Outcome of monochorionic twin pregnancies with abnormal umbilical artery Doppler between 16 and 20 weeks of gestation

Update on Management and Outcomes of Monochorionic Twin Pregnancies

The management of multiple pregnancies complicated by monochorionicity continues to evolve as new investigations support a change in clinical practice to optimize outcomes. Monochorionic twins are at risk of unique conditions such as monoamnionicity, conjoined twinning, twin reversed arterial perfusion sequence, twin-twin transfusion syndrome, twin anemia-polycythemia sequence, unequal placental sharing with discordant twin growth or selective fetal growth restriction, and single-twin death that puts co-twins at risk of death or neurologic injury attributable to the shared placenta. Contemporary practice guidelines recommend serial ultrasonographic surveillance of monochorionic pregnancies to increase the early detection of problems and timely management decisions that may include increased surveillance, selective reduction or pregnancy termination, referral for in utero treatment, or earlier delivery than initially planned. Improvements in prenatal diagnosis and antenatal testing and advances in fetal therapy have contributed to more favorable outcomes in these complicated monochorionic gestations.

Clinical Outcome of Monochorionic Diamniotic Twins with Intrauterine Growth Restriction

OBJECTIVE

This study investigated the clinical outcome of monochorionic diamniotic (MCDA) twins with selective intrauterine growth restriction (sIUGR).

STUDY DESIGN

International Peace Maternal and Child Health Hospital of Shanghai ultrasound database was investigated to identify all MCDA delivered from January 2013 to December 2017. After identifying 43 pairs of MCDA twins with sIUGR and 282 pairs of normal MCDA twins, we compared clinical outcomes between the two groups.

RESULTS

Compared with normal twins, sIUGR fetuses had significantly shorter gestational age at delivery, smaller average birth weight of both twins, more significant intertwin difference in birth weight, lower Apgar scores, and higher intrauterine fetal demise (IUFD) rate, and smaller placental weight. The rate of abnormal umbilical cord insertions and abnormal blood flow in the ductus venosus (DV) and middle cerebral artery (MCA) is significantly higher in the sIUGR group. In addition, the subtype analysis of sIUGR groups indicated the poorest outcomes in type II with no significant difference between type I and III.

CONCLUSION

MCDA twins with sIUGR generally exhibited limited clinical outcomes than normal MCDA twins. These limitations are mainly associated with abnormal umbilical cord insertions and blood flow in the DV and MCA. Clinical outcomes differed among the three types of sIUGR, with type II having the worst prognosis and the highest IUFD rate.

KEY POINTS

· sIUGR generally exhibited limited clinical outcomes than normal MCDA twins.. · These limitations are mainly associated with blood flow of the DV and MCA.. · sIUGR with type II has the worst prognosis and the highest IUFD rate..

Outcome of monochorionic diamniotic twin pregnancy with selective intrauterine growth restriction, a single center study in China

INTRODUCTION

This retrospective study aimed to evaluate clinical outcomes of monochorionic diamniotic (MCDA) twins with selective intrauterine growth restriction (sIUGR).

MATERIALS AND METHODS

MCDA twins, either sIUGR and non-sIUGR, underwent expectant management from 2016 to 2019 in our hospital were included. sIUGR fetuses were classified into three types according to umbilical artery Doppler assessment. Non-sIUGR were considered as the control group. Outcomes were pregnancy outcomes and maternal complications.

RESULTS

Forty-three sIUGR (type I: 23; type II: 14, and type III: 6) and 282 non-sIUGR fetuses were included. The sIUGR group had a significantly earlier birth, lower birth weight of the twins, larger inter-twin weight difference, lower Apgar score of the twins, and higher intrauterine fetal death (IUFD) than the non-sIUGR group (all p < 0.001). The same trend was found in the sIUGR type II group compared to type I and III groups. A significantly lower gestational diabetes rate (p = 0.01) and placenta weight (p < 0.001), and higher proportions of abnormal placental umbilical cord insertion (p < 0.001), and ultrasound Doppler monitoring indicators (p = 0.006) were found in the sIUGR group than the non-sIUGR group.

