<prompt> If division of feilized egg takes place in between 5-8 days. It would give rise to which kind of twin pregnancy: March 2009, March 2013 cMonochorionicmonoamnioticMonochorionicdiamnioticDichorionic monoamnioticSiamese twins  <response>: Ans. B: Monochorionicdiamniotic Approximately 70 of monozygotic twins are monochorionic diamniotic. If splitting occurs later ie, 9-12 d after feilization, monochorionic monoamniotic placentation occurs. Monochorionicmonoamniotic twins are rare; only 1 of monozygotic twins have this form of placentation. twins have a common placenta, with vascular communications between the 2 circulations. These twins can develop twin-to-twin transfusion syndrome TTTS. If twinning occurs more than 12 days after feilization, then the monozygotic feilized ovum only paially splits resulting in conjoined twins. 