A tool to support the clinical decisions of doctors and health professionals, not for self-diagnosis or self-treatment.
This calculator is inside the patient's file in Clinicato: open it from "Medical tools" while you chart the visit, it fills in from the patient's details and vital signs where they are recorded, and adds its result to the visit's plan in one tap, with the "Medical tools" add-on. Try it in your clinic
Calculator
How it works and when to use it
The calculator works out the pre-pregnancy BMI and shows the gain recommended by the US Institute of Medicine (IOM 2009): 12.5 to 18 kg if underweight, 11.5 to 16 at normal weight, 7 to 11.5 if overweight and 5 to 9 with obesity, with a weekly rate for the second and third trimesters.
With the current weight and weeks it compares the gain so far with the expected range, assuming 0.5 to 2 kg over the first trimester as the IOM report does, and twin pregnancies have their own provisional range.
Reference: Institute of Medicine (IOM) and National Research Council. Weight Gain During Pregnancy: Reexamining the Guidelines (2009)
Frequently asked questions
Is gaining less than recommended better with obesity?
The recommendation with obesity is already lower, but any change to the diet in pregnancy is for the doctor, and weight-loss diets are not advised in pregnancy.
Why does the rate of gain matter?
High gain is linked to gestational diabetes and a large baby, low gain to a small baby, so the doctor follows it at every visit.
Tools you may also need
- Gestational age by CRL calculator Gestational age from CRL, the due date, and whether to redate by ultrasound.
- IVF and conception due date calculator Due date and gestational age from conception or embryo transfer.
- Bishop score calculator The Bishop score out of 13 and cervical ripeness.
- Pregnancy milestones calculator The dates of the key pregnancy checks, past and coming.
- Child BMI calculator A child's BMI and how it is read on growth charts.
- Apgar score calculator The Apgar score of 10 and what it means at that minute.
Clinic software for this specialty
Try Clinicato for your clinic
These calculators are free here for everyone, and in Clinicato 49 medical tools work inside the patient's file with the "Medical tools" add-on: filled from the visit and the vital signs, with the result added to the visit's plan, next to appointments, prescriptions and invoices.