In Utero Procedure Affecting Fetus or Newborn, Maternal; Procedure, Pregnancy Complications, Vasa Previa
Conditions
Keywords
Fetoscope, Fetoscopic Laser Photocoagulation, Low-Lying Fetal Vessels
Brief summary
In this research study, the investigators want to learn more about the safety and effectiveness of a fetal surgery, known as fetoscopic laser photocoagulation (FLP), for the treatment of a pregnancy condition called vasa previa (VP). Vasa previa is a pregnancy complication that happens when blood vessels from the fetus grow over the entrance to the womb. In a VP pregnancy, natural vaginal birth is deadly for the baby in more than half of cases due to the bursting of VP vessels and severe blood loss. Currently, VP patients are recommended to be closely monitored and often hospitalized once they reach the third trimester of pregnancy. An early delivery by C-section would typically be performed in order to avoid breaking the exposed fetal vessels. Fetoscopic laser photocoagulation is a minimally invasive surgery in the womb to remove or correct abnormal blood vessels and tissues. In the FLP procedure, the surgeon uses a fetoscope (a tiny telescope) and a laser device to seal off unprotected vessels. While this surgery has been used to treat other pregnancy conditions, it has not yet been proven to be safe and/or effective for the treatment of vasa previa. This treatment aims to eliminate the VP, and, if successful, may have the potential to minimize the risk of bleeding, thereby enabling patients to avoid long hospitalization before delivery. This procedure may enable VP patients to have a vaginal delivery instead of C-section.
Interventions
Pregnant patients diagnosed with type II vasa previa will undergo fetoscopic laser photocoagulation of the involved fetal vessels. FLP will be performed laparoscopically using a fetoscope (tiny telescope) and a laser device inside of the womb. This procedure will be completed at 30w0d to 32w6d gestational age.
Sponsors
Boston Children's Hospital
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 55 Years
Healthy volunteers
No
Inclusion criteria
* Pregnant patient * Singleton pregnancy * Confirmed diagnosis of vasa previa, defined as unprotected fetal vessels running through the membranes at or within 5cm of the internal cervical os. Diagnosis must be confirmed after 26w0d, and before 32w5d * Able to undergo intervention during 30w0d to 32w6d * Type II vasa previa in which one placental lobe is considered to be accessory, defined as constituting less than 20% of the total placental mass seen on MRI and US imaging * Type II vasa previa in which multiple bridging vessels connect the two placental lobes (≥4 vessels), and only 1-2 vessel(s) run through or within 5cm of the internal cervical os * Patient is eligible to undergo anesthesia * Patient and biological father of the fetus (if available) are able to provide signed informed consent
Exclusion criteria
* Gestational age at referral higher than 32w6d * Multiple pregnancy * Vasa previa types I and III * Type II vasa previa in which the accessory lobe constitutes more than 20% of the total placental mass, as determined by the fetal surgeon during diagnostic fetoscopy * Type II vasa previa in which all of the bridging vessels between placental lobes are running over the internal cervical os * Fetal growth restriction, defined as estimated fetal weight or abdominal circumference less than the 10th percentile for gestational age * Abnormal fetal brain MRI, including delayed maturation, hemorrhage, arterial ischemic injury, abnormal ventricular size, or any congenital anomalies * Allergy or previous adverse reaction to ancillary medications with no available alternative * Preterm contractions and PPROM before surgery * Preeclampsia or uterine anomaly during the current pregnancy * Placenta previa, low-lying placenta, placenta accreta spectrum disorder * Suspicion of major recognized congenital syndrome on ultrasound or MRI that is not compatible with postnatal life * Maternal pre-pregnancy BMI \>40 * Active hepatitis B, hepatitis C, or HIV infection * High risk for congenital fetal bleeding disorders * Unreliable pregnancy dating due to an irregular menstrual cycle/uncertain last menstrual period with no confirmed dating from first trimester ultrasound * The surgeon determines that the procedure is not feasible for any other reason after diagnostic fetoscopy
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Mode of delivery | When the last (20th) participant reaches delivery, a little more than 3 years from study start date | The type of delivery, categorized as vaginal, assisted vaginal, or cesarean section. |
| Gestational age at delivery | When the last (20th) participant reaches delivery, a little more than 3 years from study start date | The duration of pregnancy, measured in completed \[weeks + days\] from the first day of the last menstrual period (in individuals with regular menses and reliable dating) or determined through first-trimester ultrasound using fetal biometric measurements. |
| Successful visualization and mapping of vasa previa | When the last (20th) participant undergoes FLP surgery, about 3 years from study start date. | Confirmation by the performing surgeon that the visualization and mapping of vasa previa by diagnostic fetoscopy matches imaging from US and MRI. |
| The rate of successful coagulation of the vasa previa - intraoperative imaging | When the last (20th) participant undergoes FLP surgery, about 3 years from study start date. | Confirmation of the complete coagulation of the vasa previa including the absence of blood flow in involved vessels. This will be measured in the OR directly after FLP surgery by ultrasound. |
| The rate of successful coagulation of the vasa previa - postoperative imaging | Two weeks after the last (20th) participant undergoes FLP surgery, about 3 years from study start date. | Confirmation of the complete coagulation of the vasa previa including the absence of blood flow in involved vessels. This will be measured 2 weeks post-surgery by ultrasound and MRI. |
