The woman was radicalized in 2013 and began posting and sharing pro-ISIS material online the following year, the Foreign Affairs Ministry said in a statement released Monday. Authorities said she planned to travel to Syria with her young child before being detained in June.
"She said that since 2015, she was looking for 'a Salafi or an ISIS supporter' to marry and settle down with him and her child in Syria. She said she would support her husband if he fought for ISIS in Syria as she believed she would reap 'heavenly rewards' if he died in battle," the ministry statement said.
The ministry also claimed the woman's family members learned of her radicalization in 2015 and unsuccessfully tried to convert her, but did not report it to authorities.
"The heightened terrorism threat worldwide and in Singapore makes it imperative for family members and friends to raise to the authorities anyone they suspect of being radicalised or planning terror activities," the statement said. "(The woman's) family members did not bring her to the attention of the authorities when she was younger and could have potentially been turned back from the path of radicalisation."
The woman's case is symbolic of the wave of radicalization in the region, said Emily Winterbotham, a senior research fellow at the Royal United Services Institute for Defence and Security Studies.
"Given the number of women who have traveled from other countries to Syria/Iraq, including from the West, it is unsurprising that Singapore has experienced a case of female radicalization," Winterbotham told CNN in an email. "Families have been central to the creation of the Islamic State (ISIS) with a focus on creating infrastructure and society through citizens living under strict sharia law. Women have therefore been sought as citizens, to marry fighters, mother children, and propagandize."
Singapore -- and to a lesser extent Malaysia -- have been strong at preventing attacks, said Anton Alifandi, an Asia analyst on the IHS Markit Country Risk team.
"Self-radicalization is the threat we're likely to see in places like Singapore and Malaysia where the government has strict control and close monitoring of social media activity," he told CNN. "I wouldn't emphasize gender so much."
The news comes as ISIS is making a push in Southeast Asia
, including a bloody campaign in the southern Philippines in which more than 50 troops and 100 civilians have been killed.
About 1,000 people are still trapped in the city of Marawi and it's expected to be at least two weeks before the city is cleared, Philippines authorities said.
Three police officers were killed in May
when a suicide bomber targeted a bus stop in nearby Indonesia, the world's most populous Muslim country.
Both the Philippines and Indonesia have been fighting attempts by Islamist militant groups to carry out attacks and stage insurgencies.