Prevalence of neurological damage in monochorionic twins with selective intrauterine growth restriction and intermittent absent or reversed end-diastolic umbilical artery flow.

OBJECTIVE

To assess the incidence of parenchymal lesions on early and late neonatal brain scans and its association with the presence or absence of intermittent absent or reversed end-diastolic umbilical artery flow velocity (A/REDV) in monochorionic twins complicated by selective intrauterine growth restriction (IUGR), as compared to dichorionic twins and monochorionic twins without selective IUGR.

METHODS

This was a prospective cohort study involving 42 monochorionic twins diagnosed with selective IUGR and managed expectantly. The presence or absence of intermittent A/REDV was recorded in all cases. This study group was compared to dichorionic twins (n = 29) and monochorionic twins without selective IUGR (n = 32) delivered at 26-34 weeks during the study period. All infants underwent an early neonatal brain scan (at or before the fourth day of postnatal life) and at least one follow-up scan during the first 28 days of postnatal life. Perinatal outcome and the incidence of neurological damage were compared between the study groups.

RESULTS

The incidence of intrauterine fetal death (IUD) and periventricular leukomalacia was significantly increased in monochorionic twins complicated with selective IUGR, as compared with the other study groups. Intermittent A/REDV was observed in 22/42 (52.4%) twin pairs, and was always present in the growth-restricted twin. The incidence of IUD (overall 9/44 (20.5%) vs. 0/40, P < 0.001; smaller twin 6/22 (27.3%) vs. 0/20, P < 0.05) and parenchymal brain damage (overall 7/35 (20.0%) vs. 2/40 (5.0%), P = 0.07; larger twin 7/19 (36.8%) vs. 1/20 (5.0%), P < 0.05) was significantly higher in pregnancies with intermittent A/REDV than in those without intermittent A/REDV. Brain damage usually occurred in the larger twin, irrespective of whether the smaller twin was liveborn or not.

CONCLUSIONS

The presence of intermittent A/REDV in monochorionic twins with selective IUGR identifies a subgroup with an elevated risk of intrauterine demise of the smaller twin and neurological damage in the larger twin; this latter finding is not restricted to cases with IUD of the cotwin.