A startling new survey found that 26% of active-duty women are unable to access birth control while deployed.

Some said their doctors denied birth control based on general orders that limit deployed troops' sexual activity.

Ellen Haring, the chief executive of the advocacy group that conducted the study, said this is "ridiculous," noting birth control is not solely used for contraception.

A Defense Department spokeswoman acknowledged it would be a privacy violation to deny birth control for this reason, but stopped short of saying whether the military would investigate or issue guidance to correct it.

Military leaders say that General Order 1, which limits alcohol consumption and cohabitation for troops deployed to war zones, reinforces good order and discipline. Advocates and troops say it's an antiquated "ban on sex" — and may in reality be harming women's health.

Women troops said in some cases that their doctors cited this controversial order to deny them access to birth control while deployed, a fact that was revealed in a survey conducted by the Service Women's Action Network advocacy group.

In their survey of nearly 800 women serving or who have served in the US military, SWAN found that 26% of active-duty women do not have access to birth control while deployed. That number jumps even higher for other communities: 41% of women veterans reported limited access during their time in uniform.

While several reasons were provided to account for these numbers, including the inability to refill prescriptions far enough in advance, advocates were shocked to find that a limitation on sexual activity would be used to deny access to birth control.

"Isn't that ridiculous," Ellen Haring, chief executive of SWAN, told Business Insider. "It astounds me that people would be denied for that reason."

It's astounding, Haring said, because birth control is not just used as a contraceptive. One of the survey's respondents said she was dismayed when she could not get enough refills to last through her deployments because she primarily used birth control to regulate, and even skip, her menstrual cycle.

Along with safely skipping a period, Planned Parenthood lists a range of medical benefits to using birth control — from reduction of acne to prevention of endometrial or ovarian cancers.

These benefits are not being ignored by the Department of Defense, which said it would be a violation of service members' privacy if their commander denied them access to birth control.

Read more: Military women are 3 times more likely to suffer infertility than civilians, but the Pentagon is forcing nearly all of them to pay for their own treatment

"Birth control ... is not just indicated for pregnancy prevention, it is also indicated for menstrual regulation, including menstrual suppression," Jessica Maxwell, spokeswoman for the Defense Department, said in an emailed statement to Business Insider.

It would be a privacy violation for a commander to deny birth control, Maxwell wrote, because taking birth control would not limit a woman's ability to perform her duties. But she could not publicly comment whether a doctor's refusal to prescribe the medication would trigger a violation of any military regulation or whether the Pentagon was investigating any reports of this occurring.

Her statement emphasized that emergency contraception, which can be obtained over-the-counter, is readily available even for service members in deployed locations.

But emergency contraceptives are singular in their purpose; these remedies do not satisfy the host of alternate uses filled by prescription birth control.