500,000 infants become infected with HIV each year. The majority of these infections result from transmission of virus from HIV-infected mothers during childbirth or by transfer of virus from milk during breast-feeding. The incidence of maternal acquired infection can be reduced as much as 67% by treatment of the infected mother with a course of Zidovudine (AZT) for several months prior to delivery, and treatment of her infant for 6 weeks after birth. This treatment regimen is widely used in the U.S. However, the majority of worldwide HIV infection of infants occurs in sub-Saharan Africa and other less developed areas, where the cost and timing of the Zidovudine regimen render it an impractical solution to the problem of maternal-infant HIV transmission.
A 1999 clinical trial of the anti-retroviral Nevirapine (viramune) brings hope for a practical way to combat infant HIV infection under less than ideal conditions of clinical care. The trial took place at Mulago Hospital in Kampala, Uganda, and enrolled 645 mothers who tested positive for HIV infection. About half of the mothers were given a single dose of Nevirapine at the onset of labor and their infants were given a single dose 24-30 hours after birth. The dose and timing were dictated by the customary rapid discharge at the hospital. The control arm of the study involved a more extensive course of Zidovudine, but in-country conditions did not allow exact replication of the full course administered to infected mothers in the U.S.
The overall rate of infection for infants born to untreated mothers is esti mated to be about 37%. When the full course of Zidovudine is used, the rate drops to 20%. The highly encouraging results of the Uganda study revealed infection in only 13.1% of the babies in the Nevirapine group when tested at 16 weeks of age. Of those given a short course of Zidovudine, 25.1% were infected at this age compared to 40.2% in a small group given placebo. From this study it appears that the single dose of Nevirapine is the most effective means found thus far to prevent maternal-infant transmission of HIV infection—even better than the more extensive and costly regimen currently used in developed countries. These results must be verified and the possibility of unexpected side effects must be explored. However, this result gives hope for reduction of infant infection in parts of the world where access to medical care is limited.
As mentioned above, the study was designed to conform to the reality of maternal health care in Kampala; it fits this system perfectly. The use of Nevirapine has other significant advantages, including stability of the drug at room temperature and reasonable cost. The dose of Nevirapine administered to the mother and infant costs about 200 times less than the Zidovudine regimen in current use in the U.S. In fact, the treatment is sufficiently inexpensive to suggest that it may be cost-effective to treat all mothers at the time of delivery in those areas where rates of infection are high, because the Nevirapine treatment costs less than the tests used to determine HIV infection. Obviously, such a strategy must be embarked upon cautiously, given the danger of long-term side effects and other unexpected problems.
Mural showing mother and child on an outside wall of Mulago Hospital Complex in Kampala, Uganda, site of the clinical trial demonstrating that maternal-infant HIV-1 transmission was greatly reduced by Nevirapine. [Courtesy of Thomas Quinn, Johns Hopkins University.]
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The first trimester is very important for the mother and the baby. For most women it is common to find out about their pregnancy after they have missed their menstrual cycle. Since, not all women note their menstrual cycle and dates of intercourse, it may cause slight confusion about the exact date of conception. That is why most women find out that they are pregnant only after one month of pregnancy.