Pulsatility Index of the Middle Cerebral Artery in Normal Fetuses
Ratana Komwilaisak MD*, Piyamas Saksiriwuttho MD*, Thawalwong Ratanasiri MD*, Pilaiwan Kleebkaow MD*, Kanok Seejorn MD*
Affiliation : * Department of Obstetrics and Gynecology, Faculty of Medicine, Khon Kaen University
Objective : To establish the reference ranges of the middle cerebral artery pulsatility index ( MCA PI ) in
normal fetuses between 20 and 37 weeks gestation.
Study
Design : A descriptive study.
Setting : Antenatal Care Clinic, Outpatient department, Faculty of Medicine, Srinagarind Hospital, Khon
Kaen University.
Subjects : At least sixteen women of each gestational age with an uncomplicated singleton pregnancy
between 20 and 37 weeks gestation.
Method : All recruited pregnant women were enrolled for abdominal Doppler ultrasonography to determine
fetal MCA PI for each week of gestational age.
Main outcome measures : The MCA PI reference range for normal fetuses between 20 and 37 completed
weeks of gestation.
Results : The MCA PI decreased as gestational age advanced from 1.97 (SD 0.48) at 20 weeks to 1.15 (SD
0.18) at 37 weeks.
Conclusion : We established the reference ranges of the fetal MCA PI for reference use in our Antenatal Care
Clinic.
Keywords : Pulsatility index, Middle cerebral artery, Doppler ultrasound
