STD Awareness: The Vaginal Microbiome and Cervical Cancer

Cervical cancer is caused by human papillomavirus (HPV), which has been nicknamed “the common cold of STDs” — because pretty much every sexually active person will get it at some point. Luckily, that scary stat is poised to change as more people receive the HPV vaccination, which protects against nine major strains of the virus.

HPV jumps easily from person to person, spread by pretty much all types of sexual contact. For most people, the infection clears up within 8 to 13 months, but sometimes the infection develops into a chronic condition, which increases risk for certain cancers — including cervical cancer, but also cancers of the anus, genitals, and throat. Unfortunately, it’s hard to predict if your immune system will vanquish your infection, or if you’ll develop a chronic infection.

Members of the lactobacilli family, keeping vaginas healthy across the globe. Image: Josef Reischig

Luckily, the vagina has some tricks up its sleeve to protect itself from HPV, and some of its best weapons are bacteria. Yep — a healthy vagina isn’t germ-free. To the contrary, it needs lactobacilli and other beneficial microbes to maintain a healthy environment. Bacteria from the Lactobacillus genus produce lactic acid and other chemicals, which help keep dangerous bugs away. Vaginal environments in which Lactobacillus gasseri dominate, for example, are more likely to clear HPV infections. L. crispatus helps trap HIV in a thick mucus, reducing infection risk. Other lactobacilli species secrete chemicals that ward off yeast infections. Sometimes, however, good bacteria lose this turf war, and “bad guys” move in.


The population of microbes that live in your vagina are known collectively as the vaginal microbiome.


University of Arizona researchers in Phoenix performed a “census” of the vaginal microbial communities of 100 premenopausal women. They learned that women who have cervical cancer or precancerous abnormalities have drastically different vaginal microbiomes. Healthy vaginas were generally dominated by lactobacilli, but as cervical health declined, their populations declined, and “bad” bacteria took over. One such bad guy, called Sneathia, was linked to HPV infection, precancer, and cervical cancer.

Which Came First?

Finding a new vaginal “bad guy” was exciting, and Sneathia had previously been linked to other gynecological problems, ranging from bacterial vaginosis to pregnancy complications. But the researchers were looking at a snapshot in time — they didn’t know what came first, the Sneathia or the cervical abnormalities. Were lactobacilli protecting the cervix whereas Sneathia were harming it, or did a chronic HPV infection set the stage for Sneathia to move in and thrive? It’s a real “chicken-and-egg” conundrum. Continue reading

Contraception Then and Now

When it comes to contraception, one thing is for sure: We’ve come a long way! And while the future might have even better things in store, like reversible male birth control, superior condoms, or remote-controlled implants, a look into the past reveals that modern contraceptors have a bevy of fantastic options to choose from. Unlike couples who had to forgo contraception or obtain birth control from the black market, nowadays Americans wishing to prevent or postpone pregnancy can select from a variety of legal, effective, and increasingly accessible family-planning methods.


While the history of birth control is fascinating, today’s contraception is the very best.


Let’s look at some old-fashioned birth-control methods and see how they stack up to their modern-day counterparts.

Linen and Guts vs. Latex and Polyurethane Condoms

Most people think of female condoms as new inventions, but the first condom recorded in history was made out of a goat’s bladder and inserted into the vagina — way back in 3000 BC. Ancient civilizations, from the Romans to the Egyptians to the Japanese, made penile sheaths and caps with a variety of materials, including linen, leather, lubricated silk paper, intestines, and tortoise shells. Linen and intestines remained popular through the Renaissance era.

A condom, with user manual, 1813. Photo: Matthias Kabel

Charles Goodyear might be most famous for tires, but his discoveries in vulcanizing rubber also led to the development of rubber condoms in the mid-1800s. Unfortunately, the Comstock Act of 1873 outlawed the manufacture and sale of contraception, and condoms were driven into a shadow economy. In the 1880s, New Yorkers might have been lucky to find black-market condoms made from surplus animal intestines, which were manufactured by Julius Schmid, a German immigrant who otherwise specialized in sausage casings — before his business was shut down by the New York Society for the Suppression of Vice. Condoms weren’t legal in the United States until the Crane ruling of 1918, just in time for the 1920 invention of latex, a form of rubber that was much stronger and more elastic — and with a shelf life of five years vs. rubber’s three months. By the 1920s, Schmid was once again on top of the condom game, peddling brands like Sheik, Ramses, and Sphinx.

