Your mom has probably told you stories of her pregnancy, some of them more frightening than others. The anecdotes about cold forceps, uncomfortable stirrups and painful tests and procedures are enough to make anyone swear off childbirth. Luckily, medicine and birth in particular have come a long way since you were in the womb, and technology has become a major part of the process.

High-tech machines will be there to assist your doctor and nurses at every step of the way. From your 99.9% accurate pee-on-a-stick home pregnancy test all the way to your touch-screen, wireless fetal monitor in the delivery room, technology will make your birth worry-free and easy. However, there is one exam that has withstood the test of time. To measure your fundal height during your pregnancy, your doctor will use a good old-fashioned tape measure.

Your fundal height is the distance from your pubic bone to the top of your uterus. The measurement is simple. After your first trimester, your fundal height in centimeters should match your week in pregnancy. For example, at 30 weeks, your fundal height should be approximately 30 centimeters. Studies show that the tape measure is consistently accurate and has always effectively clued doctors in if there was a problem with a baby’s development or fetal size.

While the measurement of our fundal height is good for detecting problems, you shouldn’t be alarmed if your fundal height doesn’t match your pregnancy’s progress like it is supposed to. There are many harmless factors that could affect your fundal height, such as your skeletal frame size, your weight, the fullness of your bladder and whether or not you are carrying multiples. However, if there is a large discrepancy in fundal height, your doctor might perform tests to rule out slow fetal growth, macrosomia, and any problems with your amniotic fluid. Though inaccuracies in fundal height examinations can usually be attributed to other issues, it’s important to diagnose these problems right away so it’s good to get checked.

Especially if you’re tired of all the beeping and winding technology whirring around you at every doctor’s appointment during your pregnancy, take a moment to appreciate the simple and minimalist process of measuring fundal height. Seek refuge in the silence and efficiency of this simple test. Out of all your mother’s pregnancy stories, the tape measure might be the only tool that has lasted through the decades.

Source: Kate Morse et al: Fetal Growth Screening by Fundal Height Measurement. Clinical Obstetrics and Gynecology Volume 23 Issue 6 pp. 809-818 December 2009