The normal value of biparietal diameter at 39 weeks is 9.21cm, which varies greatly from fetus to fetus.
Fetal growth and development are affected by maternal influences, genetic factors, racial differences and other aspects of individual differences, therefore, the value is not absolute, as long as it is similar to the standard, everything is within the normal range. However, if the difference is large, pathological factors should be considered.
Fetal biparietal diameter is large, which may be related to over-nutrition of pregnant women and rapid development of the fetus. Pregnant women need to reasonably control the diet structure and the amount of diet intake during pregnancy to avoid the fetus being too large, which will cause certain burden to the labor. It is also possible that the head of the fetus is pathologically enlarged due to fetal anomalies, which requires a hospital visit for professional evaluation.
Fetal biparietal diameter is small, consider fetal developmental delay, at this time need to further investigate the cause of developmental delay, if it is due to nutritional deficiencies, pregnant women need to strengthen the diet rational combination of meals, to provide a more comprehensive nutrition for the fetus. Fetal growth restriction may also occur, which requires medical attention and treatment.
It is recommended to go to the hospital for further examination and targeted treatment under the guidance of the doctor.