Vaginal douching, bacterial vaginosis, and spontaneous preterm birth.
OBJECTIVE
Vaginal douching and bacterial vaginosis (BV) are independently associated with spontaneous preterm birth. Because the interrelationships among these variables remain unclear, we sought to examine the associations in a prospective study.


METHODS
We conducted a nested case-control study within a prospectively recruited cohort of pregnant women. We prospectively collected demographic and health status data, data on pre-pregnancy vaginal douching, vaginal smears for bacterial vaginosis as defined by Nugent's criteria, fetal fibronectin at 26 weeks of pregnancy, and placental pathology at delivery. Spontaneous preterm births before 37 weeks' gestation were selected as cases. All spontaneous births occurring after 37 weeks were potential control subjects. To limit costs, some tests were performed only in selected control subjects.


RESULTS
Preterm birth occurred in 207 of 5092 women (4.1%). In bivariate analysis, BV was not associated with preterm birth (OR 1.2; 95% CI 0.5 to 2.4). Vaginal douching was significantly associated with bacterial vaginosis (P < 0.05) and preterm birth (P < 0.05). On multivariate analysis, vaginal douching was no longer associated with preterm birth, but a significant association with early preterm birth < 34 weeks (OR, 6.9; 95% CI 1.7 to 28.2) and preterm birth due to preterm labour (OR 3.0; 95% CI 1.1 to 8.5) persisted after controlling for the presence of bacterial vaginosis and placental inflammation.


CONCLUSIONS
Vaginal douching and bacterial vaginosis were not associated with spontaneous preterm birth overall. However, vaginal douching appears to be an independent and potentially modifiable risk factor for early preterm birth (32-34 weeks), although the mechanism remains unclear.
Luong
Me-Linh
ML
Department of Microbiology and Immunology, McGill University, Montreal QC.
Libman
Michael
M
Department of Microbiology and Immunology, McGill University, Montreal QC.
Dahhou
Mourad
M
Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal QC.
Chen
Moy Fong
MF
Department of Pathology, McGill University, Montreal QC.
Kahn
Susan R
SR
Department of Medicine, McGill University, Montreal QC.
Goulet
Lise
L
Département de médecine sociale et préventive, Université de Montréal, Montréal (Quebec).
Séguin
Louise
L
Département de médecine sociale et préventive, Université de Montréal, Montréal (Quebec).
Lydon
John
J
Department of Psychology, McGill University, Montreal QC.
McNamara
Helen
H
Department of Obstetrics and Gynecology, McGill University, Montreal QC.
Platt
Robert W
RW
Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal QC; Department of Pediatrics, McGill University, Montreal QC.
Kramer
Michael S
MS
Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal QC; Department of Pediatrics, McGill University, Montreal QC.
D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015999:Multivariate Analysis; D007752:Obstetric Labor, Premature / Q000453:epidemiology; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D011446:Prospective Studies; D012307:Risk Factors; D044364:Vaginal Douching / Q000009:adverse effects*; D016585:Vaginosis, Bacterial / Q000453:epidemiology*