Ductus venosus flow at 11-13 weeks in the prediction of birth weight discordance in monochorionic twins.

OBJECTIVE

To examine if assessment of ductus venosus (DV) flow, crown-rump length (CRL) and nuchal translucency (NT) thickness can predict the discordance in birth weight in monochorionic (MC) twin pregnancies resulting in two live births.

METHODS

In this prospective study, we assessed CRL, NT and DV flow at 11(+0)-13(+6) weeks' gestation in 326 MC twin pregnancies. The study population included 237 pregnancies without major abnormalities or prenatal interventions resulting in two live births. We examined the value of DV flow and discordance in NT and CRL in the prediction of discordance in birth weight.

RESULTS

In the 237 MC twin pregnancies the median discordance in birth weight was 8.0% (range 0-42.2%). There was no significant association between discordance in either CRL or NT and discordance in birth weight (P=0.116 and P=0.332). In pregnancies with abnormal DV flow in at least one of the fetuses the median discordance in birth weight was higher than in those with normal DV flow in both twins (13.2% vs. 7.8%, P=0.006).

CONCLUSIONS

In uncomplicated MC twin pregnancies, abnormal DV flow in at least one of the fetuses is associated with a higher discordance in birth weight than in those with normal flow in both fetuses.