Several other people were seriously injured following the smash in Manchester on Friday night and a 19-year-old man has been arrested in connection with the incident.
The woman’s baby, who was delivered in hospital by emergency Caesarian section following the collision, continues to make “good progress”, police said.
The incident happened at the junction of Great Ancoats Street and Redhill Street at about 10.45pm.
At the time of the collision, a black cab carrying four people, including the driver, was turning from Great Ancoats Street into Redhill Street. A silver VW Golf, which was travelling along Great Ancoats Street, undertook another vehicle and collided with the taxi as it turned, police said.
The collision caused the taxi to spin on to the footpath and hit a pedestrian, trapping him between the taxi and the railings.
The 29-year-old man suffered serious injuries to his legs, pelvis and hips.
The three passengers in the rear of the taxi were all seriously injured.
The 29-year-old pregnant woman suffered a head injury and chest injuries and is underwent surgery at hospital.
A 23-year-old man suffered chest injuries and is in a serious condition and a 31-year-old woman suffered a suspected fractured shoulder and facial injuries.
The driver of the taxi suffered minor injuries to his legs.
The driver of the Golf, a 19-year-old man, was not injured during the collision.
He was arrested at the scene on suspicion of causing serious injury by dangerous driving and other driving offences and has been questioned by police.
Police Sergeant Danny Byrne, from the Serious Collision Investigation Unit, said: “This is a horrific set of circumstances in which several members of a family, including a woman who was nine months pregnant, and a pedestrian have been badly injured during a collision.
“The woman’s baby was delivered by emergency C-section at hospital and although he is making good progress, unfortunately his mother remains in a critical condition.
“We are carrying out a full investigation to establish the exact circumstances leading up to this incident and are keen to hear from anyone that saw the 51-plate silver Volkswagen Golf driving along Great Ancoats Street prior to this collision, or in the nearby area, to contact us.”