What are the normal measurements of the uterus?

Normal Uterine Measurements

In reproductive-age women, the normal non-pregnant uterus measures approximately 7-9 cm in length, 4-5 cm in width, and 3-4 cm in anteroposterior diameter, with measurements varying significantly based on age, parity, and hormonal status. 1, 2

Standard Measurement Technique

Ultrasound examination must be performed systematically in at least two orthogonal planes (sagittal and transverse), tracing completely from fundus to cervix to ensure accurate assessment. 3

• Transvaginal ultrasound is the preferred approach when acceptable to the patient for optimal visualization. 3
• For transabdominal scanning, the bladder should be adequately distended to serve as an acoustic window, with the bladder dome positioned just above the uterine fundus. 3
• All three dimensions (length, width, anteroposterior diameter) and calculated volume must be recorded. 3

Age-Specific Measurements

Reproductive Age Women (15-45 years)

Nulliparous women have significantly smaller uteri than multiparous women:

• Nulliparous: 72.8 mm × 42.8 mm × 32.4 mm 2
• Multiparous: 90.8 mm × 51.7 mm × 43.0 mm 2

Uterine dimensions increase progressively with age until approximately age 40, then decrease:

• Mean length increases to 72 mm at age 40, then decreases to 42 mm by age 80. 1
• Gravidity is associated with greater uterine length, width, and AP diameter across all age groups. 1

Age-Specific Volume Changes

Postpubertal period (after menarche):

• Length: 6.8 ± 1 cm
• Volume: 33 ± 22 cm³
• Shape: Typical pear shape with corpus/cervix ratio of 2:1 4

Prepubertal period (ages 1-8 years):

• Length: 2.8 ± 0.4 cm
• Volume: 1.2 ± 0.4 cm³
• Shape: Tubular 4

Fundal Measurements

The fundal region shows progressive changes with age:

• Ages 15-24 years: Mean fundal thickness 10.8 mm (range 5.6-15.8 mm); intercornual distance 41.4 mm (range 30.6-50.7 mm) 5
• Ages 25-34 years: Mean fundal thickness 12.3 mm (range 7-18.7 mm); intercornual distance 44.5 mm (range 31.5-57.3 mm) 5
• Ages 35-45 years: Mean fundal thickness 13.6 mm (range 7.3-19.8 mm); intercornual distance 47.2 mm (range 35.2-61 mm) 5

Recent Normative Data in Nulliparous Women

The 2025 NURSE Study established precise 3D ultrasound measurements in 442 nulliparous women aged 18-35 years:

• Median fundal indentation: 1.7 mm (90th percentile: 4.8 mm) 6
• Median interostial-to-outer-contour distance: 9.1 mm 6
• Median indentation angle: 161.8° 6

These measurements provide objective criteria for distinguishing normal uterine anatomy from congenital anomalies. 6

Uterine Proportions

The length-to-width ratio follows a predictable pattern:

• At birth: 1.857 1
• At age 21: 1.618 (conforming to the classical "golden ratio") 1
• At age 91: 1.452 1
• Increasing gravidity is associated with lower mean length/width ratio. 1

Critical Documentation Requirements

The following must be documented for proper interpretation:

• Date of last menstruation, as measurements vary throughout the menstrual cycle 3
• Transducer frequency used and approach (transabdominal vs transvaginal) 3
• Endometrial thickness and appearance, noting the three-layer pattern when present 3

Common Pitfalls to Avoid

Failure to examine in two complete orthogonal planes can miss important findings such as interstitial pregnancy or fibroids located outside the central endometrial canal. 3

• Incomplete tracing from fundus to cervix may result in mistaking a large ectopic pregnancy for the uterus itself. 3
• Inadequate bladder distension significantly limits visualization quality in the transabdominal approach. 3

Clinical Context

Uterine size is significantly associated with parity and age, but not with body mass index. 2

• Knowledge of normal developmental parameters is essential for diagnosing malformations, tumors, and disorders of puberty. 4
• A fundal cleft <1 cm indicates septate uterus, while a cleft >1 cm suggests bicornuate uterus when evaluating for congenital anomalies. 7