What is the maximum biparietal diameter (BPD) size that is not recommended for vaginal delivery?

It is generally not recommended to attempt vaginal delivery when the fetal biparietal diameter exceeds 10 centimeters. The biparietal diameter refers to the widest diameter of the fetal head and is one of the key indicators used to assess fetal size and determine the mode of delivery. When the biparietal diameter is excessively large, it may lead to dystocia (difficult labor) and increase the risk of maternal and fetal complications, such as prolonged labor, fetal distress, and shoulder dystocia. Additionally, the mother's pelvic condition is also an important factor in determining whether vaginal delivery is feasible. If the biparietal diameter approaches or exceeds 10 centimeters, doctors will comprehensively consider other factors such as the size of the maternal pelvis, fetal weight, and fetal position to determine the most suitable mode of delivery.

During pregnancy, it is important to attend regular prenatal checkups, especially in the third trimester, to closely monitor fetal growth. If ultrasound examination reveals a large biparietal diameter, timely communication with the doctor is necessary to understand the specific situation and potential risks. Doctors may recommend further evaluations, such as pelvic measurements or fetal weight assessment, to determine the optimal delivery plan. At the same time, maintaining healthy lifestyle habits, such as balanced nutrition and appropriate exercise, can help control fetal weight and reduce delivery-related risks. Any concerns or discomfort should be promptly discussed with a healthcare provider to ensure maternal and fetal safety.