The value of umbilical artery Doppler velocimetry in the antenatal surveillance of uncomplicated monochorionic twin pregnancies

Predicting Adverse Outcomes in Monochorionic-Diamniotic Twins: The Role of Intertwin Discrepancy in Middle Cerebral Artery Doppler Measurements and the Cerebroplacental Ratio

OBJECTIVE

This study was aimed to evaluate the role of intertwin discrepancy in middle cerebral artery peak systolic velocity (MCA-PSV) and cerebroplacental ratio (CPR) for the prediction of adverse outcomes in monochorionic-diamniotic (MCDA) twin pregnancies.

STUDY DESIGN

A retrospective cohort study of MCDA pregnancies that underwent ultrasound surveillance at a perinatal referral center from 2007 to 2017. Intertwin MCA-PSV discrepancy (MCA-Δ_PSV-MoM) was defined as the absolute difference of MCA-PSV multiple of the median (MoM) for gestational age between twins. Intertwin CPR discrepancy (CPR-Δ) was defined as the absolute difference of CPR between twins. The maximum MCA-Δ_PSV-MoM and CPR-Δ before and after 26 weeks of gestation were assessed as predictors of pregnancy and neonatal outcomes through simple logistic regression models and Pearson's correlation coefficients. Receiver operating characteristic (ROC) curves were generated to determine the predictive value of maximum MCA-Δ_PSV-MoM and CPR-Δ.

RESULTS

A total of 143 MCDA pregnancies met inclusion criteria. There was a significant association between MCA-Δ_PSV-MoM at <26 weeks and the development of twin anemia-polycythemia sequence (TAPS; p = 0.007), intrauterine fetal demise (IUFD; p = 0.009), and neonatal intensive care unit (NICU) admission (p < 0.05). MCA-Δ_PSV-MoM at ≥26 weeks was associated with the development of TAPS (p < 0.001). CPR-Δ at <26 weeks was associated with the development of twin-twin transfusion syndrome (TTTS; p = 0.03) and NICU admission (p = 0.02). MCA-Δ_PSV-MoM at ≥26 weeks was highly predictive of TAPS (area under curve [AUC] = 0.92). A cut-off of 0.44 would identify TAPS with 100% sensitivity and 73% specificity.

CONCLUSION

In MCDA pregnancies, intertwin MCA and CPR discrepancies are associated with adverse pregnancy and neonatal outcomes, including TAPS, TTTS, IUFD, and NICU admission. Evaluation of intertwin MCA and CPR differences demonstrated the potential for clinical predictive utility in the surveillance of MCDA twin pregnancies.

KEY POINTS

· Intertwin discrepancy of MCA-PSV and CPR is associated with adverse pregnancy outcomes.. · Intertwin differences in Doppler ultrasound may occur prior to meeting diagnostic criteria for TTTS or TAPS.. · There is potential clinical predictive utility in MCA and CPR surveillance of MCDA twin pregnancies..

Do Doppler studies enhance surveillance of uncomplicated monochorionic diamniotic twins?

OBJECTIVES

To determine whether isolated abnormal Doppler indices before 28 weeks predict adverse pregnancy outcomes in uncomplicated monochorionic diamniotic (MCDA) twins.

METHODS

A retrospective cohort study of MCDA twin pregnancies receiving antenatal testing at a single center between 2007 and 2013 was conducted. Sonographic surveillance, including Doppler velocimetric studies of the umbilical artery, ductus venosus, and middle cerebral artery of each twin, was initiated by 28 weeks and repeated at least every 2 weeks. All pregnancies were deemed "uncomplicated" at initial sonography, without evidence of polyhydramnios, oligohydramnios, intrauterine growth restriction, twin growth discordance of at least 20%, structural or chromosomal anomalies, or unclear chorionicity. Pregnancies were divided into 2 groups: those with isolated Doppler abnormalities before 28 weeks and those with normal Doppler indices. The primary outcome was a composite including twin-twin transfusion syndrome, intrauterine growth restriction of more than 1 twin, growth discordance of at least 20%, preterm delivery before 34 weeks for fetal indications, or demise of more than 1 fetus.

