Dr. Laurent Mandelbrot of the University of Paris, France and associates investigated mother-to-child transmission in twins, compared with singletons, born to HIV-1-infected mothers in the French Perinatal HIV Cohort.

Before the advent of highly active antiretroviral therapy (HAART), the mother-to-child transmission rate in twin pregnancies was two to three times that in singleton pregnancies, the investigators report. Since HAART began in 1997, rates have been similarly low in both groups.

The pre-HAART data indicate that, after adjustment for gestational age, parity, geographical origin, maternal CD4 cell count, and mode of delivery, the results indicate, twin pregnancy remained associated with a 2.3-fold increased risk of MTCT.

The association was particularly strong, the researchers note, in case of premature rupture of the membranes (which occurred nearly three times as often in twin pregnancies), which conveyed a 4.5-fold increased risk of vertical transmission.

"In cases of multiple pregnancies in HIV-infected women, management must take into account the risk of preterm premature rupture of the membranes and preterm delivery," the investigators conclude. "In particular, we would recommend starting effective antiretroviral therapy no later than beginning of the second trimester."

AIDS 2007;21:993-1002.

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