SAN FRANCISCO — Uber is still working to stem its losses ahead of going public next year.

The ride-hailing company said on Wednesday that it lost $1.07 billion in the third quarter, more than in the prior period and slightly less than in the same period a year ago, as it has invested heavily outside of its core business in areas such as bicycles, scooters and freight shipments.

At the same time, Uber’s growth appears to be slowing. The company’s revenue rose 38 percent in the third quarter from a year ago to $2.95 billion, down from a gain of 51 percent in the prior quarter. Gross bookings, which is what Uber earns before paying commissions to drivers and delivery people, totaled $12.7 billion, up 34 percent from the previous year.

The report card comes as Uber is preparing for an initial public offering next year, in what would likely be one of the biggest technology offerings. The I.P.O. is set to be a litmus test for other highly valued private tech companies, such as Airbnb and Lyft, which are also considering the public markets in 2019. As a private company, Uber is not obligated to publicly report its earnings, but has made a habit of doing so.