Weight gain during pregnancy is normal and necessary, but the 'right' amount depends on where you started. The ranges reflect the balance between supporting the baby and keeping the pregnancy healthy.
BMI sets the target
Guidelines from medical bodies tie the recommended gain range to pre-pregnancy BMI. Lower starting weight supports higher gains; higher starting weight supports lower ones. Your provider will personalise this for your situation.
Gain isn't steady
The first trimester typically adds only about 1–2 kg total, with most gain coming in the second and third trimesters at a steady weekly pace. Comparing your week's progress against that curve is more useful than watching the overall number.
What the gain represents
The baby is just part of it — placenta, amniotic fluid, increased blood volume and stored energy all contribute. Understanding that makes the ranges feel less arbitrary and supports a balanced, nutrient-focused approach.
Frequently asked questions
It depends on your pre-pregnancy BMI: roughly 12.5–18 kg if underweight, 11.5–16 kg at a healthy weight, 7–11.5 kg if overweight, and 5–9 kg if obese.
Only part is the baby. The rest is placenta, amniotic fluid, extra blood, enlarged uterus and breasts, and stored fat — all supporting the pregnancy.
Slow the gain by focusing on nutritious foods and regular activity (as cleared by your provider), rather than dieting — restrictive dieting in pregnancy is not advised.