Ultrasonography of the uterus after normal vaginal delivery.

Objective: To define the appearance of the uterus and the uterine cavity, as revealed by ultrasound in normal women following a vaginal delivery.

Methods: This prospective, longitudinal study took place at the Prince Hashem and Prince Ali Military Hospitals, Amman, Jordan from December 2002 to March 2003. Fifty-four women were scanned on postpartum days 1, 7, 14, 28, and 56. Ultrasound examination was performed transabdominally for all women. The involution process of the uterus was assessed by measuring the anteroposterior diameter and uterine cavity. The appearance of the uterine cavity contents was documented. Factors related to the involution process: parity, breast-feeding, smoking and infant's birth weight were also evaluated.

Results: The maximum anteroposterior diameter of the uterus diminished substantially and progressively from 93 mm on day one postpartum to 38.5 mm on day 56. The maximum anteroposterior diameter of the uterine cavity diminished from 15.2 mm on day one to 4.0 mm on day 56. The position of the uterus, its shape and the appearance of its cavity during the normal puerperium were observed. The uterus was most often retroverted and empty in the early puerperium. Fluid and debris in the whole cavity were seen in mid puerperium. In late puerperium, the cavity was empty and appeared as a thin white line. No correlation was found between the involution of the uterus and parity, breast-feeding and the infant's birth weight.

Conclusion: Transabdominal sonography is suitable for examination of the uterus during the early puerperium period. The uterine body and position, as well as the cavity, are easy to examine by ultrasound. Accumulation of fluid and debris in the uterine cavity is a common and insignificant finding of the involuting uterus.