History

Fact Explanation
Twin pregnancy [1] In general, only twin gestations with monochorionic diamniotic (MCDA) placentation are at significant risk for TTTS (Twin-to-Twin Transfusion Syndrome), which complicates about 8-10% of MCDA pregnancies. TTTS is very uncommon in MZ (monozygotic) twins with dichorionic or monoamniotic placentation. The prevalence of TTTS is approximately 1-3 per 10,000 births. [1]
History of in vitro fertilization (IVF) [1] Although most twins conceived with in vitro fertilization (IVF) are dichorionic, it is important to remember that there is a 2- to 12-fold increase in MZ twinning in embryos conceived with IVF, and TTTS can therefore occur for IVF MCDA pregnancies [1]
Sudden increase in body weight / Rapid enlargement of the abdomen [2] In MCDA twins,single placenta contains blood vessel connections between the twins.Blood flow through these blood vessel connections becomes unbalanced in TTTS. The smaller twin (often called the donor twin) does not get enough blood while the larger twin (often called the recipient twin) becomes overloaded with too much blood. In an attempt to reduce its blood volume, the recipient twin will increase the urine it makes. This will eventually result in the twin having a very large bladder on ultrasound as well as too much amniotic fluid around this twin, giving rise to polyhydramnios [2]
References
  1. SIMPSON LYNN L.. Twin-twin transfusion syndrome. American Journal of Obstetrics and Gynecology [online] 2013 January, 208(1):3-18 [viewed 25 August 2014] Available from: doi:10.1016/j.ajog.2012.10.880
  2. BAUD D., WINDRIM R., VAN MIEGHEM T., KEUNEN J., SEAWARD G., RYAN G.. Twin-twin transfusion syndrome: a frequently missed diagnosis with important consequences. Ultrasound Obstet Gynecol [online] December, 44(2):205-209 [viewed 26 August 2014] Available from: doi:10.1002/uog.13328

Examination

Fact Explanation
Rapid increase in symphisio fundal height [1] Due to polyhydroamnios caused by increased urine out put In an attempt to reduce its blood volume by the recipient twin[1]
References
  1. BAUD D., WINDRIM R., VAN MIEGHEM T., KEUNEN J., SEAWARD G., RYAN G.. Twin-twin transfusion syndrome: a frequently missed diagnosis with important consequences. Ultrasound Obstet Gynecol [online] December, 44(2):205-209 [viewed 26 August 2014] Available from: doi:10.1002/uog.13328

Differential Diagnoses

Fact Explanation
Selective intra uterine growth restriction in one twin [1] fetus whose estimated weight is below the 10th percentile for its gestational age. Placental insufficiency in one of the twins, will not produce polyhydramnios in opposite twin Umbilical artery doppler studies - changes in diastolic flow [1]
References
  1. SIMPSON LYNN L.. Twin-twin transfusion syndrome. American Journal of Obstetrics and Gynecology [online] 2013 January, 208(1):3-18 [viewed 25 August 2014] Available from: doi:10.1016/j.ajog.2012.10.880

Investigations - for Diagnosis

Fact Explanation
Ultra sound scan abdomen / trans vaginal ultra sound scan[1] The diagnosis requires 2 criteria: (1) the presence of a monochorionic diamniotic (MCDA) pregnancy; and (2) the presence of oligohydramnios (defined as a maximal vertical pocket [MVP] of <2 cm) in one sac, and of polyhydramnios (a MVP of >8 cm) in the other sac (Figure 1).1 MVP of 2 cm and 8 cm represent the 5th and 95th percentiles for amniotic fluid measurements, respectively [1]
References
  1. SIMPSON LYNN L.. Twin-twin transfusion syndrome. American Journal of Obstetrics and Gynecology [online] 2013 January, 208(1):3-18 [viewed 25 August 2014] Available from: doi:10.1016/j.ajog.2012.10.880

