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Sonographic evaluation of the development of the fetal rectum and anal canal
Author(s) -
Su YiMing,
Ye Zhen,
Chen XiaoYu,
Liu XinXiu,
Chen ShuQiang
Publication year - 2011
Publication title -
journal of clinical ultrasound
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.272
H-Index - 61
eISSN - 1097-0096
pISSN - 0091-2751
DOI - 10.1002/jcu.20810
Subject(s) - rectum , medicine , anal canal , nomogram , fetus , gestational age , anatomy , pregnancy , nuclear medicine , surgery , genetics , biology
Purpose. To describe the sonographic (US) appearance of fetal anal canal and rectum and establish nomograms of their normal measurements. Methods. This was a prospective, cross‐sectional study of 524 healthy women (mean age, 27 years; range, 21–37 years) with normal singleton pregnancy between 18 and 40 weeks of gestational age (GA). High‐resolution transabdominal US was used to visualize and measure the normal fetal anal canal and rectum. Results. Satisfactory images and measurements of the fetal anal canal and rectum were obtained in 496 normal fetuses. The diameters of the normal anal canal and rectum were plotted as a function of GA in a sigmoid curve. The curve estimations were expressed by the following cubic regression equations with R 2 of 0.87 and 0.88, respectively ( p < 0.001): anal canal diameter (mm) = 18.272 − 2.151 × GA + 0.0095 × GA 2 − 0.0011 × GA 3 , and rectal diameter (mm) = 18.545 − 2.543 × GA + 0.1237 × GA 2 − 0.0016 × GA 3 . Conclusions. The fetal anal canal and rectum are visible sonographically between 18 and 40 weeks of GA. The knowledge of their normal US appearance and size from the second trimester of pregnancy onwards may help identify developmental anomalies. © 2011 Wiley Periodicals, Inc. J Clin Ultrasound, 2011