Condoms made out of intestines are still on the market, sold as lambskin or “natural” condoms. However, they are not recommended for STD protection: Just as intestines need to allow nutrients to enter the body from digesting food, so too are viruses able to pass through condoms made from intestines. (Sperm, on the other hand, are thought to be too big.) These days, latex is the gold-standard material for condoms, while polyurethane can be used by people with latex allergies. Condoms constructed with these modern materials protect users from unintended pregnancy as well as many sexually transmitted infections, such as HIV and chlamydia. Continue reading

STD Awareness: Is Bacterial Vaginosis a Sexually Transmitted Disease?

Not to scale: Gardnerella vaginalis under a microscope. Image: K.K. Jefferson/Virginia Commonwealth University

Gardnerella vaginalis under a microscope. Image: K.K. Jefferson/Virginia Commonwealth University

Bacterial vaginosis, or BV, is the most common vaginal infection among people 15 to 44 years of age. It’s caused by an overgrowth of harmful bacteria, such as Gardnerella vaginalis. A healthy vagina hosts thriving populations of Lactobacillus bacteria species, but when these “good” bacteria are crowded out by certain types of “bad” bacteria, the vaginal ecosystem can be shifted, causing BV.

There is a lot of confusion about BV. Is it a sexually transmitted disease (STD)? What are the symptoms? How can you avoid it?

All good questions. Let’s examine them one by one.

Is BV an STD?

The consensus seems to be that BV isn’t officially an STD, but even reliable sources have somewhat contradictory information. Planned Parenthood doesn’t list BV as an STD on their informational webpages. The Centers for Disease Control and Prevention (CDC) does include BV on their STD website, but also says that “BV is not considered an STD.”

On the other hand, the Office on Women’s Health says that “BV can … be caused by vaginal, oral, or anal sex” and that “you can get BV from male or female partners.” And there’s an entire chapter devoted to BV in the premier medical textbook on STDs, and its authors say that, while sexually inexperienced females can get BV, “the weight of evidence supports sexual transmission” of G. vaginalis, the bacteria species most famously implicated in BV infections.

The same webpage on which the CDC declared BV not to be an STD also says that it can be transferred between female sexual partners. Indeed, women who have sex with women have higher rates of BV. Since vaginal fluid could spread BV, partners can change condoms when a sex toy is passed from one to another, and use barriers like dental dams when engaging in cunnilingus (oral contact with the female genitalia) or rimming (oral contact with the anus).

What about heterosexual transmission? Continue reading

Is Douching Safe?

This vintage douche ad claims that its product is “safe to delicate tissues” and “non-poisonous.”

Douching is the practice of squirting a liquid, called a douche, into the vagina. Many people believe it helps keep the vagina clean and odor-free, and some are under the impression that it helps prevent pregnancy and sexually transmitted diseases. An estimated 25 percent of American women 15 to 44 years old douche regularly. But just because douching is widespread doesn’t mean it’s safe; indeed, there are two possible mechanisms by which douching might be harmful.

First, douching might alter the pH of the vagina, changing its ecosystem. You might not think of a vagina as an “ecosystem,” but the bacteria and other microscopic organisms that live there sure do — and altering their habitat can harm the beneficial microbes that live there, opening the door for disease-causing microbes to take over the territory. Frequent douching can result in the vagina’s normal microbial population having difficulty reestablishing its population.


Douching increases risk for infections and fertility problems, and has no proven medical benefits.


Second, a douche’s upward flow might give pathogens a “free ride” into the depths of the reproductive tract, granting them access to areas that might have been difficult for them to reach otherwise. In this manner, an infection might spread from the lower reproductive tract to the upper reproductive tract. Douching might be an even bigger risk for female adolescents, whose reproductive anatomy is not fully formed, leaving them more vulnerable to pathogens.

While douching is not guaranteed to harm you, there is no evidence that it is beneficial in any way. Establishing causation between douching and the problems that are associated with it is trickier — does douching cause these problems, or do people who douche also tend to engage in other behaviors that increase risk? So far, the best evidence indicates that douching is correlated with a number of diseases and other problems, including sexually transmitted diseases (STDs), bacterial vaginosis, pelvic inflammatory disease, fertility and pregnancy complications, and more. Continue reading

Teen Talk: I Can’t Get Pregnant … Can I?

teen pregnancy testIt’s wasn’t something you thought would happen. Your period is LATE!!! And you were sooooo careful — you didn’t use any contraception because you heard if he didn’t ejaculate or pulled out right away, you couldn’t get pregnant. And, just to be extra sure, you did jumping jacks for several minutes right after! What went wrong? Is it possible that the information you heard from your friends about how not to get pregnant was incorrect?


