The value of adding a universal booking scan to an existing protocol of routine mid-gestation ultrasound scan.

Objective: To compare 2 routine obstetric ultrasound protocols regarding number of clinically relevant events detected and total ultrasound workload.

Methods: An interventional before-and-after study comparing 2 groups of 750 consecutive low-risk pregnant women was conducted. The 1st group was routinely offered mid-trimester ultrasound and selective ultrasound examinations for specific indications; the 2nd group was, in addition to this, offered a scan at 1st prenatal visit.