Sex Ed for Grown-Up Girls

It’s been several years since you sat through that sixth-grade sexual health class and then giggled shyly about it afterward with your girlfriends. And in those intervening years, you've undoubtedly learned a lot more than what was on the grade-school curriculum. But just because you're older and wiser now—and have been doing responsible things like going for your annual gyno appointment, using appropriate birth control, and protecting yourself from sexually transmitted diseases—that still doesn’t mean you know it all.

So consider this a little refresher course. We asked Dr. Nanette Santoro, professor of obstetrics/gynecology and women's health at the Albert Einstein College of Medicine in New York City, to weigh in on the stuff you really should know about your sexual health.

You don't have to get your period.

With the U.S. Food and Drug Administration's approval of so-called "continuous birth control pills," the monthly menstrual cycle may soon become of thing of the past. While it may seem somehow wrong not to bleed every 28 days or so, doctors assert that women on any form of oral contraceptives don't need that week of placebo pills. "There is a belief that the pill [when taken on a 28-day cycle] produces a normal period, but that's not the case," explains Santoro. Taking the pill reproduces the hormones of pregnancy (which is why ovulation is suppressed) rather than the hormonal fluctuations of a menstrual cycle. When you’re not on the pill, the endometrial lining builds up and needs to be shed monthly. "But a woman taking the pill has a very, very thin endometrial lining," says Santoro. "And if nothing builds up, nothing needs to be shed."

At least 50 percent of men and women are infected with HPV.

This STD (full name: human papillomavirus) is not only ubiquitous, it is also dangerous. Several varieties of the virus have been identified as a cause of cervical cancer. And while condoms can help prevent transmission, since the virus can spread through any genital contact, they can't offer complete protection. Currently, the best bet for prevention is Gardasil, the recently approved HPV vaccine. It's most effective if received before you've engaged in any sexual activity, and it's only recommended for women under age 26. For everyone else, safe sex and regular testing by your gyno is still your best bet.

The most effective birth control method is the one you use correctly.

The pill advertises a better than 99 percent efficacy rate, and condoms (when used "perfectly") rate about 98 percent. But skip a few pills or take them on an irregular schedule, and you could easily find yourself pregnant. And the failure rate for "typical use" of condoms is as much as 15 percent. "That's why I favor those that do not require forethought," says Santoro. Such options would include Mirena (an estrogen-free intrauterine contraception device that can be left in place for up to five years) and the NuvaRing (a flexible ring placed high in the vagina that releases hormones similar to the pill and is replaced each month).

You can get pregnant before, during, or after ovulation.

Since sperm can survive for 24 to 48 hours in your reproductive tract, you could conceive if you have sex a day or so before you ovulate or up to a few days after. So if you are trying to have a baby, that's the time to get busy. And if you're not planning a pregnancy, that's a good time to be extra-diligent about birth control.

Peeing after sex can prevent a urinary tract infection.

"Trauma to the urethra during sex can cause germs to spread upwards to the bladder and cause an infection," Santoro says. The best preventive measures are also the simplest: Head to the bathroom after you have sex, drink plenty of water, and if you are prone to UTIs, drinking cranberry juice has been shown to help flush bacteria out of the system.