Monoamniotic monochorionic twins develop if division occurs after:

Ans: c (8 days) Ref: Dutta, 6th ed, p. 203If the division occurs after 8th day of fertilization, when the amniotic cavity has already formed, a monoamniotic--monochorionic twins developsTwins:There are two different types of twins -- dizygotic and monozygotic(i) Biovular - (Dizygotic/ Fraternal twins) - Diamniotic dichorionic(ii) Uniovular (Monozygotic, Identical)(a) Diamniotic - Monochorionic division occurs between 4-8 days. (After formation of inner cell mass)(b) Diamniotic - Dichorionic - division occurs within 3 days(c) Monoamniotic mono chorionic - division occurs after 8 days(d) Conjoint twins (Siamese twins) - division occurs after 2 weeks of the development of embryonic disc.Most common type of fusion is thoracophagusCommonest lie of fetus in twins -Commonest presentation -Rarest presentation-LongitudinalBoth cephalicBoth transverseComplication of twin pregnancyCommonest complication of twin pregnancy - preterm labourCommonest complication during labour is post partum hemorrhageOther complications during labour - PROM, cord prolapse, prolonged labour, increased operative interference and interlocking.Other complications are hyperemisis, anaemia, preeclampsia, polyhydramnios, APH (PP), malpresentationUnique complications of monozygotic twinAcardiac twinsTwin - Twin transfusion syndromeConjoint twinsCord entanglementHellin ruleAccording to Hellin rule the mathematical frequency of multiple birth is twins 1 in 80 pregnancies, Triplets 1 in 802, Quadruples - 1 in 8(P Incidence of monozygotic twins - 1 in 250Discordant twin - When there is a difference of 25% wt between the two twins then they are called discordant twins.SuperfecundationIt is the fertilization of two ova released in different menstrual cycle, by separate acts of coitus within a short period of time.SuperfetationIt is the fertilization of two ova released in different menstrual cycles.