Is a femur length of 68 mm considered short for the leg?
Dec 09, 2022
Source: Cainiu Health
Dr. Wang Jianjun
Introduction
If the femur length of a fetus over 36 weeks is 68 mm, it generally indicates relatively short legs. After excluding chromosomal abnormalities and structural malformations, appropriate nutritional enhancement should be considered to improve the condition. However, between 32 and 34 weeks, the normal femur length ranges from 64 to 71 mm; thus, a fetal femur length of 68 mm is within the normal range and does not indicate short limbs.
Femur length of 68 mm may or may not indicate short legs, depending on the specific gestational week.
1. Short
Femur length is one of the indicators used to predict fetal weight and fetal biometry, and is an important parameter in estimating fetal weight during pregnancy. It generally increases as gestation progresses. If a woman is beyond 36 weeks of gestation and fetal femur length is measured at 68 mm during examination, this typically suggests relatively short legs. After excluding chromosomal abnormalities and structural malformations, it is advisable to improve the situation by enhancing maternal nutrition appropriately.
2. Not short
If the pregnant woman is between 32 and 34 weeks of gestation, the normal range for femur length is generally 64–71 mm. Although the measured femur length can be influenced by the fetus's position and posture within the uterus—leading to some variation in measurements—as long as the result falls within the normal range, it is considered normal. Therefore, a fetal femur length of 68 mm detected during routine ultrasound at 32–34 weeks is typically within the normal range and does not indicate short legs.
