UN Population Division, Department of Economic and Social Affairs,
with support from the UN Population Fund (UNFPA)

STD Protection After Intercourse


The electronic version of Network is being made available by the

Population Information Network (POPIN) of the United Nations

Population Division/DESIPA and Family Health International (FHI).



                      Vol. 16, No. 3, Spring 1996

                             Barrier Methods

Copyright 1996, Family Health International

STD Protection After Intercourse

     Emergency protection after STD exposure has limitations and should

be used for specific situations, not routinely.

     For couples to prevent unintended pregnancy after unprotected

intercourse, emergency contraception offers a means. Yet unprotected

intercourse also increases the risks of contracting a sexually

transmitted disease (STD). Are there emergency measures that can be

taken to reduce this risk after exposure?

     Yes, experts say. However, these measures have limitations and are

recommended only for certain groups of people, such as women who are

victims of sexual assault. Emergency treatment of STDs is not

recommended for routine use.

     "The principal problem [with emergency treatment] is the multitude

of STDs," says Dr. Robert Johnson, a medical epidemiologist with the

Division of STD Prevention at the U.S. Centers for Disease Control

and Prevention (CDC). "There isn't a single drug that can treat all

STDs. The viral agents cannot be treated. Coming up with a regimen

is problematic."

     There are more than 20 types of sexually transmitted diseases. While

latex condoms, used consistently and correctly, can reduce the risks

of all of them, no single drug can successfully treat all of them. 

     Combinations of antibiotics may be used to reduce a woman's risks of

infection from some bacterial STDs following sexual assault. Genital

washing and medications have shown some effectiveness in preventing

STDs among men serving in the military. Douches, used by many women

to cleanse the vagina, may not help prevent STDs and may actually

promote infection in cases where contamination is introduced. 

Worldwide, an estimated 250 million new cases of STDs occur

annually.1/  Most scientists now agree that STD infection increases

an individual's risk of contracting HIV, the virus that causes AIDS.

There is evidence that STDs that cause genital sores, such as herpes,

chancroid and syphilis, can enhance the risks of HIV transmission by

creating a site of entry for the AIDS virus. Other STDs, which do not

produce ulcers but do produce inflammation, may also increase

susceptibility to HIV.2/ 

     Because latex condoms can prevent transmission of both bacterial and

viral STDs, and because antibiotics can successfully treat bacterial

STDs once a diagnosis has been made, research to find a method of

emergency STD prevention -- one that could be used after unprotected

sexual intercourse but before symptoms develop -- has been limited. 

     However, research is under way to develop microbicides, which would

kill both bacterial and viral STD pathogens. Some researchers have

speculated that these products, designed for use prior to sexual

intercourse to prevent infection, might also be used for postcoital

or emergency STD prevention.

     "The need for such a product is evidenced by emerging data concerning

the widespread prevalence of non-consensual and coercive sex in

women's lives, even within married and consensual unions," write

Christopher Elias of the Population Council and Lori Heise of the

Health and Development Policy Project. "A postcoital method might

also have some utility for women, especially adolescents, in

communities where `planning' to have sex is unacceptable."3/

     Postcoital STD treatment could also be helpful for couples who use

condoms as a means of STD prevention but experience condom breakage

or slippage, much as emergency contraception is used to prevent

pregnancy when a couple experiences condom failure.

Sexual assault

     For women who are the victims of sexual assault or non-consensual

sex, the CDC has developed guidelines for emergency STD treatment.

The guidelines recommend a combination of antibiotics, given within

hours after sexual intercourse. This combination is designed to

prevent the infections most commonly diagnosed after sexual assault

-- trichomoniasis, chlamydia, gonorrhea and vaginal bacteriosis. 

     The CDC recommends: 125 milligrams of ceftriaxone injected

intramuscularly in a single dose; two grams of metronidazole orally

in a single dose; and 100 milligrams of doxycycline taken orally

twice a day for seven days.4/

     The CDC also recommends that health-care providers counsel the client

about symptoms of STDs and the need for her to return to the clinic

if these occur. Providers should counsel the client to use condoms

until the antibiotic treatment is complete, to prevent the

possibility of any STD transmission to her partner.

     If available, clients should be given a vaccine to protect against

Hepatitis B. If laboratory tests are available for STDs, the client

should return for follow-up examinations at two weeks and 12 weeks

after the sexual assault.

