Contemporary Management of Complicated Monochorionic Twins

JOGNN CNE Continuing Nursing Education (CNE) Credit A total of one contact hour may be earned as CNE credit for reading “Contemporary Management of Complicated Monochorionic Twins”, and for completing an online post-test and evaluation The Association of Women’s Health, Obstetric, and Neonatal Nurses (AWHONN) is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center’s Commission on Accrditation. AWHONN holds a California BRN number, California CNE Provider #CEP580

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Contemporary Management of Complicated Monochorionic Twins Karen Y. Moise, Lisa Kugler, and Tyra Jones

ABSTRACT Monochorionic twins are at increased risk for unique complications including twin–twin transfusion syndrome (TTTS), selective intrauterine growth restriction (sIUGR), and twin-reversed arterial perfusion (TRAP) sequence. Twin–twin transfusion syndrome is treated with laser photocoagulation whereas selective reduction is an option in previable sIUGR or TRAP sequence. The nurse is integral in the management, education, care and support of women with complicated pregnancies.

JOGNN, 00, 1-13; 2012. DOI: 10.1111/j.1552-6909.2012.01355.x Accepted January 2012

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Keywords twin–twin transfusion syndrome TTTS monochorionic twins twin-reversed arterial perfusion sequence TRAP acardiac twinning selective IUGR laser photocoagulation bipolar cord coagulation BCC radiofrequency ablation RFA Correspondence Karen Y. Moise, RN, 6410 Fannin Street, The Texas Fetal Center, University of Texas Health Science Center, Children’s Memorial Hermann Hospital, Houston, TX 77030. [email protected] The authors and planners for this activity report no conflict of interest or relevant financial relationships. The article includes no discussion of off-label drug or devise use. No commercial support was received for this educational activity. Karen Y. Moise, RN, is clinical coordinator of the Texas Fetal Center, University of Texas Health Science Center, Children’s Memorial Hermann Hospital, Houston, TX. (Continued)

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he incidence of twin pregnancies continues to rise in the United States. Data from the Centers for Disease Control and Prevention (CDC) indicate that the incidence was 32.2 per 1,000 live births in 2007 (Martin et al., 2010). The increased use of assisted reproductive technologies (ART) and the fact that women are delaying childbearing have contributed to this rising trend (Little, 2010). The greatest impact of multiple gestations is their contribution to the overall rate of perinatal morbidity in the United States (Norwitz, Edusa, & Park, 2005). Monochorionic pregnancies account for only 20% of spontaneous twin gestations but are associated with a much higher rate of perinatal complications than dichorionic twins or singleton pregnancies (Lewi, Jacques, et al., 2008). By understanding the pathophysiology, diagnosis, and management of the complications that may occur in monozygotic (MZ) twins, care providers will be better equipped to care, educate, and support women with twin pregnancies and their families.

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The Origin of Twins Twins that develop from two zygotes (each fetus develops from a separate egg and sperm) are called dizygotic (DZ) or fraternal twins. Twins that develop from one zygote (the fertilized egg splits early in pregnancy and develops into two fetuses) are monozygotic (MZ). Assisted reproductive technologies such as assisted zygote hatching and intracytoplasmic sperm injection (ICSI) have resulted in increased monozygotic twinning by as much as eightfold (Saito, Tsutsumi, Noda, Ibuki, & Hiroi, 2000). Monozygotic pregnancies account for only 30% of spontaneously conceived twins (Bebbington et al., 2010). In MZ twins the timing of the twinning process determines the type of placenta and membranes that develop. If the embryo divides during the first 3 days of development, dichorionic/diamniotic (DC/DA) twins may result. This phenomenon occurs in about 25% to 30% of MZ twins. Division of the embryo between 4 to 8 days of development results in MZ twins that are monochorionic/diamniotic (MC/DA)

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Early ultrasound determination of chorionicity in a twin gestation is important for risk stratification.

resulting in a single, shared placenta with each twin having its own amnion (inner membrane) but surrounded by one chorion (outer membrane). The incidence of MC/DA twins occurs in about 75% of MZ twins. Zygotic division that occurs later than the first week results in monochorionic/monoamniotic (MC/MA) twins. Figure 1. Evidence of different membrane thickness in a

Diagnostic Criteria of Twins Modern management of a twin gestation involves the diagnosis of chorionicity. Chorionicity is the examination of the chorion, the outer fetal membranes. Diagnosis of chorionicity early in gestation is important so that different risk assessments can be assigned to the pregnancy. Current joint guidelines from the American College of Radiology and the American Institute of Ultrasound in Medicine recommend that chorionicity be determined and documented in all multiple gestations (American Institute of Ultrasound in Medicine, 2008). Chorionicity should be determined at the time of a late first trimester ultrasound (10–13 weeks gestation) (Shetty & Smith, 2005). The presence of placental tissue between the layers of the intervening twin membrane near the placenta is indicative of a dichorionic/diamniotic gestation. This ultrasound finding is known as the “lambda” or “twin peak” sign. The absence of intervening placental tissue between the membranes is known as a “T sign” and indicates the presence of a single chorion, a monochorionic/diamniotic twin gestation.

Tyra Jones, MSN, CRNP, RNC, is a women’s health nurse practitioner at the Center for Fetal Diagnosis and Treatment, Children’s Hospital of Philadelphia, Philadelphia, PA.

