The comparison of antenatal umbilical coiling index, Sonographic characteristics, and placenta pathology between normal pregnant women and gestational diabetes: correlation with adverse perinatal outcomes.

Introduction: Recent studies have shown that there is an important relationship between the umbilical vascular coiling index (UCI) and adverse perinatal outcome. Evaluation of umbilical cord coiling by sonography in the second trimester correlates with UCI at birth. In addition, the extent of umbilical coiling is not related to the umbilical cord thickness, and antenatal UCI is a better predictor of neonatal birth weight than is umbilical cord thickness. It has been shown that umbilical cord diameter measurements at 18-23 weeks were correlated with gestational age and estimated fetal weight. In pregnancies complicated by diabetes, none coiling and hypercoillingare significantly more frequent. These abnormalities of umbilical vascular coiling are also significantly associated with adverse perinatal outcomes and emergency cesarean delivery. In this study, we are going to explore the antenatal UCI, Gray scale sonography characteristics, and placenta pathology in normal pregnant women and gestational diabetes. We would also compare these findings, in relation to maternal metabolic control and perinatal outcomes.

Methods: A prospective Cohort study of 400 pregnant women will perform in Akbarabadi teaching hospital in Tehran, Iran between 2014 and 2016.Two hundred normal pregnant women and 200 with gestational diabetes will be enrolled in the study. Screening for gestational diabetes will be done in 24-28 weeks' of gestation according to the ADA and ACOG guidelines with one- step OGTT. Demographic and clinical data of the participants and serum samples will be extracted from the patients. A fetal anatomical ultrasound survey of placenta and umbilical cord will be performed at 18-23 and 37-40 weeks' gestation by an expert sonologist. The evaluation of the umbilical cord midsegment (free loop) will include recording of longitudinal cord images for the assessment of cord coiling. Immediately after delivery, the umbilical cord willbe evaluated for complete vascular coiling. Umbilical cord length willbe measured with a tape, from its insertion into the placenta up to the neonatal umbilicus. A complete vascular coil will be defined as a 360ᵒ complete round coiling of the vasculature, and the total number of these complete vascular coils will be determined.  Then the total number of vascular coils will be divided by the total length of the cord in centimeters in order to determine the umbilical coiling index (UCI). After delivery neonatal visit will be done by neonatologist, a VBG sample from umbilical cord will be sent for all neonates. Finally, placenta and umbilical cord will be sent to pathology department. 

Primary and Secondary outcomes:

Evaluation of antenatal umbilical coiling index and its pattern in normal pregnant women and gestational diabetes.

Evaluation of relationship between UCIto second and third trimester Sonographic characteristics.

Evaluation of relationship between UCI to placenta pathology.

Evaluation of relationship between UCItoperinatal outcomes.