Approximately 20% of twin pregnancies are monochorionic. The management of monochorionic twin pregnancy involves several additional interventions beyond the routine management of singletons or dichorionic twins. In 2015, the Society for Maternal–Fetal Medicine posted checklists for monochorionic/diamniotic twins and monochorionic/monoamniotic twins. The Society presents updated versions of these 2 checklists reflecting recent changes in practice recommendations. Suggestions for implementing the use of the checklists into antenatal care practices are also included.
Key words
Introduction
The incidence of twin births in the United States nearly doubled in the 3 decades between 1980 and 2009, from 18.9 to 33.3 per 1000 births.
1
Most of the increased incidence is attributable to the increased use of assisted reproductive technology and a shift toward an older maternal age.1
The incidence has remained stable at 33 to 34 per 1000 births from 2010 to 2018.2
Twin gestation, regardless of chorionicity, is associated with increased rates of maternal and perinatal complications compared with singleton gestation, including preterm birth, hypertensive disorders, gestational diabetes, fetal growth restriction, stillbirth,3
,4
and neonatal death.5
Approximately 20% of twin pregnancies are monochorionic. Compared with dichorionic twins, monochorionic twins are at even greater increased risk of stillbirth,
3
congenital fetal anomalies, preterm birth, and fetal growth restriction.5
In addition, monochorionicity carries unique risks owing to vascular anastomoses within the monochorionic placenta that can lead to complications such as twin-twin transfusion syndrome, twin anemia-polycythemia syndrome, and twin reversed arterial perfusion sequence. These complications occur in approximately 15% of monochorionic twin pregnancies.5
Monoamniotic twinning, which occurs in approximately 3% of monochorionic twins, carries a high risk of stillbirth owing to umbilical cord entanglement.6
,7
With appropriate management, some of the complications of monochorionic twin pregnancy can be prevented (eg, low-dose aspirin prophylaxis to decrease the risk of preeclampsia, early delivery to decrease the risk of stillbirth) or treated (eg, photocoagulation of intraplacental vascular anastomoses in twin-twin transfusion syndrome). Other complications can be mitigated with early diagnosis (eg, ultrasound examinations to detect congenital anomalies or growth discordance). Thus, the management of monochorionic twin pregnancy involves several additional interventions beyond the routine management of singletons or dichorionic twins. These interventions include early-pregnancy counseling about potential complications; a detailed sonographic fetal anatomy survey and fetal echocardiogram; serial sonographic surveillance to detect signs of twin-twin transfusion, hydrops, or growth discordance; antepartum fetal surveillance; and antenatal corticosteroids in preparation for planned early delivery.
5
Because of the number and complexity of extra management steps recommended for monochorionic twin pregnancy and because these steps are done at various time points throughout the pregnancy, the use of a cognitive aid such as a checklist can help reduce errors of omission.
8
In 2015, the Society for Maternal-Fetal Medicine (SMFM) posted on its Patient Safety Checklists webpage9
2 checklists for monochorionic twin pregnancy, one for monochorionic/diamniotic twins and the other for monochorionic/monoamniotic twins. SMFM presents updated versions of these 2 checklists reflecting recent changes in practice recommendations. Suggestions for implementing the use of the checklists into antenatal care practices are also included.Society for Maternal-Fetal Medicine
SMFM patient safety checklists.
SMFM patient safety checklists.
https://www.smfm.org/checklists-and-safety-bundles
Date accessed: September 24, 2020
Checklists for the Management of Monochorionic Twin Gestations
The updated checklists for monochorionic/diamniotic and monochorionic/monoamniotic twin gestations are shown in Boxes 1 and 2, respectively. The content is based largely on the American College of Obstetricians and Gynecologists’ (ACOG) Practice Bulletin No. 169 endorsed by SMFM.
5
The checklist design adheres to the guidance from A Checklist for Checklists presented by Ariadne Labs.10
Each checklist uses a sans-serif font; avoids the use of color; includes a version date; has a simple, uncluttered format; and fits on 1 page.Ariadne Labs
A checklist for checklists.
A checklist for checklists.
https://www.ariadnelabs.org/wp-content/uploads/sites/2/2019/10/checklist_for_checklists_final_10.3-1-1.pdf
Date: 2010
Date accessed: September 24, 2020
Box 1
Sample checklist for management of monochorionic/diamniotic twin pregnancy
Pregnancy Management Checklist
Monochorionic Diamniotic (MC/DA) Twin Gestation
This checklist is a sample and should be modified to fit local practice circumstances
All elements of routine prenatal care are assumed. Checklist shows additional items for MC/DA twins.
