The Preterm Prediction Study: association of second-trimester genitourinary chlamydia infection with subsequent spontaneous preterm birth.
OBJECTIVE
This study was undertaken to determine the association between genitourinary tract infection with Chlamydia trachomatis and spontaneous preterm birth.


METHODS
Genitourinary tract infection with C trachomatis was determined with a ligase chain reaction assay of voided urine samples collected at 24 weeks' gestation (22 weeks' to 24 weeks 6 days' gestation) and 28 weeks' gestation (27 weeks' to 28 weeks 6 days' gestation). Case patients (spontaneous preterm birth at <37 weeks' gestation; n = 190) and control subjects (delivery at >/=37 weeks' gestation, matched for race, parity, and center; n = 190) were selected from 2929 women enrolled in the Preterm Prediction Study of the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.


RESULTS
Genitourinary C trachomatis infection (11% overall) was significantly more common among the case patients than among the control subjects at 24 weeks' gestation (15.8% vs 6.3%; P =.003) but not at 28 weeks' gestation (12.6% vs 10.9%; P =.61). Women with chlamydia infection were more likely to have bacterial vaginosis (57.1% vs 32.9%; P =.002) and a short cervical length (</=25 mm; 33.0% vs 17.9%; P =.02) but not a body mass index <19.8 kg/m(2) (35.0% vs 23.9%; P =.17) or a positive fetal fibronectin test result (7.1% vs 9.5%; P =.62). After adjustment for risk factors for spontaneous preterm birth, women with C trachomatis infection at 24 weeks' gestation were 2 times as likely as uninfected women to have a spontaneous preterm birth at <37 weeks' gestation (odds ratio, 2.2; 95% confidence interval, 1.03-4.78) and 3 times as likely to have a spontaneous preterm birth at <35 weeks' gestation (odds ratio, 3.2; 95% confidence interval, 1.08-9.57).


CONCLUSIONS
Genitourinary C trachomatis infection at 24 weeks' gestation was associated with a 2-fold to 3-fold increased risk of subsequent spontaneous preterm birth.
Andrews
W W
WW
National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network, the University of Alabama at Birmingham, Birmingham, AL 35249-7333, USA.
Goldenberg
R L
RL
Mercer
B
B
Iams
J
J
Meis
P
P
Moawad
A
A
Das
A
A
Vandorsten
J P
JP
Caritis
S N
SN
Thurnau
G
G
Miodovnik
M
M
Roberts
J
J
McNellis
D
D
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002690:Chlamydia Infections / Q000150:complications* / Q000453:epidemiology; D002692:Chlamydia trachomatis / Q000235:genetics / Q000302:isolation & purification; D011088:DNA Ligases; D004269:DNA, Bacterial / Q000652:urine; D005260:Female; D052776:Female Urogenital Diseases / Q000382:microbiology*; D005784:Gene Amplification; D005865:Gestational Age; D006801:Humans; D007752:Obstetric Labor, Premature / Q000382:microbiology*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D011262:Pregnancy Trimester, Second; D012189:Retrospective Studies; D012307:Risk Factors
D004269:DNA, Bacterial; D011088:DNA Ligases