Table 1.

Overview of the Placental Pathology Severity Score

Variables
Macroscopic abnormalities	Score
Placental weight
<10th Percentile	7
>90th Percentile	1
Umbilical cord insertion
Paracentral	0
Central	0
Marginal	1
Velamentous	3
Single umbilical artery	1
Umbilical cord coiling index
Hypocoiling (index <0.1)	1
Hypercoiling (index >0.3)	7
Microscopic abnormalities
Placental maturation
Delayed	7
Normal	0
Accelerated	3
Maternal vascular malperfusion
Placental ischemia	5
Placental infarct	<5%: 2, 5%−10%: 3, >10%: 5
Distal villous hypoplasia	3
Fetal vascular malperfusion	<10%: 3, 10%−25%: 4, >25%: 6
Nucleated red blood cells	2
Chorangiosis	3
Inflammation or reactive changes
Villitis of unknown cause	<50%: 3, >50%: 7
Intervillositis	<50%: 3, >50%: 7
Perivillous fibrin	<50%: 3, >50%: 7
Sustained villitis	2
Chorioamnionitis	1
Meconium pigment membrane	0

The placental pathology severity score was adapted from Harteman et al. ²⁷