On Facebook recently, Nyanzi rebuked First Lady Janet Museveni, who also serves as education minister, for saying the government had no money to buy sanitary towels for poor schoolgirls.
Many Ugandan girls are reported to drop out of school because of the shame they feel for lacking sanitary pads.
Nyanzi was arrested over the weekend and charged with "cyber harassment" and "offensive communication" under Ugandan law governing computer misuse.
However, Janet Museveni said in February the government did not have "the funding for this in our budget yet". Her most recent campaign over the last few months has been to provide free sanitary pads to Ugandan schoolgirls.
Nyanzi is popular on Facebook for her relentless criticism of Museveni, who has ruled since 1986 and who is increasingly accused of planning to rule this East African country for life.
"Dr Stella Nyanzi underwent the normal medical check-up [that] all other prisoners go through; nothing special", said the spokesperson of Uganda Prisons, Frank Baine.
The news of her arrest Friday caused outrage on social media as Ugandans accused the government of using intimidation and oppression to silence critics.
Amnesty International has condemned the Nyanzi's prosecution as one that "serves no legitimate goal".
South Korean supporters of arrested ex-president to protest
She is accused of colluding with Choi to receive tens of millions of USA dollars in bribes from Samsung's Vice Chairman Lee. She is the third former president of South Korea to be arrested over criminal charges, Yonhap reports.
To each charge, she responded with a short animated speech before taking plea.
The Makerere researcher will return to court on April 25 to apply for bail. Nyanzi frequently writes that Uganda is under "despotic family rule".
"Over the last two years, local NGOs working on these issues have been shut down and had their funding blocked". The country ranked 102 out of 180 in the 2016 Press Freedom Index compiled by Reporters without Borders.
In an interview with a local TV station, the first lady said she had chosen to "forgive" Nyanzi's criticisms, which she described as hurtful.
"She [Uwitware] was eventually released and opened a case with local police". Her attack on Janet has since earned her a suspension from Makerere University. "So, by them claiming that Nyanzi might be mad, they want to shoot down their own case but we will not allow them", Semakadde said.
After Dr. Nyanzi's arrest she was injudiciously confined without being charged for over 48 hours a clear violation of Ugandas constitutional provisions.
"I still don't know what kind of wrong I committed to deserve that kind of language and the names she chose to call me, and all that". "I am happy to take on the mantle of insanity, the mantle of truth-teller, if this is going to be the only time this regime is told of its offenses against Ugandans", she said.