Investigations - Fitness for Management

Fact Explanation
Ultra sound scan abdomen / trans vginal ultra sound scan [1] All women with a twin pregnancy should be offered an ultrasound examination at 10-13 weeks of gestation to assess viability, chorionicity, crown-rump length, and nuchal translucency, First- and second-trimester sonographic findings associated with twin-twin transfusion syndrome (TTTS) : First-trimester findings - Crown-rump length discordance, Nuchal translucency >95th percentile or discordance >20% between twins, Reversal or absence of ductus venosus A-wave. Second-trimester findings - Abdominal circumference discordance, Membrane folding, Velamentous placental cord insertion (donor twin), Placental echogenicity (donor portion hyperechoic) Screening by transvaginal ultrasound for short cervical length in TTTS cases has also been proposed, as this is associated with preterm birth, a known complication of TTTS [1]
Fetal echocardiography [1] To detect congenital heart disease with fetal echocardiography is warranted in all monochorionic twins as the risk of cardiac anomalies is increased 9-fold in monochorionic-diamniotic (MCDA) twins and up to 14-fold in cases of TTTS. Although many cases are minor septal defects, an increase in right ventricular outflow tract obstruction has also been reported [1]
References
  1. SIMPSON LYNN L.. Twin-twin transfusion syndrome. American Journal of Obstetrics and Gynecology [online] 2013 January, 208(1):3-18 [viewed 25 August 2014] Available from: doi:10.1016/j.ajog.2012.10.880

Investigations - Followup

Fact Explanation
Ultra sound scan abdomen [1] TTTS (Twin-to-Twin Transfusion Syndrome) usually presents in the second trimester, and is a dynamic condition that can remain stable throughout gestation, occasionally regress spontaneously, progress slowly over a number of weeks, or develop quickly within a period of days with rapid deterioration in the well-being of the twins. In monochorionic-diamniotic (MCDA) start ultra sound scan surveillance with MVP (maximal vertical pocket) in each sac and fetal bladder in each etus every 2 weekly until delivery [1]
Growth and developmental assessment [2] After discharge from hospital, the infants should be followed up in the outpatient clinic where the growth, development, and neurological sequelae should be assessed as growth and neurological imapairment may occur [2]
References
  1. SIMPSON LYNN L.. Twin-twin transfusion syndrome. American Journal of Obstetrics and Gynecology [online] 2013 January, 208(1):3-18 [viewed 25 August 2014] Available from: doi:10.1016/j.ajog.2012.10.880
  2. SENG Y C. Twin-twin transfusion syndrome: a five year review. [online] 2000 November, 83(3):168F-170 [viewed 26 August 2014] Available from: doi:10.1136/fn.83.3.F168

Investigations - Screening/Staging

Fact Explanation
Ultra sound scan abdomen / trans vaginal ultra sound scan [1] The most commonly used TTTS (Twin-to-Twin Transfusion Syndrome) staging system was developed by Quintero et al in 1999, and is based on sonographic findings. stage 1 - MVP (maximal vertical pocket) <2 cm in donor sac; MVP >8 cm in recipient sac . stage 2 - Nonvisualization of fetal bladder in donor twin over 60 min of observation stage 4 - hydrops in one or both twins stage 5 - Absent fetal cardiac activity-Fetal demise in one or both twins [1]
Umbilical artery, ductus venosus, and umbilical vein Doppler studies [1] For staging of TTTS. stage 3 - Absent or reversed umbilical artery diastolic flow, reversed ductus venosus a-wave flow, pulsatile umbilical vein flow [1]
References
  1. SIMPSON LYNN L.. Twin-twin transfusion syndrome. American Journal of Obstetrics and Gynecology [online] 2013 January, 208(1):3-18 [viewed 25 August 2014] Available from: doi:10.1016/j.ajog.2012.10.880

