The incident occurred as she was walking to a bus stop from Punggol Secondary School, where she works as an administrator.
Her husband, who declined to be named, told The New Paper on Wednesday (Aug 29): "The wild boar suddenly attacked her from behind."
He said the attack ended only after a passing cyclist used his bike to fend off the animal, which ran away, leaving her in pain and bleeding badly from her wounds.
It was not clear if the boar, which weighs 40kg, had gored her, but her husband said she had many bite marks.
When the story broke on Tuesday night, netizens had speculated whether the woman had provoked the animal.
But her husband denied that she had provoked the animal. "She was attacked from behind."
The wild boar later entered the nearby Waterbay executive condominium, where security guards trapped it in the bin centre. It was then tranquillised and captured.
The husband said students from the school also helped his wife, who is in her 30s. She later underwent surgery at Khoo Teck Puat Hospital.
Chinese newspaper Shin Min Daily News reported that her foetus was unharmed in the attack.
The Singapore Civil Defence Force said it responded to a call for medical assistance at about 5.15pm at 51 Edgefield Plains, and the woman was conscious when taken to the hospital.
Punggol Secondary School principal Benedict Keh told TNP on Wednesday: "We have reminded our staff and students to be vigilant and watchful of their surroundings.
"We are also working with the relevant authorities to ensure (their) safety."
Waterbay's security supervisor, Mr Douglas Rabin, 44, told TNP that the wild boar charged into the bin centre where several cleaners and a security guard were resting, at about 5.30pm.
"When we shouted, they dashed out. That's when we closed the gate so it could not get out," he said.
The animal was finally subdued at about 8.10pm after the condominium management called the police and the Agri-Food and Veterinary Authority (AVA).
Mr Rabin added that the boar had smashed some items in the bin centre but no one was hurt.
Animal Concerns Research and Education Society (Acres) personnel relocated the boar to the Lorong Halus area after sedating it.
Acres said the young boar could have come from Lorong Halus, a couple of kilometres south-east of where the attack occurred.
AVA said the boar could have also come from forested areas at the end of Punggol or Coney Island. It said there has been no increase in wild boar sightings there.
Mr Ben Lee, 54, founder of nature conservation group Nature Trekker, told TNP that animals usually do not attack humans unless provoked.
He wondered if the woman might have unknowingly made a movement that the boar found threatening in the unfamiliar urban environment.
Mr Kalai Vanan Balakrishnan, Acres' deputy chief executive, said development works could have caused the boar to venture out of its comfort zone.
Mr Kalai said: "Feeding by people may have had a part to play as well."
TNP reported in 2016 that some families would feed wild boars in the Lorong Halus area.
An AVA spokesman advised the public not to approach, disturb, feed or try to catch any wildlife, including boars.
Residents in the area said they were not surprised by the appearance of a wild boar because of the loss of forested areas to development.
Some, like Mr Eric Kam, 58, were concerned about the safety of the young and the elderly.
"I'm definitely worried because this area has a lot of children. There are so many schools here," he said.