| The rate of successful coagulation of the vasa previa - pathology | When the last (20th) participant reaches delivery, a little more than 3 years from study start date | Confirmation of the complete coagulation of the vasa previa including the absence of blood flow in involved vessels. This will be measured after delivery during placental analysis by pathology. |
| Placental function | Two weeks after the last (20th) participant undergoes FLP surgery, about 3 years from study start date. | Successful maintenance of placental function after surgery. This will be measured by MRI 2 weeks after surgery. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| GA at hospital admission | When the last (20th) participant is admitted to the hospital, a little less than 3 years from study start date | The gestational age at hospital admission before birth. |
| Duration of hospital stay | When the last (20th) participant is discharged from the hospital, a little more than 3 years from study start date | The length of hospital stay for the pregnant person will be recorded, from the time of admission to discharge. |
| Cause for hospital admission | When the last (20th) participant is admitted to the hospital, a little less than 3 years from study start date | The reason for hospital admission before birth will be recorded. |
| The rate of spontaneous preterm labor | When the last (20th) participant reaches delivery, a little more than 3 years from study start date | The incidence of labor occurring naturally before 37 completed weeks of pregnancy with regular uterine contractions and progressive cervical dilation in the absence of medical or obstetric intervention. |
| The rate of preterm premature rupture of membranes (PPROM) | When the last (20th) participant reaches delivery, a little more than 3 years from study start date | The incidence of PPROM, defined as rupture of the amniotic sac after FLP surgery and before 37 completed weeks of pregnancy. |
| The rate of placental abruption | When the last (20th) participant reaches delivery, a little more than 3 years from study start date | The rate of separation of the placenta from the uterine wall after FLP surgery and before delivery. |
| The rate of chorioamnionitis | When the last (20th) participant reaches delivery, a little more than 3 years from study start date | The rate of infection of the fetal membranes and amniotic fluid after FLP surgery and before delivery. |
| The rate of chorioamniotic separation | When the last (20th) participant reaches delivery, a little more than 3 years from study start date | The rate of separation of the amniotic and chorionic membranes after FLP surgery and before delivery. |
| Interval from procedure to delivery | When the last (20th) participant reaches delivery, a little more than 3 years from study start date | The length of time from FLP surgery to delivery will be recorded in weeks and days. |
| The rate of fetal growth restriction | When the last (20th) participant reaches delivery, a little more than 3 years from study start date | The rate of fetal growth restriction, defined as an estimated fetal weight or abdominal circumference below the 10th percentile for gestational age, at any time after FLP surgery up to delivery. |
| Fetal brain structure | Two weeks after the last (20th) participant undergoes FLP surgery, about 3 years from study start date | Normal or abnormal fetal brain structure will be assessed by MRI 2 weeks after surgery. |
| The rate of NICU admission | When the last (20th) participant reaches delivery, a little more than 3 years from study start date | The rate of NICU admission after birth will be recorded |
| NICU length of stay | When the last baby is discharged from the NICU, a little more than 3 years from study start date | The number of days that the baby spends in the NICU after birth. |
| Short term neonatal morbidity | When the last baby is discharged from the hospital, a little more than 3 years from study start date | The rate of short term morbidity during the first 30 days of life or until hospital discharge, whichever is latest. Short-term morbidity includes neurological problems, gastrointestinal problems, respiratory problems, infections, and other problems associated with prematurity including but not limited to: necrotizing enterocolitis, bronchopulmonary dysplasia, respiratory distress syndrome, neonatal sepsis, neonatal intensive care unit admission and need for extracorporeal membrane oxygenation (ECMO). |
| Neonatal survival | When the last baby is discharged from the hospital, a little more than 3 years from study start date | The rate of neonates surviving to 30 days of age, or hospital discharge, whichever is latest. |
| Maternal mental health score | Two weeks after the last (20th) participant undergoes FLP surgery, about 3 years from study start date | The Postpartum Depression Screening Scale (PDSS) - Antenatal Version will be used to assess and compare the levels of depression and anxiety before and after FLP surgery. This assessment will be given once before surgery, and once again 4-8 weeks later (at least 2 weeks after surgery). |
| Postnatal examination of the placenta | When the last (20th) participant reaches delivery, a little more than 3 years from study start date | The placenta will be examined for disrupted or ruptured vessels after dye staining. Secondary changes in the accessory lobe will also be checked, which are features resulting from cessation of blood supply due to prior ablation. These could include fibrin deposition, evidence of hypoxia in the chorionic villi, eventual necrosis, and parenchymal atrophy |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORAlireza Shamshirsaz, MD
Director, Maternal Fetal Care Center; Chief, Division of Fetal Medicine and Surgery
Outcome results
None listed