Twins With Specific Vs. Traditional Fetal Growth Charts (Twist): A Randomized Controlled Trial
Comparing Growth Monitoring Methods in Twin Pregnancies
Hiba Mustafa, MD
Primary Investigator
Brief description of study
This study will compare two different ways of monitoring growth in twin pregnancies. One method uses growth charts designed for single babies, while the other uses charts made specifically for twins. We want to find out which method better identifies babies who are truly at risk and helps avoid unnecessary medical interventions.
THIS STUDY IS ENROLLING BY INVITATION ONLY - Eligible participants will be identified through routine review of the electronic medical record (EMR) by authorized study staff. Individuals with dichorionic diamniotic (DCDA) twin pregnancies who meet inclusion criteria will be flagged and approached in person during scheduled prenatal visits. Recruitment will be conducted privately in exam rooms to maintain confidentiality, and no initial contact will be made outside the clinical setting
Detailed description of study
Participants will be recruited between 16 and 28 weeks of gestation during routine prenatal care.
Participants will be randomized in a 1:1 ratio to one of two clinical management arms: (1) monitoring and decision-making based on singleton growth charts (e.g., Hadlock), or (2) monitoring and management guided by twin-specific growth charts. Participants in both arms will undergo serial ultrasound evaluations every four weeks starting at 20 weeks’ gestation, per institutional standard of care, to assess fetal biometry, growth trends, amniotic fluid volume, and Doppler parameters as clinically indicated. Clinical management decisions, including frequency of follow-up, hospitalization, antenatal corticosteroid administration, and timing/mode of delivery, will be at the discretion of the primary obstetrical provider but informed by the assigned chart interpretation.
The procedures involved in this study—serial ultrasounds and clinical management based on fetal growth chart interpretation—are part of standard prenatal care and do not introduce physical interventions beyond routine practice.
Research procedures will take place during routine prenatal visits at affiliated obstetric clinics.
All data used for the study will be collected as part of standard prenatal and hospital care. No study-specific procedures will be performed. This approach minimizes disruption to care and protects participants’ privacy in familiar healthcare settings.
Eligibility of study
You may be eligible for this study if you meet the following criteria:
- Conditions: Dichorionic diamniotic (DCDA) twin pregnancy, Riley
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Age: 18 weeks - 100 years
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Gender: All
Inclusion:
Dichorionic diamniotic (DCDA) twin pregnancy, confirmed by first-trimester ultrasound
Two live fetuses at the time of enrollment
Gestational age ≥18+0 weeks at enrollment.
Normal anatomy scan (or no major anomalies detected at time of enrollment)
Signed informed consent, including permission to request external delivery and neonatal records
Final EFW scan performed within 14 days of delivery
Exclusion:
Monochorionic, monoamniotic, or higher-order multiple pregnancies
IUFD of one or both twins prior to enrollment
Major structural anomalies or confirmed chromosomal abnormalities
Fetal reduction, miscarriage, or pregnancy termination
Prior clinical diagnosis of FGR with management initiated before randomization
Declined release of medical records from delivery/neonatal sites if delivery occurs outside the study center
This study investigates the effectiveness of using different fetal growth charts for monitoring twin pregnancies. The purpose of this study is to compare traditional growth charts, designed for single babies, with charts specifically made for twins to determine which method better identifies babies at risk and reduces unnecessary medical interventions.
Participants will be assigned to one of two study arms: one group will be monitored using singleton growth charts, while the other group will use twin-specific charts. All participants will undergo regular ultrasounds every four weeks starting at 20 weeks of pregnancy to assess fetal growth and health. These procedures are part of standard prenatal care and do not introduce any additional physical interventions.
- Who can participate: Eligible participants are those with dichorionic diamniotic (DCDA) twin pregnancies confirmed by first-trimester ultrasound. They must have two live fetuses at the time of enrollment, be at least 18 weeks pregnant, and have a normal anatomy scan. Signed informed consent is required.
- Study details: Participants will be involved in regular prenatal visits where routine ultrasounds will be conducted to monitor fetal growth. No additional procedures beyond standard care will be performed. Clinical decisions will be guided by the growth chart assigned to each participant.
