Twin Pregnancy and Fundal Height

By on April 26, 2023

Have you ever heard of the term fundal height when it comes to pregnancy? Read on to learn more about this measurement and what you should know about it regarding twin pregnancies.

What is Fundal Height?

Fundal height is used to indicate gestational age and may also indicate the possibility of preterm birth. It is the measurement of the largest distance in centimeters from the cartilage joint between the public bone and the top of the uterus.

If you are pregnant, you will most likely have your fundal height measured at each prenatal visit. The average height is around 22 cm at 20 weeks gestation, though this may vary. However, with a twin pregnancy, the fundal height will grow much faster since the uterus will grow to accommodate both babies.

What Week Will Measurement Start and Stop?

Fundal height is usually measured starting around 20 weeks gestation. This is because before 20 weeks the fundus (area of the uterus that is furthest from its opening) is too close to the public bone. However, measurement may start sooner with multiple birth pregnancies. Your practitioner will determine when the best time is to begin measuring. Most obstetricians will stop measuring fundal height around 36 weeks gestation when the baby begins to descend into the pelvis in preparation for delivery.

How is Fundal Height Measured?

During a visit with your healthcare professional, you will be asked to lie down on the treatment table. A paper or plastic measuring tape will then be extended from your public bone to the top of your uterus. Taking this measurement is painless and quick.

Does Fundal Height Determine the Size of Babies?

One common misconception is that fundal height is a measure of fetal weight. The main purpose of measuring fundal height is to determine gestational age. Ultrasound is a more accurate way to determine fetal weight.

Factors that May Affect Fundal Height Measurements

The position of the baby, or babies, can affect these measurements. For example, if the baby is lying low in the pelvis (breech position) it can make the fundal height appear smaller than it really is, while high levels of amniotic fluid can make the height appear larger than it is. The height of the mother is also a factor, as taller women will usually have larger fundal measurements than shorter women.

The Importance of Your Twin Pregnancy Fundal Height

A woman’s uterus is typically only capable of holding one baby. Because of this, if your fundal height measurement is too small, your doctor may choose to induce you to ensure the safety of you and your twins. However, women carrying twins should never lose sleep over their fundal height, as there are many factors that can affect it. Your healthcare professional will always let you know if they find any concerning data.

Schedule a Consultation

If you are interested in learning more about twin pregnancy, fundal height, and more, please contact our office today to schedule an appointment with a MFM Associates/Carnegie Imaging for Women Specialist.

Maternal Fetal Medicine blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!