(Patient Sticker Here) or Enter:
Name ___________________________________ EDC: __________________________________
DOB ____________________________________ Planned Delivery (weeks): _______________
Record #_________________________________ Planned Delivery Date: __________________
- □Establish EDC, chorionicity, and amnionicity, preferably before 14 weeks of gestation
- □Low-dose aspirin starting at 12 to 28 weeks of gestation, optimally before 16 weeks of gestation
Counseling About Risks of MC/DA Twins. Document discussion of:
- □Fetal anomalies
- □Complications of monochorionicity, including twin-twin transfusion syndrome, twin anemia/polycythemia sequence
- □Pregnancy complications, including spontaneous preterm birth, growth restriction, preeclampsia/hypertension, gestational diabetes, and postpartum hemorrhage
- □Intrauterine fetal death including potential sequelae to a surviving co-twin
- □Option for selective termination of one twin by cord occlusion technique
Monitoring and Surveillance (specified interval and gestational ages are approximate)
- □Ultrasound at 10 to 13 weeks of gestation to evaluate nuchal translucency, size concordance
- □Serial ultrasound exam starting at 16 weeks of gestation
- □Every 2 weeks for assessment of amniotic fluid volume and bladder filling
- □Every 2 to 4 weeks for evaluation of fetal growth
- □
- □Detailed fetal anatomy survey at 18 to 22 weeks of gestation (or earlier if technically feasible)
- □Fetal echocardiogram at 18 to 22 weeks of gestation
- □Antepartum surveillance (nonstress test or biophysical profile), specify starting time and interval
Delivery Timing
- □Antenatal corticosteroids within 7 days before delivery if delivery anticipated before 34 weeks of gestation
- □Planned delivery by 37 6/7 weeks of gestation, or earlier if complications
Version: September 24, 2020
DOB, date of birth; EDC, estimated date of confinement.
Hoskins. SMFM Special Statement: Updated checklists for management of monochorionic twin pregnancy. Am J Obstet Gynecol 2020.
Box 2
Sample checklist for monochorionic/monoamniotic twin pregnancy
Pregnancy Management Checklist
Monochorionic Monoamniotic (MC/MA) Twin Gestation
This checklist is an example and should be modified to fit local practice circumstances
All elements of routine prenatal care are assumed. Checklist shows additional items for MC/MA twins.
(Patient Sticker Here) or Enter:
Name ___________________________________ EDC __________________________________
DOB ____________________________________ Planned Delivery (weeks)_______________
Record #_________________________________ Planned Delivery Date _________________
- □Establish EDC, chorionicity, and amnionicity, preferably before 14 weeks of gestation
- □Low-dose aspirin starting at 12 to 28 weeks of gestation, optimally before 16 weeks of gestation
Counseling About Risks of MC/MA Twins. Document discussion of:
- □Fetal anomalies
- □Complications of monochorionicity, including twin-twin transfusion syndrome, twin anemia/polycythemia sequence
- □Pregnancy complications, including spontaneous preterm birth, growth restriction, preeclampsia/hypertension, gestational diabetes, and postpartum hemorrhage
- □Intrauterine fetal death including potential sequelae to a surviving co-twin
- □Option for selective termination of one twin by cord occlusion technique
- □Planned antepartum surveillance regimen (inpatient vs outpatient)
- □Planned cesarean delivery; complications with early preterm delivery
Monitoring and Surveillance (specified interval and gestational ages are approximate)
- □Ultrasound at 10 to 13 weeks of gestation to evaluate nuchal translucency, size concordance
- □Serial ultrasound exam starting at 16 weeks of gestation
- □Every 2 weeks for assessment of amniotic fluid volume and bladder filling
- □Every 2 to 4 weeks for evaluation of fetal growth
- □
- □Detailed fetal anatomy survey at 18 to 22 weeks of gestation (or earlier if technically feasible)
- □Fetal echocardiogram at 18 to 22 weeks of gestation
- □Antepartum surveillance (nonstress test or biophysical profile), specify inpatient vs outpatient, starting gestational age and interval
Delivery planning
- □Antenatal corticosteroids within 7 days before anticipated delivery
- □Planned cesarean delivery at 32 0/7 to 34 0/7 weeks of gestation, or earlier if complications
Version: September 24, 2020
DOB, date of birth; EDC, estimated date of confinement.
