Medline ® Abstracts for References 2-4

OBJECTIVE: The objective of this study was to determine the incidence of velamentous cord insertion and placental territory discordancy in monochorionic twins with and without twin-to-twin transfusion syndrome (TTTS).

STUDY DESIGN: All consecutive placentas of monochorionic twins delivered at our center between June 2002 and April 2006 were studied with vascular injection of the umbilical vessels with colored dyes. Velamentous cord insertions were recorded and individual placental territories were calculated by computer analysis.

RESULTS: A total of 76 monochorionic placentas with TTTS and 63 monochorionic placentas without TTTS were studied. The incidence of velamentous cord insertion (per fetus) in the TTTS group and the non-TTTS group was 13% (20 of 152) and 14% (18 of 126), respectively (P = .79). Placental territory discordancy in the TTTS group and the non-TTTS group was 20% and 20% (P = 0.83). In the TTTS group, donor twins had a velamentous cord insertion more often than recipient twins (24% and 3%, respectively,P<.001) and a smaller placental territory (44% and 56%, respectively, P<.001).

CONCLUSION: Our findings suggest that velamentous cord insertion and unequal placental territory are not critical factors for the development of TTTS.

OBJECTIVE: The purpose of this study was to evaluate the impact of noncentral placental cord insertion on birthweight discordance in twins.

STUDY DESIGN: We performed a multicenter, prospective trial of twin pregnancies. Placental cord insertion was documented as central, marginal, or velamentous according to a defined protocol. Association of the placental cord insertion site with chorionicity, birthweight discordance, and growth restriction were assessed.

RESULTS: Eight hundred sixteen twin pairs were evaluated; 165 pairs were monochorionic, and 651 pairs were dichorionic. Monochorionic twins had higher rates of marginal (P = .0068) and velamentous (P<.0001) placental cord insertion. Noncentral placental cord insertion was more frequent in smaller twins of discordant pairs than control pairs (29.8% vs 19.1%; P = .004). Velamentous placental cord insertion in monochorionic twins was associated significantly with birthweight discordance (odds ratio, 3.5; 95% confidence interval, 1.3-9.4) and growth restriction (odds ratio, 4; 95% confidence interval, 1.1-14.3).

CONCLUSION: Noncentral placental cord insertion contributes to birthweight discordance in monochorionic twin pregnancies. Sonographic delineation of placental cord insertion may be of value in antenatal assessment of twin pregnancies.

Placental lesions identified in cases of stillbirth are of clinical interest and are frequently invoked as having a causal role. However, most of the placental changes found in stillbirth are also seen in liveborn pregnancies, and are of uncertain pathogenetic significance. Much of the literature addressing placental lesions found in stillbirth is descriptive, listing cases of interest without adequate controls. Further, lesions are described qualitatively, often with inadequate description of examination and sampling protocols. In this manuscript we describe the placental characteristics that are most frequently listed in stillbirth case series, including entities associated with maternal diseases. First, we describe how macroscopic placental, cord, and membrane findings can provide answers to midwives and physicians at the time of delivery and how the placenta should be handled in the delivery room to optimize the histopathological examination. Second, we provide a brief organization of histological findings of the pathogenesis of conditions associated with fetal death.