Sperm have one mission: to find and fertilize an egg. They don’t care what position you’re in, whether you have an orgasm, or if it’s your first time.


You know how babies are made, but you may have misunderstood some basic facts of human biology. The male body produces that tiny resilient sperm — actually millions of tiny resilient sperm — whose only mission is to find and fertilize a woman’s egg. They are so resilient that they can travel farther and live longer than you might think. They are present in men’s ejaculated fluid (semen) and also in the pre-ejaculate (the small amount of fluid that leaks out of the penis before a guy ejaculates). If any of that semen comes in contact with a woman’s vaginal area, there is a chance of her becoming pregnant. And if you don’t use some form of contraception with each and every act of intercourse, you are having unprotected sex, which increases your risk of getting pregnant. It only takes one sperm to fertilize an egg.

Let’s look at some common misconceptions you may have heard about how not to get pregnant. Continue reading

Does Douching Work?

illustration of a douching apparatus from an 1882 medical handbook

As a newly minted teenager, I was helping my mother go through some of my recently deceased great-grandmother’s things. I held a mysterious object in my hands and studied it curiously, puzzling over its unfamiliar form, pastel color scheme, and floral pattern. Finally, I gave up: “What is this?” I exclaimed. My mom, instantly uncomfortable, muttered her answer through clenched teeth: “It’s a douche bag,” she replied.

I remember being rather scandalized, but also a bit amused to be holding a piece of ancient misogynist history in my hands. Even as a junior high student, I knew that douching was marketed toward women with the message that their vaginas were “dirty” and in need of “cleansing” — scientifically invalidated ideas to which we surely no longer adhered. It seemed fitting that we were sorting through the belongings of a person born in the 19th century, dividing them into the useful and useless. Surely the douche bag belonged in the latter category.


Just because douching products are available in drugstores doesn’t mean they’re safe or effective.


Little did I know, more than 20 years ago, that douching hasn’t exactly been relegated to a historical footnote. Overall, nearly 25 percent of American women 15 to 44 years old douche regularly — which is down from nearly a third in 2002. Douching rates may vary by ethnic group: CDC data from 2005 found that 59 percent of non-Hispanic black women, 36 percent of Latinas, and 27 percent of white women douche. Socioeconomic status and education level can also be a factor.

For those of you who don’t know, vaginal douching is the practice of flushing the vagina with a liquid, which is administered through a nozzle that is inserted into the vagina. Some people believe that douching cleanses or deodorizes the vagina, or can prevent pregnancy or infections. Some might think their partners expect them to douche, or that douching will “tighten” or “rejuvenate” their vaginas.  Continue reading

STD Awareness: 10 Myths About Sexually Transmitted Diseases

The Internet is brimming with contradictory claims about sexual health, and you don’t know what to believe. Your friends give you advice, but you’re not sure if it sounds right. To make things worse, you might not have had evidence-based, medically accurate sex education in your school. In this edition of our STD Awareness series, we’ll take on a few myths about sexually transmitted diseases to help you sort fact from fiction.

1 MYTH: You can tell if someone has an STD by looking at them.
You might expect that if someone has an STD, their genitals would have blisters, warts, or noticeable discharge. But your partner looks fine, so you might think there’s no need to ask when his or her last STD test was.

However, while many people with STDs do have visible symptoms, they’re the exception rather than the rule. For example, three out of four women and half of men with chlamydia have no symptoms. Herpes is often spread when there are no symptoms present. Someone can be infected with HIV — and capable of transmitting it to others — and go years without showing any signs. A quick visual inspection can’t tell you very much about someone’s STD status.

2 MYTH: You can’t get an STD from oral sex.
While it is generally true that oral sex presents less of a risk for contracting STDs, this risk is not trivial. Most STDs can be passed along by oral sex, including chlamydia, gonorrhea, syphilis, hepatitis B, herpes, human papillomavirus (HPV), and HIV. You can reduce your risk by using barrier methods like condoms and dental dams consistently and correctly.

3 MYTH: Condoms can’t prevent the spread of HIV.
Many proponents of abstinence-only education state that condoms don’t protect against HIV, claiming that latex condoms have holes that are large enough for viruses to pass through. This claim isn’t backed by evidence. An intact latex condom dramatically reduces your risk of being exposed to sexually transmitted viruses such as HIV. (It is true that a lambskin condom does not provide adequate protection against HIV.) Continue reading