HIV and Aids During Pregnancy

 

Mother to Child Transmission of Hiv

Mother-to-child transmission (MTCT) or vertical transmission of HIV is one of the major causes of HIV infection in children. It is estimated that about 600 000 children are infected in this way each year, and this figure accounts for 90% of HIV infections in children (WHO, 2000a). Unless preventative measures are taken, 20-40% of children born to HIV-positive women are infected. HIV can be transmitted from an infected mother to her baby via the placenta during pregnancy, through blood contamination during childbirth, or through breastfeeding.

A mother is more is more likely to pass the HI virus to the baby during pregnancy, childbirth or breastfeeding if:

• She becomes infected with HIV just before the pregnancy, during the pregnancy or during the breastfeeding period (because she will have a high viral load in her blood or breast milk during seroconversion)
• She has advanced, symptomatic HIV disease with:
  1. high viral load (>50 000 viral particles/ml);
  2. A low CD4 cell count (<2000 cells/mm³); and
  3. Symptoms of AIDS.

PREGNANCY

Although most mother-to-child transmissions occur close to the time of delivery or during the birth process, it is estimated by some researchers that up to 23% of transmissions occur in utero even as early as the first trimester of pregnancy (Schoub, 1999). As has been explained, a woman is more likely to transmit the virus to her fetus during pregnancy if she becomes infected just before or during pregnancy, or if she has an HIV-related illness or AIDS (the last phase of the infection). This is because at these times the viral load is usually very high and the CD4 cell count low. Any situation that may result in an increase in the viral load (e.g. an infection such as tuberculosis) will add to the risk of transmitting the virus to the baby.

 

Pregnancy itself does not seem to have any significant effect on the progress of HIV disease if the mother is in the early asymptomatic phase of infection. In women who have more advanced HIV pregnancy may cause more rapid progress to AIDS. Generally, HIV seems not to have a serious affect on pregnancy, but there are indications from some parts of Africa that HIV infection may cause increased likelihood of intra-uterine growth retardation, prematurity, stillbirths and congenital infections (Evian, 2003).

 

Mother-to-child transmission of HIV during pregnancy can be reduced in the following ways:

• Prevent new HIV infections. New infections during pregnancy may increase the viral load which will increase the risk of mother-to-child transmission.
• Prevent and treat sexually transmitted infections. Genital infections and sexually transmitted infections may result in infections of the placenta.
• Give nutritional supplements such as iron, folate and multivitamins including vitamin A. These supplements have been shown to reduce the incidence of stillbirth, prematurity and low birth weight.
• Offer prophylactic antiretroviral therapy. This can reduce mother-to-child transmission by 50-60% when given during pregnancy and labour (see 'Using antiretroviral therapy to prevent mother-to-child transmission of HIV' on page 108).
• Encourage frequent follow-up visits to the clinic so that the mother's health can be monitored regularly.
• Perform fetal monitoring with non-evasive procedures.
• Offer counselling on safe sexual practices during pregnancy - preferably to both partners..

 

Re-infection with HIV should be avoided

• HIV-positive individuals often think that they no longer have to protect themselves against infection by HIV. It is, however, very important for an HIV-positive person to protect himself or herself against re-infection with HIV. Each new infection can cause an increase in the viral load in the blood, and the person infected for a second or subsequent time may get a new strain of the virus. HIV-positive women should always use condoms to prevent re-infection. Any new HIV infection during pregnancy or breastfeeding is likely to result in an increase in the viral load, and this will increase the likelihood of mother-to-child transmission. Re-infection may also cause the mother's disease to progress more rapidly

 

CHILDBIRTH

 

More than 60% of cases of transmission of HI infection from a mother to her baby occur during labour and delivery. The main reason for this is contact with the mother's blood and mucus in the birth canal during the birth process.

 

Mother-to-child transmission during labour can be reduced in the following ways (Evian, 2003)

• Give antiretroviral therapy to mother and baby (see ‘Using antiretroviral therapy to prevent mother-to-child transmission of HIV’ on page 108).
• Disinfect the birth canal with an antiseptic solution such as 1.25% chlorhexidine during vaginal examinations.
• Avoid unnecessary artificial rupture of the membranes. Rupture of membranes for longer than four hours before delivery is associated with increases in mother-to-child transmission. Artificial rupture of the membranes should only be done if there are specific obstetric indications and then as late as possible.
• Avoid episiotomy (cutting the vulva to avoid lacerations of the perineum during labour) unless it is absolutely necessary.
• Minimise trauma to the baby by avoiding procedures such as fetal scalp monitoring, forceps delivery and vacuum extraction. These may cause minor skin lacerations.
• In women with very high viral loads, carry out elective caesarean sections if possible. Elective caesarean sections are not recommended as a routine measure, because they are costly and impractical in resource-constrained settings and pose the risk of postoperative complications.

