An analytical cross-sectional study: determining gestational age using fetal clavicle length during the second...

Area of Science:

• Medical imaging
• Fetal development
• Obstetrics

Background:

• Accurate gestational age estimation is crucial for prenatal care.
• Fetal biometry via ultrasound is a standard method for assessing fetal growth and development.
• The clavicle, a long bone, is routinely measured during fetal ultrasounds.

Purpose of the Study:

• To determine the correlation between fetal clavicle length (CL) and gestational age (GA) in pregnant patients.
• To evaluate the reliability of CL as a biometric parameter for GA estimation.
• To explore the potential application of CL measurements in specific obstetric situations.

Main Methods:

• A retrospective cross-sectional study involving 552 pregnant patients.
• Ultrasonographic measurements including abdominal circumference (AC), femur length (FL), humerus length (HL), clavicle length (CL), head circumference (HC), biparietal diameter (BPD), estimated fetal weight (EFW), and transverse cerebellum diameter (TCD) were obtained.
• Statistical analysis, including Pearson's correlation and regression analysis, was performed to assess the relationship between CL and GA.

Main Results:

• Fetal clavicle length (CL) showed a significant and strong positive correlation with gestational week (Pearson's r = 0.965, p < 0.001).
• All measured fetal biometric parameters, including CL, demonstrated strong correlations with gestational age.
• A regression equation was derived: Gestational Week = 0.894 + CL × 0.961.

Conclusions:

• A significant positive correlation exists between fetal clavicle length and gestational age from 14 to 27 weeks.
• The study suggests a potential clinical utility for a "1 mm = 1 week" rule using fetal clavicle length.
• This rule may be particularly useful in cases of cerebellar anomalies or when the last menstrual period is uncertain.