- For a normal pre-pregnancy BMI: 11.3–15.8 kg, i.e. 25–35 lbs total
- It's not all fat - baby, placenta, fluid, and blood volume account for most of it
- Gain is not linear - it's slower in the first trimester, steadier after
- Your own provider's number matters more than any general chart, especially outside a 'normal' starting BMI
The number I was given for a normal pre-pregnancy BMI: 11.3–15.8 kg, or 25–35 lbs, total across the pregnancy. Here's where it actually goes.
Where the weight actually goes
It's easy to picture pregnancy weight as just "fat," but most of it is specific and functional: the baby itself, the placenta, amniotic fluid, increased blood volume (up roughly 150% by some points in pregnancy), breast tissue changes, and fluid retention. Fat stores make up a real but smaller share, laid down partly as an energy reserve for breastfeeding afterward.
The pace isn't even
Gain is typically slower in the first trimester - a few pounds, sometimes less if nausea is heavy - and steadier through the second and third. That uneven pace is normal; it's not something to try to smooth out by eating more early on.
Why the range varies by person
The 25–35 lb range applies to a normal pre-pregnancy BMI. If you're starting from underweight or overweight, the recommended range shifts - this is exactly the kind of number worth getting directly from your own provider rather than a general chart, since it's individualized on purpose.
- PregnancyInfo.ca (SOGC) - weight gain during pregnancy
- HealthLink BC - healthy weight gain in pregnancy