Accuracy of pregnancy dating
The safety of ultrasound has also come into question, and these concerns have been addressed by the AIUM.
Ultrasound energy generates sound waves in a pulsed fashion that can theoretically raise the temperature of body tissues.
This variance has evolved from years of study by several esteemed researchers who have sought the most accurate measurement parameters in determining gestational age and normal patterns of fetal growth.
At first glance, it may appear that some of these studies do not report consistent findings in terms of ultrasound's overall accuracy in predicting gestational age.
Patients' wishes and feelings about ultrasound testing should be taken into consideration, and regardless of how their EDD is calculated, the rationale for this decision thoroughly explained to them and clearly documented in the prenatal record.
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in their study of more than 17,000 women, found that the proportion of postterm deliveries decreased from 10.3% with reliable LMP dating to 2.7% when the EDD was determined by ultrasound.
In more recent randomized controlled trials, researchers have continued to report substancially fewer postterm inductions when the EDD was determined by first-trimester ultrasound.
has also published specific guidelines that address training, quality assurance, safety, and clinical recommendations.
When one also considers the costs of postterm surveillance, which typically includes twice weekly nonstress tests and weekly amniotic fluid measurements, there are potential cost savings with accurate dating by early ultrasound assessment -- not to mention the costs of fetal fibronectin cultures or the clinical and legal implications of inappropriately managing preterm labor.
Does it not then behoove all obstetric providers to discuss and offer routine ultrasound screening to every pregnant woman, even in the absence of medical indications?
reported no significant differences in pre- or postterm delivery rates, the benefits of appropriately managing either of these clinical scenarios far outweigh the potential costs of the scan itself.
Cost ratios aside, several studies have demonstrated a decrease in postterm induction rates when gestational age has been established by ultrasound.