During the second trimester, it is much more difficult to determine chorionicity by ultrasound (Carroll et al., 2002). If there is no first trimester ultrasound, the presence of an intertwin membrane is first confirmed. Then fetal gender is determined, and dichorionicity is assumed if a male and female fetus are present. The presence of two separate placental masses also confirms dichorionicity. Finally, the thickness of the intervening membrane can be used if the twins are like sex and there is a single placenta mass. A membrane thickness of < 2 mm suggests a monochorionic gestation, whereas > 2 mm suggests dichorionicity (see Figure 1). Once monochorionicity of a twin gestation is established in the first trimester, a first trimester ultrasound at 11 to 14 weeks gestation is performed for aneuploidy risk assessment. A

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Lisa Kugler MSN, CNM, is a certified nurse midwife in the Special Delivery Unit, Children’s Hospital of Philadelphia, Philadelphia, PA.

triplet pregnancy. The small white arrow on the left points to a thicker intertwin membrane that is dichorionic/diamniotic. The larger white arrow on the right points to the thin monochorionic/diamniotic membrane.

limited ultrasound is generally done at 16 weeks gestation to assess for discordance in fetal size and amniotic fluid volumes (Lewi, Lewi, et al., 2008). As a group, twins contribute disproportionately to the overall perinatal morbidity and mortality rate, with MC/DA twins demonstrating higher mortality rates than DC/DA twins (Bebbington et al., 2010). In complex monochorionic pregnancies where fetuses share a single placenta, the death of one of the fetuses has significant implications for the surviving cotwin. Intertwin placental vascular anastomoses allow transfer of blood from the surviving twin to the dead cotwin allowing for periods of hypoperfusion, hypotension, and acute anemia. Consequences include death of the co-twin or survival with cerebral impairment. Ong, Zamora, Khan, and Kilby (2006) reported the odds of monochorionic twin death following single-twin death after 20 weeks gestation to be 6 times higher than for dichorionic survivors. They also reported the odds of neurological abnormality in monochorionic survivors following single-twin death to be 4 times higher than dichorionic survivors (Ong et al., 2006).

Twin–Twin Transfusion Syndrome (TTTS) Twin–Twin transfusion syndrome is a complication of monochorionic twins resulting from vascular connections (anastomoses) within the single, monochorionic placenta that complicates 1 in 40 to 65 twin pregnancies with approximately 2,500 cases occurring in the United States each year. Approximately 9% to 15% of MC/DA twin

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Table 1: Physiology of Twin–Twin Transfusion Syndrome Recipient

Hypervolemic, polyuric →hypertrophic cardiomyopathy, polyhydramnios →hydrops (heart failure) resulting in fetal death, prelabor rupture of the membranes (PROM), or preterm labor (PTL)

Donor

The death of one monochorionic twin poses a significant risk to the other.

Anemic, hypovolemic, oliguric →renin-angiotensin system activated →increased tubular reabsorption →oliguria →oligohydramnios (stuck twin)

in TTTS. By contrast, bidirectional or paired AA anastomoses are likely protective of such an unequal distribution of blood; in fact, if sufficient numbers of AA anastomoses are present in a placenta with AV anastomoses, they may compensate for the AV-mediated intertwin transfusion and prevent morbidity. Likewise, VV anastomoses may help to protect twins from TTTS but to a lesser extent, as the lower pressure differential present in the venous system produces less of a shunting effect (Harkness & Crombleholme, 2005) (see Figure 2).

→increased angiotensin II →hypertension →increased vascular resistance →placental vascular changes (IUGR), umbilical artery Doppler changes (AEDF/REDF)

pregnancies ultimately develop TTTS (Lewi, Lewi, et al., 2008). Because monochorionic fetuses share the same placenta, vascular connections form within and on the surface of the placenta that carry blood from one fetus to the other. In the great majority of monochorionic placentas, vessels carry blood from one twin to the other without creating an imbalance of flow. In these cases, TTTS does not occur. However, if an imbalance of flow from the one twin to the other results, a reduced blood volume occurs in one fetus, subsequently referred to as the donor twin. The donor twin no longer produces urine and eventually develops oligo- or anhydramnios. An increase in blood volume to the other fetus, referred to as the recipient twin, leads to increased urine production and polyhydramnios (Bajoria, Ward, & Chatterjee, 2002). As the disease progresses, the recipient twin can no longer compensate for the increased volume. Hypertension, congestive heart failure, and eventually fetal hydrops develop if the condition is left untreated. Ultimately fetal death occurs in one or both fetuses (see Table 1). The underlying etiology of the changes associated with TTTS is three types of placental vascular anastomoses between the fetuses: artery to vein (AV), artery to artery (AA), or vein to vein (VV). Artery to vein anastomoses are thought to be the vessels primarily responsible for the movement of blood from the donor twin to the recipient twin

