No mother-to-child HIV transmissions in Denmark since 2000 when treatment guidelines followed

Not a single mother-to-child HIV transmission occurred in Denmark when national treatment guidelines were followed, investigators report in the online edition of HIV Medicine. In the modern HIV treatment era, the overall transmission rate was 0.5%. Late diagnosis was implicated in every transmission.

“No women in this study treated according to national guidelines transmitted HIV to her children”, comment the investigators.

Antiretroviral treatment during pregnancy and labour, an appropriately managed delivery, infant prophylaxis, and the avoidance of breastfeeding can reduce the risk of mother-to-child HIV transmission to below 1%.

Danish investigators performed a retrospective study, which monitored the characteristics of HIV-positive pregnant women, their treatment and care, and the rate of mother-to-child transmission. The researchers analysed data from 1994 to 2008.

A total of 210 women were included in the study. They had a total of 255 pregnancies, giving birth to 258 infants. The annual number of births increased from seven in 1994 to 39 in 2006.

The majority (51%) of women were African. Before 1999, only 8% of women were aware that they were HIV-positive before their pregnancy. However, this increased to 80% between 2000 and 2008.

A total of eight women (six before 2001) were diagnosed so late that their HIV was not detected until delivery or after.

In the period after 2000, two-thirds of pregnancies were planned, a third with the assistance of an HIV physician. Fertility treatment was provided to 14% of women.

Overall 50% of women took antiretroviral drugs before pregnancy. The proportion increased as HIV treatment improved, from just 11% before 1999 to 58% after 2000.

HIV treatment was started during the first 14 weeks of pregnancy by 18% of women. Once again, a temporal trend was detected, the proportion increasing from 6% before 1999 to 19% in the period 2000 to 2008.

Antiretroviral therapy was started in the third trimester by 8%, and 7% never received any anti-HIV drugs. The main reason for this was very late diagnosis, but a small number of women refused treatment.

After 2000, nearly all women received triple-drug therapy, the preferred regimens being AZT and 3TC with either lopinavir/ritonavir or nevirapine.

An intravenous dose of AZT during labour was provided to 91% of women. The main factor associated with this treatment not being provided was late diagnosis.

Median CD4 cell count at the time of delivery was 444 cells/mm³. CD4 cell counts were higher amongst women who started treatment before the fourteenth week of pregnancy than those who initiated therapy later (p < 0.05).

Viral load was below 40 copies/ml at the time of delivery in 81% of women. Women who had started therapy before week 14 of pregnancy were significantly more likely to have a viral load of this level than those who started therapy later (87% vs 71%, p = 0.02).

Only 5% of women had a viral load above 1000 copies/ml – the threshold associated with a significant risk of transmission – at the time of delivery.

Before 2000, 84% of infants were delivered by caesarean section. However, between 2007 and 2008, 46% of women opted for a planned vaginal delivery.

A total of six infants were infected with HIV, providing an overall rate of 2.4%. This fell from 10% before 1999 to 0.5% in the period 2000 to 2008.

Five of the HIV-infected babies were delivered vaginally. None of the mothers received antiretroviral therapy.

In addition, four of the women were diagnosed so late that it was not possible to provide them with a dose of AZT during delivery.

One women who was unaware of her HIV infection until after delivery started breastfeeding.

“Mother-to-child transmission decreased from 10.4% in 1994-1999 to 0.5% in 2000-2008. In each case, the mother was diagnosed with HIV either during or shortly after delivery and none received antiretroviral therapy”, comment the investigators.

They add that there was only one case of vertical transmission in the period after 2000 and “no woman treated according to national guidelines transmitted HIV to her child.”

Denmark introduced routine antenatal HIV testing in January 2010. “This is expected to further reduce the mother-to-child transmission of HIV in Denmark”, conclude the researchers.