Hoskins. SMFM Special Statement: Updated checklists for management of monochorionic twin pregnancy. Am J Obstet Gynecol 2020.
The checklists have several content updates since the 2015 versions:
- 1.“Delivery date” is replaced by “estimated date of confinement” (EDC; the date corresponding to 40 weeks of gestation) for clarity. The planned delivery date and the EDC typically differ by several weeks in monochorionic twins.
- 2.Low-dose aspirin is recommended per guidance from ACOG and SMFM.11
- 3.Serial ultrasound surveillance is recommended every 2 weeks starting at 16 weeks of gestation per guidance from the North American Fetal Therapy Network,12rather than spacing to every 2 to 3 weeks after 28 weeks of gestation.
- 4.Antenatal corticosteroids are recommended within 7 days before delivery if delivery is anticipated before 34 weeks of gestation. Delivery at 34 weeks of gestation or earlier is recommended for all monochorionic/monoamniotic twins and may be anticipated for some monochorionic/diamniotic twins if there are complications such as severe preeclampsia, fetal growth restriction, preterm labor, or rupture of membranes. If the patient has received a previous course of antenatal corticosteroids, a single repeat or “rescue” course can be considered if at least 7 days have elapsed since the initial course.13
Suggestions for Implementation
The checklists are intended to guide the antepartum care of monochorionic twin pregnancy. Thus, they are primarily intended to be used in the prenatal care clinic and not the hospital. Their purpose is to reduce the probability that prenatal care professionals will forget to perform any of the special tasks expected for the management of these complex pregnancies.
Each prenatal care practice should decide whether they want to use the checklists or whether they expect their staff to rely on training and memory to perform all the tasks listed. Lapses in care may be less likely if the checklists are used. If the practice decides to use checklists, the practice members should develop a consensus regarding several items that are discretionary. These items include the following:
- 1.Inclusion of routine umbilical artery Doppler measurements during the serial ultrasound examinations. Doppler examination of the umbilical artery has value in the staging of twin-twin transfusion syndrome14and selective fetal growth restriction,15but it is not clear whether routine Doppler exam is beneficial in uncomplicated monochorionic twins.12
- 2.Inclusion of middle cerebral artery Doppler measurements to rule out twin anemia-polycythemia sequence during the serial ultrasound examinations. The North American Fetal Therapy Network was unable to reach a consensus on this practice.12
- 3.Routine antepartum fetal surveillance (nonstress test or biophysical profile) for all monochorionic-diamniotic twins or only those with abnormal findings on routine ultrasound surveillance. If fetal growth, fluid volume, and bladder filling are all normal, there is no specific national recommendation regarding the need for, type of, or timing of surveillance.12
- 4.Routine recommendations for hospitalization of patients with monochorionic/monoamniotic twin pregnancy for intensified surveillance and, if so, at what gestational age and using what type and frequency of monitoring. Inpatient monitoring may decrease the risk of stillbirth compared with outpatient monitoring.6If outpatient monitoring is agreed upon, practice members should reach a consensus regarding the type and frequency of monitoring to be used.
- 5.Specification of different “deliver by” gestational ages than the ones we have listed based on ACOG and SMFM guidelines16(37 6/7 weeks of gestation for monochorionic/diamniotic pregnancies and 32 0/7 to 34 0/7 weeks of gestation for monochorionic/monoamniotic pregnancies). Some evidence suggests that earlier delivery may reduce the overall risk of perinatal death.6,17
- 6.Any other management issues in which variation within the practice exists.
If the practice members reach a consensus on these issues, they should modify the checklists to fit their practice.
An important point for each practice to consider is whether to have the checklist exist as a digital form in the patient’s electronic health record, a paper form in a physical chart, or simply a task list for practice members to reference without specifically including the form in the patient’s record. If a practice wants to use digital forms, then resources will need to be directed toward the development of a special module within the electronic charting system. Paper chart forms may be relatively easier to implement, but they raise additional questions. For example, does each entry need a practice member’s signature, date, and time? Where will the paper form be kept if the practice primarily uses electronic charting? If a practice decides to simply use the checklist as a reference and not include it in the patient chart, will they store a copy of the checklists where members can quickly reference it, such as a practice protocol binder or a digital reference file on each member’s computer?
Another point to consider is whether and how a checklist generated in the outpatient clinic will be made available at the hospital when the patient is admitted for antepartum hospitalization or delivery. If the clinic and hospital share a common electronic record platform, integration of the checklist into the records at both sites will be relatively straightforward but may require some technical support to accomplish. If the clinic and hospital records are not integrated, then cross-site availability of the checklist will be more challenging.