RESULTS

Ninety-six patients were included, with 22 (22.9%) having isolated Doppler abnormalities before 28 weeks. The incidence of the primary outcome did not differ between groups (36.4% versus 28.4%; P = .47). The abnormal Doppler group underwent a greater number of sonographic examinations (15 versus 10; P= .001) and more antenatal admissions for fetal concerns (50.0% versus 12.2%; P < .001).

CONCLUSIONS

Isolated Doppler abnormalities are commonly encountered in uncomplicated MCDA pregnancies before 28 weeks yet are not clearly predictive of twin-specific complications. Doppler abnormalities were associated with increased sonographic surveillance and antenatal hospitalizations, suggesting an influence on physician practice patterns. Data may not support Doppler studies before 28 weeks for routine MCDA twin monitoring.

Perinatal mortality and mode of delivery in monochorionic diamniotic twin pregnancies ≥ 32 weeks of gestation: a multicentre retrospective cohort study

OBJECTIVE

To study perinatal mortality rates in a cohort of 465 monochorionic (MC) twins without twin-twin transfusion syndrome (TTS) born at 32 weeks of gestation or later since reported interauterine fetal death (IUFD) rates >32 weeks of gestations in the literature vary, leading to varying recommendations on the optimal timing of delivery, and to investigate the relation between perinatal mortality and mode of delivery.

DESIGN

Multicentre retrospective cohort study.

SETTING

Ten perinatal referral centres in the Netherlands.

POPULATION

All MC twin pregnancies without TTTS delivered at ≥ 32 weeks of gestation between January 2000 and December 2005.

METHODS

The medical records of all MC twin pregnancies without TTTS delivered at the ten perinatal referral centres in the Netherlands between January 2000 and December 2005 were reviewed.

MAIN OUTCOME MEASURES

Perinatal mortality in relation to gestational age and mode of delivery at ≥ 32 weeks of gestation.

RESULTS

After 32 weeks of gestation, five out of 930 fetuses died in utero and there were six neonatal deaths (6 per 1000 infants). In women who delivered ≥ 37 weeks, perinatal mortality was 7 per 1000 infants. Trial of labour was attempted in 376 women and was successful in 77%. There were three deaths in deliveries with a trial of labour (8 per 1000 deliveries), of which two were related to mode of delivery. Infants born by caesarean section without labour had an increased risk of neonatal morbidity and respiratory distress syndrome.

CONCLUSIONS

In MC twin pregnancies the incidence of intrauterine fetal death is low ≥ 32 weeks of gestation. Therefore, planned preterm delivery before 36 weeks does not seem to be justified. The risk of intrapartum death is also low, at least in tertiary centres.

Contemporary management of monochorionic diamniotic twins: outcomes and delivery recommendations revisited

OBJECTIVE

We sought to investigate outcomes of contemporaneously managed monochorionic diamniotic (MCDA) twins, stratified by pregnancy complication.

STUDY DESIGN

Four hundred eighteen MCDA pregnancies from 2001 through 2008 were retrospectively reviewed.

RESULTS

There were 236 ongoing pregnancies at 24 weeks' gestation. The likelihood of progressing from 24 weeks to 2 live births was 98.7% in uncomplicated pregnancies, 89.7% with twin-twin transfusion syndrome, and 100% with growth discordance, increasing at 32 weeks to 99.5%, 93.8%, and 100%, respectively. The relative risk (RR) of birth <32 weeks was significantly greater in twin-twin transfusion syndrome (RR, 4.1; 95% confidence interval, 2.7-6.1) and growth discordant (RR, 2.1; 95% confidence interval, 1.8-3.8) pregnancies than in uncomplicated pregnancies (P < .0001).

CONCLUSION

This represents one of the largest cohorts of MCDA twins. The risk of third-trimester fetal loss was low. The likelihood of both intrauterine fetal demise and preterm birth were greater in complicated pregnancies. In the absence of a clinical indication for delivery, these data do not support elective preterm delivery for prevention of intrauterine fetal demise in uncomplicated MCDA twins.