Ultrasound and histological measurements of dividing membrane thickness in twin gestations

Twin pregnancies

Twin pregnancies, resulting in 2-3 % of all deliveries, are high risk pregnancies which need specialized care. A correct dating of pregnancy and the assessment of the chorionicity/amnionicity in the first trimester (< = 13 + 6 gestational weeks, GW) is essential for further monitoring. During first trimester risk stratification of monochorionic pregnancies includes evaluation of discordance of crown-rump-lengths, nuchal translucencies and amniotic fluid. At 16 GW sonographic risk evaluation of monochorionic twins involves differences in amniotic fluid and abdominal circumferences and detection of a velamentous cord insertion. A screening for fetal malformations with cervical length measurement as screening for preterm birth (cut-off < 25 mm) should be offered all twin pregnancies around 20 GW. In uncomplicated dichorionic pregnancies US examination should be performed every 4 weeks onwards to check fetal growth and amniotic fluid. An intertwin weight discordance > 20 % identifies pregnancies at increased risk of adverse outcome. Monochorionic pregnancies should be followed at least every two weeks for screening of twin-twin transfusion syndrome (TTTS), twin-anemia-polycythemia-sequence (TAPS) and selective fetal growth retardation (sFGR) with a start at 16 GW. The type 1-3 classification of sFGR in monochorionic twins depends on the pattern of end-diastolic velocity at the umbilical artery Doppler. The diagnosis of TTTS requires the presence of an oligyohydramnios (deepest vertical pocket (DVP) < 2 cm) in the donor twin and a polyhydramnios (DVP > 8 cm) in the recipient twin. However, the diagnosis of TAPS is based on the finding of discordant MCA Doppler values with a delta-MCA PV > 0.5 MoM.

A Case of Intertwin Membrane Hemorrhage with Spontaneous Resolution

Vaginal bleeding during pregnancy places women at increased risk of spontaneous abortion. Etiologies for threatened and spontaneous abortions have been well studied, but there is little information on intertwin membrane hemorrhage. We present a patient with a multiple gestation pregnancy who experienced first trimester vaginal bleeding with visualization and subsequent rapid resolution of an intertwin membrane hemorrhage. The patient had an otherwise normal pregnancy until the third trimester when she developed preeclampsia with severe features and elected for a primary cesarean section at 35 + 5 weeks. The implications of an intertwin membrane hemorrhage are not well understood, although there could be a possible correlation between the hemorrhage and the ultimate progression to preeclampsia with severe features. Despite the final diagnosis, the patient did not have any noticeable complications due to the hemorrhage both when it was discovered and in the weeks following its discovery.