Dichorionic twin pregnancy with selective fetal growth restriction: prognosis, complications and implications of Doppler abnormalities.

OBJECTIVES

To evaluate maternal and perinatal outcomes in dichorionic (DC) twin pregnancies complicated by selective fetal growth restriction (sFGR), and to investigate the occurrence of Doppler abnormalities, their natural progression during gestation and their associations with adverse outcome in these pregnancies.

METHODS

This was a retrospective study of all DC twin pregnancies that delivered between January 2011 and December 2023 at a single hospital in Hong Kong. sFGR was defined according to Delphi consensus criteria. The rates of intrauterine death (IUD), neonatal death (NND), perinatal death (PND) (sum of IUD and NND), composite neonatal morbidity, admission to the neonatal intensive care unit (NICU), 5-min Apgar score < 7 and pre-eclampsia or related conditions were compared between pregnancies with sFGR and those without. Outcomes were also compared between pregnancies with early vs late sFGR, using a cut-off of 32 weeks of gestation, and between those with vs without umbilical artery (UA) Doppler abnormality, middle cerebral artery (MCA) Doppler abnormality and oligohydramnios. The mean interval between stages of deterioration of Doppler indices was characterized.

RESULTS

Of 865 eligible DC twin pregnancies, 96 (11.1%) were diagnosed with sFGR. sFGR was associated with a higher risk of IUD (odds ratio (OR), 8.24 (95% CI, 1.64-41.40)), PND (OR, 5.53 (95% CI, 1.53-19.96)), composite neonatal morbidity (OR, 2.51 (95% CI, 1.61-3.92)), NICU admission (OR, 3.05 (95% CI, 1.96-4.74)), and pre-eclampsia or related complications (OR, 3.72 (95% CI, 2.17-6.37)). Early sFGR was associated with a higher rate of composite neonatal morbidity and Doppler abnormality in the UA and MCA. DC twin pregnancies with UA Doppler abnormality had a significantly higher risk of IUD, PND and composite neonatal morbidity. The mean intervals from normal UA pulsatility index (PI) to high UA-PI (> 95 centile), from high UA-PI to absent end-diastolic velocity (AEDF) and from AEDF to reversed end-diastolic velocity were 26.67, 9.67 and 46.67 days, respectively.

CONCLUSIONS

DC twin pregnancies with sFGR, especially those with abnormal Doppler studies, have a higher risk for adverse perinatal outcome compared to DC twins without sFGR. These findings support the management of sFGR in DC twins according to guidelines for singleton pregnancy. © 2025 International Society of Ultrasound in Obstetrics and Gynecology.