First trimester diagnosis of monoamniotic twin pregnancies

Abstract

This study reports the ultrasound findings and pregnancy outcome for a series of monoamniotic twin pregnancies diagnosed at 11-14 weeks' gestation. Of 315 monochorionic twin pregnancies examined, there were 12 (3.8%) monoamniotic, including four sets of conjoined twins (1.3%). The parents opted for termination of pregnancy in all cases of conjoined twins. In four other cases, there was discordancy for major structural fetal abnormality (kyphoscoliosis, anencephaly, body stalk defect, diaphragmatic hernia), and the cotwin was structurally normal. In the four cases in which both twins were structurally normal, ultrasound examination demonstrated normal nuchal translucency thickness in all cases but cord entanglement was demonstrated from the first trimester. Two cases were managed expectantly; one resulted in livebirth of both twins at 31 weeks' gestation and the second in intrauterine death of both fetuses at 21 weeks. Two pregnancies were treated with Sulindac; one resulted in a single intrauterine death at 30 weeks and delivery of a normal cotwin, the other, in intrauterine death of both fetuses at 31 weeks'. Monoamniotic twin pregnancies are associated with a high risk of fetal abnormalities and perinatal death and the mortality rate is higher than previously reported from series with recruitment later in gestation.

Non‐identical monozygotic twins, intermediate twin types, zygosity testing, and the non‐random nature of monozygotic twinning: A review

“…MA twins show both concordance and discordance for major regional malformations. In a report of 12 pairs of MA twins diagnosed in the first trimester, 4 pairs were conjoined and 4 pairs were discordant for major malformation: kyphoscoliosis, anencephaly, body stalk defect, diaphragmatic hernia [Sebire et al, 2000]. Of the remaining four structurally normal pairs, three fetuses died of cord entanglement.…”

Monochorionic monoamniotic twins: neonatal outcome

“…[8][9][10] Postnatal angiograms of the placenta demonstrating deep arteriovenous anastomoses with cotyledon sharing may confirm the diagnosis. 15 Sebire et al 26 suggested that acute TTS may be responsible for antepartum fetal demise in MoMo twins, speculating that imbalances between the two fetal circulations cannot be sustained for any prolonged time. The differences in cord Hgbs X5 g/dl in cases other than those three TTS pregnancies suggests that acute transfer of fetal blood from one twin to the other at the time of delivery is possible.…”

Pautas De Manejo Clínico De Embarazos Gemelares

“…Los gemelos monocoriales monoamnióticos resultan cuando la división de la masa celular interna ocurre después del noveno día de la fecundación. Los gemelos monocoriales son muy poco frecuentes, ocurren en 1 de cada 10.000 embarazos y en un 5% de los gemelos monocoriales (63). Dentro de los gemelos monoamnióticos se incluyen los gemelos unidos o siameses con una incidencia de 1 en 50.000 embarazos.…”