     The likelihood of contracting an STD after sexual intercourse is less

than the risk of becoming pregnant. Fewer than one in five people are

infected with an STD at any given time, while nine out of 10 women

under age 35 are fertile and could become pregnant.5/ The use of

antibiotics as a preventive measure is often done for psychological

reasons as well as biological ones. The client, who has already

undergone the physical and emotional trauma of assault, may have one

less consequence to worry about if she takes antibiotics.


     There is some risk a woman will acquire HIV infection after sexual

assault, but the CDC says the risks are very low. There are no

emergency measures a health-care provider can take to reduce a

woman's risk of HIV in this situation. Providers should offer HIV

counseling and testing to clients, but some experts recommend that

this be done during a return visit to the clinic, not during the

initial visit when the client is frightened and upset.

     Outside of use to prevent the development of STDs among sexual

assault victims, the use of antibiotics for emergency STD prevention

in the larger population is regarded by most experts as an

unnecessary and an expensive use of scarce medical resources.

"Emergency treatment will result in the overtreatment of people who

are not infected," says Dr. Jonathan Zenilman, associate professor

of medicine in the Infectious Disease Division of Johns Hopkins

University in the United States. Given that some STDs have developed

a resistance to certain antibiotics, treatment before diagnosis is

not recommended.

Military experience

     The use of postcoital emergency treatment for STDs has had some

success in the U.S. military. During World War I, military officials

tried to reduce the incidence of STDs through educational campaigns

that emphasized the need for servicemen to be "100 percent efficient

to win the war." Military personnel were encouraged to practice

abstinence to prevent sexually transmitted diseases.

     Servicemen who did engage in sexual activity with prostitutes were

told to return to their military base and report for emergency

treatment within three hours after sexual intercourse. The procedure

involved several steps. First, the soldier urinated, then washed his

genitals with soap and water, followed by bichloride of mercury. A

medical attendant inspected the soldier's genital area, then injected

Protargol, which contains silver protein, into the penis. The soldier

would urinate five minutes later. Finally, calomel ointment was

rubbed onto the penis, and the penis was wrapped in wax paper. The

soldier was not to urinate for at least four to five hours after


     To further reduce the incidence of sexually transmitted disease

during World War I, U.S. soldiers were given an emergency treatment

packet they could administer themselves. This was done on an

experimental basis for soldiers who did not have access to a health

clinic. The packet contained calomel ointment, carbolic acid and


     Military health officials estimated this treatment could be 99.6

percent effective in preventing syphilis, gonorrhea and chancroid.

Statistics on the success of military efforts to reduce STDs were not

published. However, military officials estimate that several million

men received emergency STD treatment.

     During World War II, the U.S. military sought to reduce the incidence

of STDs by offering educational programs, emergency STD treatment and

condoms for STD prevention. With the discovery that antibiotics could

effectively treat bacterial STDs, and the knowledge that condoms

could prevent STD transmission, the use of emergency STD clinics


     In the 1970s, a study among some 500 U.S. male sailors who had sexual

intercourse with women while on shore leave in the western Pacific

concluded that STD infection rates did not decrease significantly if

a man urinated within 30 minutes after intercourse or if he washed

his genitals within an hour.7/  Another study among 1,000 male

sailors found that 200 mg of minocycline, taken orally a few hours

after intercourse, offered some protection against the subsequent

development of gonorrhea. However, researches did not recommend

widespread use of the antibiotic because drug-resistant strains of

gonorrhea could develop.8/

Vaginal douching

     Because many women practice routine vaginal douching for hygienic

purposes, there has been speculation that postcoital douching might

reduce the incidence of STDs. Studies have shown that douching may

not offer any type of protection against STDs. In fact, it may

promote some types of reproductive tract infections.

