PlacentaNCT07124312
Placental Characteristics Within Monochorionic Twin Pregnancies
An observational study of Placenta and Monochorionic Twins, run by Birmingham Women's NHS Foundation Trust at 1 site in United Kingdom.
Trial summary
This prospective study aims to collate a comprehensive database of all main monochorionic twin groups to enable comparisons to be made within each twin group and additionally between each group with regards to several placental characteristics, whilst understanding their impact on several fetal outcomes. Read more about this study
- Who is it for?
- Any age, women onlyHealthy volunteers can take part
- Conditions the study is for
- Placenta, Monochorionic Twins, Anatomy
- How many people
- 65 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 12 Dec 2024to 1 Feb 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- Women only
- Healthy volunteers accepted
- Child, Adult, Older adult
Study population: Placentas received within the pathology department from monochorionic twin groups . These groups include: * Uncomplicated monochorionic twins * Monochorionic twins with complications (e.g. selective intrauterine growth restriction, twin-twin transfusion syndrome , twin anaemia-polycythaemia sequence etc).
Who may be able to join
- All consecutive placentas of monochorionic twin pregnancies whereby the placenta is transferred to the pathology department for analysis.
Who cannot join
- Singleton, dichorionic and higher order pregnancies (e.g. triplet).
- Fetus with known major congenital anomalies or aneuploidy
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United Kingdom1 site, 1 recruiting
- Recruiting
Birmingham Women's and Children's NHS Foundation Trust
Birmingham, West Midlands, B15 2TG
Jack Hamer, 0121 472 1377, jack.hamer1@nhs.net
About this study
Official title: Placental Characteristics Within Monochorionic Twin Pregnancies: a Prospective Cohort Study.
This prospective study aims to collate a comprehensive database of all main monochorionic twin groups to enable comparisons to be made within each twin group and additionally between each group with regards to several placental characteristics, whilst understanding their impact on several fetal outcomes. This study aims to provide new insights in to how the placental architecture influences pregnancy care within the UK pregnancy cohort. Results of this study may impact how clinicians conduct antenatal surveillance for these anatomical placental factors.
Patients of both uncomplicated and complication monochorionic twin groups will be consented at a single site and recruited during the antenatal period. Following delivery the placenta will then be analysed macroscopically and assessed for several anatomical features. This will be compared with the antenatal complications and perinatal outcomes for the respective twin.
- Conditions
- Placenta, Monochorionic Twins, Anatomy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Uncomplicated monochorionic twins | Monochorionic twins which do not develop any complications during the antenatal period | |
| Complicated monochorionic twins | Monochorionic twins which develop any type of complication during the antenatal period such as TTTS, sIUGR and TAPS. |
What is being measured
The primary outcome is the main question the study is designed to answer.
What is the impact of intertwin vascular anastomoses on fetal complications and perinatal outcome
To determine the prevalence of intertwin vascular anastomoses (overall, artery-artery, artery-vein, vein-vein) on adverse perinatal outcome (e.g. stillbirth and neonatal death) and fetal complications (e.g. small for gestational age). Measures will be as overall percentages and also raw numbers which will be calculated in to odds ratio's when comparing anastomoses versus no anastomoses against the respective perinatal outcome and fetal complication
Measured: Throughout the study period (approximately 2 years)
What is the impact of abnormal cord insertion on fetal complications and perinatal perinatal outcome
To determine the prevalence of abnormal cord insertion (marginal and velamentous) on adverse perinatal outcome (e.g. stillbirth and neonatal death) and fetal complications (e.g. small for gestational age, selective growth restriction). Measures will be as overall percentages and also raw numbers which will be calculated in to odds ratio's when comparing abnormal cord insertion versus normal cord insertion against the respective perinatal outcome and fetal complication
Measured: Throughout the study period (approximately 2 years
What is the impact of twin placental sharing on fetal complications and perinatal outcome
To determine the impact of placental sharing between each twin on adverse perinatal outcome (e.g. stillbirth and neonatal death) and fetal complications (e.g. birthweight discordance and selective growth restriction). Placental sharing will be defined as a percentage of overall share between each twin which sums up to 100%. The difference between each twin's share will be determine by minimising the larger percentage from the smaller percentage. The difference will then be compared to adverse perinatal outcomes and complications such as selective growth restriction using odds ratio's. Birthweight discordance will be defined as a percentage ( difference between the larger twin weight and smaller twin weight, divided by the larger twin weight). This will be compared to placental sharing using a graphical comparison of all placental sharing results, individually compared against each respective birthweight discordance.
Measured: Throughout the study period (approximately 2 years)
Secondary outcomes (8)
The influence of abnormal cord insertion in monochorionic twins complicated by twin-twin transfusion syndrome
To understand the frequency of abnormal cord insertion (marginal and velamentous) within monochorionic twins complicated by twin-twin transfusion syndrome following laser ablation and determine the impact on fetal outcomes such as stillbirth, neonatal death, recurrent twin-twin transfusion syndrome and twin anaemia-polycythaemia sequence. Results will be collected as overall number of placentas with abnormal cord (both marginal, velamentous and both) and those with normal cord insertion, and compared against the number of events in the respective fetal outcome. Results will be presented as odds ratio's.
