ResearchObstetricsUltrasonographic evaluation of myometrial thickness in twin pregnancies
Section snippets
Study design and sonographic procedures
Patients carrying twin or singleton gestations who presented for ultrasound in our 2 Yale Perinatal Ultrasound Units were enrolled in a prospective observational study from August 2004-May 2006. The purpose of our study was to assess MT longitudinally during gestation. For twins, the primary endpoint was spontaneous delivery at less than 35 weeks' GA.1, 11
Patients with twins who delivered at less than 35 weeks' GA comprised the preterm twin group. Patients with twins who delivered at 35 weeks
Study population
Two hundred three patients pregnant with twins (n = 99) or singletons (n = 104), who presented for ultrasound in our 2 Yale Perinatal Ultrasound Units were enrolled in the study (Figure 1). Overall, 14 patients were lost to follow-up, and thus, at the end of the recruitment period, we examined data from 92 twin and 97 singleton pregnancies. Thirty-eight patients pregnant with twins delivered at less than 35 weeks GA and comprised the preterm twin group. Fifty-four patients with twins delivered
Comment
With the present investigation, we report the progression of MT in vivo in a cohort of twin and singleton pregnancies followed up prospectively throughout gestation. In multiples, it is thought that the myometrial tissue stretches and thins more to accommodate the increased volume corresponding to the 2 fetuses, placentas, and respective amniotic fluid and that the increased incidence of PTB is the result of myometrial activation that occurs earlier because of this stretch.17
Contrary to this
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The human myometrium differentially expresses mTOR signalling components before and during pregnancy: Evidence for regulation by progesterone
2014, Journal of Steroid Biochemistry and Molecular BiologyCitation Excerpt :It is attractive to speculate that the down-regulation of the mTOR/DEPTOR ratio in all non-labouring myometrial might compromise the activity of mTORC1 complex thus preventing a full reconstruction of the uterine cavity during pregnancy that can affect the contractile phenotype towards the end. Interestingly, in a study of twin pregnancies, in the absence of uterine contractions or symptoms of preterm labour, twins that delivered preterm had a significantly thinner lower uterine segment at an earlier gestation, compared with twins that delivered at term; suggesting that lower uterine segment thinning occurred earlier in these cases [27]. There is increasing evidence that mTOR signalling is under the influence of steroids.
Preterm and term labour in multiple pregnancies
2010, Seminars in Fetal and Neonatal MedicineCitation Excerpt :However, there is remarkably little evidence for this. A recent study comparing ultrasonographically measured myometrial thickness in women carrying twins and singletons found no differences between the groups despite a substantial increase in the estimated uterine volume in twins.34 Progressive thinning of the lower uterine segment was seen in both singletons and twins towards the third trimester, but the thinning occurred at earlier gestations in twins that delivered preterm.
A short review of twin pregnancy and how oxytocin receptor expression may differ in multiple pregnancy
2009, European Journal of Obstetrics and Gynecology and Reproductive BiologyCitation Excerpt :In twin pregnancies the additional pressure of the contents and curvature may be expected to thin the uterine wall and increase stress. Ultrasound evaluations of myometrial thickness in twin pregnancies have shown that the lower uterine segment (LUS) does progressively become thinner with increasing gestation, but that there was no difference between singleton and twin groups [22]. In twin pregnancies that delivered pre-term, the thickness of the LUS was similar to that of twin pregnancies that delivered at term; however, the pre-term LUS became thinner at an earlier point in gestation.
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Cite this article as: Sfakianaki AK, Buhimschi IA, Pettker CM, et al. Ultrasonographic evaluation of myometrial thickness in twin pregnancies. Am J Obstet Gynecol 2008;198:530.e1-530.e10.