About 20% of women currently use the "rhythm method" to determine when they're most likely to conceive. Essentially, these women track their periods and then reference a digital ovulation calendar to either get pregnant or avoid pregnancy.

Historically, this hasn't proven to be the most accurate method. It doesn't account for the many factors that can change the timing of ovulation each cycle. As a result, about one in four women using this method has an unplanned pregnancy. In fact, millions of women who use period tracker apps are getting the wrong information on their fertile windows, according to a recent study in the Journal of Obstetrics and Gynaecology Canada.

Despite these inaccuracies, many women reluctantly stick with these apps out of a desire to avoid artificial hormones. Fortunately, there are better alternatives.

Over 200 "femtech" startups worldwide are pioneering technology and medical products — ranging from fertility tracking devices to breast cancer detectors — designed to meet women's unique health needs.

For example, my company, Valley Electronics, recently launched the DaysyDay app, which pairs with the Daysy Fertility Tracker to provide women with their daily fertility status. A green light signifies an infertile day, while red signifies fertile.

Daysy — which analyzes a user's waking basal body temperature, menstruation data, and has the experience of 10 million successfully evaluated cycles — employs a highly calibrated temperature sensor and algorithm to limit user error.

In fact, a recent Daysy study analyzed an unprecedented 110,000 menstrual cycles of 5,328 women over a 10-year period, accounting for factors that impact ovulation. The result? Just 0.6% of all green (infertile) days were calculated incorrectly. Of these incorrect days, more than half occurred five days before the expected day of ovulation and thus held only a 6.8% chance of pregnancy.

Daysy's accuracy is excellent news for the women who choose to use hormone-free tracking methods to manage their fertility.

Many other femtech companies are doing important work on women's health issues. Cyrcadia Health has developed iTBra, a WiFi-connected patch that can detect breast cancer and send the data to a lab.

London startup Astinno is working to develop a wearable wrist patch called "Grace" that alleviates menopausal hot flashes. Hot flashes occur when the brain falsely believes the body's temperature is too high -- a common symptom of menopause. Engineers are designing Grace to detect this biometric reaction and activate a cooling patch that halts the hot flash before it happens.

Until relatively recently, the private sector often neglected women's health research. A decade ago, the femtech industry attracted just $23 million in venture capital investments. By 2019, investment jumped to nearly $600 million. And by 2025, femtech companies are projected to generate $50 billion in sales.

It's heartening that researchers are finally delving into issues like menopause and fertility. But there's still plenty of work left. One in 10 reproductive-aged women suffers from endometriosis. That's nearly 200 million women worldwide.

PCOS, a disorder that affects between 6 and 12% of U.S. women, is one of the most common hormonal and endocrine disorders.

Yet endometriosis and PCOS are both under-researched and underfunded. Femtech startups can change that -- by generating the volumes of user data needed to better understand and treat these health issues.

The past decade showed us what a dynamic femtech industry could do for women. This decade, the industry will no doubt explore previously underfunded areas. Now is the time to take the industry's potential seriously and support women.

Natalie Rechberg-Egly is a femtech entrepreneur, founder of Daysy, and CEO of Zurich-based Valley Electronics AG.