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Recent studies suggest that the volume shifts attributed to AV anastomoses are only partly responsible for TTTS. The renin-angiotensin system (RAS), for example, may also play a role in the pathophysiology of TTTS. At an early stage in the disease, the twins’ hemodynamic conditions (hypervolemia in the recipient twin and hypovolemia in the donor twin) result in polyuria and polyhydramnios and oliguria and oligohydramnios respectively. Mahieu-Caputo et al. (2000) found that changes in the RAS may compound these initial changes (see Figure 3). In the past, a diagnosis of twin–twin transfusion was made postnatally on discordance in neonatal birth weights and hemoglobins (Wenstrom, Tessen, Zlatnik, & Sipes, 1992). Routine secondtrimester prenatal ultrasound is now used as the primary diagnostic tool. The following ultrasound criteria are generally accepted for a diagnosis of TTTS: polyhydramnios in the amniotic fluid compartment of the larger or recipient twin, > 8 cm maximum vertical pocket at < 20 weeks gestation, or > 10 cm vertical pocket at > 20 weeks gestation. The smaller twin, or donor twin, shows evidence of oligohydramnios diagnosed as < 2 cm maximum vertical pocket. A staging classification for TTTS has been developed by Quintero et al. (1999). In Stage I, polyhydramnios occurs in the recipient twin’s sac and oligohydramnios in the donor twin, but the donor twin’s bladder is still visible. In Stage II, the donor twin’s bladder is no longer visible, and the donor twin is often described as “stuck.” In Stage III, discordant amniotic fluid persists and umbilical Doppler changes occur, such as absent/reversed umbilical artery end diastolic velocity (UAEDV), reversed flow in the ductus venosus (DV), and/or

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Figure 2. Connections in the monochorionic placenta. Image courtesy of The Children’s Hospital of Philadelphia. Reprinted with permission.

pulsatile flow in the umbilical vein (UV). In Stage IV, the presence of hydrops is found, and in Stage V either one or both of the fetuses have died. The severity of TTTS varies with the gestational age at which it is diagnosed; that is, the earlier the diagnosis, the poorer the prognosis (Crombleholme, 2003). The Quintero staging system does not account for the cardiac implications in TTTS. Investigators at The Children’s Hospital of Philadelphia (CHOP) reported a scoring system in 2007 that utilizes the addition of a cardiovascular scoring system for assessment of severity of cardiovascular disease, as cardiovascular abnormalities contribute significantly to the morbidity and mortality seen in TTTS (Rychik et al., 2007). Various scores are assigned based on the findings from fetal echocardiography (Rychik et al.). Further assessment of the severity of TTTS was based on the cumulative score and graded for severity of cardiovascular abnormality with scores of 0 to 5 for Grade I, 6 to 10 for Grade II, 11 to 15 for Grade III, and 16 to 20 for Grade IV (see Table 2). Most cases of TTTS follow a systematic progression of stages, although regression of the disease can occur in as many as 41% of Stage I cases

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(O’Donoghue, Cartwright, Galea, & Fisk, 2007). In addition, the cardiovascular score may designate severity of disease that does not correlate with the Quintero staging system (Rychik et al., 2007). Higher stages of disease are generally associated with a worse prognosis. In severe cases of TTTS left untreated, the mortality rate reaches 90% (Corsello & Piro, 2010).

Selective Intrauterine Growth Restriction (sIUGR) Growth discordance in twins is usually defined as greater than 20% difference in the estimated fetal weight (EFW) by ultrasound. In monochorionic gestations, when the EFW of the small fetus falls below the 10th percentile, sIUGR is diagnosed (Valsky, Eixarch, Martinez, Crispi, & Gratacos, 2010). This parameter is the most widely accepted diagnostic criterion. The reported prevalence of sIUGR based on an EFW below the 10th percentile is approximately 10% to 15% of MC/DA twins (Orbitus et al., 2009). Although significant weight discordance is an important criterion of sIUGR, the etiology is based on the principles of inadequate placental sharing and the presence of AA anastomoses within the monochorionic placenta (Valsky et al.). The

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Table 2: CHOP Cardiovascular Score Recipient Twin Ventricular Characteristics

Valve Function

Venous Doppler Characteristics

0

1

2 >Mild

Cardiac Enlargement

None

Mild

Vent Hypertrophy

None

Present

3

Systolic Dysfunction

None

Mild

>Mild

Tricuspid Regurgitation (TR)

None

Mild

>Mild

Mitral Regurgitation (MR)

None

Mild

>Mild

Tricuspid Valve Flow

2 Peaks

1 Peak

Mitral Valve Flow

2 Peaks

1 Peak

Ductus Venosus

All Forward

Decreased Atrial

Reversal

Contraction

Great Vessel

Umbilical Vein Pulsation

None

Present

Outflow Tracts

Pulmonary Artery

PA = Ao

PA < Ao

(PA) >Aorta (Ao)

Analysis Pulmonary Insufficiency

RV Outflow Obstruction

None

Present

Normal

Decreased

Donor Twin Umbilical Artery (UA) Doppler

Diastolic Flow

Absent or Reversed Diastolic Flow

Scoring: Mild = 0-4, Moderate = 5-9, Moderate-severe = 10-14, Severe = 15-20 From Rychik, J., Tian, Z., Bebbington, M., Xu, F., McCann, M., Mann, S., . . . Johnson, M. P. (2007). The twin-twin transfusion syndrome:Spectrum of cardiovascular abnormality and development of a cardiovascular score to assess severity of disease. American Journal of Obstetrics & Gynecology, 197(4), 392. e391–e398. Used with permission from Elsevier

