Aim: To determine whether or not the change in cervical length (CL) over time is valuable in predicting spontaneous preterm delivery (SPTD) in asymptomatic twin pregnancies with a normal mid-trimester CL (>25 mm). Methods: This was a prospective study including 190 consecutive asymptomatic twin gestations with a CL > 25 mm at 20–24 weeks. The women underwent an initial CL measurement at the time of routine ultrasound examination between 20 and 24 weeks’ gestation, followed 4–5 weeks later by a repeat CL measurement. The primary outcome measure was SPTD at <32 completed weeks’ gestation. Multicollinearity was a concern in the multivariable model since change in CL and follow-up CL were highly correlated. Results: The rate of SPTD at <32 weeks was 4.2%. Multiple logistic regression analyses demonstrated that the change in CL and the follow-up CL were significantly associated with SPTD before 32 weeks after adjusting for baseline covariate such as in vitro fertilization. The best cut-off values for the prediction of SPTD at <32 weeks’ gestation were 13% for the change in CL with a sensitivity of 87.5% and a specificity of 63.2%. There was no significant difference in the area under the receiver operating characteristic curves between the change in CL and the follow-up CL. Conclusions: A greater change in CL is a good predictor of SPTD in asymptomatic twin pregnancies with a normal mid-trimester CL. However, the change in CL cannot provide data beyond the follow-up CL. In the setting of a normal mid-trimester CL, a follow-up CL measurement should be considered in asymptomatic twin pregnancies.

Because otoacoustic emissions (OAEs) are transmitted from the cochlea to the ear canal via the middle ear, the transmission properties of the middle ear directly influence OAEs’ characteristics. In general, middle-ear effusion (MEE) reduces measured emission amplitudes and sometimes eliminates the response entirely. The purpose of this study was to establish the relationship between the conduction of the middle ear and OAEs’ properties and to elucidate the effect of middle-ear effusion on detecting OAEs’. Spontaneous otoacoustic emissions (SOAEs), transiently evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) were recorded from 44 normal ears and 32 ears with middle-ear effusion. DPOAEs were collected in two basic forms consisting of distortion product audiograms (DP grams) and input-output (I-O) functions, elicited by two primary tones F1 and F2 and varying geometric mean frequencies between 1–6 kHz. The results of air and bone conduction hearing levels in pure tone audiogram were also analysed. In 21 ears out of 32 otitis media with effusion (OME) ears, SOAEs were absent. In the 28 ears with middle-ear effusion, the response and wave reproducibility were diminished, and in the 17 ears with middle-ear effusion, the DP gram was diminished or eliminated. In particular, I-O function curves at 3 kH and 4 kHz were diminished by the primary tones of 45 and 55 dB under the condition of MEE. The SOAEs, TEOAEs and DPOAEs (DP gram and I-O function curve) are highly reliable and useful tests for monitoring changes in middle-ear condition in children with OME and in predicting the course of OME.