Placental weight, birth weight and fetal:placental weight ratio in dichorionic and monochorionic twin gestations in function of gestational age, cord insertion type and placental partition

Reference values were generated for placental weight, birth weight and FPR in monochorionic and double-disc dichorionic twins. The generally lower FPR per placental weight in monochorionic twins compared with dichorionic twins is suggestive of inherently lower placental functional efficiency in monochorionic gestations. The mechanisms and clinical implications of the apparent differential modulation of FPR/efficiency in monochorionic twins according to placental partitioning remain to be determined.