AA anastomoses have a protective effect on the IUGR fetus, which receives blood from its cotwin (Valsky et al.). However, these same anastomoses may have a detrimental effect on the twins due to periods of intrauterine hemodynamic instability (Munoz-Abellana et al., 2007). This effect poses a serious risk of fetal demise and/or neurologic injury for one or both twins (Gratacos et al., 2004). Umbilical artery (UA) Doppler is an important tool for diagnosis and surveillance during a pregnancy complicated by sIUGR (Valsky et al., 2010). Researchers have shown that UA Doppler changes seen in sIUGR cannot be interpreted in the same way as in other pregnancies due to the vascular anastomoses present in a monochorionic placenta (Vanderheyden et al., 2005). Changes in UA Doppler waveforms in sIUGR are usually seen prior to 20th week of gestation, and unlike other pregnancies, these changes persist and may progress until birth (Vanderheyden et al.). To more accurately predict fetal outcomes, a classification system of three types of sIUGR was developed based on UA Doppler waveforms in

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the smaller fetus (Gratacos et al., 2007). Type I sIUGR, occurring in 29% of cases, has normal end-diastolic flow present on Doppler waveforms. These cases are associated with good outcomes and have a reported intrauterine mortality of 2% to 4% (Gratacos et al.). Doppler patterns in Type I usually do not progress to Type II, although close surveillance is required throughout the pregnancy. In most instances of Type I sIUGR, elective delivery is scheduled around 34 to 35 weeks gestation (Valsky et al., 2010). Type II occurs in 22% of cases and has continuous absent or reversed diastolic flow in the UA with severe placental discordance. The average latency time from onset of Type II sIUGR to severe fetal deterioration is 10 weeks (Vanderheyden et al., 2005). Depending on gestational age, venous Doppler waveforms and biophysical profile evaluations can be used as criteria to assess for signs of fetal deterioration and delivery prior to 30 weeks is usually indicated (Gratacos et al., 2007). Type III occurs in 49% of cases and has intermittent absent or reversed end-diastolic flow in the UA Doppler waveform. Type III sIUGR twins usually have a large arterio-arterial placental anastomoses when compared to the other two types (Gratacos et al.).

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Figure 3. Left panel: 3D reconstruction of volume of the parabiotic twin mass on ultrasound. Right panel: 3D surface rendering of a second parabiotic twin mass. Note the absence of a cranium at the top of the picture and a rudimentary right arm. Both legs are present.

Type III sIUGR also has a long latency period and delivery is recommended at 32 to 34 weeks gestation. However, a 15% incidence of unexpected fetal demise is associated with the smaller twin with a 20% chance of neurologic injury in the surviving cotwin (Gratacos et al., 2004).

Twin Reversed Arterial Perfusion (TRAP) Sequence Twin reversed arterial perfusion sequence, also known as acardiac twinning, occurs in approximately 1 in 35,000 pregnancies (Lewi, Vlencia, Gonzalez, Deprest, & Nicolaides, 2010). The cotwin, often called the pump twin, completely perfuses the parabiotic twin via abnormal vascular anastomoses between the two umbilical cords (Jelin et al., 2010). On ultrasound the parabiotic twin has an absent, rudimentary, or nonfunctioning heart. Often the parabiotic fetus is thought to represent a “vanishing twin” during a first trimester ultrasound, but the amorphic mass has increased in size at the time of a second trimester ultrasound. The parabiotic twin most commonly appears as a tumor-like mass with lower fetal extremities present and abnormal or absent structures in the upper body. Another important ultrasound Doppler finding of TRAP sequence is reversed flow in the umbilical artery of the parabiotic twin due to retrograde perfusion with deoxygenated blood from the pump twin (Figure 3). A thorough anatomical ultrasound should be performed on the pump twin to exclude abnormalities. Signs of cardiac failure in the pump

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twin may or may not be present on the initial ultrasound when TRAP sequence is diagnosed. Continued surveillance of the pump twin is necessary to monitor for polyhydramnios and signs of progressive heart failure (hydrops) due to its need to perfuse itself as well as that of the parabiotic fetus. Left untreated, fetal demise of the pump twin occurs in more than 55% of cases (Moore, Gale, & Bernirschke, 1990).

Treatment Options The management of MC twin disorders is dependent on the underlying cause and the gestational age at diagnosis. In pregnancies complicated by TTTS, treatment options are available to women, and they should be educated on the therapies available to them. These options are expectant management, serial amnioreduction, laser photocoagulation, and selective reduction. Amnioreduction uses amniocentesis to aspirate a large volume of amniotic fluid from the recipient sac, thereby controlling polyhydramnios. Attempts at amnioreduction to reduce the symptoms of polyhydramnios resulted in some increase in survival (78% at birth and 60% at 4 weeks of age); however, neurologic injury was evident in 25% of fetal survivors (Mari et al., 2001). Laser photocoagulation utilizes a fetoscope through which a laser is directed to photocoagulate the vascular anastomoses, thus interrupting the vascular communication between the twins. Selective reduction uses bipolar cord coagulation (BCC) to occlude the blood vessels in the umbilical cord of one twin (Jackson & Mele, 2009) but is reserved for

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instances of advanced cardiomyopathy in which recipient twin death is imminent (Cromblehome, 2003).

70% of cases; survival of at least one fetus occurs in 90% of cases (Chmait et al., 2011). In a 6-year follow-up study from Europe, more than 80% of survivors were free of neurologic deficits (Salomon et al., 2010).

