Are fetal gender and gestational age related to the size of cisterna magna?

OBJECTIVES

The purpose of this article was to explore whether the gestational age(GA)and gender could affect the size of the cisterna magna (CM).

METHODS

This study that included pregnant women who were between 20 ∼ 39. The recorded included BPD, HC, anteroposterior diameter of CM and gender. The fetuses were divided into normal and isolated enlargement of the CM (IECM)group for statistical analysis.

RESULTS

Seven hundred ninety six fetuses with normal CM, 412 cases were boys and 384 cases were girls. 73 fetuses with IECM, 59 cases were boys and 14 cases were girls. The anteroposterior diameter of the CM increased with GA during 20-26weeks. After 27 weeks, the anteroposterior diameter of CM became stable. In the IECM group, the mean anteroposterior of male and female fetuses were 1.31 ± 0.18 cm and 1.24 ± 0.15 cm, respectively. The IECM fetus accounted for 8.4% of the total number of fetuses, male IECM accounted for 14.3% of normal male fetus, and female fetus was 3.6%, which showed that male fetus had a higher rate of IECM than female (2 = 21.6, <.001).

CONCLUSIONS

There is a gender difference between normal fetuses and IECM fetuses. Based on our finding, it is reasonable to establish the normal value of CM according to the gender difference.