Three - Dimensional Ultrasound Estimation of Fetal Adrenal Gland Enlargement Compared to Assessment of Cervical Changes Alone & Prediction of Impending Preterm Birth

Preterm birth ( PTB) is one of the leading causes of neonatal morbidity and mortality Early PTB (≤ 34 weeks' gestation) carries a 7-fold increased risk of Neonatal death . Following PTB, survivors can experience significant long term cognitive, behavioral, emotional, sensory, and motor deficits. Hence, there is growing interest in the identification of women who are at Risk for spontaneous PTB. Many biophysical and biochemical markers have been discovered to identify those women who are at risk for spontaneous PTB.

Unfortunately, none of the various maternal and fetal biomarkers such as:

cytokines, CRH, C-reactive protein, fetal fibronectin ,.... etc. are sufficiently sensitive or specific to be used alone or in combination to help decrease the rate of preterm births. Obviously, there's a need for an accurate method with high sensitivity and specificity for prediction of preterm labor. So that an appropriate management or referral to a higher center can be done to women likely to have PTB. Whereas unnecessary tocolytic therapy can be avoided in women who are unlikely to have PTB. Convincing data have shown that 2-dimensional (2D) ultrasound measurement of cervical length (CL) can identify women at risk for PTB.

Accordingly, CL is now widely used in clinical practice for risk estimation. However, as understanding of the mechanisms of preterm labor (PTL) have evolved, obstetricians have learned that, in some women, cervical shortening is a phenomenon that carries no increased risk for prematurity. Therefore, the search for early and accurate markers that distinguish between physiologic processes and abnormal activation of the labor cascade has been ongoing.

Literature has suggested that activation of the fetal hypothalamic-pituitary-adrenal axis play a crucial rule in commencement of labor. A previous study demonstrated that three -dimensional ultrasound measurement of fetal adrenal gland volume (AGV) may identify women at risk for impending PTB. In a more recent study receiver operator characteristics (ROC) curve analysis revealed that three -dimensional ultrasound measurement of (AGV) was superior to two-dimensional ultrasound measurement of (AGV) for anticipation of PTB within 7 days of the scan. The aim of this study is to investigate the utility of 3D fetal adrenal gland volume measurement in the early prediction of PTB and to determine whether these measurements could be combined with 2D ultrasound cervical assessment to improve the early prediction of PTB.