A prospective cross-sectional study of fetal middle cerebral artery peak systolic velocity in a normal obstetric population attending an Indian Medical College.

Purpose: Fetal middle cerebral artery peak systolic velocity (MCA-PSV) is now an established method of noninvasive diagnosis of moderate to severe fetal anemia of different origins. This being a population-based parameter, it may have different values in individuals from different locations. A standard local reference range of normal individuals specific to each geographic locality is therefore needed.

Materials And Methods: Fetal MCA-PSV was measured in 1,015 healthy pregnant women attending the antenatal ultrasound clinic at least once between 12 and 40 weeks of gestation (35 patients per week of gestation). Statistical analysis was done using the SPSS 12 software.

Results: A positive correlation between MCA-PSV and gestational age was found. MCA-PSV was seen to increase with advancing gestational age. The Tukey-Kramer multiple comparisons test showed a normal distribution that was highly significant (p < 0.01). The multiples of median values of fetal MCA-PSV to label a fetus as severely anemic were consistently and significantly lower than internationally accepted values.

Conclusions: A normal reference range of fetal MCA-PSV for local use was thus scientifically and successfully constructed. Significant differences between local values and internationally accepted value were found.