Laser Photocoagulation Fetoscopic-guided laser photocoagulation of the placental anastomoses was first introduced by DeLia in 1990 (DeLia, Cruikshank, & Keye, 1990). Many perinatologists initially considered the therapy to be experimental. In 2004, the EuroFETUS group reported the results of a randomized, multicenter clinical trial that indicated significant improvements in overall fetal survival, gestational age at delivery and 6-month survival without neurologic problems (Senat et al., 2004). More recently, a meta-analysis supported the superiority of laser over amnioreduction (Rossi & D’Addario, 2008). Laser is now accepted around the world as the standard of care for the treatment of TTTS. In the United States, women with extreme symptoms related to extensive polyhydramnios with Stage I disease or women with Stage II to IV disease are considered candidates for therapy between 18 and 26 weeks gestation. The woman first undergoes an extensive ultrasound to determine the location of the placenta and the placental cord insertion sites and a site for entry into the uterus that is free of blood vessels. A needle, followed by a plastic cannula, is inserted into the amniotic sac of the recipient twin under continuous ultrasound guidance. A small fetoscope is introduced to visualize, locate, and map the connecting vessels between the two fetal circulations. The fetoscope is attached to a camera that allows the images of the placenta to be seen on multiple viewing screens in the operating room. Laser energy is then directed down a quartz fiber through a special channel in the fetoscope to individually coagulate each of the problem vessels. Excess amniotic fluid is drained (amnioreduction) at the end of the procedure to normalize the amount of amniotic fluid in the recipient’s sac. Potential complications associated with the above interventions may include preterm premature rupture of membranes (PPROM), preterm delivery, intrauterine fetal demise of one or both twins, and neurologic abnormalities. Infection and abruption rarely occur. In TTTS, PPROM complicates as many as 30% of laser procedures. Senat et al. (2004) reported 42% of women that underwent laser therapy delivered prior to 32 weeks gestation. In centers with laser intervention availability, survival of both fetuses occurs in approximately

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Bipolar Cord Coagulation and Radio-Frequency Ablation Selective reduction by bipolar cord coagulation (BCC) or radiofrequency ablation (RFA) (Shevell, Malone, Weintraub, Thaker, & D’Alton, 2004) is offered to women if sIUGR or TRAP sequence is detected at a gestational age prior to viability (< 24 weeks gestation) to prevent sequelae in the normal co-twin. In the pregnancy complicated by TRAP sequence, selective reduction is offered when the parabiotic twin has an estimated fetal weight (EFW) > 50% that of the pump twin (Jelin et al., 2010). In cases where the parabiotic twin is < 50% EFW of the pump twin, conservative management can be considered. In these cases, a 91% survival rate is associated with the pump twin (Jelin et al.). BCC and RFA are performed between 18 and 25 weeks gestation (Wimalasundera, 2010). In BCC, a disposable forceps connected to a standard bipolar bovie generator is used. A fetoscope is used to visualize the umbilical cord of the affected fetus. Ultrasound is then used to direct the forceps to that umbilical cord. Once the cord is grasped and flow through the cord is occluded by closing the forceps, bipolar energy is used to coagulate the cord. The cord is coagulated in three different adjacent areas for up to 60 seconds each (Wimalasundera). Color flow Doppler ultrasound is used to ensure that blood flow through the cord has ceased. Ultrasound guided RFA utilizes a 17-gauge needle that is inserted into the umbilical cord insertion site of the affected fetus’s abdomen (Moise & Johnson, 2010). The prongs in the needle are deployed, and heat energy is utilized for 2 minutes to coagulate the blood vessels in the umbilical cord. A 1-minute cooling cycle is allowed to prevent possible injury to the co-twin (Paramasivam et al., 2010). The cycles of heating and cooling are alternated until cessation of blood flow occurs. In the study conducted by Paramasivam et al., two or three cycles were required to confirm cessation of flow. In the treatment of sIUGR and TRAP sequence, PPROM rates for BCC and RFA cases are approximately 28% (Bebbington, Danzer, Moldenhauer,

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Khalek, & Johnson, 2012). If delivery occurs after 28 weeks gestation no difference exists in the survival rate between RFA or BCC (Bebbington et al.). Fifty-six percent of women undergoing BCC deliver prior to 34 weeks gestation as compared to 42% for RFA cases (Bebbington et al.). Bebbinton et al. conducted a 14-year single center study and reported the risk of death to the co-twin after selective reduction was approximately 6.7% in women undergoing BCC versus 15.5% with RFA.

Maternal Management When a diagnosis of MC/DA complication is noted on a prenatal ultrasound, the woman and her family may be referred for an evaluation at a fetal treatment center. Initial evaluation at the fetal center should include a detailed fetal ultrasound to confirm the diagnosis and assess for additional anomalies in each fetus and a fetal echocardiogram of both fetuses to assess cardiac status. After the woman has completed the imaging studies, the perinatologist, nurse, and other members of the health care team meet with her and her family to discuss the diagnosis, management options, and available interventions. An amniocentesis may be recommended if not previously obtained because a slightly higher rate of chromosomal abnormalities are associated with monochorionic pregnancies. The amniocentesis can be performed at the time of the procedure if one is indicated. Women who decide to undergo fetal therapy undergo a multidisciplinary preoperative process. A surgical history and physical are performed by an advance practice nurse (APN), and routine laboratory studies are collected to assess for maternal medical concerns. The APN reviews the procedure, preoperative and postoperative care, and provides an opportunity for the woman and her family to ask questions. Preoperative instructions are provided, and a tour of the surgical unit offered. This meeting is also a chance for the nurse to begin a discussion addressing any feelings the woman and her family have regarding the loss of one and possibly both twins. An anesthesiologist meets with the woman to review her history, ensure she has no contraindications to a surgical procedure, and review the plan for intraoperative pain control with intravenous sedation. A social worker meets with the woman and her family to assist with lodging arrangements if temporary relocation is required to be near the fetal center. They also provide anticipatory guid-

