Fetal Head Circumference as a Predictor of Operative Delivery

Study Overview
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Brief Summary
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This study set out to investigate whether antenatal ultrasound evaluation of the Fetal Head Circumference (FHC) could potentially possess a predictive role in determining women at increased risk for operative delivery or cesarean section.

Detailed Description
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When vaginal delivery poses a danger to the mother or newborn infant, operative delivery (instrumental or cesarean section) is indicated. Some specific indications for operative delivery include prolonged second-stage of labor, suspected compromise of the fetus, health-related disorders of the fetus or the mother that justify shortening of the second-stage of active labor and more. In cases where cephalo-pelvic disproportion (CPD) is suspected or when instrumental delivery is not possible or fails, cesarean section plays a critical role . Studies trying to identify women at greatest risk of CPD have concluded that neither x ray, nor computed tomography or magnetic resonance imaging have a proven value in labor management or in predicting clinical outcomes . Previous studies assessing fetal factors that are associated with operative delivery have focused mainly on estimated fetal weight to predict macrosomia. Nonetheless, ultrasound estimation of the fetal weight was shown to differ by as much as 20% from actual birth weight, and identifying cases with suspected fetal macrosomia, other than for diabetic pregnancies, was not found to improve labor outcome . As weeks may possibly elapse between the time of last antenatal assessment and onset of labor, a further challenge is related to the timing of ultrasound assessment. Several studies have shown an association between increased Fetal Head Circumference (FHC) and prolonged second-stage of labor, instrumental delivery and cesarean section . However, FHC can only be acquired following delivery and has no predictive value for interventions in labor.

Official Title
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Fetal Head Circumference as a Predictor of Operative Delivery

Conditions
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Pregnancy

Intervention / Treatment
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* Device: Ultrasound


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Women at term (37+0 - 42+0 weeks' gestation) Singleton pregnancies Cephalic presentation Anticipated vaginal delivery Exclusion Criteria: Younger than 18 years old and older than 45 years old Women who incapable of providing informed consent

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Device: Ultrasound|Patients will receive ultrasound in the ultrasound unit at Hillel Yaffe Medical Center within 10 days before onset of induced or spontaneous labors. The ultrasound team has been trained in FHC , Estimated Fetal Weight (EFW) and Biparietal Diameter (BPD) measurement .Optimal ultrasound measurements of FHC and BPD will be obtained. The average of 3 fetal head circumference measurements will be recorded. Investigators consider the FHC and BPD to be optimal when a clear outline of the entire fetal skull is measured, and the landmarks (the thalamus, cavum septum pellucidum and choroid plexus in the atrium of the lateral ventricles) are visualized. Subsequent information of labor outcome as well as normal head circumference ,post-delivery will be obtained from maternal and neonatal medical records.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The rate of operative delivery including instrumental deliveries or cesarean sections. |  | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Length (in hours) of the first and second stages of labor. |  | 1 year | 
| Rate of obstetric anal sphincter injury. |  | 1 year | 
| Rate of early postpartum hemorrhage (PPH). |  | 1 year | 
| Rate of neonatal trauma. |  | 1 year | 
| Rate of admission to the neonatal intensive care unit. |  | 1 year |