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Core Outcome Set for studies on vasa previa (COVasP)

COVasP is a multi-method study conducted between 2018 and 2024, wherein 115 people with lived experience of vasa previa and 89 pregnancy care providers from 27 countries identified 13 core outcomes and 22 reporting checklist items, which researchers are encouraged to measure and report in all future studies.

Core Outcome Set for studies on vasa previa (COVasP)

Study
Study
Link to Full Publication
Copy Citation
Yeretsian T, Javid N, Hirschhorn-Edwards N, Ashraf R, Adams A, Kingdom J, D’Souza R. Core Outcome Set and Reporting Checklist for Studies on Vasa Previa. JAMA Network Open. 2025;8(3):e251000. doi:10.1001/jamanetworkopen.2025.1000
This is the first iteration of COVasP. Your feedback and comments on these checklists are very welcome,
and we aim to incorporate them into the next iteration. Please feel free to reach out to us via email at oros@mcmaster.ca.

Core Outcome Set

# Core Outcome Explanations and reporting recommendations Reported
Yes / No		 Location/page number where
item is reported.
Justification if not/partly reported
1.
1.
Pregnancy outcome
Pregnancy outcome 		This includes all cases of livebirth, fetal loss (miscarriage or stillbirth) and neonatal deaths providing a definition of each outcome based on threshold of viability used.
i
2.
2.
Severe neonatal morbidity
Severe neonatal morbidity 		This includes only the very serious or life-threatening conditions experienced by neonates. State what conditions/indicators were used to define this term.
i
3.
3.
Fetal or neonatal blood loss
Fetal or neonatal blood loss 		Significant fetal or neonatal blood loss attributable to rupture or laceration of fetal vessels, leading to exsanguination, severe anemia, hypovolemic shock, or the necessity for blood transfusion.
i
4.
4.
Gestational age at birth
Gestational age at birth 		Where relevant, subcategorize into early preterm (<34 weeks), late preterm (34–36 weeks), and term (≥37 weeks) deliveries.
i
5.
5.
Rupture of membranes
Rupture of membranes 		Antepartum or intrapartum rupture of membranes and the mean/median interval in hours between membrane rupture and delivery.
i
6.
6.
Admission to the neonatal intensive care unit (NICU) or special care nursery for > 24 hours
Admission to the neonatal intensive care unit (NICU) or special care nursery for > 24 hours 		Mention the mean/median length of stay in days and specify any interventions initiated during the stay.
i
7.
7.
Neurocognitive and developmental outcomes
Neurocognitive and developmental outcomes 		Baby’s physical, neurodevelopmental, cognitive and psychological development after birth requiring ongoing health care monitoring and testing and the age at which this was tested.
i
8.
8.
Third-trimester confirmation of diagnosis of vasa previa
Third-trimester confirmation of diagnosis of vasa previa 		Diagnosis could be confirmed through one or more of the following: (1) third-trimester transvaginal or transabdominal ultrasound; (2) direct visualization of vessels during childbirth; or (3) histopathological examination of the placenta and membranes. Specify the diagnostic modality employed.
i
9.
9.
Maternal death (all cause) or severe maternal morbidity
Maternal death (all cause) or severe maternal morbidity 		For maternal mortality - specify gestational age (antepartum) or days following childbirth/ pregnancy loss (postpartum) at death and the cause.

For severe maternal morbidity, specify definition/indicators used.
i
10.
10.
Mother's quality of life / perceived health status
Mother's quality of life / perceived health status 		Include instrument used as well as timing and frequency of measurement. For repeated measurements, provide baseline and follow-up data where applicable.
i
11.
11.
Duration of maternal antenatal hospitalization
Duration of maternal antenatal hospitalization 		Report the cumulative duration of antenatal hospitalization in days, and the primary reasons for admission (e.g., preterm labor, preeclampsia, vasa previa management).
i
12.
12.
Mode of birth
Mode of birth 		Cesarean or vaginal birth.
i
13.
13.
Antepartum or Intrapartum Hemorrhage
Antepartum or Intrapartum Hemorrhage 		Indicate whether antepartum or intrapartum hemorrhage occurred, the estimated blood loss and the time interval between bleeding onset and delivery.
i

