A stand-alone microcomputer was installed at St. Bartholomew's Hospital to obtain the booking (first prenatal) history. This system has many well-documented advantages over the manual method, particularly with respect to the completeness and quality of the history produced. However, a single microcomputer system is unable to deal with the load of a busy clinic, and initially, several independent terminals were required. We now describe the installation of a local area network to link several microcomputers with a single database in the Antenatal Clinic at Queen Charlotte's Maternity Hospital.