There are two types of human immunodeficiency virus, HIV-1 and HIV-2. The majority of the estimated 49 500 cases of HIV in the UK are due to HIV-1 with less than 100 cases due to HIV-2. In the UK, approximately 4400 people are diagnosed as being HIV-positive in 2001 and 36% of new infections are attributed to heterosexual intercourse. Many people who are HIV-positive (including about 50% of those acquiring the infection through heterosexual exposure) are unaware of their HIV status. Between 1986 and 2001 the number of diagnoses of HIV infection attributed to heterosexual intercourse increased from 80 to 2444 a year. The majority (over 70%) of these are acquired abroad, predominantly in Africa. The rise in the number of infected women increases the potential for vertical transmission. The majority of cases of vertical transmission are preventable if maternal infection is diagnosed prenatally or in early pregnancy with appropriate antenatal, intrapartum and neonatal care.
The major advance in the management of men and women with HIV is the development of highly active antiretroviral therapy (HAART) which delays the onset of AIDS and death in many of those treated; it is of note that deaths due to AIDS fell by two-thirds between 1995 and 1999 and has remained at the same level since.
Table Approximate risks of HIV transmission in various settings in Europe and the USA
|Female to male||1:1000 to 1:10000|
|Male to female||0,7361111|
|Receptive anal intercourse||1:30 to 1:125|
|Mucous membrane exposure||0,7361111|
|Needle stick injury||0,25|
|HJV-infected blood in blood transfusion||1:500 000 per unit transfused|
The risk of HIV transmission from a single act of unprotected vaginal intercourse has been estimated to be approximately 1 in 1000 from a male to a female and less for female to a male (Table Approximate risks of HIV transmission in various settings in Europe and the USA). The risk is higher following unprotected receptive anal inter-course. The risk of transmission from oral intercourse is thought to be very low, but has been reported. The likelihood of infection varies considerably according to the stage of disease, therapy taken by the infected person and the presence of other conditions such as sexually transmitted infections. The risk is increased if other sexually transmitted infections are present, if sexual intercourse takes place during menstruation and in women with cervical ectopy. The risk for acquiring or transmitting HIV infection is reduced in circumcised men. Condoms, when used correctly, offer good protection against HIV transmission. Condoms or latex barriers (also known as dental dams) are recommended for oral intercourse. The value of prophylactic therapy after condom failure or unprotected intercourse with an infected person is widely debated. Prophylactic therapy is not widely available and each case should be considered individually. Prophylactic treatment for needle-stick injury is more established and should be offered to those affected. Without treatment, if the needle is contaminated with HIV, the risk of infection is estimated to be approximately 3 per 1000.
Testing for the human immunodeficiency virus
Until routine antenatal screening was advised in the UK, women were less likely to be tested for HIV than gay men and, if infected, were less likely to seek medical care, take medication and to participate in clinical trials.
When HIV infection has been recognized, the patient’s immune state can be monitored and, if appropriate, prophylaxis offered for the opportunistic infections caused by Pneumocystis carinii and cytomegalovirus (CMV). Early diagnosis in women gives the opportunity to screen more frequently for cervical dysplasia and to provide appropriate counseling and medical management of contraception, preconception and pregnancy. Cervical dysplasia is 10 times more common in HIV-positive women and is related to immunosuppression rather than HIV itself.
Women who are aware that they are infected with HIV may qualify for certain social and welfare benefits and are able to make more informed decisions about their lives. Early diagnosis means that they have longer to live with the knowledge that they are infected and the associated psychologic and social sequelae. For many women this is overridden by the benefits of an improved prognosis, choices about pregnancy and the ability to reduce the risk of transmission to others, including their children. In addition, those too frightened to have a test may become depressed and engage in risk-laden behavior and so need support.
It is important, therefore, to make HIV testing as routine and accessible as possible. Testing should be performed only with the client’s informed consent with refenal to special-ist counselors reserved for those who are at high risk of infection or are extremely anxious. Patients should understand the meaning of a positive and negative test and the 3-month window period. The advantages and disadvantages of testing include medical benefit, stigma, social and psychologic effects, impact on relationships, work and insurance. Any service providing HIV testing must have a protocol for managing people with positive results, who may need immediate psychologic support and medical referral. This is particularly important in areas of low prevalence where facilities and expertise may be limited. Both negative and positive results should be given in person, preferably at morning clinics, when help for those with positive results can be sought. Clients who test negative may need to repeat the tests after the window period and may require advice about how to remain uninfected.
Prevention of vertical transmission of the human immunodeficiency virus
The prevalence of HIV among women giving birth in London has risen five-fold since 1988 and in 2001 it was 0.35% in London and 0.04% in the rest of the UK. In London, the prevalence of HIV in women having a termination of pregnancy is approximately two times that of women continuing with their pregnancy. Unless maternal HIV infection is diagnosed before or in pregnancy the risk of vertical transmission is approximately 20%, and possibly as high as 30% in the developing world. Additional 12-14% are infected if the mother breastfeeds the infant into the second year. In the US Center for Disease Control study ACTG 076, vertical transmission of HIV was reduced from 25.5% to 8.3% by giving zidovudine to mothers during pregnancy and labor and to the neonate. Other interventions to reduce vertical transmission are elective Cesarean section and abstaining from breast-feeding. The combined intervention of antiretroviral drugs, elective Cesarean section at 38 weeks and no breastfeeding reduces the risk of HIV transmission to less than 2%. The options of drug therapy, Cesarean section and alternatives to breastfeeding may not be available in the developing world. A child born with HIV despite these measures can benefit from early intervention such as prophylaxis for P. carinii infection. Due to the transplacental passage of maternal antibodies to HIV, the status of the neonate cannot be determined until the child is approximately 18 months old; until this time the HIV status of the child is referred to as being ‘indeterminate’.
Human immunodeficiency virus infection and infertility treatment
HIV infection is not in itself a contraindication to infertility treatment and each case should be considered on its merits by the general practitioner, gynecologist and patient. Patients considering a pregnancy should see a special-ist, particularly if the couple are discordant. Women with HIV require information on reducing the risk of transmission to their partner and fetus. Where the male partner is HIV-positive, recent work to reduce HIV transmission by washing semen samples prior to insemination is encouraging.