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ance for any financial and child care concerns the family may have due to being away from home. Additionally, the social worker is available to support the woman and her family with any additional psychosocial needs they may have. Preoperatively, oral indomethacin is administered to decrease uterine irritability during the procedure (Roman et al., 2010). A broad-spectrum antibiotic is administered as prophylaxis prior to the procedure. The perioperative nurse provides emotional support to reduce the woman’s anxiety in the operating room, including education about intraoperative procedures (e.g., application of sequential compression boots for deep vein thrombus prophylaxis and positioning in lateral tilt position) that occur prior to the start of surgery. The nurse ensures safety in the operating room by checking for properly functioning equipment, correct documentation, and adherence to proper procedures. The perioperative nurse is an advocate for the woman and ensures the operating room environment is respectful and considerate of the woman’s feelings related to the impending or potential loss of one of her fetuses. After the procedure, the woman receives standard postoperative nursing care, including assessment of uterine contractions, vaginal bleeding, and leaking of amniotic fluid. Acetaminophen is usually sufficient to provide adequate pain relief for any discomfort the woman may experience at the insertion site. The pain management regimen is modified as needed based on the individual’s level of discomfort. Because these procedures are usually all performed under IV sedation, women are able to tolerate a regular diet and ambulate shortly after the recovery period. All women who remain hospitalized overnight have a fetal ultrasound the morning after surgery to assess viability, amniotic fluid volumes, evidence of chorioamniotic membrane separation and the presence or absence of visible bladders in the fetuses. At some fetal centers, women also have a follow-up fetal echocardiogram prior to discharge. Prior to leaving the hospital, the nurse reviews the discharge instructions, including decreased activity and pelvic rest. Although no research to date validates decreased maternal activity lowers the incidence of premature labor and delivery, many fetal surgery centers recommend a reduction of the woman’s normal activity for the first 4 weeks following the procedure. An ultrasound at the fetal center is scheduled for one week following the procedure. If there are no complications at this

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time the woman is discharged to the care of the referring physician.

The nurse is integral in the management, education, care and support of women with complicated pregnancies.

Perinatal Management Monochorionic twins are at increased risk for unexplained loss late in gestation (Hack et al., 2008). At present, antenatal fetal testing is recommended in twin pregnancies, but it is not known at which exact gestational age testing should be initiated. Often, antenatal testing for a twin pregnancy begins at 32 weeks gestation. Amniotic fluid volumes and UA Doppler studies should be alternated with complete fetal growth assessments for the remainder of the pregnancy. Maternal nutrition is critical for fetal development. Counseling for these women should include a discussion on increased calories, vitamins, iron, and protein in their diet. The 2009 Institute of Medicine guidelines recommend a weight gain of 37 to 54 pounds for a body mass index within the normal range (Fox et al., 2010). The increased incidence of gestational diabetes and hypertension in twin pregnancies calls for screening and monitoring for these complications at each prenatal visit. The role of the nurse is to assess the woman at each visit and review with her the signs and symptoms to report. As previously discussed, these women have increased risk for preterm delivery. Preterm labor symptoms should be carefully reviewed with the woman at each of her visits. Physical discomforts (e.g., backache, varicose veins, fatigue) are exacerbated in women with twin pregnancies and must be addressed by the nurse. Because most of these pregnancies result in cesarean birth, the nurse also initiates a discussion with the woman and the family on what to expect.

Nursing Considerations It is important for nurses caring for these women to address their psychological needs. The financial responsibilities can be overwhelming to families, especially in instances where the woman has had to stop work early, and nurses may be able to help the family identify resources. A complicated twin pregnancy affects a family’s ability to cope and deal with other children in the family. Monochorionic twins may be delivered at a tertiary care facility where special resources such as child life specialists are available. These resources help the family and their children to deal with the changing family dynamics. Centers specializing in fetal care may potentially have improved outcomes based on the collaborative approach they use in deal-

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ing with families with complicated pregnancies (Besuner & Imhoff, 2007).

Bereavement Families that experience perinatal loss due to the death of one or both fetuses endure a unique form of grieving (Callister, 2006). The woman and her family may continue to experience anxiety, grief, and loss throughout the pregnancy, and these feelings may be magnified closer to the time of the birth. Nurses encounter these families at all stages of their pregnancies, can assess emotional well-being, and can offer sensitive communication. This process begins during the initial counseling session at the fetal treatment center and continues through the postpartum period (Sumner, Kavanaugh, & Moro, 2006). Nurses provide anticipatory guidance to the woman and her family regarding what to expect from specific procedures performed during the pregnancy. For example, for women who have undergone selective reduction, it is not unusual to deliver the live twin first and then the fetus papyraceous (mummified compressed fetus of the twin that was reduced). The woman and her family often have varied emotions including guilt, relief, anger, sense of failure, and worry (Callister). For mothers who have lost one twin, to avoid additional feelings of distress it is best to continue to refer to the pregnancy as a twin pregnancy (Jackson & Mele, 2009). The nurse caring for families experiencing bereavement needs to recognize that the experience of grief often differs between fathers and mothers, and children should not be forgotten (Callister). Nurses must consider the diverse cultural responses that the woman and her family may have to perinatal loss. Offering families the opportunity to contact their religious community at home or in the hospital may be a comfort. Other resources that may be beneficial include social work and behavioral health services. Providing families with mementos to create lasting memories and validate loss after the death of one or both of the fetuses helps to facilitate healthy grieving (Munson & Leuthner, 2007). The type of mementos offered is dependent on the condition of the deceased fetus(es) at the time of birth. Families should be permitted to take photographs if they desire and should be given as much time to spend with their fetus(es) as they need.

