[Selective removal of one twin with trisomy 21 by sectio parva in the 23rd week of pregnancy and later spontaneous birth of the healthy twin].

In a 41-year old tertipara with twin pregnancy, foetal chromosome analysis showed a boy without abnormal findings, 46, XY, and a boy with free trisomy 21. Abortion of the abnormal twin was performed in the 23rd week of pregnancy via sectio parva. Despite preoperative onset of tocolysis and ultimately performed circular suture of the cervix, premature rupture of the membranes occurred in the 28th pregnancy week, followed by spontaneous birth of the second twin weighing 1010 g. Raising of the premature baby did not present any special problems.