Theses days, use of powerful anti-HIV therapies have helped make transmission of HIV from mother to child a rarity. However, at the same time, there have been several cases of mother-to-child transmission of drug-resistant HIV, including multi-drug resistant HIV. Most of these have occurred in the setting of detectable viral load or high viral load during pregnancy, despite the use of anti-HIV therapies.
A few studies explored concerns about the prevalence and effect of drug resistance during pregnancy. One found that resistance to AZT at time of delivery was common among those who had received the drug prior to pregnancy. After adjusting for maternal viral load, CD4+ cell count and duration of labor, it also found that AZT resistance was independently linked to an increased risk of HIV vertical transmission. Additionally, the nevirapine study discussed above also found that resistance mutations associated with nevirapine at the time of delivery and six weeks after are common and may increase with lower CD4+ cell count (below 400). It also found that resistance to reverse transcriptase inhibitors and protease inhibitors were common. It is unknown whether resistance to these drugs increases risk of HIV transmission.
While there is still a lot to learn about the prevalence and risks of resistance during pregnancy, it remains an important concern. The prognosis for babies born with drug-resistant virus is poor. Pregnant women who are taking anti-HIV therapies, especially before pregnancy, are now encouraged to undergo a resistance test. This will help women and their doctors construct the most effective anti-HIV regimen in the course of pregnancy, minimizing potential risks linked to drug resistance, including the potential increased risk of mother-to-child HIV transmission.
Finally, a European study investigated the impact of pregnancy on CD4+ cell counts in women that became pregnant in the course of the study. All women had a known date of when they became HIV-positive (seroconversion). The study found that pregnant women had slightly lower CD4+ cell counts than non-pregnant women (401 vs. 450). In general, pregnant women have lower CD4+ cell counts than women who are not pregnant. During pregnancy CD4+ cell counts decline temporarily, but return to pre-pregnancy levels after the child is born. This return to pre-pregnancy CD4+ cell levels occurred in this study as well. These results suggest that pregnancy -- and potentially hormonal changes that occur therein -- does impact CD4+ cell count, though they do not seem to have an overall negative impact on HIV disease progression rates.
Women with abnormal Pap results usually undergo what is considered a more sensitive screening technique called colposcopy. Sometimes, but not always, colposcopy is accompanied by biopsy. The results of these tests are then used to determine the most appropriate course of treatment.
A new study by the Women's HIV Interagency Study (WHIS) shows that colposcopy alone, without an accompanying biopsy, does a poor job showing cervical abnormalities. Because identifying the degree of the problem is critical in treating it, the study suggests that biopsy -- which can best show the degree of damage -- should become a routine component of colposcopy. But because biopsy can hurt and cause bleeding, it may not be preferable for everyone. Colposcopy plus biopsy may best be warranted in women most at risk for high-grade cervical abnormalities, such as those women with a history of problems related to HPV and/or lower CD4+ cell counts.
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