My period was late.

It was just part of female fluctuations. I know this not because I am meticulous or particularly in tune with my bodily cycles. I know it because my clever little period tracking application informed me.

Period-tracking apps are exactly what they sound like — simple menstrual calendars that help you keep track of monthly cycles as well as symptoms like mood fluctuations or headaches. The market is flooded with them — iPeriod, PTracker, Clue, Period Diary — and nearly every woman I know uses one.

They are the rare corner of the trendy quantitative self and health movement that has resonated with me, largely because they provide useful insights into my life, how I’m feeling and what’s going on with my body. As much as I’ve enjoyed apps and wearables that give me information on the number of steps I’ve taken in a week, the number of calories I’ve magically managed to burn or how much sleep I’ve gotten, I often question the accuracy of the data and struggle with figuring out how to use that information to reshape my daily behavior and habits. But nothing has been as exciting or revealing as tracking my menstrual cycle.

I now switch between several apps and the information they offer. They have worked their way into the permanent part of my daily digital regime, right alongside services like Instagram, Twitter, Facebook and the like.

Logging such delicate and intimate information might seem strange or foreign to people or technology users who aren’t used to having to monitor their bodies so closely. But in an era when enthusiastic entrepreneurs promise that technology and their services can improve lives, this is the one instance where that seems to be true.

Ida Tin, a entrepreneur based in Berlin who released the application Clue, said she sees these applications as an all-purpose life tracker, one that documents a women’s relationship to her body throughout her life, from the beginning of menstruation to menopause. They offer insight into what’s happening inside your body and can relay information that helps women make informed choices about having sex (or avoiding it), something that is invaluable.

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“There is a basic need among women to understand their bodies and know more about it,” she said. “When body awareness goes up, it creates a sense of being in charge and being in control.”

That understanding could even someday be used to study regional and global trends about women’s habits and bodies, she said.

The period-app category came to Silicon Valley’s attention last August, when a team of pedigreed entrepreneurs introduced Glow, a fertility tracking application that promised to leverage data to help women conceive. The company soon raised $6 million from several venture firms, including Andreessen Horowitz.

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Like many of its peers, Glow marketed itself primarily as a tool to help women get pregnant. And, like its peers, the company found that many users were not interested in conception at all.

“Even during the beta period, before we released our app, people were asking us if there’s a mode they can turn on that is not about getting pregnant,” said Mike Huang, the chief executive of the company.

On Thursday, the company is releasing a revamped version of its application that will let users select whether they are trying to conceive and tailor the experience accordingly. For instance, the version of the app aimed toward women who are trying to avoid pregnancy shows them a “percentage risk for pregnancy” as they progress each month throughout their cycle.

Although many women can use these as an alternative or supplement to birth control, Mr. Huang was quick to say that Glow is not marketing itself as a replacement for birth control — none of these cycle management services are.

Instead, Jennifer Tye, the head of marketing at Glow, said they can be helpful for early detection of health problems. If a Glow users regularly reports menstrual irregularity or particularly painful cramping, it will recommend a visit to the doctor to check for conditions like endometriosis or ovarian cysts.

But regardless of the category that women fall into — wanting children or not, worried about potential health conditions or simply looking to understand their bodies more — “we are trying to create an experience for you,” she said.