     While vaginal douching may decrease the risks of gonorrhea, it may

increase the risks of pelvic inflammatory disease and ectopic

pregnancy.9/  A study of more than 600 women in the United States

found those who douched were more likely to have risk factors for

STDs, including multiple sexual partners and first sexual intercourse

at an early age. However, others say it is difficult to determine

whether douching increases a woman's risk of infection or whether

douching is simply a common practice among women at risk of STDs for

other reasons.10/ 

     Normally, the pH in the vagina is low (acidic), but the pH levels

change during intercourse with ejaculation, menses, estrogen

deficiency, menopause and bacterial vaginosis. Researchers believe

that pH levels in the vagina may play an important role in STD


     Several small studies have examined the changes in normal vaginal

microorganisms after douching. One study of 20 women in the United

States found that small amounts of a douche preparation containing

the antiseptic, chlorhexidine gluconate, did not significantly alter

the vaginal flora after 30 days of use.11/  A small study at the

Universita di Sassari in Italy evaluated seven vaginal douche

preparations to determine their in vitro effects on lactobacilli, a

bacteria commonly found in the vagina. Lactobacilli produce hydrogen

peroxide, which inhibits the growth of some pathogens, possibly STD

pathogens.12/  Researchers concluded that frequent use of these

douches could change the composition of the normal vaginal flora.13/

A study of 10 women in the United States, which compared two types

of douche preparations, found that those containing acetic acid (the

acid in vinegar) caused short-term minor changes in the vaginal

flora, while solutions containing povidone-iodine (Betadine) caused

significant changes in the vaginal flora, which could increase the

risks of infections and possibly the risks of pelvic inflammatory


     The use of soft drinks as a postcoital douche is frequently suggested

as a folk remedy to prevent pregnancy after unprotected sex, but is

not effective since sperm enter the cervix within seconds after

ejaculation. A study of seven men in Nigeria examined the effects of

four different types of soft drinks on in vitro motility of sperm.

The study found that one brand of drink, Krest bitter lemon,

immobilized all sperm within one minute. The study did not, however,

explore microbicidal effects.15/  A study conducted in the United

States investigated the spermicidal effects of Coca-Cola and found

that different formulations of the soft drink did reduce sperm

motility.16/  A separate study of cola drinks found little effect on

sperm motility. Researchers suggested the introduction of these

liquids into the vagina might cause infection.17/

     Some researchers suggest that a microbicidal postcoital douche might

be more culturally acceptable than condoms, which require negotiation

between partners. A postcoital douche of tea or beer, which has a low

pH, or sour milk, which contains lactobacilli that result in low pH

levels, might offer protection against STDs, including AIDS,

researchers suggest. 

Soap and water

     Genital washing has been suggested as a means to prevent STD

transmission to men. Studies of military personnel in World War I and

World War II found that washing with soap and water soon after

exposure to STDs helped prevent chancroid.

     In sub-Saharan Africa, genital washing has been theoretically

proposed as a way to reduce STD and HIV incidence. Lack of

circumcision in men may be a risk factor for development of

chancroid, a common cause of genital ulcer disease in Africa. Genital

ulcer disease appears to be a risk factor for contracting HIV. Health

advocates suggest that education about postcoital and precoital

washing with instructions on how to clean the area beneath the

foreskin of the penis might be one way to reduce the incidence of

STDs in east, central and southern Africa, where male circumcision

is less common and genital ulcer disease more common than in west


     But a study in Singapore, which questioned 100 prostitutes about

methods they used to prevent sexually transmitted diseases, found

that postcoital washing with antiseptic solutions had no STD

prevention effect for this group of women.19/ 

     -- Barbara Barnett


     1. Crosignani PG, Diczfalusy E, Newton J, et al. Sexually

transmitted diseases. Hum Reprod 1992; 9:1330-34.

     2. Mauck CR, Cordero M, Gabelnick H, et al., eds. Barrier

Contraceptives: Current Status and Future Prospects. Proceedings of

the Fourth Contraceptive Research and Development Program

International Workshop, March 22-25, 1993, Santo Domingo, Dominican

Republic. New York: John Wiley and Sons Inc., 1994.

     3. Elias CJ, Heise LL. Challenges for the development of

female-controlled vaginal microbicides. AIDS 1994; 8:1-9.


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Sexually Transmitted Diseases Treatment Guidelines. Atlanta: CDC,


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transmitted diseases and contraceptive choice; a literature update

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     9. Chow WH, Daling JR, Weiss NS, et al. Vaginal douching as

a potential risk for tubal ectopic pregnancy. Am Obstet Gynecol 1985;

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disease. JAMA 1990; 263:1936-41.

     10. Rosenberg MJ, Phillips RS, Holmes MD. Vaginal douching:

who and why? Journal of Reproduct Med 1991; 36(10):753-58. Rosenberg

MJ, Phillips RS. Does douching promote ascending infection? J

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     11. Shubair M, Stanek R, White S, et al. Effects of

chlorhexidine gluconate on normal vaginal flora. Gyn Obstet

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     12. Klebanoff SJ, Hillier SJ, Eschenbach DA, et al. Control

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Copyright 1996, Family Health International.

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