Quality Indicators
Checklists should evolve as new knowledge is gained and practice patterns change. After implementation, practice members should pay attention to any checklist items that might need to be added, revised, or corrected. If revisions are made, the version date should be edited, and copies of older versions should be discarded.
We suggest the following quality indicators to assess the effectiveness of utilization of the checklist:
- 1.Percentage of patients who started low-dose aspirin by 16 weeks of gestation.11
- 2.Percentage of patients who had fetal echocardiogram by 22 weeks of gestation.18
- 3.Percentage of patients who delivered by the suggested gestational age.16
- 4.Percentage of patients with perinatal survival of 2, 1, or 0 twins.
To address racial and ethnic disparities in perinatal outcomes, each of these indicators should be stratified by race and ethnicity.
References
- Three decades of twin births in the United States, 1980-2009.NCHS Data Brief. 2012; : 1-8
- Births: final data for 2018.Natl Vital Stat Rep. 2019; 68: 1-47
- Twin chorionicity and the risk of stillbirth.Obstet Gynecol. 2008; 111: 301-308
- Risk of late-preterm stillbirth and neonatal morbidity for monochorionic and dichorionic twins.Am J Obstet Gynecol. 2014; 210: 578.e1-578.e9
- Practice Bulletin no. 169: multifetal gestations: twin, triplet, and higher-order multifetal pregnancies.Obstet Gynecol. 2016; 128: e131-e146
- Improved perinatal survival of monoamniotic twins with intensive inpatient monitoring.Am J Obstet Gynecol. 2005; 192: 96-101
- Monoamniotic twins in contemporary practice: a single-center study of perinatal outcomes.J Matern Fetal Neonatal Med. 2010; 23: 506-510
- The development and implementation of checklists in obstetrics.Am J Obstet Gynecol. 2017; 217: B2-B6
- SMFM patient safety checklists.(Available at:)https://www.smfm.org/checklists-and-safety-bundlesDate accessed: September 24, 2020
- A checklist for checklists.(Available at:)https://www.ariadnelabs.org/wp-content/uploads/sites/2/2019/10/checklist_for_checklists_final_10.3-1-1.pdfDate: 2010Date accessed: September 24, 2020
- American College of Obstetricians and Gynecologists. Committee Opinion no. 743: low-dose aspirin use during pregnancy.Obstet Gynecol. 2018; 132: e44-e52
- The North American Fetal Therapy Network consensus statement: prenatal surveillance of uncomplicated monochorionic gestations.Obstet Gynecol. 2015; 125: 118-123
- Committee Opinion no. 713: antenatal corticosteroid therapy for fetal maturation.Obstet Gynecol. 2017; 130: e102-e109
- Staging of twin-twin transfusion syndrome.J Perinatol. 1999; 19: 550-555
- A classification system for selective intrauterine growth restriction in monochorionic pregnancies according to umbilical artery Doppler flow in the smaller twin.Ultrasound Obstet Gynecol. 2007; 30: 28-34
- American College of Obstetricians and Gynecologists. Committee Opinion no. 764: medically indicated late-preterm and early-term deliveries.Obstet Gynecol. 2019; 133: e151-e155
- Prospective risk of stillbirth and neonatal complications in twin pregnancies: systematic review and meta-analysis.BMJ. 2016; 354: i4353
- AIUM practice parameter for the performance of fetal echocardiography.J Ultrasound Med. 2020; 39: E5-E16
Article info
Publication history
Published online: August 26, 2020
Footnotes
All authors and Committee members have filed a conflict of interest disclosure delineating personal, professional, and/or business interests that might be perceived as a real or potential conflict of interest in relation to this publication. All conflicts have been resolved through a process approved by the Executive Board. The Society for Maternal-Fetal Medicine (SMFM) has neither solicited nor accepted any commercial involvement in the development of the content of this publication.
This document has undergone an internal peer review through a multilevel committee process within SMFM. This review involves critique and feedback from the SMFM Patient Safety and Quality and Document Review Committees and final approval by the SMFM Executive Committee. SMFM accepts sole responsibility for document content. SMFM publications do not undergo editorial and peer review by the American Journal of Obstetrics & Gynecology. Publications are reviewed 36 to 48 months and updates are issued as needed. Further details regarding SMFM publications can be found at www.smfm.org/publications.
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© 2020 Published by Elsevier Inc.
