Noelia Zork

Decreasing Prematurity in Twin Gestations: Predicaments and Possibilities

The twin birth rate has been steadily increasing in the United States over the past 10 years attributable in large part to the increased use of reproductive technologies. Despite advancements in the prevention of preterm labor for singletons, the overall rate of preterm birth has decreased only minimally. Several interventions to prevent preterm birth in twins have been studied, but none has proven effective. Inpatient bedrest has not been shown to be effective and can cause significant maternal morbidity. Although intramuscular 17&agr;-hydroxyprogesterone caproate is effective in decreasing the risk of recurrent preterm delivery in singletons, neither it nor cerclage is effective in twin gestations, even in those with a short cervix. However, small trials, subgroup analyses, and a meta-analysis suggest that vaginal progesterone and the Arabin cervical pessary may reduce rates of preterm birth in twins of mothers with a short cervix. Given the current lack of effective therapies to prevent preterm birth in twins, large multicenter trials are needed to assess the effectiveness of vaginal progesterone and pessary in twins of mothers with a short cervix.

Perinatal outcome in the live-born infant with prenatally diagnosed omphalocele

We compared perinatal outcomes between live-born nonisolated and isolated omphaloceles diagnosed during a prenatal ultrasound. Fetuses (n = 86) with omphalocele were identified between 1995 and 2007 at a single institution. Inclusion criteria were an omphalocele >14 weeks gestation, available fetal and/or neonatal karyotype, and a live-born infant (n = 46). Perinatal outcomes were compared in nonisolated (n = 23) and isolated omphaloceles (n = 23). For all omphaloceles, the majority delivered after 34 weeks by cesarean. Mean birth weight (2782 versus 2704 g), median length of stay (27 versus 25 days), and mortality (two deaths in each group) were not different between the nonisolated and isolated groups (p > 0.05). In the nonisolated group, seven major anomalies were not confirmed postnatally. Of the prenatally diagnosed isolated omphaloceles, 8 (35%) were diagnosed with a syndrome or other anomalies after birth. The outcomes were similar in nonisolated and isolated prenatally diagnosed omphaloceles, but ultrasound did not always accurately determine the presence or absence of associated anomalies.

Vaginal progesterone in women with twin gestations complicated by short cervix: a retrospective cohort study.

To determine whether the use of vaginal progesterone in twin gestations with a cervical length (CL) of ≤2.5 cm is associated with a reduced risk of preterm delivery.

Do Doppler studies enhance surveillance of uncomplicated monochorionic diamniotic twins

To determine whether isolated abnormal Doppler indices before 28 weeks predict adverse pregnancy outcomes in uncomplicated monochorionic diamniotic (MCDA) twins.

The effect of cervical cerclage on the rate of cervical shortening

Although cerclage has been shown to reduce the risk of recurrent preterm birth in a high‐risk patient population, the mechanism by which this occurs is not well understood. Our objective was to evaluate whether cerclage affects the rate of cervical shortening taking into account exposure to 17‐hydroxyprogesterone and vaginal progesterone.

Predicting fetal karyotype in fetuses with omphalocele: The current role of ultrasound

OBJECTIVEnTo assess the ability of ultrasound in predicting abnormal karyotype in pregnancies with prenatally diagnosed omphaloceles and to compare its test characteristics to previously published studies.nnnMETHODSnA retrospective case-control study of omphaloceles diagnosed at one center was performed from 1995-2007. Cases were those with an abnormal karyotype and controls were those with a normal karyotype. Data collection included demographics, karyotype results, and ultrasound findings. The number and type of associated anomalies were compared between the cases and controls. The sensitivity, specificity, positive predictive value, and negative predictive value for predicting an abnormal karyotype were calculated from previously published studies.nnnRESULTSnOf the 73 subjects, there were 12 cases and 61 controls. The majority of women were Caucasian and primigravida. The cases were less likely to have an isolated omphalocele [1 (8.3%) vs. 27 (42.6%), OR = 0.122; 95% CI: 0.02-0.08] but were more likely to have two or more major anomalies [8 (66.7%) vs. 17 (27.9%), OR = 5.18; 95% CI: 1.19-24.04)] compared to the controls. Cardiac anomalies and only one additional major anomaly were not different between the two groups, P > 0.05. The test characteristics for this study were similar to previously published studies.nnnCONCLUSIONSnIsolated omphaloceles were more likely to have a normal karyotype; however fetuses with multiple anomalies were more likely to have an abnormal karyotype. Despite advances in ultrasound technology, its ability for predicting an abnormal karyotype in these fetuses has not improved.

Inverse Finite Element Analysis of the Indentation Response of Human Cervical Tissue

The mechanical function of the cervix is crucial during pregnancy when it is required to resist the compressive and tensile forces generated from the growing fetus. Pathologies of the cervical extracellular matrix (ECM), premature cervical remodeling, and alterations of cervical material properties have been implicated in placing women at high-risk for preterm birth (PTB). To understand the mechanical role of the cervix during pregnancy and to potentially identify etiologies for PTB, the overall goal of our group is to quantify ECM-material property relationships in normal and diseased human cervical tissue. In this study we present an inverse finite element analysis (IFEA) that optimizes material parameters of a viscoelastic material model to fit the stress-relaxation response of excised tissue slices to spherical indentation. Here we detail our IFEA methodology, report viscoelastic material parameters for cervical tissue slices from nonpregnant (NP) and pregnant (PG) hysterectomy patients, and report slice-by-slice data for whole cervical tissue specimens.Copyright