overall weight gain goal for your pregnancy, there is a trimester-by-trimester guide. You can expect to gain one or two kilograms in the first 3 months of your pregnancy.

The recommended weight gain in the second and third trimester depends on your pre-pregnancy BMI. Calculate your BMI and refer to the table below.

If your pre-pregnancy BMI was …

You should gain…

Less than 18.5 kg/m2

18.5 to 24.9 kg/m2

Above 25 kg/m2

½ kg/week


Less than 300g/week


If you are expecting more than one baby, you will need to gain more weight. Calculate your BMI and refer to the table below.


If your pre-pregnancy BMI was…

You should gain…

Less than 18.5 kg/m2

18.5 to 24.9 kg/m2

Talk with your dietitian/obstetrician

16 to 24 kg

25 to 29.9 kg/m2

Above 30 kg/m2

14 to 23 kg

11 to 19 kg


Sometimes women who have morning sickness early in pregnancy find it difficult to gain enough weight. They may even lose a small amount of weight. If this happens to you, you do not need to be concerned as long as you start to gain weight in the second trimester of your pregnancy.

It is important for you to maintain a healthy weight gain during pregnancy to avoid any adverse health effects to you or your baby.  To control your weight gain, limit foods that are high in fat and sugar. Make sure you are not ‘eating for two’ especially if you are already overweight or obese. Regular, moderate intensity physical activity for at least 30 minutes on most days can help you keep within your healthy weight range. Seek advice from your doctor first if you were previously inactive or currently have a health or medical condition.

If you are planning another pregnancy, it is a good idea to return to your pre-pregnancy weight first. Getting pregnant when you are overweight or obese puts you and your baby at greater health risks during and after pregnancy. Retaining excess weight over subsequent pregnancies increases your risk of lifestyle diseases.

Life Ready Physio offers pre and post pregnancy Pilates and exercise classes to help you keep within your health weight range during and after your pregnancy. We also offer antenatal and postnatal classes conducted by a qualified women’s health physiotherapist and midwife to assist and support you as you journey through pregnancy and prepare for labour and the transition to parenting after birth.

Cogswell ME, Scanlon KS, Fein SB, Schieve LA (1999) Medically advised, mother’s personal target and actual weight gain during pregnancy. Obstetrics and Gynaecology 94(4): 616-622.

Cohen TR, Koski KG (2013) Limiting excess weight gain in healthy pregnant women: importance of energy intakes, physical activity and adherence to gestational weight gain guidelines. Journal of pregnancy

de Jersey SJ, Nicholson JM, Callaway LK, Daniels LA (2012) A prospective study of pregnancy weight gain in Australian women. Australian and New Zealand Journal of Obstetrics and Gynaecology 52: 545-551.

Institute of Medicine (2009) Weight gain during pregnancy

International Association of Diabetes and Pregnancy Study Groups (2010) Recommendations on the diagnosis and classification of hyperglycemia in pregnancy. Diabetes Care 33: 676-782.

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Editor’s Note: Valerie is the women’s health and continence physiotherapist at our Midland clinic. She also treats general musculoskeletal conditions and has a keen interest in Clinical Pilates. She is a strong advocate for self-management and uses progressive exercise-based rehabilitation to address underlying causes of pain, injury and overload, and ultimately optimise function

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