Discontinuing combination antiretroviral therapy during the first trimester of pregnancy: Insights from plasma human immunodeficiency virus-1 RNA viral load and CD4 cell count

Efavirenz use during pregnancy and for women of child-bearing potential

BACKGROUND

Efavirenz is the preferred non-nucleoside reverse transcriptase inhibitor for first-line antiretroviral treatment in many countries. For women of childbearing potential, advantages of efavirenz are balanced by concerns that it is teratogenic. This paper reviews evidence of efavirenz teratogenicity and considers implications in common clinical scenarios.

FINDINGS

Concerns of efavirenz-induced fetal effects stem from animal studies, although the predictive value of animal data for humans is unknown. Four retrospective cases of central nervous system birth defects in infants with first trimester exposure to efavirenz have been interpreted as being consistent with animal data. In a prospective pregnancy registry, which is subject to fewer potential biases, no increase was detected in overall risk of birth defects following exposure to efavirenz in the first-trimester.

DISCUSSION

For women planning a pregnancy or not using contraception, efavirenz should be avoided if alternatives are available. According to WHO guidelines for resource-constrained settings, benefits of efavirenz are likely to outweigh risks for women using contraception. Women who become pregnant while receiving efavirenz often consider drug substitution or temporarily suspending treatment. Both options have substantial risks for maternal and fetal health which, we argue, appear unjustified after the critical period of organogenesis (3-8 weeks post-conception). Efavirenz-based triple regimens, initiated after the first trimester of pregnancy and discontinued after childbirth, are potentially an important alternative for reducing mother-to-child transmission in pregnant women who do not yet require antiretroviral treatment.

CONCLUSION

Current recommendations for care for women who become pregnant while receiving efavirenz may need to be re-considered, particularly in settings with limited alternative drugs and laboratory monitoring. With current data limitations, additional adequately powered prospective studies are needed.

Treating HIV During Pregnancy

The expanded use of multiple antiretroviral drugs during pregnancy has led to a reduction in the occurrence of perinatal transmission of HIV to <2%, but has led to concerns regarding both short-term toxicity and the long-term impact on the woman and her child. Enhanced toxicity of nevirapine has been noted among women with CD4+ lymphocyte counts >250 cells/microL at treatment initiation and among pregnant women on long-term didanosine and stavudine. These drugs should be avoided in such situations if alternatives are available. Efavirenz has been associated with birth defects in monkeys, and several cases of neural tube defects have been reported in humans after first trimester exposure, so treatment with this drug should be avoided during the first trimester. Protease inhibitors have been associated with an increased risk of maternal glucose intolerance, pre-eclampsia and preterm birth in some, but not all, studies. Pregnancies exposed to antiretroviral therapy should be registered with the Antiretroviral Pregnancy Registry as early in pregnancy as possible in order to provide data on the risk of birth defects after exposure. The pharmacokinetics of nucleoside and non-nucleoside reverse transcriptase inhibitors are not significantly changed in pregnancy, so standard dosing may be used. However, concentrations of several protease inhibitors are lower in pregnancy, so ritonavir-boosting or increased doses are required. Of great theoretical concern is the impact of resistance mutations that develop following single-dose nevirapine therapy on the response to later therapy among women and their infected infants. The use of dual nucleoside therapy for 3-7 days after single-dose nevirapine in the mother reduces but does not eliminate the risk of nevirapine resistance; alternative regimens for prevention of resistance are under study, as are the subsequent responses of the mother and her infant to therapy. Short courses of prophylactic zidovudine and nevirapine have been well tolerated in neonates. Concern has been raised, however, that these exposures may lead to persistent mitochondrial dysfunction or later cancers, underscoring the need for long-term surveillance of antiretroviral-exposed, HIV-uninfected infants.

Early invasive diagnostic techniques in pregnant women who are infected with the HIV: a multicenter case series

OBJECTIVE

Studies that mostly were conducted before the widespread use of combination antiretroviral treatments have reported that antenatal invasive procedures markedly increase the risk of human immunodeficiency virus vertical transmission. We aimed to evaluate the vertical transmission rate and other maternal and neonatal complications among women who were infected with human immunodeficiency virus who underwent antenatal invasive procedures during the second trimester of pregnancy and who were delivered after the advent of antiretroviral regimens.

STUDY DESIGN

We conducted a multicenter case series of women who were infected with human immunodeficiency virus who underwent amniocentesis or chorionic villus sampling or cordocentesis during the second trimester of pregnancy and who were delivered after January 1, 1997.

RESULTS

Sixty-three of 775 recruited women (8.1%) had performed early invasive diagnostic techniques . This rate has improved progressively from 4% in 1997 to 14%. Two of 60 viable infants (3.3%; 95% CI, 0.6%-10.1%) were infected with the human immunodeficiency virus. This rate did not differ significantly from the transmission rate that was observed in women who did not undergo antenatal invasive techniques (1.7%; P = .30).

CONCLUSION

The current risk of human immunodeficiency virus vertical transmission that is associated with early invasive diagnostic techniques is lower than previously reported.