It makes sense that someone who has a growing baby in the belly gains weight. However, many pregnant women are unhappy about their extra kilos and worried about putting on too much weight.1 Learn about the factors that contribute to a healthy pregnancy weight gain!
Soon after fertilization the growing fetus is supported by a totally new – and fascinating – organ: the placenta. This organ weighs approximately 700 g at the end of the pregnancy.2 The muscular wall of the uterus also grows, and together with the shock absorbing amniotic fluid, it creates a protective environment for the growing fetus. The baby, the reproductive organs (the uterus and the placenta) and the breast tissue represent close to half of the recommended added body weight (see table below).3
The mother’s blood volume also increases during pregnancy due to a higher demand for blood in her organs, but also as nature’s preparation for possible blood loss during delivery.3 Edema, i.e excessive absorption of water by the body’s cells, is also a common phenomenon towards the end of pregnancy.4 Overall, the increase in fluids accounts for nearly a quarter of the weight gain.3
Finally, almost a third of the increase in body weight is fat tissue. During pregnancy, energy is retained more efficiently than usual to ensure proper growth of the baby and as a preparation for breastfeeding.5 This is an advantage when nutrition is scarce, but in societies where energy rich food is available in excess, it can become a challenge.
The mother’s BMI before the pregnancy indicates the recommended weight gain during pregnancy.3 See the table for guidance. There are several health problems associated with excessive weight gain, e.g. gestational diabetes, pregnancy related hypertension and retention of a higher weight after pregnancy.6
It is logic to think that a much higher energy intake is needed during pregnancy since the body is going through such an endeavor. However, that is not the case. In the first trimester only a little extra energy is needed: an additional egg or a slice of whole grain bread daily is enough. In the second trimester somewhat more extra energy is needed, but not more than a banana smoothie or similar. In the last trimester an extra bowl of chili con carne or baked salmon with potatoes daily gives enough extra energy.7
In summary, for you and your baby’s health you should continue with regular physical exercise and healthy food, just a little more than usual.
|BMI before pregnancy
||Recommended weight gain
||12,5 – 18
|18,5-24,9 (Normal weight)
||11,5 – 16
||7 – 11,5
|≥ 30 (Obese)