Healthy signs

The height of the uterus matches the gestational age of the fetus, i.e. the number of weeks or months of pregnancy (gestation).

The top of the uterus rises in the mother’s abdomen by about two finger-widths, or 4 cm every month.

Warning signs

The height of the uterus does not match the number of weeks or months of pregnancy.

The top of the uterus rises more than, or less than, two finger-widths or 4 cm every month.

This could be due to several reasons: 

The due date you got by counting from the Last Normal Menstrual Period (LNMP) is wrong

Sometimes the woman does not remember the date of her LNMP correctly.

If the due date does not match the size of the uterus at the first visit, measure again in 2-4 weeks. If the uterus grows about two finger-widths or 1 cm a month - the due date is probably correct.

The uterus is growing too quickly. She may have:

Twins

Diabetes

Too much water (amniotic fluid) in the uterus

Molar pregnancy (a tumour instead of a baby)

The uterus is growing too slowly. She may have:

Too little water in the uterus

Poor diet

High blood pressure which can keep the baby from getting the nutrition it needs

She may be drinking too much alcohol, smoking or using drugs

The baby may be dead so the uterus stops getting bigger