How much weight gain is normal in pregnancy?

There is no single number that fits everyone: someone starting underweight should gain considerably more than someone with obesity. This calculator places your current weight within the range intended for your week and your pre-pregnancy BMI, following the Institute of Medicine guidelines used in Austrian counselling.

This is what the recommendation depends on – not your weight today.

Why there is no single number

The recommended range depends on the BMI before the pregnancy, and it differs by more than ten kilograms across the groups: someone starting underweight should gain 12.5 to 18 kg, someone with obesity 5 to 9. The same figure for everyone would be wrong for almost everyone.

BMI before pregnancy Category Total (single) Total (twins) Per week, 2nd/3rd trimester
unter 18,5Underweight12,5–18 kg–0,44–0,58 kg
18,5–24,9Normal weight11,5–16 kg16,8–24,5 kg0,35–0,50 kg
25,0–29,9Overweight7–11,5 kg14,1–22,7 kg0,23–0,33 kg
30 and aboveObesity5–9 kg11,3–19,1 kg0,17–0,27 kg

Where the weight actually goes

Of about 12 kg in a normal-weight pregnancy, the child accounts for roughly 3.4 kg. The rest is placenta (0.7 kg), amniotic fluid (0.8 kg), the enlarged uterus (1 kg), breast tissue (0.5 kg), an additional 1.5 litres of blood and around 3 kg of fat reserves – the body’s provision for breastfeeding.

In the first trimester the gain is small for everyone – 0.5 to 2 kg. Many women lose weight instead, because of nausea. That is not a problem in itself.

Sources

  1. Institute of Medicine and National Research Council: Weight Gain During Pregnancy – Reexamining the Guidelines. Washington 2009
  2. Rasmussen KM, Yaktine AL (Hrsg.): Weight Gain During Pregnancy. National Academies Press, Washington 2009
    The ranges set out there remain the basis of counselling today, in German-speaking countries as well.
What this tool cannot do

It works with averages. Your body does not. The result is a starting point for a conversation, not a finding – and it cannot see what an examination would show.

Questions about your result? Arrange an appointment.