Obstetric Rule (Pregnancy Wheel): What is it? How does it work? What is it for?

Although these are approximate calculations, according to these indications it is possible:

• Schedule the controls foreseen during gestation;
• To monitor that the development of the fetus inside the uterus proceeds according to the normal physiological rhythms;
• Know the presumed date the baby will be born, then prepare for the event.

When using the obstetric ruler, the gynecologist takes the beginning of the last menstruation as a reference and takes into account an average gestational duration of 280 days, ie 40 weeks.

The result that is obtained provides a dating of the week of pregnancy in which the woman is and, consequently, establishes the day near which the birth of the child could occur.

The information provided by the obstetric ruler is part of the data collected in the anamnesis by the gynecologist and therefore contributes to monitoring the fetal growth parameters, which will then be supported by laboratory analyzes, ultrasound investigations and other medical evaluations.