CONCLUSIONS

The MCDA twins with sIUGR showed poorer outcomes than the non-sIUGR group. Doppler interrogation was a useful clinical marker for fetal outcome.

Outcome of radiofrequency ablation for selective fetal reduction before vs at or after 16 gestational weeks in complicated monochorionic pregnancy

OBJECTIVE

To investigate whether gestational age at intervention (< or ≥ 16 weeks) and other factors affect the risk of loss of the cotwin after selective fetal reduction using radiofrequency ablation (RFA) in monochorionic (MC) pregnancy.

METHODS

This was a single-center retrospective analysis of 63 consecutive RFA procedures performed at our institution from January 2011 to October 2019 for selective fetal reduction in complicated MC pregnancies. Indications for RFA were twin reversed arterial perfusion sequence (13 cases), twin-to-twin transfusion syndrome (12 cases), twin anemia-polycythemia sequence (two cases), selective fetal growth restriction (10 cases), discordant anomalies (17 cases) and multifetal pregnancy reduction in triplets or quadruplets with a MC pair (nine cases). Twenty-six (41.3%) of these procedures were performed before and 37 (58.7%) after 16 weeks. Potential factors that could affect the risk of loss of the cotwin, including gestational age at RFA, order of multiple pregnancy, amnionicity, indication for RFA and number of ablation cycles, were assessed first by univariate analysis and then by multivariate analysis.

RESULTS

There were 17 (27.0%) cotwin losses. Ablation cycles numbering four or more was the only factor among those investigated to be associated with loss of the cotwin after RFA (P = 0.035; odds ratio, 5.21), while the indication for RFA, order of multiple pregnancy, amnionicity and gestational age at RFA had no effect. Comparing RFA performed at < 16 vs ≥ 16 weeks, there was no difference in the rate of cotwin loss (23.1% vs 29.7%; P = 0.558) or preterm prelabor rupture of the membranes before 34 weeks (7.7% vs 5.4%; P = 0.853), or in the median gestational age at delivery (36.2 vs 37.3 weeks; P = 0.706).

CONCLUSIONS

RFA is a promising tool for early selective fetal reduction in MC pregnancy before 16 weeks. Four or more ablation cycles is a major risk factor for cotwin loss. Careful assessment pre- and post-RFA, together with proficient operative skills to minimize the number of ablation cycles, are the mainstay to ensure that this procedure is effective and safe. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Prevalence of umbilical artery Doppler waveform abnormality during the early second trimester and the subsequent variation of waveforms in monochorionic diamniotic twin pregnancies: A prospective cohort study

AIM

To investigate the prevalence of qualitative abnormal umbilical artery Doppler waveforms (Abnormal UA) during the early second trimester and the subsequent variation of waveforms in monochorionic diamniotic (MCDA) twin pregnancies.

METHODS

This prospective cohort study included 153 MCDA twin pregnancies. Pulsed Doppler examinations for UA were performed at four points, including the free-loop (FL) and near the placental cord insertion site (CI) of each UA, between 16 and 17 weeks' gestation. Cases were classified into positive diastolic waveforms (Type I), persistent Abnormal UA (Type II), and intermittent Abnormal UA (Type III). When the diastolic velocity in UA Doppler was positive twice after different sequential recordings, the cases were determined to have achieved normalization. Follow-up Doppler examinations of the UA were performed at 24, 28, and 32 weeks' gestation.

RESULTS

Of all 153 cases, 38 (25%; 19 Type II and 19 Type III cases) showed Abnormal UA at the first examination. Abnormal UA was detectable at FL in all selective intrauterine growth restriction (sIUGR) cases, whereas it was noted only at CI site in some non-sIUGR cases. Abnormal UA normalized in 12 (63%) Type II and 15 (79%) Type III cases.

