The diagnosis of discordant karyotype, with the presence of a serious anomaly in a pair of twins may require termination of the affected foetus. The most frequent anomalies that are indicative for selective termination are central nervous system (CNS) anomalies. Selective termination is a clinical procedure that can be performed in either the first or second trimester of gestation. The technique used depends on the chorionicity of the pregnancy.
The perinatal outcomes following the procedure of selective termination appear to be comparable or better and offer a good alternative to termination of whole pregnancy or conservative management. [21]
In dichorionic twins, selective reduction may be performed transabdominally in the second trimester and transabdominally or transvaginally in the first. The technique consists of injection of potassium chloride (KCl) into the foetal heart using a 21-gauge needle guided by a probe. Fetal cardiac activity is expected to stop within 1 min after the injection. In rare cases, the injection needs to be repeated. Intracranial KCl injection is an alternative method. …show more content…
Due to the presence of vascular anastomoses in monochorionic pregnancies, KCl injection is contraindicated, because this would lead to the death of the co-twin. The currently used methods include bipolar cord coagulation (BCC) and radiofrequency ablation (RFA).
Selective foetal reduction in dichorionic twins is associated with excellent maternal and perinatal outcomes for the unselected co-twin. For monochorionic twins, the live birth rate is approximately 90% for BCC.