Placental weights from normal deliveries in Ireland

The weight of the delivered placenta gives a useful representation of placental function in utero. In the absence of Irish data, many pathologists rely on data from other populations, many of which are now 15 to 30 years old. The development of a population-specific nomogram would aid in the examination of placentas after delivery, allowing pathologists and medical scientists to more easily distinguish between placental physiological changes and pathology.

To record placental weights among women having a singleton delivery in Dublin and to establish median placental weights for each gestational age after 37 weeks.

Prospective cohort study in a Tertiary level University Hospital. All singleton pregnancies were included; stillbirths, multiple gestations, and cases with obstetric complications involving the placenta were excluded. The placentas were weighed both untrimmed and trimmed with standard scales. Demographic features including birth weight and maternal parity were also recorded.

Four hundred thirty placentas were weighed over a 6-week period. A median term placental weight based on gestational age was established, with a range from the tenth to ninetieth centiles.

The weight of the placenta is one of several measurements that are easy to acquire, and when recorded in a systematic fashion, provide information not just on an individual, but also on a population basis. Birth weights have increased over the last century, and this study provides national data helping distinction between placental physiology and pathology.