Research showed that mothers who believed they were having large babies were nearly five times more likely to ask for a scheduled C-section.

This New York Times article mentions the outcomes of two women who’s babies’ guesstimated birth weights were significantly inaccurate, one by almost fur pounds.

If you’re a numbers person, check these out:

The medical definition of a “large baby” is 8 lbs 13 oz (4,000 grams.)

In a national survey of 1,960 women:

  • 1/3 one third of them were told their babies would be “quite large.”
  • Only 4 out of 5 babies actually weighed more than 8 lbs 13 oz.


ACOG acknowledges that using an ultrasound in late pregnancy has been associated with an increased rate of c-sections which have no benefit to the baby.

Thus, ultrasonography for estimated fetal weight in the third trimester should be used sparingly and with clear indications.

Safe Prevention of the Primary Cesarean Delivery
Labor and Delivery Experiences of Mothers with Suspected Large Babies

Source: When a Big Baby Isn’t So Big