12 - Obs - Multiple Pregnancy

Question 1

Epedimiology
Twins 1/??, triplets 1/1000. Geographic variation. Incidence of twins incr due to ? trt and incr no of ? mothers. In UK ? and higher order now ? due to better fertility trt regulation.

Answer 1

80
subfertility
older
triplets
decreasing

Question 2

DZ twins (?/3 of all multiple pregs) or triplets due to fert of different ? by ? sperm. May be different ? and no more ? similar than normal siblings

Answer 2

2/3
oocyte
different
sex
genetically

Question 3

MZ twins from mitotic ? of ?
zygote into ? twins. Sharing of ? or ? depends on ? at which division into separate zygotes occurred. Division before day ? (30%) -> twins w ? placentas and amnions (?
? DCDA). Division 4-?days (70%) -> twins w shared ? and separate ? (????). Division ?-13days -> v rare, shared ? and single ?(????). Incomplete division -> ? twins. MC twins have higher fetal ?, esp pre ?wks.

Answer 3

division
one
identical
placenta
amnion
time
3
separate
dichorionic 
diamniotic
8
placenta
amnion
MCDA
9
placenta
amnion
MCMA
conjoined
loss
24

Question 4

Aetiology
Assisted ?, ? factors and incr maternal ?/? are most important factors, largely affecting ?? twinning. ?% of all IVF conceptions and 5-10% ?-assisted conceptions are multiple.

Answer 4

conception
genetic
age/parity
DZ
20%
clomiphene

Question 5

Diagnosis
? may be more marked in early preg. Uterus ? than expected for ? and palpable before ?wks. Later in preg, 3 or more fetal ? felt. Many diagnosed only at ???.

Answer 5

vomiting
larger
dates
12
poles
USS