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Management of Complicated Monochorionic Twins

CNE http://JournalsCNE.awhonn.org lar cord coagulation (BCC) in the management of complex

Table 3: Select Resources for Families

monochorionic pregnancies: A 14-year single center experience. Ultrasound in Obstetrics & Gynecology, Feb 3. doi:

1. Twin to Twin Transfusion Syndrome Foundation, http://www.tttsfoundation.org 2. UK Twin to Twin Transfusion Syndrome Association, http://www.twin2twin.org

10.1002/uog.11122. [Epub ahead of print]. Bebbington, M. W., Tiblad, E. Huesler-Charles, M., Wilson, R. D., Mann, S. E., & Johnson, M. P. (2010). Outcomes in a cohort of patients with Stage I twin-to-twin transfusion syndrome. Ultrasound in Obstetrics & Gynecology, 36, 48–51.

3. Fetal Hope Foundation, http://www.fetalhope.org

Besuner, P., & Imhoff, S. (2007). The fetal patient: Coordinated care for

4. The Center for Fetal Diagnosis and Treatment at The

Callister, L. C. (2006). Perinatal loss: A family perspective. Journal of

families. Newborn & Infant Nursing Reviews, 7(4), 211–215.

Children’s Hospital of Philadelphia, http://www.fetalsurgery.chop.edu

Perinatal & Neonatal Nursing, 20(3), 227–234. Carroll, S. G., Soothill, P. W., Abdel-Fattah, S. A., Porter, H., Montague, I., & Kyle, P. M. (2002). Prediction of chorionicity in twin preg-

5. The Fetal Treatment Center, University of California, San Francisco, http://www.fetus.ucsfmedicalcenter.org/ twin/twin_twin_transfusion.asp

nancies at 10–14 weeks of gestation. BJOG: An International Journal of Obstetrics & Gynaecology, 109(2), 182–186. Chmait, R. H., Kontopoulos, E. V., Korst, L. M., Llanes, A., Petisco, I., & Quintero, R. A. (2011). Stage-based outcomes of 682

6. Fetal Care Center at Cincinnati, http://www.fetalcarecenter .org 7. Texas Fetal Center, http://www.texasfetalcenter.org

consecutive cases of twin-twin transfusion syndrome treated with laser surgery: The USFetus experience. American Journal of Obstetrics & Gynecology. 204(5), 393.e1–e6. doi:S00029378(11)00164-5 [pii]10.1016/j.ajog.2011.02.001. Corsello, G., & Piro, E. (2010). The world of twins: An update. Journal of Maternal-Fetal & Neonatal Medicine, 23(S3), 59–62.

Support groups that families can attend or visit online can also be helpful. See Table 3 for additional resources for families.

Crombleholme, T. M. (2003). The treatment of twin-twin transfusion syndrome. Seminars in Pediatric Surgery, 12(3), 175–181. De Lia, J. E., Cruikshank, D. P., & Keye, W. R., Jr. (1990). Fetoscopic neodymium: YAG laser occlusion of placental vessels in severe twin-twin transfusion syndrome. Obstetrics & Gynecology, 75(6),

Conclusion Monochorionic twins are at significant risk for unique complications not seen in singletons or dichorionic twins. Early diagnosis of complications provides an opportunity for families to explore available treatment options. Nurses have the opportunity to work collaboratively with other health care providers to educate, coordinate and care for women and their families’ physical and emotional well-being.

1046–1053. Fox, N. S., Rebarber, A., Roman, A. S., Klauser, C. K., Peress, D., & Saltzman, D. H. (2010). Weight gain in twin pregnancies and adverse outcomes: Examining the 2009 Institute of Medicine guidelines. Obstetrics & Gynecology, 116(1), 100–106. Gratacos, E., Carreras, E., Becker, J., Lewis, L., Enriquez, G., Perapoch, J., . . . Deprest, J. (2004). Prevalence of neurological damage in monochorionic twins with selective intrauterine growth restriction and intermittent absent or reversed enddiastolic umbilical artery flow. Ultrasound in Obstetrics & Gynecology, 24, 159–163. Gratacos, E., Lewi, L., Munoz, B., Acosta-Rojas, R., Hernandez-

With the increase in multifetal gestations and the expanding use of effective fetal interventions, research is needed to address the long-term neurologic outcomes for monochorionic twin(s) that have undergone in-utero procedures as well as the long-term impact on their cardiovascular health. In addition, research is needed regarding the behavioral health implications on the women and their families around perinatal loss.

