Is a biparietal diameter of 74 mm at 29 weeks of pregnancy normal?

Generally, whether a fetal biparietal diameter of 74mm at 29 weeks of gestation is considered normal needs to be determined based on specific circumstances. If other developmental indicators are also normal, it is usually considered normal. However, if other developmental indicators are abnormal, it may be considered abnormal. Detailed analysis is as follows:

At 29 weeks of gestation, the normal range for fetal biparietal diameter is generally between 68-82mm. A biparietal diameter of 74mm falls within this range. If other developmental indicators such as head circumference, abdominal circumference, and femur length are also normal, and the overall fetal development is good, a biparietal diameter of 74mm can be considered normal.

If at 29 weeks of gestation the fetal biparietal diameter is 74mm, but the head circumference is significantly smaller or larger than normal, disproportionate to other indicators such as abdominal circumference and femur length, or if there is oligohydramnios (low amniotic fluid), poor placental function, or abnormal fetal movement (such as excessively frequent or significantly reduced movements), this may indicate an abnormal condition. It could suggest that the fetus may have growth restriction, developmental malformations, chromosomal abnormalities, or other issues, and further examination and evaluation are required.

In prenatal monitoring, measurement of the biparietal diameter is only one aspect of assessing fetal health. A comprehensive evaluation must be made in conjunction with other data and clinical judgment. If there are any concerns or discomfort, it is recommended to seek medical advice promptly.