It’s one of those things everyone seems to have an opinion on—pregnancy weight gain: what’s normal and healthy. Whether it’s from your doctor, a well-meaning aunt, or that friend who “barely gained anything,” the pressure can feel overwhelming. But here’s the truth: your body is doing something incredible, and some weight gain is not just normal—it’s essential. Let’s unpack what’s truly healthy, without judgement or stress.
How much weight should you gain during pregnancy? It’s a question so many expecting moms ask. But weight gain in pregnancy is incredibly variable – so how much is too much? Or too little? Sister Lilian from Sensitive Midwifery weighs in.
The average weight gain in a woman who is not under- or overweight when falling pregnant, and has an uncomplicated pregnancy, is between 2–4kg in the first 20 weeks, and a further 10–14kg in the next 20 weeks. Generally, one expects an increase of at least 1.5–2kg each month from 20 weeks, but there will be times that this is a little more or less.
Appropriate weight gain during pregnancy: use your BMI as a starting point
Assessing how much is an appropriate amount of weight to put on during pregnancy is not without its challenges. A healthy pregnant woman who is not under- or overweight would have a BMI (body mass index) between 18.5 and 24.9, and would have an expected weight gain as mentioned above.
A useful guide to BMI variations from the norm and suggested weight gain for a singleton pregnancy is as follows:
- An underweight woman would have a BMI below 18.5 and should gain between 12.7–18kg
- An overweight woman would have a BMI of 25–29.9 and should gain no more than 6.8–11.36kg
- An obese woman would have a BMI of 30 or higher and should gain no more than 5–9kg
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If a woman is pregnant with twins:
- A healthy pregnant woman who is not under- or overweight should gain between 16.8–24.5kg
- A pregnant woman who is overweight should gain no more than 14–22.7kg
- An obese woman should gain no more than 11.4–19kg
BMI & weight gain during pregnancy
The body mass index (BMI) is a statistic first developed by astronomer, mathematician, statistician and sociologist Adolphe Quetelet around 1830–50, although it was only named as such by physiologist Ancel Keys in 1972. It is calculated by dividing body mass in kg by the square of body height (in m).
The BMI is not infallible and cannot take every determining factor into account, but has proven its worth as a useful guide.
Weight gain during pregnancy: where does the weight go?
Often in the earlier weeks of pregnancy, due to nausea and other digestive discomforts, a woman will not pick up any weight at all – or may even lose some. Weight loss in pregnancy may at times be problematic, but not if the mother eats healthily and her baby seems to develop as expected. Some women pick up less weight generally, some more than the average values.
Here’s how an average of 13.6kg is distributed in a woman’s body at the end of pregnancy:
- Baby 3.4kg
- Placenta 0.7kg
- Increased tissue fluid volume 1.8kg
- Increased uterine weight 0.9kg
- Increased breast tissue weight 0.9kg
- Amniotic fluid 0.9kg
- Increased blood volume 1.8kg
- Maternal nutrient stores 3.2kg
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Gaining and losing weight during pregnancy
- If a woman is overweight to begin with, it is possible to lose weight while pregnant if eating and exercising sensibly. She may follow sensible and well-known pregnancy eating plans approved by a pregnancy diet specialist – note that this is not always the doctor or midwife!
- If a pregnant woman retains a lot of fluid, it can significantly affect her weight and should always be investigated for possible pre-eclampsia or HELLP.
- If weight gain is excessively low, this needs to be evaluated in terms of overall development of the baby – if there are no developmental delays and the mother also seems healthy, there is usually no reason for concern.
Most importantly, pregnant women should be advised to eat healthy foods 90% of the time and exercise regularly. In most cases, simply being mindful about healthy choices is the key to gaining the appropriate amount of weight during pregnancy.
This article was written by Midwife Louette Maccallum and was originally published on Sensitive Midwifery. You can read the original article here.
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FAQs: Pregnancy Weight Gain
Is it normal to gain most of the weight in the third trimester?
Yes, it’s common for weight gain to increase during the third trimester as the baby grows rapidly and your body retains more fluid in preparation for birth.
What if I’m gaining too much weight?
Gaining more than the recommended amount may increase the risk of complications such as gestational diabetes or high blood pressure. Speak to your midwife or doctor for support and advice on healthy eating and activity.
What if I’m not gaining enough weight?
If you’re struggling to gain weight, especially in the second or third trimester, speak to your healthcare provider. It’s important your baby is growing well and you’re getting the nutrients you need.
Does weight gain mean I’m eating too much?
Not necessarily. Many factors affect weight gain, including fluid retention, metabolism, and how your body adapts to pregnancy. Focus on eating balanced meals rather than calorie counting.
Can I diet while pregnant?
Restrictive dieting is not recommended during pregnancy. Instead, aim for a healthy, varied diet and speak to a healthcare professional if you’re concerned about your weight.
What foods should I focus on to support healthy weight gain?
Choose whole grains, lean proteins, dairy, fruits, vegetables, and healthy fats. Limit sugary snacks and processed foods, but don’t stress over occasional treats. Also take a look at: Pregnancy Nutrition: Why Your Diet Matters.
Is it safe to exercise during pregnancy?
Yes, unless advised otherwise by your doctor. Moderate activities like walking, swimming, or prenatal yoga can support healthy weight gain and overall wellbeing. Get more insights: Exercise during pregnancy: benefits, safety precautions & what to avoid.
Will I lose the pregnancy weight after birth?
Some weight is lost immediately after delivery, but the rest may take weeks or months. Healthy eating, gentle exercise, and breastfeeding (if you choose to) can help, but give your body time to recover.
Does every woman gain weight the same way during pregnancy?
No. Weight gain varies greatly depending on body type, lifestyle, genetics, and other factors. It’s important not to compare yourself to others.
Should I weigh myself regularly during pregnancy?
Your healthcare provider will monitor your weight at antenatal visits. Weighing yourself at home is optional, but avoid becoming overly focused on the numbers.
Disclaimer: This information is for general guidance only and does not replace medical advice. Always consult your GP, midwife or healthcare provider regarding healthy weight gain and nutrition during pregnancy.
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