Clinical outcome and placental characteristics of monochorionic diamniotic twin pairs with early- and late-onset discordant growth.
OBJECTIVE
The purpose of this study was to examine the clinical and placental characteristics of monochorionic diamniotic twin pregnancies with early-onset discordant growth diagnosed at 20 weeks, late-onset discordant growth diagnosed at 26 weeks or later, and concordant growth.


METHODS
We studied a prospective cohort that underwent an ultrasound scan in the first trimester, at 16, 20, and 26 weeks. We excluded pregnancies complicated by twin-to-twin transfusion syndrome, miscarriage, fetal death less than 16 weeks, or severe congenital anomalies. Placental sharing and angioarchitecture were assessed by injection of each cord vessel with dyed barium sulphate. The 2 territories were delineated on an X-ray angiogram. The diameter of each intertwin anastomosis was measured on a digital photograph.


RESULTS
We included 178 twin pairs. Early onset discordant growth, late-onset discordant growth, and concordant growth occurred in 15, 13, and 150 pregnancies, respectively. Twin pairs with early-onset discordant growth had lower survival rates and were delivered at an earlier gestational age than pairs with late-onset discordant and concordant growth. The degree of birthweight discordance was similar in early- and late-onset discordant growth. Severe intertwin hemoglobin differences at the time of birth occurred in 0%, 38%, and 3% of pairs with early-onset discordant growth, late-onset discordant growth, and concordant growth, respectively. The placentas of pairs with early-onset discordant growth were more unequally shared and had larger arterioarterial anastomoses and a larger total anastomotic diameter as compared with placentas of pairs with late onset-discordant or concordant growth.


CONCLUSIONS
Unequal placental sharing appears to be involved in the etiology of early-onset discordant growth, whereas a late intertwin transfusion imbalance may be involved in some cases with late-onset discordant growth.
Department of Obstetrics and Gynecology, University Hospitals, Leuven, Belgium.
Liesbeth
L
Lewi
Leonardo
L
Gucciardo
Agnes
A
Huber
Jacques
J
Jani
Tim
T
Van Mieghem
Elisa
E
Doné
Mieke
M
Cannie
Eduardo
E
Gratacós
Anke
A
Diemert
Kurt
K
Hecher
Paul
P
Lewi
Jan
J
Deprest
D000792:Angiography; D001158:Arteries / Q000196:embryology; D001724:Birth Weight; D015331:Cohort Studies; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D005330:Fetofetal Transfusion; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D010781:Photography; D010920:Placenta / Q000098:blood supply / Q000000981:diagnostic imaging; D011247:Pregnancy; D011446:Prospective Studies; D038522:Twinning, Monozygotic; D014430:Twins, Monozygotic; D014680:Veins / Q000196:embryology