Correspondence
Prolonged Rupture of Membranes and Transmission of the Human Immunodeficiency Virus
N Engl J Med 1996; 335:1533-1534November 14, 1996
- Article
To the Editor:
Landesman et al. (June 20 issue)1 report that the risk of transmission of the human immunodeficiency virus type 1 (HIV-1) from mother to infant increases rapidly when the amniotic membranes rupture more than four hours before delivery. That this factor plays an important part in HIV infection, as it does in most perinatally acquired infections of newborns, appears to be true, as the authors state. Our reading of their Table 2 leads us to a different conclusion about the four-hour limit, however.
When the rupture of membranes occurred less than 1 hour before delivery, the infection rate was 13 percent (21 of 158); when it occurred 1 to 4 hours before delivery, the rate was 15 percent (18 of 123); when it occurred 5 to 12 hours before delivery, the rate was 21 percent (24 of 114); when it occurred 13 to 24 hours before delivery, the rate was 18 percent (9 of 50); and when it occurred more than 24 hours before delivery, the rate increased to 45 percent (19 of 42). The infection rate in the group that had ruptured membranes for less than one hour probably indicates the rate of antepartum infection. So there may be a very slight increase in maternal–infant transmission of HIV-1, up to approximately 19 percent, when the rupture of membranes occurs 1 to 24 hours before delivery. The infection rate increases tremendously after 24 hours, however, with nearly half the infants being infected.
Therefore, it seems incorrect simply to include the women with rupture of membranes more than 24 hours before delivery in the group with rupture more than 4 hours before delivery. It would be more correct to say that among mothers with prolonged rupture of membranes, the transmission of HIV-1 is reduced from 45 percent to 19 percent when the length of time from rupture to delivery is limited to 24 hours at most. This 24-hour limit would be similar to the limit in the case of most perinatal infections.
1 ReferencesMarina A.W. Umans-Eckenhausen, M.D.
Harrie N. Lafeber, M.D., Ph.D.
Free University Hospital, 1081 HV Amsterdam, the Netherlands1
Landesman SH ,Kalish LA ,Burns DN , et al. Obstetrical factors and the transmission of human immunodeficiency virus type 1 from mother to child. N Engl J Med 1996;334:1617-1623
Full Text | Web of Science | Medline
Author/Editor Response
The authors reply:
To the Editor: Umans-Eckenhausen and Lafeber correctly point out that the relative risk of transmission was highest for women who had ruptured membranes for more than 24 hours. However, the small number of women in this category (8 percent of the cohort) makes inferences and conclusions drawn from this finding less certain.
We chose to emphasize the difference between rupture of membranes lasting four hours or less and that lasting more than four hours for two reasons. First, as we mentioned in the article, this cutoff was one we chose a priori on the basis of previously published studies. Second, our categorical analysis and the regression model both indicated that the risk of transmission first began to increase when the rupture of membranes occurred four hours before delivery or thereabouts, making women in whom it occurred earlier preferable candidates for intervention.
We do not agree that women whose membranes were ruptured for less than one hour who transmitted HIV-1 to their infants probably did so ante partum. To assess this matter, we studied mothers who gave birth to infected infants with at least one “early” viral culture (i.e., a culture performed at seven days of age or earlier). It has been proposed that a positive culture obtained in an infant during that period indicates antepartum (in utero) transmission. Only 4 of the 16 infants whose mothers had ruptured membranes for less than 1 hour (25 percent) had positive early cultures, as compared with 2 of 12 infants born to mothers who had ruptured membranes for more than 24 hours. This is as would be expected. If the duration of ruptured membranes is an important factor in HIV-1 transmission (one presumably related to an increased rate of transmission in the intrapartum period), we would expect women who transmit HIV after a short period of ruptured membranes to be overrepresented among cases of in utero or early transmission as compared with those who transmit the virus after a lengthy period of rupture. However, even with rupture of membranes occurring less than one hour before delivery, there was evidence clearly suggestive of antepartum or in utero transmission in only 25 percent of cases.
Sheldon H. Landesman, M.D.
State University of New York Health Science Center at Brooklyn, Brooklyn, NY 11203David N. Burns, M.D., M.P.H.
National Institute of Child Health and Human Development, Bethesda, MD 20892Leslie A. Kalish, D.Sc.
New England Research Institutes, Watertown, MA 02172
