Placental weight is a valuable indicator of its function, predicting both pregnancy outcome and lifelong health. Population-based centile charts of weight-for-gestational-age and parity are useful for identifying extremes of placental-weight but fail to consider maternal size. To address this deficit a multiple regression model was fitted to derive coefficients for predicting normal placental-weight using records from healthy pregnancies of nulliparous/multiparous women of differing height and weight (n=107,170 deliveries, 37-43weeks gestation). The difference between actual and predicted placental-weight generated a z-score/individual centile for the entire cohort including women with pregnancy complications (n=121,591). The association between maternal BMI and placental-weight extremes defined by the new customised versus population-based standard was investigated by logistic regression, as was the association between low placental-weight and pregnancy complications. Underweight women had a greater risk of low placental-weight [<10thcentile, OR1.84(95%CI 1.66,2.05)] and obese women a greater risk of high placental-weight [>90thcentile, OR1.98(95%CI 1.88,2.10)] using a population-standard. After customisation, the risk of high placental-weight in obese/morbidly-obese women was attenuated [OR1.17(95%CI 1.09,1.25)]/ no longer significant, while their risk of low placental-weight was 59 to 129% higher (P<0.001). The customised placental-weight standard was more closely associated with stillbirth, hypertensive disease, placental abruption and neonatal death than the population standard. Our customised placental-weight standard reveals higher risk of relative placental growth-restriction leading to lower than expected birthweights in obese women, and a stronger association between low placental-weight and pregnancy complications generally. Further, it provides an alternative tool for defining placental-weight extremes with implications for the placental programming of chronic disease.
|Number of pages||10|
|Journal||Journal of Developmental Origins of Health and Disease|
|Early online date||7 Oct 2019|
|Publication status||Published - Aug 2020|
Bibliographical noteJW and GH were funded by the Scottish Government’s Rural and Environmental Science and Analytical Services Division (RESAS) who had no input into the content or preparation of the manuscript.
- Placental weight
- body mass index
- customised weight standards
- pregnancy complications
- PRETERM BIRTH
- BODY-MASS INDEX
- PERCENTILE CURVES