Management - General Measures

Fact Explanation
Conservative management [1] Expectant management involves no intervention. This natural history of TTTS (Twin-to-Twin Transfusion Syndrome) , also called conservative management, has limited outcome data according to stage, particularly for advanced disease. It is important that the limitations in the available data are discussed with the patient with TTTS, and compared with available outcome data for interventions [1]
Patient education [1] increased risk of several complications, including preterm birth, fetal demise, and cerebral injury [1] significant neonatal problems, including perinatal asphyxia, hyaline membrane disease, transient tachypnoea of the newborn, congenital pneumonia, retinopathy of prematurity, necrotising enterocolitis, patent ductus arteriosus, intraventricular haemorrhage, and congenital malformations [2]
Steroids [1] Because of the increased risk of preterm birth, 1 course of steroids for fetal maturation should be considered at 24 to 33 6/7 weeks, particularly in pregnancies complicated by stage ≥III TTTS, and those undergoing invasive interventions [1]
References
  1. SIMPSON LYNN L.. Twin-twin transfusion syndrome. American Journal of Obstetrics and Gynecology [online] 2013 January, 208(1):3-18 [viewed 25 August 2014] Available from: doi:10.1016/j.ajog.2012.10.880
  2. SENG Y C. Twin-twin transfusion syndrome: a five year review. [online] 2000 November, 83(3):168F-170 [viewed 26 August 2014] Available from: doi:10.1136/fn.83.3.F168

Management - Specific Treatments

Fact Explanation
Amnioreduction [1] Amnioreduction involves the removal of amniotic fluid from the polyhydramniotic sac of the recipient. It is usually done only when the Maximum vertical pocket (MVP) is >8 cm, with an aim to correct it to a MVP of <8 cm, often to <5 cm or <6 cm. Amnioreduction can be performed either as a 1-time procedure, as at times this can resolve stage I or II TTTS, or serially, eg, every time the MVP is >8 cm. It can be performed any time >14 weeks. Amnioreduction is hypothesized to reduce the intraamniotic and placental intravascular pressures, potentially facilitating placental blood flow, and/or to possibly reduce the incidence of preterm labor and birth related to polyhydramnios. has been associated with average survival rates of 50%. Stages I and II TTTS have been shown to regress following amnioreduction in up to 20-30% of cases, a rate that is not significantly different than with expectant management, especially for stage I. [1]
Septostomy [1] Septostomy involves intentionally puncturing with a needle the amniotic membranes between the two monochorionic-diamniotic (MCDA) sacs, theoretically allowing equilibration of amniotic fluid volume in the two sacs. In 40% of the septostomy cases, additional procedures were needed. No data on neurologic outcome are available.[1]
Fetoscopic laser photocoagulation of placental anastomoses [1] Photocoagulating the vascular anastomoses crossing from one side of the placenta to the other. Criteria for laser have included MCDA pregnancies between about 15-26 weeks with the recipient twin having MVP ≥8.0 cm at ≤20 weeks or ≥10.0 cm at >20 weeks and a distended fetal bladder, and donor twin having MVP ≤2.0 cm in 1 trial, and MCDA pregnancies at <24 weeks with the recipient twin having MVP >8 cm, and donor twin having MVP ≤2 cm and nonvisualized fetal bladder in the other. There is insufficient evidence to recommend management in MCDA pairs with TTTS in higher-order multiple gestations, but laser has been proposed as feasible and effective. Currently, fetoscopic laser photocoagulation of placental anastomoses is considered by most experts to be the best available approach for stages II, III, and IV TTTS in continuing pregnancies at <26 weeks [1]
Dogoxin [2] Treating the mother with digoxin when the recipient twin is showing signs of cardiac failure has had favourable results [2]
timing of delivery [1] There are no clinical trials regarding optimal timing of delivery for TTTS pregnancies. This depends on several factors, including disease stage and severity, progression, effect of interventions (if any), and results of antenatal testing. Recommendations regarding timing of delivery with TTTS vary, with some endorsing planned preterm delivery as early as 32-34 weeks, and others individualizing care and allowing gestation to progress to 34-37 weeks, particularly in cases of mild disease (eg, stages I and II) with reassuring surveillance. [1]
Mode of delivery [1] By Caesarean section if there are complications [1]
References
  1. SIMPSON LYNN L.. Twin-twin transfusion syndrome. American Journal of Obstetrics and Gynecology [online] 2013 January, 208(1):3-18 [viewed 25 August 2014] Available from: doi:10.1016/j.ajog.2012.10.880
  2. SENG Y C. Twin-twin transfusion syndrome: a five year review. [online] 2000 November, 83(3):168F-170 [viewed 26 August 2014] Available from: doi:10.1136/fn.83.3.F168