The relationship between birth and placental weights changes with placental size

- We studied a sample of a population based term singleton cohort with universal placental examination.
- Placental weights were grouped as < 10th, 25-75th, and > 90th centiles according to published data for 37-41 weeks gestation.
- Fetoplacental weight ratios differed among Groups (1-3: FPR 8.5 + 1.13, 6.9 + 0.74, and 5.5 + 0.70, each p < 0.0001).
- Group 1 lower quartile was the 90th centile of Group 2 and Group 2 lower quartile was the 90th centile of Group 3.