Measured: Throughout the study period (approximately 2 years)
The influence of residual vascular anastomoses monochorionic twins complicated by twin-twin transfusion syndrome
To understand the frequency of residual vascular anastomoses within monochorionic twins complicated by twin-twin transfusion syndrome following laser ablation and determine their impact on fetal outcomes such as stillbirth, neonatal death, recurrent twin-twin transfusion syndrome and twin anaemia-polycythaemia sequence. Results will be collected as overall number of placentas with residual vascular anastomoses, alongside the individual types of anastomoses (artery-artery, artery-vein, vein-vein) and compared against the number of events in the respective fetal outcome. Results will be presented as odds ratio's.
Measured: Throughout the study period (approximately 2 years)
The influence of abnormal cord insertion on residual anastomoses development in monochorionic twins complicated by twin-twin transfusion syndrome undergoing laser ablation
To understand the impact of abnormal cord insertion (marginal and velamentous) on residual anastomoses development in monochorionic twins complicated by twin-twin transfusion syndrome undergoing laser ablation. Results will be collected as overall number of placentas with abnormal cord insertion and whether they have residual anastomoses versus those without abnormal cord insertion and if they have residual anastomoses seen. Results will be presented as odds ratio's.
Measured: Throughout the study period (approximately 2 years)
Examine the association between Quintero staging during laser ablation for monochorionic twins complicated by twin-twin transfusion syndrome on residual anastomoses development
To examine the impact of Quintero staging during laser ablation for twin-twin transfusion syndrome on the frequency of post-laser residual anastomoses. Quintero staging will be split in to the four stages and expressed as overall numbers versus the number of placentas with and without residual anastomoses. Results will be expressed as odds ratio's.
Measured: Throughout the study period (approximately 2 years)
Examine the relationship between placenta position during laser ablation for monochorionic twins complicated by twin-twin transfusion syndrome and the rate of residual anastomoses development.
To examine the impact of placenta position during laser ablation for twin-twin transfusion syndrome on the frequency of post-laser residual anastomoses. Placenta position will be either anterior or posterior and expressed as overall numbers versus the number of placentas with and without residual anastomoses. Results will be expressed as odds ratio's.
Measured: Throughout the study period (approximately 2 years)
The influence of intertwin cord distance on fetal complications
The assess the intercord twin distance on fetal complications such birthweight discordance. The distance of the twin cords will be measured in centimetres. This distance will be divided by the distance of the overall placental length to form a number between 0-1. This will then be compared graphically against birthweight discordance, which will be presented as a percentage (difference between the larger twin weight and smaller twin weight, divided by the larger twin weight).
Measured: Throughout the study period (approximately 2 years)
Determine the frequency of abnormal cord insertion in monochorionic twin groups
To determine the frequencies of abnormal cord insertion (velamentous and marginal) in monochorionic twin groups. This will be defined as percentages (number of cases with abnormal cord (velamentous, marginal and both) divided by the overall number) in each twin group (uncomplicated, twin-twin transfusion, selective growth restriction, twin anaemia-polycythaemia, TRAP, monoamniotic). Results will be compared to each group using P values.
Measured: Throughout the study period (approximately 2 years)
Determine the frequency of intertwin anastomoses in monochorionic twin groups
To determine the frequencies of intertwin vascular anastomoses (overall, artery-artery, artery-vein, vein-vein) in monochorionic twin groups. This will be defined as percentages (number of cases with intertwin vascular anastomoses (overall, artery-artery, artery-vein, vein-vein) divided by the overall number in each twin group (uncomplicated, twin-twin transfusion, selective growth restriction, twin anaemia-polycythaemia, TRAP, monoamniotic). Results will be compared to each group using P values
Measured: Throughout the study period (approximately 2 years)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Aug 2025
- Study start12 Dec 2024
- Primary completion1 Jan 2027 (estimated)
- Study completion1 Feb 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for PlacentaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 65 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Birmingham Women's NHS Foundation Trust
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Jack Hamer, Birmingham Women's NHS Foundation Trust
- Investigators
- Jack Hamer, MBChB, Principal investigator, Birmingham Women's and Children's NHS Foundation Trust
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07124312
- Sponsor's protocol ID
- 24/BW/MAT/NO/852
- Status last verified
- Aug 2025
- First submitted
- 1 Aug 2025
- Last updated
- 15 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 15 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Placental Characteristics Within Monochorionic Twin Pregnancies: a Prospective Cohort Study.
- ClinicalTrials.gov ID
- NCT07124312
- Acronym / sponsor ID
- 24/BW/MAT/NO/852
- Conditions
- Placenta, Monochorionic Twins, Anatomy
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 65 participants (estimated)
- Lead sponsor
- Birmingham Women's NHS Foundation TrustOther government
- Study start
- 12 Dec 2024 (actual)
- Primary completion
- 1 Jan 2027 (estimated)
- Study completion
- 1 Feb 2027 (estimated)
- First posted
- 15 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This prospective study aims to collate a comprehensive database of all main monochorionic twin groups to enable comparisons to be made within each twin group and additionally between each group with regards to several placental characteristics, whilst understanding their impact on several fetal outcomes. This study aims to provide new insights in to how the placental architecture influences pregnancy care within the UK pregnancy cohort. Results of this study may impact how clinicians conduct antenatal surveillance for these anatomical placental factors.
