Thickness of fetal membranes: a possible ultrasound marker for preterm delivery.
OBJECTIVE
To evaluate whether measurement of the thickness of the fetal membranes by high-resolution ultrasound is a useful marker to predict preterm delivery.


METHODS
One hundred and fifty-eight women with singleton pregnancies at 18-35 gestational weeks were enrolled consecutively at our referral center for obstetric care and the thickness of their fetal membranes was measured using high-resolution ultrasound equipment. Data were analyzed to determine whether there were significant differences between those delivering at term and those delivering preterm. Receiver-operating characteristics (ROC) curves were used to determine the best cut-off point of membrane thickness for predicting preterm birth.


RESULTS
Women who delivered preterm had greater fetal membrane thickness than did those who delivered at term (1.67 +/- 0.27 mm vs. 1.14 +/- 0.30 mm, P < 0.0001). For the best cut-off indicated by ROC curve analysis (1.2 mm), the sensitivity and specificity for predicting preterm birth were 100% (95% CI, 80.3-100) and 69.5% (95% CI, 61.2-77.0), respectively, and positive and negative likelihood ratios were 3.3 and 0.0, respectively.


CONCLUSIONS
Sonographic measurement of fetal membrane thickness could be helpful in the prediction of preterm delivery.
Severi
F M
FM
Division of Obstetrics and Gynecology, Department of Pediatrics, Obstetrics and Reproductive Medicine, University of Siena, Siena, Italy.
Bocchi
C
C
Voltolini
C
C
Borges
L E
LE
Florio
P
P
Petraglia
F
F
D000328:Adult; D005321:Extraembryonic Membranes / Q000000981:diagnostic imaging* / Q000502:physiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D047928:Premature Birth / Q000175:diagnosis* / Q000517:prevention & control; D012372:ROC Curve; D016216:Ultrasonography, Prenatal / Q000379:methods*; D055815:Young Adult