Reporting Checklist for Studies
on Vasa Previa

Study

Reporting Checklist Items

Relevant to all studies on vasa previa
# Reporting Checklist Item Explanations and reporting recommendations Reported
Yes / No		 Location/page number where
item is reported.
Justification if not/partly reported
1.
1.
Availability and accessibility to interventions
Availability and accessibility to interventions 		Report availability of high-quality and necessary interventions including diagnostic ultrasound, trained healthcare providers, and emergency intervention capabilities. Where applicable, include geographic and socioeconomic barriers.
i
2.
2.
Type of vessel (artery or vein) ruptured or in proximity to the internal os
Type of vessel (artery or vein) ruptured or in proximity to the internal os 		If histopathology is available.
i
3.
3.
Adherence and compliance to treatment/interventions
Adherence and compliance to treatment/interventions 		Report the proportion of cases adhering to recommended management protocols and specify deviations from protocol and reason for deviation (e.g., patient preference, resource limitations).
i
4.
4.
Presence of risk factors for vasa previa
Presence of risk factors for vasa previa 		List any known risk factors for vasa previa such as assisted reproductive techniques, twin or higher order gestation, placenta previa/low-lying placenta, bilobed or succenturiate lobed placenta, or velamentous cord insertion.
i
5.
5.
Antenatal corticosteroids injections
Antenatal corticosteroids injections
  • Document administration of antenatal corticosteroids (yes/no).
  • Specify timing e.g., ≤34 weeks for fetal lung maturity.
  • Indication of corticosteroid use e.g. cervical shortening, routine administration according to protocol, signs of threatened preterm labour, or antepartum bleeding.
i
6.
6.
Care continuity
Care continuity 		Report continuity of care during antenatal, intrapartum, and postpartum periods, including transitions between healthcare professionals or facilities.
i
7.
7.
Antenatal monitoring of fetal growth and wellbeing
Antenatal monitoring of fetal growth and wellbeing 		Specify methods for monitoring fetal growth (e.g., Doppler ultrasound, biometry). Where appropriate, include growth centiles and reference charts.
i
8.
8.
Reduced fetal movements during pregnancy
Reduced fetal movements during pregnancy 		Report gestational periods when reduced fetal movements are reported.
i
9.
9.
Isolated structural fetal anomalies (diagnosed by ultrasound or postnatally)
Isolated structural fetal anomalies (diagnosed by ultrasound or postnatally) 		Mention each specific congenital anomaly diagnosed by ultrasound or postnatally.
i
10.
10.
Peer Support Services
Peer Support Services 		Indicate availability of peer support services, their nature/type, and issues related to access.
i
11.
11.
Pain relief and anesthetic for birth
Pain relief and anesthetic for birth 		Detail pain management strategies, including non-pharmacologic and pharmacologic (e.g., epidural, general anesthesia) methods.
i
12.
12.
Patient care satisfaction
Patient care satisfaction 		List the validated measure that was used to assess patient satisfaction with care received.
i
13.
13.
Abnormal fetal heart rate pattern in pregnancy and/or labor
Abnormal fetal heart rate pattern in pregnancy and/or labor 		Specify type(s) of abnormalities (e.g., late decelerations, bradycardia) and classification system/guideline that was used.
i
14.
14.
Fetal growth restriction
Fetal growth restriction 		Report the definition and relevant citation that was used.
i

Only relevant to studies where antenatal screening for vasa previa is performed

Only relevant to studies where antenatal screening for vasa previa is performed
# Reporting Checklist Item Explanations and reporting recommendations Reported
Yes / No		 Location/page number where
item is reported.
Justification if not/partly reported
15.
15.
Type of vasa previa
Type of vasa previa 		Classify vasa previa as Type I, II, III, or combinations based on ultrasound findings and vessel location.
i
16.
16.
Screening for vasa previa by trained professionals at the routine anatomy ultrasound scan
Screening for vasa previa by trained professionals at the routine anatomy ultrasound scan 		Yes/no.
i
17.
17.
Use of published clinical guidelines to diagnose vasa previa (based on distance of exposed fetal vessel to the os at first and last ultrasound prior to birth, gestational age at which diagnosis was made, and whether the diagnosis was made using transabdominal or transvaginal ultrasound)
Use of published clinical guidelines to diagnose vasa previa (based on distance of exposed fetal vessel to the os at first and last ultrasound prior to birth, gestational age at which diagnosis was made, and whether the diagnosis was made using transabdominal or transvaginal ultrasound) 		Report adherence of the diagnosis and management of vasa previa to published guidelines and mention guideline.
i
18.
18.
Inpatient versus outpatient management in pregnancy
Inpatient versus outpatient management in pregnancy 		Specify the rationale for inpatient or outpatient care, including institutional protocols or patient preferences.
i
19.
19.
Parental comprehension of diagnosis of vasa previa; its implications and evidence to guide care
Parental comprehension of diagnosis of vasa previa; its implications and evidence to guide care 		Assess and document parental understanding of the diagnosis, its implications, and the proposed care plan.
i
20.
20.
Antenatal monitoring for fetal anemia during pregnancy using ultrasound
Antenatal monitoring for fetal anemia during pregnancy using ultrasound 		If yes, specify methods (e.g., Doppler middle cerebral arterial peak systolic velocity) used for fetal anemia surveillance.
i
21.
21.
Cervical length monitoring using ultrasound
Cervical length monitoring using ultrasound 		If yes, report cervical length measurements, timing, and methods (e.g., transvaginal ultrasound).
i
22.
22.
Change in diagnosis on subsequent ultrasound; for e.g., vasa previa not confirmed; vasa previa resolved
Change in diagnosis on subsequent ultrasound; for e.g., vasa previa not confirmed; vasa previa resolved 		Indicate whether the diagnosis changed on subsequent imaging. If yes, specify gestational age at initial diagnosis and gestational age when diagnosis was revised.
i
From: Yeretsian T, Javid N, Hirschhorn-Edwards N, Ashraf R, Adams A, Kingdom J, D’Souza R. Core Outcome Set and Reporting Checklist for Studies on Vasa Previa. JAMA Network Open. 2025;8(3):e251000. doi:10.1001/jamanetworkopen.2025.1000.