Timing of Serial Ultrasounds

Study Overview
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Brief Summary
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The purpose of this randomized controlled trial is to compare the frequency of the diagnosis of fetal growth abnormalities when ultrasound assessment is performed at 2 versus 4 week intervals.

Detailed Description
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While there is an agreement that women at risk for abnormalities of fetal growth should have serial ultrasound examinations in the 3rd trimester, there is a lack of consensus on how frequently these exams should be done. The American College of Obstetrics and Gynecology recommend that an ultrasound to assess fetal growth be performed between 2 to 4 weeks; however, there have been no prospective or randomized trials to determine whether the optimal interval should be closer to 2 weeks or delayed to 4 weeks. Currently, only 60% of fetuses' with abnormal growth are detected antenatally. There is equipoise of whether ultrasound every 2 versus 4 weeks improves the detection and subsequent newborn outcomes or merely leads to an increase in false positives and unnecessary interventions. It has been proposed, that if delivery occurs within 2 weeks of the ultrasound, the antenatal detection of abnormal growth may be more accurate and hence more likely to improve outcomes. Conversely, a shorter interval may result in confusion as to whether there is actual change in growth or merely variation in the measurement technique itself. Moreover, with the cost of ultrasound averaging approximately $200 per examination, the interval between ultrasounds can have major implications on public-health costs as well as the interventions that subsequently follow if an abnormality is detected. The purpose of this randomized controlled trial is to compare the frequency of the diagnosis of fetal growth abnormalities when ultrasound assessment is performed at 2 versus 4 week intervals.

Official Title
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Timing of Serial UltrasouNds in High-Risk Pregnancies: A Randomized Controlled Trial

Conditions
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Interval Growth Ultrasound

Intervention / Treatment
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* Device: Ultrasound


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Maternal age ≥ 18 years Singletons Gestational age ≥ 20 weeks to 27 weeks 6 days Has insurance, whether private or government issued High-risk pregnancy requiring serial fetal growth assessment as determined by the treating physician. Dating of pregnancy by ultrasound ≤ 21 weeks and 6 days of gestation or known date of conception in the setting of in vitro fertilization No known major anomalies Exclusion Criteria: Known major fetal anomaly Multiple gestation (twins or triplets)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 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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Design Details

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Fetal growth ultrasound every 2 weeks<br>Ultrasound to measure fetal growth every 2 weeks (i.e. 28, 30, 32, 34, 36, 38 weeks gestation). | Device: Ultrasound<br>* Estimation of fetal weight by ultrasound<br>|
| Active Comparator: Fetal growth ultrasound every 4 weeks<br>Ultrasound to measure fetal growth every 4 weeks (i.e. 28, 32 and 36 weeks gestation). Usual Care. | Device: Ultrasound<br>* Estimation of fetal weight by ultrasound<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Frequency of detection of fetal growth abnormalities, starting at 28 weeks gestational age |  | up to 72 hours after delivery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Birthweight compared to antenatal estimated fetal weights | Comparison of estimated fetal weight by ultrasound to actual birth weight at delivery | At delivery | 
| Frequency of detection of amniotic fluid abnormality, starting at 28 weeks gestational age |  | Up to 72 hours after delivery | 
| Cost of interventions resulting from detection of abnormal growth or amniotic fluid | e.g. additional ultrasounds, antenatal testing, hospital admission, induction, antepartum or intrapartum complications | up to 72 hours from neonatal discharge from hospital | 
| Composite neonatal morbidity (CNM) |  | up to 72 hours from neonatal discharge from hospital | 
| Composite maternal morbidity (CMM) |  | up to 72 hours from mother's discharge from hospital |