 

Mother-to-child transmission after the birth can be reduced in the following ways::

• Avoid trauma to the newborn;
• Wipe away secretions from the baby's face;
• Give the baby antiretroviral prophylaxis for the first 6 weeks;
• Consider alternatives to breastfeeding if possible.

 

BREASTFEEDING

About 20 - 30% of babies who are infected through mother-to-child transmission contract the virus through breastfeeding (WHO, 2000a). The baby may be at greater risk from breastfeeding if the mother was infected with HIV late in her pregnancy or in the months following birth because of the higher viral load during the seroconversion phase of infection. Women are also more infectious when they show symptoms of AIDS. Mother-to-child transmission from breastfeeding can, however, occur at any time during the course of the mother's HIV infection, and HIV-infected cells are present in the breast milk of HIV-positive mothers throughout the breastfeeding period. What makes this risk even higher is that 80 - 90% of women in rural and remote areas in Africa breastfeed their babies for as long as 2 years. Some African studies have shown that breastfeeding increases the risk of infection by 12 - 43%.

 

Factors that may also affect mother-to-child transmission during breastfeeding are a vitamin A deficiency in the mother or child, breast diseases such as mastitis, cracked nipples, and diseases such as thrush and gastroenteritis in the infant.

 

The debate on breastfeeding versus bottle feeding in Africa involves complex issues that include the following::

• Formula milk may not be readily available in poor communities.
• Mothers may not have access to clean and safe water supplies with which to prepare the feed.
• Mothers may not know how to sterilise bottles.
• Mothers may not know how to prepare the formula mild and what the correct powder-to-water ratio should be.
• Mothers may not know that they should use clean, boiled-and-cooled water for formula feeding.
• Mothers may not have access to fuel to boil water.
• Some mothers may also not realise that they will compromise the baby's health if they add more water (increase the water in the water-powder ratio) in an attempt to save money or to use the extra milk powder to feed other children in the family.

 

Expression and pasteurisation of breast milk

Mother-to-child transmission of HIV may also be prevented if breast milk is expressed and pasteurised. Researches at Kalafong Hospital in South Africa investigated methods of pasteurising infected breast milk which would render the HI virus inactive. Pasteurisation usually occurs at temperatures of 56 - 62 degrees Celsius. The HI virus is inactivated at these temperatures because its protein structure is broken down. To pasteurise the milk in hospitals, it should be heated to 62.5 degrees Celsius for 30 minutes. At home it can be heated and then cooled immediately by putting it in a refrigerator or standing the container in cold water. Heat-treated breast milk should be put in a sterilised or very clean container and kept in a refrigerator or in a cool place before and after heat treatment to minimise contamination (prevention of mother-to-child transmission 2000)

The following method for pasteurising HIV-positive mothers' milk at home was proposed by researchers at Kalafong Hospital. The mother boils 500ml of water in an aluminium pot. After the water has reached boiling water, she takes the pot off the stove and places a glass container (for example a clean peanut-butter jar) containing her expressed milk into the pot. As soon as the glass container is placed into the water, the temperature of the water begins to cool down while the temperature of the milk begins to rise to about 60 degrees Celsius - the ideal temperature for pasteurisation (Jeffery et al., 2000).

 

The World Health Organisation's View on Breastfeeding

The World Health Organisation still recommends breastfeeding in poor countries to prevent babies dying from gastroenteritis and malnutrition. The health care professional should take all the circumstances of each mother into account before making a decision about whether to advise a mother to breastfeed or feed a breast -milk substitute from a bottle. She should also consider the health status of the other children in the area where the mother lives. If other children in the community are at risk of or already dying from infections (such as respiratory infections or diarrhoea) and suffering poor nutrition, it is probably safer to breastfeed her baby.

The issue of bottle feeding should be handled very sensitively in Africa. Since mothers usually breastfeed in public, they are often stigmatised as being HIV-positive when they do not breastfeed their babies.

                    (Extracted from"HIV/AIDS Care & Counselling" - Alta van Dyk; 2008)