Changes in shear wave speed pre- and post-induction of labor: a feasibility study.

OBJECTIVE: To explore the feasibility of using shear wave speed (SWS) estimates to detect differences in cervical softening pre- and post-ripening in women undergoing induction of labor. METHODS: Subjects at 37-41 weeks' gestation undergoing cervical ripening before induction of labor were recruited (n = 20). Examinations, performed prior to administration of misoprostol and 4 h later included Bishop score, transvaginal ultrasound measurement of cervical length, and 10 replicate SWS measurements using an ultrasound system equipped with a prototype transducer (128 element, 3 mm diameter, 14 mm aperture) attached to the clinician's hand. Subjects were divided into two groups, 'not-in-labor' and 'marked-progression', based on cervical evaluation at the second examination. Measurements were compared via individual paired hypotheses tests and using a linear mixed model, with the latter also used to compare groups. Spearman's rank correlation coefficient was used to compare SWS with Bishop score. The linear mixed model can take into account clustered data and accommodate multiple predictors simultaneously. RESULTS: The Wilcoxon signed-rank paired test established a significant difference in pre- and post-ripening SWS, with mean SWS estimates of 2.53 ± 0.75 and 1.54 ± 0.31 m/s, respectively (P < 0.001) in the not-in-labor group (decrease in stiffness) and 1.58 ± 0.33 and 2.35 ± 0.65 m/s for the marked-progression group (increase in stiffness). The linear mixed model corroborated significant differences in pre- and post-ripening measurements in individual subjects (P < 0.001) as well as between groups (P < 0.0001). SWS estimates were significantly correlated with digitally-assessed cervical softness and marginally correlated with Bishop score as assessed by Spearman's rank correlation coefficient. CONCLUSIONS: In-vivo SWS estimates detected stiffness differences before and after misoprostol-induced softening in term pregnancies. This ultrasonic shear elasticity imaging technique shows promise for assessing cervical softness.

Differentiation of genetic abnormalities in early pregnancy loss.

OBJECTIVE: To characterize the types of genetic abnormalities and their prevalence in early pregnancy loss at different developmental stages. We hypothesized that the prevalence of genetic abnormalities in pregnancy loss would differ across developmental stages. METHODS: Women with a pregnancy loss at < 20 weeks' gestation (n = 86) were enrolled at the time of diagnosis. Maternal tissue without a fetal component was found in 13 samples. Chromosomal microarray analysis (CMA) was performed on 74 samples (including two samples from a twin pregnancy); 15 were pre-embryonic (no visible embryo on ultrasound examination), 31 were embryonic (embryo; 6 + 0 to 9 + 6 weeks' gestation) and 28 were fetal (fetus; 10 + 0 to 19 + 6 weeks' gestation) losses. The twin pregnancy was found to be monochorionic diamniotic and was subsequently treated as a single sample in our analysis. Nine samples that underwent CMA were excluded from analysis because of 100% maternal-cell contamination. RESULTS: The overall prevalence of genetic abnormalities differed across developmental stages (9.1% pre-embryonic, 69.2% embryonic and 33.3% fetal; P < 0.01). This difference persisted when comparing pre-embryonic with embryonic samples (P < 0.01) and embryonic with fetal samples (P = 0.02) but not pre-embryonic with fetal samples (P = 0.12). Additionally, the prevalence of aneuploidy differed significantly across developmental stages (0.0% in pre-embryonic samples vs 65.4% in embryonic samples vs 25.9% in fetal samples, P < 0.001). Abnormalities were most common in embryonic cases, followed by fetal and then pre-embryonic. Maternal cell contamination (MCC) was noted in 47.4% of 46,XX cases assessed. CONCLUSIONS: Genetic abnormalities detected by CMA are more likely to occur in the embryonic period than in pre-embryonic or fetal stages. MCC is common in early pregnancy loss and should be excluded when results demonstrate a 46,XX karyotype.