HIV in Pregnancy: A Review (UNAIDS, 1999, 67 p.): SECTION A : HIV IN PREGNANCY: Interventions to prevent mother-to-child transmission of HIV

HIV in Pregnancy: A Review (UNAIDS, 1999, 67 p.)

SECTION A : HIV IN PREGNANCY

		(introduction...)
		Epidemiology of HIV
		Susceptibility of women to HIV infection
		Effect of pregnancy on the natural history of HIV infection
		Effect of HIV infection on pregnancy
		Mother-to-child transmission
		Interventions to prevent mother-to-child transmission of HIV
		Appropriate interventions to reduce mother-to-child transmission
		Voluntary HIV counselling and testing in pregnancy

Interventions to prevent mother-to-child transmission of HIV

With increasing knowledge about the underlying mechanisms of mother-to-child transmission of HIV-1 has come an increased emphasis on the search for interventions to prevent or reduce the risk of transmission^{111,113,243,244}. The successful use of antiretroviral therapy and replacement feeding in developed countries has lead to suggestions that it may eventually be possible to reduce perinatal transmission rates to less than 2%¹³¹. A number of possible intervention strategies have been proposed or are under investigation. These are shown in Table 2.

Table 2:Possible strategies known or under investigation for the prevention of mother-to-child transmission of HIV

TERMINATION OF PREGNANCY

BEHAVIOURAL INTERVENTIONS

Reduction in the frequency of unprotected sexual intercourse during pregnancy
Reduction in the number of sexual partners during pregnancy
Lifestyle changes, including avoidance of drug use and smoking in pregnancy

THERAPEUTIC INTERVENTIONS

Antiretro viral therapy: zidovudine alone or combination, long- or short-regimen
Vitamin A and other micronutrients
Immunotherapy
Treatment of STI

OBSTETRIC INTERVENTIONS

Avoidance of invasive tests
Birth canal cleansing
Caesarean section delivery

MODIFICATION OF INFANT FEEDING PRACTICE

Avoidance of breastfeeding
Early cessation of breastfeeding

Heat treatment of expressed breast milk

The prevention of new infections in women of reproductive age remains an important component²⁴⁵. This includes the reduction of women's vulnerability to HIV-1 infection through the improvement of women's status in society, the provision of information about HIV/AIDS and its prevention, the promotion of safer sex including the use of barrier methods, and the adequate treatment of sexually transmitted infections^246,247. Women known to be HIV positive should have access to appropriate contraception and information to help them determine their future fertility. Access to termination of pregnancy for HIV positive women can also reduce the burden of paediatric AIDS cases, but should be viewed as an option for individual women, rather than a public health intervention for the prevention of transmission. Most women living with HIV will decide to continue with pregnancy, even where termination is offered^248,249.

Table 3: Some research projects in progress on the prevention of mother-to-child transmission of HIV (1998)

STRATEGY	RESEARCH PROJECTS
A: ANTIRETROVIRAL THERAPY	Phase III:
	1. PETRA: ZDV & 3TC
	2. ZDV alone in short-reginmen in breastfeeding women
	3. Nevirapine (HIVNET 012 & PACTG 316)
	Phase I/II:
	Drugs under investigation include: ddi, d4T, Nevirapine, Melfinavir, Ritonavir, Indinavir, Saquinavir, PMPA, MKC-442
B: ACTIVE IMMUNIZATION	1. Recombinant Gp120 vaccine to pregnant women (PACTG 235).
	2. Recombinant Gp120 to newborns; phase I/II (PACTG 230)
	3. Canary pox vaccine to newborns (PACTG 327)
C: PASSIVE IMMUNIZATION	1. HIVIG (Uganda)
	2. Phase I Katinger antibody
D: MICRON UTRIENTS	1. Vitamin A (Malawi: 10 OOOIU)
	2. Vitamin A (South Africa: 5000 IU+ B Carotene 30 mg)
	3. 13 Vitamin A 10 000 IU and 12 other vitamins and minerals (Zimbabwe)
	4. Factorial design Vitamin A & B Carotene (United Republic of Tanzania)
	5. Vitamin A (Zvitambo) (Zimbabwe) postpartum and to children
E: VAGINAL CLEANSING	Chlorhexidine (Kenya)
F: INFANT FEEDING	Randomized trial of breast vs formula feeding (Kenya)

The only interventions proven to be effective in reducing mother-to-child transmission of HIV at present are the use of zidovudine (either as long-course through pregnancy, labour and for six weeks to the infant, or as short-regimen), Caesarean section and the avoidance of breastfeeding^250,251,226. Research continues into a number of other alternatives, with a major focus on interventions active at the time of labour and delivery, when much of the transmission is believed to occur. Studies that are completed and in the analysis stage include a vitamin A study in Malawi, a randomized formula feeding study conducted in Nairobi and a self-selection study looking at the effects of breastfeeding on transmission in Soweto. Other studies on the effect of vitamin A administration (South Africa, the United Republic of Tanzania and Zimbabwe), vaginal disinfection (Kenya), and short-regimen antiretrovirals are ongoing. Postpartum interventions besides the use of formula feeding have not been studied. These trials are summarized in Table 3.