CONCLUSIONS

A quarter of MCDA twin pregnancies in the early second trimester demonstrated Abnormal UA. In MCDA twins with Abnormal UA between 16 and 17 weeks' gestation, it is preferable to follow them up to consider the possibility of normalization of Abnormal UA as well as features of UA waveforms specific to FL and CI.

ACR Appropriateness Criteria® Multiple Gestations

Women with twin or higher-order pregnancies will typically have more ultrasound examinations than women with a singleton pregnancy. Most women will have at minimum a first trimester scan, a nuchal translucency evaluation scan, fetal anatomy scan at 18 to 22 weeks, and one or more scans in the third trimester to evaluate growth. Multiple gestations are at higher risk for preterm delivery, congenital anomalies, fetal growth restriction, placenta previa, vasa previa, and velamentous cord insertion. Chorionicity and amnionicity should be determined as early as possible when a twin pregnancy is identified to permit triage of the monochorionic group into a closer surveillance model. Screening for congenital heart disease is warranted in monochorionic twins because they have an increased rate of congenital cardiac anomalies. In addition, monochorionic twins have a higher risk of developing cardiac abnormalities in later gestation related to right ventricular outflow obstruction, in particular the subgroups with twin-twin transfusion syndrome or selective intrauterine growth restriction. Monochorionic twins have unique complications including twin-to-twin transfusion syndrome, twin embolization syndrome, and acardius, or twin-reversed arterial perfusion sequence. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Doppler abnormalities in monochorionic diamniotic twin pregnancies with discordant growth

OBJECTIVE

We studied whether abnormal umbilical artery (UA) Doppler flow velocity waveforms occur with higher frequency in monochorionic diamniotic (MCDA) twin gestations with discordant fetal growth and whether this impacted neonatal outcome.

STUDY DESIGN

We performed a retrospective study of MCDA twin pairs. We collected data from an electronic medical record. We classified pregnancies as discordant if there was at least 20% birth weight discordance. Abnormal UA Doppler velocity waveforms included absent or reversed end diastolic flow. We analyzed the data with chi square, Student's t-test and analysis of variance as appropriate.

RESULT

Seventy-three twin pairs met criteria for inclusion, including 16 with discordant growth. The discordant group was significantly more affected with twin-to-twin transfusion syndrome (TTTS) (P=0.02). The smaller fetuses in discordant pairs were more likely to display abnormal UA Doppler flow velocity waveforms (P<0.01). These neonates also had lower Apgar scores (P=0.03) and were more likely to require care in a neonatal intensive care unit. Our findings persisted after excluding pregnancies with TTTS.

CONCLUSION

In MCDA twin gestations complicated by discordant growth, there is an increased frequency of abnormal UA Doppler flow velocity waveforms in small fetuses, and these neonates face clinical challenges after birth.

Presence of an umbilical artery notch in monochorionic/monoamniotic twins

OBJECTIVE

To examine the association between an umbilical artery notch and fetal deterioration in monochorionic/monoamniotic (MC/MA) twins.

METHODS

Six MC/MA twin pregnancies were admitted at 24-28 weeks of gestation for close fetal surveillance until elective delivery at 32 weeks or earlier in the presence of signs of fetal deterioration. Ultrasound (US) examinations were performed twice weekly. The presence of cord entanglement, umbilical artery notch, abnormal Doppler parameters, a non-reassuring fetal heart rate pattern, or an abnormal fetal biophysical profile were evaluated.

RESULTS

Umbilical cord entanglement was observed on US in all pregnancies. The presence of an umbilical artery notch was noted in four out of six pregnancies and in two of them an umbilical artery notch was seen in both twins. The umbilical artery pulsatility index was normal in all fetuses. Doppler parameters of the middle cerebral artery and ductus venosus, fetal biophysical profile and fetal heart rate monitoring remained normal until delivery in all pregnancies. All neonates experienced morbidity related to prematurity; however, all were discharged home in good condition.

CONCLUSION

The presence of an umbilical artery notch and cord entanglement, without other signs of fetal deterioration, are not indicative of an adverse perinatal outcome.