Intrauterine growth restriction (IUGR) is caused when the placenta cannot provide enough nutrients to allow normal growth of the fetus during pregnancy. It is unclear why IUGR happens, but an increase in inflammatory T cells in the placenta known as villitis of unknown etiology (VUE) is observed in many IUGR infants. The investigators aim to develop ultrasound methods for diagnosing VUE to understand it's role in IUGR.
Intrauterine growth restriction (IUGR) occurs in 3-10% of all pregnancies and is associated with significant morbidity and mortality during pregnancy, after birth and throughout the child's lifespan. IUGR is caused by the inability of the placental vasculature to provide enough oxygen and nutrients to support the fetus; yet, the mechanisms leading to disruption of placental vasculature are unknown. The placenta of \~50% of IUGR fetuses are infiltrated with inflammatory cells, specifically maternal T cells, which destroy placental blood vessels that support the fetus. This infiltration of T cells is known as villitis of unknown etiology (VUE). The diagnosis of VUE is problematic because it occurs without clinical signs and symptoms of maternal (or fetal) distress and puts the fetus at significant risk of demise. Additionally, VUE commonly recurs in subsequent pregnancies putting future offspring at risk. Yet, the exact prevalence of VUE and its significance in IUGR pathogenesis and outcomes are poorly understood as VUE is only diagnosed after the infant is outside the womb. Therefore, the study aims to recognize risk factors and cellular mechanisms associated with VUE and develop methods for diagnosing and treating VUE in utero, in order to improve infant health.
Study Type
OBSERVATIONAL
Enrollment
60
Ultrasound measures to be collected include uterine artery (UtA) and umbilical artery (UA), systolic/diastolic (S/D) ratio, resistance index (RI), pulsatility index (PI) and presence of early diastolic notch.
In addition, a Verasonics ultrasound scanner will be used for ultra-sensitive Doppler imaging. Data will be collected on vessel density, periphery-to-center vessel density ratio (VDR) and microvessel morphology.
Mayo Clinic
Rochester, Minnesota, United States
Number of Participants With Uterine Artery Indices Completed
Measured by Doppler and 3D microvessel imaging, used to calculate outcomes 3-5
Time frame: Gestational age of 34-36 weeks
Number of Patients With Umbilical Artery Indices Completed
Measured by Doppler and 3D microvessel imaging, used to calculate outcomes 3-5
Time frame: Gestational Age of 34-36 weeks
Systolic(S)/Diastolic(D) Ratio
S = Systolic peak (max velocity); Maximum velocity during contraction of the fetal heart. D = End-diastolic flow; Continuing forward flow in the umbilical artery during the relaxation phase of the heartbeat. S/D ratio = (systolic / diastolic ratio)
Time frame: Gestational Age of 34-36 weeks
Resistance Index (RI)
Resistance index (RI) = (systolic velocity - diastolic velocity / systolic velocity)
Time frame: Gestational Age of 34-36 weeks
Pulsatility Index (PI)
Pulsatility index (PI) = (systolic velocity - diastolic velocity / mean velocity)
Time frame: Gestational age of 34-36 weeks
Number of Participants With Placental Pathology Indicating Chronic Villitis
Using the Amsterdam criteria, following delivery, placentae will be histologically examined for placental villitis (presence of maternal T cells) and graded by severity. High grade involves greater than 10 villi while low grade affects fewer than 10 villi.
Time frame: Gestational age up to 42 weeks
Gestational Age at Birth
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The gestational age in weeks of when the baby was delivered.
Time frame: Gestational age up to 42 weeks
Preterm Labor
Pregnancy that delivered prior to 37 weeks gestational age
Time frame: Gestational age up to 37 weeks
Birth Weight of Infant
Weight of infant at time of birth
Time frame: Gestational age up to 42 weeks