Patients of both uncomplicated and complication monochorionic twin groups will be consented at a single site and recruited during the antenatal period. Following delivery the placenta will then be analysed macroscopically and assessed for several anatomical features. This will be compared with the antenatal complications and perinatal outcomes for the respective twin.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Uncomplicated monochorionic twins | – | –Monochorionic twins which do not develop any complications during the antenatal period |
| Complicated monochorionic twins | – | –Monochorionic twins which develop any type of complication during the antenatal period such as TTTS, sIUGR and TAPS. |
Who may qualify
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Placentas received within the pathology department from monochorionic twin groups . These groups include: * Uncomplicated monochorionic twins * Monochorionic twins with complications (e.g. selective intrauterine growth restriction, twin-twin transfusion syndrome , twin anaemia-polycythaemia sequence etc).
Key inclusion criteria (1 listed)
- All consecutive placentas of monochorionic twin pregnancies whereby the placenta is transferred to the pathology department for analysis.
Key exclusion criteria (2 listed)
- Singleton, dichorionic and higher order pregnancies (e.g. triplet).
- Fetus with known major congenital anomalies or aneuploidy
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
What is the impact of intertwin vascular anastomoses on fetal complications and perinatal outcome
Time frame: Throughout the study period (approximately 2 years)
To determine the prevalence of intertwin vascular anastomoses (overall, artery-artery, artery-vein, vein-vein) on adverse perinatal outcome (e.g. stillbirth and neonatal death) and fetal complications (e.g. small for gestational age). Measures will be as overall percentages and also raw numbers which will be calculated in to odds ratio's when comparing anastomoses versus no anastomoses against the respective perinatal outcome and fetal complication
What is the impact of abnormal cord insertion on fetal complications and perinatal perinatal outcome
Time frame: Throughout the study period (approximately 2 years
To determine the prevalence of abnormal cord insertion (marginal and velamentous) on adverse perinatal outcome (e.g. stillbirth and neonatal death) and fetal complications (e.g. small for gestational age, selective growth restriction). Measures will be as overall percentages and also raw numbers which will be calculated in to odds ratio's when comparing abnormal cord insertion versus normal cord insertion against the respective perinatal outcome and fetal complication
What is the impact of twin placental sharing on fetal complications and perinatal outcome
Time frame: Throughout the study period (approximately 2 years)
To determine the impact of placental sharing between each twin on adverse perinatal outcome (e.g. stillbirth and neonatal death) and fetal complications (e.g. birthweight discordance and selective growth restriction). Placental sharing will be defined as a percentage of overall share between each twin which sums up to 100%. The difference between each twin's share will be determine by minimising the larger percentage from the smaller percentage. The difference will then be compared to adverse perinatal outcomes and complications such as selective growth restriction using odds ratio's. Birthweight discordance will be defined as a percentage ( difference between the larger twin weight and smaller twin weight, divided by the larger twin weight). This will be compared to placental sharing using a graphical comparison of all placental sharing results, individually compared against each respective birthweight discordance.
8 secondary outcomes
The influence of abnormal cord insertion in monochorionic twins complicated by twin-twin transfusion syndrome
Time frame: Throughout the study period (approximately 2 years)
The influence of residual vascular anastomoses monochorionic twins complicated by twin-twin transfusion syndrome
Time frame: Throughout the study period (approximately 2 years)
The influence of abnormal cord insertion on residual anastomoses development in monochorionic twins complicated by twin-twin transfusion syndrome undergoing laser ablation
Time frame: Throughout the study period (approximately 2 years)
Examine the association between Quintero staging during laser ablation for monochorionic twins complicated by twin-twin transfusion syndrome on residual anastomoses development
Time frame: Throughout the study period (approximately 2 years)
Examine the relationship between placenta position during laser ablation for monochorionic twins complicated by twin-twin transfusion syndrome and the rate of residual anastomoses development.
Time frame: Throughout the study period (approximately 2 years)
The influence of intertwin cord distance on fetal complications
Time frame: Throughout the study period (approximately 2 years)
Determine the frequency of abnormal cord insertion in monochorionic twin groups
Time frame: Throughout the study period (approximately 2 years)
Determine the frequency of intertwin anastomoses in monochorionic twin groups
Time frame: Throughout the study period (approximately 2 years)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Aug 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Jack Hamer, MBChB principal investigator
Birmingham Women's and Children's NHS Foundation Trust
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Placenta and Monochorionic Twins, run by Birmingham Women's NHS Foundation Trust at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 15 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Jack Hamer, MBChB (0121 472 1377, jack.hamer1@nhs.net), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
What is the impact of intertwin vascular anastomoses on fetal complications and perinatal outcome (time frame: Throughout the study period (approximately 2 years)). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Aug 2025.