Middle cerebral artery peak systolic velocity in monochorionic and dichorionic twin pregnancies.

Abstract

OBJECTIVE:

The purpose of this study was to compare middle cerebral artery (MCA) peak systolic velocity (PSV) values in monochorionic (MC) and dichorionic (DC) twin pregnancies.

METHODS:

This was a prospective cohort study in which MCA Doppler evaluation was performed in unselected twin pregnancies at time of routine sonography between 28 and 32 weeks. Pregnancies with known fetal anomalies, twin-twin transfusion syndrome, and red cell alloimmunization or other conditions associated with anemia were excluded. The intertwin MCA PSV difference, defined as the larger minus smaller PSV value within a pair, was compared in MC and DC pregnancies and was correlated with estimated fetal weight and birth weight discordance. Statistical analyses included Spearman correlation, analysis of variance, a t test, and a chi(2) test.

RESULTS:

Doppler indices were analyzed from 48 twin pregnancies, of which 32 (67%) were DC and 16 (33%) were MC. There was no difference in proportion of values above or below the singleton median for either the larger or smaller DC or MC twins (all P > or = .3). The median intertwin MCA PSV difference was 4.9 cm/s in MC pregnancies and 4.5 cm/s in DC pregnancies (P = .6). There was no significant correlation between the MCA PSV difference and either estimated fetal weight discordance or birth weight discordance in either MC or DC pregnancies (all P > or = .3).

CONCLUSIONS:

Middle cerebral artery PSV values in uncomplicated twin pregnancies are comparable with published singleton norms, with a median intertwin MCA PSV difference of approximately 5 cm/s. We found no significant correlation between the intertwin MCA PSV difference and discordance in MC or DC twin gestations.

• Authors: Jodi S Dashe, Ronald M Ramus, Rigoberto Santos-Ramos, Donald D McIntire, Diane M Twickler
• Journal: Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine (J Ultrasound Med) Vol. 26 Issue 2 Pg. 195-200 (Feb 2007) ISSN: 0278-4297 [Print] England
• PMID: 17255181 (Publication Type: Journal Article, Twin Study)

Topics

• Adult
• Blood Flow Velocity (physiology)
• Blood Pressure (physiology)
• Female
• Humans
• Middle Cerebral Artery (diagnostic imaging, physiology)
• Pregnancy
• Prognosis
• Reproducibility of Results
• Retrospective Studies
• Sensitivity and Specificity
• Twins (physiology)
• Ultrasonography, Prenatal (methods)