Weight gain during pregnancy

To find out approximately how much weight you should gain during pregnancy, your midwife or gynaecologist will determine your personal body mass index, or BMI for short. Your BMI is calculated as your weight divided by the square of your height. 

Weight in kg : (height in m)2 = BMI kg/m2

Here’s an example for a woman who is 1.65 m tall and weighed 65 kg before pregnancy: BMI = 65 kg : (1.65 m)2 = 23.9 kg/m2

The normal BMI for women of childbearing age is between 18 kg/m2 and 25 kg/m2. Those with a BMI below 18 kg/m2 are considered underweight and those above 25 kg/m2 are considered overweight. Women with a BMI of 30 kg/m2 and above are considered obese. We do want to stress, though, that a person’s BMI is only of limited significance. Because of the different density of muscles and fat, very sporty women, for example, can be considered overweight based on their BMI, even though they have little body fat. Age is another important factor that needs to be considered when it comes to the BMI.

Despite it all, the BMI is used as a guide in obstetrics to evaluate whether weight gain during pregnancy is within a healthy range or not. Based on the BMI, the following ranges are considered unproblematic for weight gain during pregnancy:

Depending on which trimester you are in, the amount of weight you are going to gain will vary week by week. While you might see little difference on the scale at the beginning of your pregnancy, this can change quickly during the second trimester. Your baby will grow and put on weight, your blood volume will increase and your body will retain water and build up fat reserves to prepare for breastfeeding.

Most women will gain almost no weight in their first trimester, while their weight seems to relentlessly go up in their second and third trimester. And that’s exactly how it should be!

It is also normal to have a sudden jump in weight from one week to the next when you are pregnant. Whenever your baby has a growth spurt, your weight gain might not be as slow and steady as it normally is. This is where the HiPP weight gain graph comes in handy: As long as you stay within the recommended range (grey area in the chart), there’s usually little to worry about.

You can also have a look at our weight gain table to get an idea of what to expect when it comes to weight gain during pregnancy:

Particularly in the case of pregnant women who are overweight or underweight or have pre-existing conditions, midwives and gynaecologists also like to look at their weekly weight gain. They use these benchmark values for orientation:

• until week 13: almost no weight gain
• week 14-24: 250-300 grams per week
• after week 25: 400 grams per week

The average weight gain ranges apply primarily to single pregnancies. The benchmarks for women expecting multiples are, of course, higher. This is because there are more babies growing in mummy’s belly, and because these babies need more blood, more amniotic fluid, more placental tissue, etc. to thrive.

So if you are expecting twins, gaining about 15.5 to 20 kilograms is quite normal. If you are pregnant with triplets, gynaecologists and midwives estimate about 20.5-23 kilograms of weight gain.

If the expectant mother is underweight at the beginning of her pregnancy, she is particularly encouraged to gain weight. This is because being underweight is associated with a risk of spontaneous preterm delivery as the body is not able to sustain the pregnancy to full term without harming itself. Additionally, being underweight can lead to nutritional deficiencies that can be detrimental to the baby’s health and even cause serious harm. Underweight mothers are also a lot more likely to deliver babies with a very low birth weight.

If the weight remains the same throughout the pregnancy or if there is only a small increase in weight, there can be several underlying causes. Especially women who struggle with severe morning sickness in early pregnancy also have a reduced appetite. Together, this can lead to a slow weight gain. Women affected by hyperemesis gravidarum (HG) often even lose weight in the first weeks of pregnancy due to the vomiting. Women with persisting HG can have difficulties gaining enough weight.

If the weight stagnates for several weeks during pregnancy, this can be a serious sign of foetal growth restriction (FGR) and an indication of malnutrition. Should this be the case, please consult your gynaecologist or midwife as soon as possible to rule out any health issues for you and your baby.

If the expectant mother is very overweight or obese, there is an increased risk of gestational diabetes mellitus (GDM – type 4 diabetes). If mummy overeats, her baby is at risk of becoming diabetic too. Pregnant women who are very overweight or obese and eat a sugary and fatty diet often give birth to very large and heavy babies. This is called macrosomia.

If the maternal weight increases very quickly, this is often a sign of a poor diet. This means, for example, that they eat too many meals per day or tend to eat foods that are very sugary or fatty. However, if this is the case with you, we advise against trying to lose weight just now. You should rather try to switch to a healthier diet. Following these tips can help you regulate your weight gain in a healthy way:

• Eat only when you are really hungry.
• Eat at least three servings of vegetables and two servings of fruits per day. One serving is more or less the amount that you could fit in your hand.
• Save any snacks and sweets for special moments and enjoy sugary and fatty foods only in moderation.
• Also make sure to include plenty of exercise in everyday life.