Substantial increases in prenatal HIV testing rates in USA and Canada 1998-2001

The availability of increasingly effective antiretroviral drugs for prevention of transmission and maternal treatment has resulted in greater emphasis on prenatal HIV testing. In 2000, preliminary unpublished data from the Centers for Disease Control (CDC) in Atlanta indicated that 766 (93%) of 824 HIV-positive women in 25 States knew their status before delivery.

Each year an estimated 280-370 perinatal HIV transmissions occur in the USA.

In the USA and Canada three different prenatal HIV testing approaches have been implemented. The CDC reviewed prenatal HIV antibody testing rates to assess their effectiveness.

Under the opt-in approach, women typically are provided pre-HIV test counseling and must consent specifically to an HIV test. Under the opt-out approach, women are notified that an HIV test will be included in a battery of prenatal tests and procedures and that they may refuse testing. Under mandatory newborn HIV testing, newborns are tested for HIV, with or without the mother’s consent, if the mother’s HIV status is unknown at delivery.

Medical record data suggest that the opt in voluntary testing approach is associated with lower testing rates than either the opt-out or the mandatory newborn HIV testing approach.

Three different approaches were used to estimate prenatal testing rates among all women who delivered, regardless of whether they received prenatal care; firstly, eight U.S. areas that participated during 1998-1999 in CDC’s Active Bacterial Core Surveillance/Emerging Infections Program (ABC) Network assessed HIV testing during prenatal care and

Secondly, public health investigators in each of the five Canadian provinces tallied the number of HIV tests among pregnant women that were submitted to provincial laboratories and divided the total by an estimate of all live and stillborn births in each province during the same year. Finally CDC analysed weighted data collected in 1999 by interviewers in nine states for CDC’s Pregnancy Risk Assessment Monitoring System (PRAMS) (an ongoing, population based survey conducted in 32 states and New York City among women who have given birth in the preceding 2-6 months) who had asked women if they had been tested for HIV during pregnancy.

HIV testing rates varied depending upon which approach was used. Rates for states using the opt in approach to prenatal HIV testing included in the ABC Network ranged from 25% to 69%, testing rates in Canada ranged from 54% to 83%, and rates derived from the PRAMS data ranged from 61% to 81%.

Two U.S. states Arkansas and Tennessee and two Canadian provinces (Alberta, and Newfoundland and Labrador) reported using an opt-out prenatal HIV testing policy. ABC Network data indicated that Tennessee had a testing rate of 85%. Canada’s population-based data indicated a 98% testing rate in Alberta and a 94% testing rate in Newfoundland and Labrador. PRAMS interview data indicated a 71% testing rate in Arkansas, compared with a 57% testing rate in early 1997 before the law was implemented. Two states New York and Connecticut require HIV testing of newborns whose mothers were not tested during pregnancy.

Network review of medical records in the seven counties in the Rochester area indicated that the proportion of pregnant women who received a prenatal HIV test increased from 52% of 438 charts during January 1998-July 1999 to 83% of 112 charts during August-December 1999 after New York required that newborn HIV testing results be made available within 48 hours of specimen collection. PRAMS data for the state of New York in 1999 indicated that the proportion of women statewide who reported having received an HIV test during pregnancy increased from 69% of 758 women during January-July to 93% of 502 during August-December.

Among the three prenatal HIV testing approaches assessed, opt out voluntary testing and the mandatory testing of newborns appear to be associated with the highest testing rates. CDC is working with states with high HIV prevalence rates among women of childbearing age and high numbers of paediatric AIDS cases to ensure standardized monitoring of prenatal testing rates. The data suggest that jurisdictions that use an opt-in approach and that have low prenatal HIV testing rates should reevaluate their approach.