The overall mother-to-child transmission (MTCT) rate among HIV-positive women in St. Petersburg, Russia was 6.3%, a three-year study has revealed; the shorter the duration of treatment, the fewer drugs used and the later the start, the higher the rate of transmission.
A significantly reduced transmission rate of 2.7%, seen in a minority of women (12.8% or 149) who had dual or triple antiretroviral therapy throughout their pregnancy, showed the possibility for further reductions in perinatal transmission in Russia, Susan D Hillis and colleagues reported in a study published in the advance online edition of the Journal of Acquired Immune Deficiency Syndromes.
Over two-thirds of women started ART late in their pregnancy or not at all, and these women were more likely not to have received antenatal care, were active injecting drug users and were non-residents of the city.
While interventions that include antiretroviral prophylaxis have reduced MTCT rates from 15% to 30% to below 2% in some parts of the world, it is still the primary route of HIV infection in children worldwide.
The proportion of new infections among women continues to increase in Russia. From 1998 to 2002 the prevalence of HIV among women giving birth in St. Petersburg increased 100-fold (from 0.013% to 1.3%). The increase in HIV infection among women and the high rates of unintended pregnancies has led to increasing numbers of infants at risk of HIV infection.
Maternal and child health services are free in the Russian Federation. However, those women especially vulnerable and at high risk of HIV infection, notably intravenous drug users (IDUs), non-IDU sex partners of drug users and migrant women from other regions of Russia, do not use these services, which include antenatal care with routine HIV testing.
So women who do not get antenatal care do not get HIV counselling and testing, and miss out on family planning counselling and contraceptive methods. This means increased risk to their own health, risk of unintended pregnancies and of mother-to-child transmission.
Women at high risk who deliver in a maternity hospital are tested for HIV, but often they are not tested until the onset of labour. If the woman does test positive, the results are received too late to provide ART during labour.
The Russian Ministry of Health specifies a number of regimens that can be used in pregnancy, according to the mother’s health. These include dual (zidovudine and lamivudine) or triple antiretroviral therapy (AZT, 3TC and lopinavir/ritonavir), zidovudine (AZT) monotherapy, or single-dose nevirapine (sdNVP) to the mother and infant (for women who do not get any treatment until they go into labour).
The authors analysed data from 2004 to 2007 from a surveillance system set up to collect routine data on all HIV-infected women who gave birth in any of the three (out of 17 maternity) hospitals in St. Petersburg that provide services for this population.
They looked at MTCT rates, how type of regimen and length of treatment affected these rates and whether women who got treatment late or not at all had particular characteristics.
Of the three hospitals, one provides care to women with serious infectious diseases including HIV. The other two are referral hospitals for women at high-risk with no or incomplete HIV testing. Transportation by ambulance is provided at no cost.
A total of 1498 (75%) HIV-infected women delivered live-born infants. Testing data were available for 1159 mother-infant pairs. Of these, 85% were city residents and so eligible for free HIV care and treatment.
Over half of the mothers reported a history of injecting drug use, and close to one-third reported injecting drugs during the pregnancy. The latter group, as well as those who started ART late or not at all, were the most likely to abandon their infants to the care of the state.
The lowest risk for perinatal transmission (2.7%) was associated with women who received full-course antiretroviral therapy, of whom 140 received two-drug prophylaxis; nine women received three-drug prophylaxis.
MTCT rates increased the later ART was started: if started at 20 weeks or less into the pregnancy, the rate was 1.8%; from 21 to 28 weeks, 4%; at or later than 29 weeks, 8.6%; and for those receiving treatment at the onset of labour and during delivery, the rate rose to 11.3%.
MTCT rates increased with less complete types of treatment regimen: 607 (52.4%) women who received full-course AZT had a 4.1% rate; 173 (14.9%) women received single-dose nevirapine with a corresponding 9.3% rate and 230 (19.8%) women who received an incomplete regimen had a 12.2% rate.
The authors note that their study highlights that, even with ART widely available in Russia, only a minority of HIV-positive pregnant women in St. Petersburg had access to a full course of ART. However, given the low transmission rate among this minority, the authors point to the opportunity this presents to further reduce MTCT rates in Russia.
The authors suggest that referral into care is feasible for those newly identified women as well as those known to be HIV-positive who access antenatal care late in pregnancy. Rapid HIV testing, together with case management, would help women get started on ART early. In addition, they add, case management would also help women who report intravenous drug use get HIV care earlier.
The authors suggest that current outreach to IDUs could be enhanced by actively linking women of reproductive age to health care at the first signs of pregnancy.
They note that their study revealed that, while less than a third of HIV-positive women failed to present for health care until labour and delivery, they represented over half of all cases of mother-to-child transmission.
The authors conclude that their estimates suggest that “improvements in clinic-based antepartum interventions alone (assuming 1.8% transmission in all women presenting before labour and delivery) which do not include active outreach for this group (assuming 11.3% transmission in those presenting at labour and delivery), have the potential to reduce the overall transmission rate from 6.3% to 5%. “
They add, however, that the recent growth in HIV resources in Russia supports the possibility of an accelerated reduction of MTCT by “combining clinic-based and community-based interventions so that transmission rates more closely resemble the 2% rate observed in other countries.”
Hillis SD et al. Antiretroviral prophylaxis to prevent perinatal HIV transmission in St. Petersburg, Russia: too little, too late. Journal of Acquired Immune Deficiency Syndromes, advance online edition, March 2010.