Normative values for ultrasound measurements of the female pelvic organs throughout childhood and adolescence

Background: Normative data from pelvic ultrasonography (US) of the pediatric female reproductive organs are outdated and limited by sample size.

Objective: The purpose of this study was to report normal uterine and ovarian volumes and endometrial stripe thickness in children and young adults and throughout the menstrual cycle in post-menarchal adolescents.

Materials and methods: Females ages 0 through 20 years who underwent pelvic US between January 2010 and May 2014 were identified. After excluding patients with pelvic and/or endocrine pathology, nomograms of uterine and ovarian volumes and endometrial thickness by age year were created. Data for patients ages 12 years and older with a recorded day of last menstrual period were used to create additional nomograms of volumes/thickness throughout the menstrual cycle. Student's t-tests and linear regression were performed to assess differences in measurements between groups and association of volumes/thickness with age.

Results: During our study period, 5,647 patients underwent 6,953 pelvic US examinations. After further review, 907 examinations from 889 patients were included (mean age: 11.3±6.0 years). Mean pelvic US volumes (cm³) per organ were 25.5±27.0 (uterus), 4.5±4.7 (right ovary) and 4.0±4.1 (left ovary). Mean endometrial thickness was 4.5±3.7 mm. Right ovarian volume was significantly larger than the left (P=0.0126). Uterine volume, ovarian volume and endometrial thickness were significantly associated with age (P-values<0.0001). Plots of mean organ measurements with respect to week of menses are provided.

Conclusion: We report normal volumes of the uterus and ovaries and endometrial stripe thickness measured by pelvic US throughout childhood and adolescence with reference to the menstrual cycle. These values are significantly associated with age and vary visually by menstrual cycle week.