Andrade, E., Martinez, J. M., . . . Deprest, J. (2007). A classification system for selective intrauterine growth restriction in monochorionic pregnancies according to umbilical artery Doppler flow in the smaller twin. Ultrasound in Obstetrics & Gynecology, 30(1), 28–34. doi:10.1002/uog.4046. Hack, K. E., Derks, J. B., Elias, S. G., Franx, A., Roos, E. J., Voerman, S. K., . . . Visser, G. H. (2008). Increased perinatal mortality and morbidity in monochorionic versus dichorionic twin pregnancies: Clinical implications of a large Dutch cohort study. BJOG: An International Journal of Obstetrics & Gynaecology, 115(1), 58– 67. doi:BJO1556 [pii] 10.1111/j.1471-0528.2007.01556.x. Harkness, U. F., & Crombleholme, T. M. (2005). Twin-twin transfusion

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CNE http://JournalsCNE.awhonn.org

Continuing Nursing Education To take the test and complete the evaluation, please visit http://JournalsCNE.awhonn.org. Certificates of completion will be issued on receipt of the completed evaluation form, application and processing fees. Note: Accredited status does not imply endorsement by the Association of Women’s Health, Obstetric, and Neonatal Nurses (AWHONN) or American Nurses Credentialing Center of any commercial products displayed or discussed in conjunction with this activity. Learning Objectives Upon completion of this activity, participants will be able to 1. Understand the significance of the early diagnosis of monochorionic twins. 2. Describe the various complications and various treatment options unique to monochorionic twins. 3. Describe the nurse’s role in caring for women with monochorionic twins.

Questions 1. Which of the following type of twins result from the division of the embryo between 4–8 days of development? a. Dichorionic, diamniotic twins b. Monochorionic, diamniotic twins c. Monochorionic, monoamniotic twins 2. What term is used to describe the ultrasound finding in the first trimester that would indicate monochorionic twins? a. Delta sign b. Lambda sign c. T sign 3. The best definition of twin–twin transfusion syndrome is based on discordance in which of the following parameters? a. Amniotic fluid measurements b. Cord hemoglobin at birth c. Estimated fetal weight by ultrasound 4. A woman presents with symptoms of extreme abdominal distention with a known twin gestation. Ultrasound reveals polyhydramnios (deepest vertical pocket of 12 cm) in one twin’s sac and a second “stuck twin” (no measureable fluid seen). A fetal bladder is not seen in the donor twin. Dopplers are normal in both twins. The proper Quintero stage assigned to this woman would be

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a. I b. II c. III 5. Which of the following type of placental anastomoses are protective of twins from twin– twin transfusion syndrome? a. Arterio-arterial (AA) b. Arterio-venous (AV) c. Veno-venous (VV) 6. The most effective treatment for twin-twin transfusion syndrome is a. amnioreduction. b. laser. c. microseptostomy. 7. What is the most common complication of fetal therapy? a. Abruption b. Infection c. Preterm premature rupture of membranes 8. What difference in estimated weight between twin fetuses would indicate intrauterine growth restriction? a. 10% b. 20% c. 30% 9. A woman with a monochorionic twin gestation presents with one twin’s estimated weight being at the 40th percentile and the second twin’s weight being at the 3rd percentile. Doppler of the umbilical cord of the smaller twin reveals intermittent absent end-diastolic flow in the umbilical artery. According to the Gratocos staging system for selective growth restriction, this case would be classified as which of the following: a. Type I b. Type II c. Type III 10. Twin-reversed arterial perfusion (TRAP) sequence can result in the death of the normal fetus due to which of the following: a. anemia. b. cardiac failure. c. entangled umbilical cords. 11. The best treatment for twin reversed arterial perfusion TRAP sequence is a. laser therapy.

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b. premature delivery. c. selective reduction of the parabiotic twin. 12. The nurse caring for a woman undergoing laser therapy is responsible for the woman’s safety in the operating room. What does she need to ensure? a. Assessment of uterine contractions b. Assessment of leaking of amniotic fluid c. Application of sequential compression boots for deep vein thrombus prophylaxis 13. Which of the following would a perinatal nurse counsel a woman pregnant with twins? a. Gestational diabetes rarely occurs in twin pregnancies b. Birth is anticipated at 40 weeks c. The need to increase consumption of calories, iron, vitamins and protein 14. At which gestational age is laser photocoagulation considered as a treatment option for twin–twin transfusion syndrome (TTTS)? a. 15–20 weeks b. 16–28 weeks c. 18–26 weeks 15. Nurses need to be cognizant that all family members who experience loss a. want mementos to commemorate the loss. b. experience loss the same. c. experience loss in their own unique ways.

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16. The CHOP Cardiovascular Score measures the a. correlation with the Quintero staging system. b. origin of disease in the newborn. c. severity of cardiovascular abnormality in the fetus. 17. The consequences of the death of one fetus in a monochorionic gestation include a. abruption. b. death of the cotwin. c. maternal infection. 18. Using the Quintero staging system, in Stage III TTTS the donor exhibits the following: a. Abnormal Dopplers b. A visible bladder c. Polyhydramnios 19. Providing mementos to families a. allows them to hold on to their loss. b. can assist them in validating their loss. c. is beneficial to all cultures. 20. Radiofrequency ablation involves a. cycles of heating and cooling. b. occlusion of the umbilical cord with forceps. c. the use of a fetoscope.

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