Fetal fibronectin, endotoxin, bacterial vaginosis and cervical length as predictors of preterm birth and neonatal morbidity in twin pregnancies

Abstract

Objective To evaluate the predictive values of fetal fibronectin, bacterial vaginosis, endotoxin and cervical length for preterm birth (< 35 and < 37 weeks) and neonatal morbidity in twin pregnancies.Participants One-hundred and twenty-one women with twin pregnancies recruited into a prospective longitudinal study at three antenatal clinics in the southwest of Sweden.Methods Cervical or vaginal fluid was sampled and determined for fetal fibronectin (2 0.05 pg/mL was used as cutoff), endotoxin (2 100 pg/mL) and bacterial vaginosis (presence of clue cells) at two week intervals from 24 to 34 weeks of gestation. The cervical length was measured with transvaginal sonography at the same time intervals.Main outcome measures Occurrence of preterm birth (< 35 and < 37 weeks of gestation) and neonatal morbidity.Results All positive fetal fibronectin samples obtained at screening between 24 and 34 weeks predicted birth < 35 weeks (RR 18.0; 95% CI 2-2-145.9). A positive fetal fibronectin at 28 weeks of gestation predicted delivery < 35 weeks (RR 6.3; 95% CI 2.6-15.1) with a sensitivity, specificity, positive and negative predictive value of 50-0, 92.0, 62.5 and 87.3%, respectively. An independent association between fetal fibronectin at 28 weeks and preterm birth (< 35 weeks) was verified with logistic regression (P = 0.03). A positive fetal fibronectin at 28 weeks of gestation predicted neonatal morbidity (RR 5.1; 95% CI 2.4-1 1.0) and a longer period of care at the neonatal intensive care unit. The predictive power of cervical sonography was generally low but cervical length (cutoff 5 33 mm) measured at 28 weeks of gestation was significantly associated with birth < 37 weeks (RR 2.2; 95% CI 1.1-4-2). The presence of endotoxin correlated to bacterial vaginosis, but these tests were not significantly related to preterm birth or neonatal morbidity. ConclusionsFetal fibronectin predicted preterm birth and neonatal morbidity in twin pregnancies. The predictive value of cervical length determinations was low. Endotoxin and bacterial vaginosis had no predictive power for preterm delivery in this study.

Microbial invasion and cytokine response in amniotic fluid in a Swedish population of women with preterm prelabor rupture of membranes

“…Our data show that the occurrence of culture-positive patients in pPROM was not different from previous studies performed in other countries (if expressed as a percentage of patients sampled). This is somewhat surprising as the incidence of birth < 37 weeks of gestation is only 5-6% (and birth < 34 weeks 1.5%) (2) and the rate of bacterial vaginosis, postpartum endometritis and neonatal sepsis are reported to be comparatively low in Sweden (8)(9)(10). Furthermore, all the patients with positive cultures or with PCR-detectable microorganisms in the AF delivered prior to 34 weeks of gestation.…”

“…The cause of PTB seems to be multifactorial but several studies indicate that microbial invasion of the amniotic fluid (AF) is an important risk factor for PTB (7). One possible explanation for the difference in PTB incidence in the Scandinavian countries and in the USA could be a lower number of patients with infection-related PTB, as the rate of infections in the reproductive tract and of neonatal sepsis appears to be comparatively low in Sweden (8)(9)(10). There are two forms of spontaneous PTB: preterm labor (PTL) and preterm prelabor rupture of membranes (pPROM).…”

Preterm birth: the value of sonographic measurement of cervical length

“…Cervical length was a poor predictor of preterm birth, and a cervical length of less than 25 mm had no predictive value for preterm birth. 12 Gibson et al 13 published a study of 91 twin pregnancies in which a short cervix of less than 22 mm at 24 weeks increased the risk of preterm birth prior to 35 weeks by ten times. In contrast, FFN at 24 weeks was not useful in predicting preterm birth.…”

Microbial invasion and cytokine response in amniotic fluid in a Swedish population of women in preterm labor

“…One possible explanation for the difference in PTB incidence could be a lower number of patients with infectionrelated PTB, as the rate of infection in the genitourinary tract (e.g. urinary tract infections, bacterial vaginosis, clinical chorioamnionitis) and of neonatal sepsis appear to be comparatively low in Sweden (6)(7)(8). Several recent studies have shown that microbial invasion of the amniotic fluid (AF) is one important risk factor for PTB (9,10).…”