C Haavaldsen1, S O Samuelsen, A Eskild. 1. Department of Gynaecology and Obstetrics, Akershus University Hospital, Institute of Clinical Medicine, University of Oslo, Norway. marit.camilla.haavaldsen@ahus.no
Abstract
OBJECTIVE: To study the association of maternal age with placental weight, birthweight and placental weight/birthweight ratio. DESIGN: Population-based study. SETTING: Medical Birth Registry of Norway. POPULATION: All singleton births in Norway in the period 1999-2008 (n = 536,954). METHODS: Z-scores of placental weight and birthweight were calculated and divided into deciles. The proportions with a small or a large placenta were calculated within each maternal age group. Also, the odds ratios of having a small (lowest decile) and a large (highest decile) placenta, according to maternal age, were estimated, with and without adjustment for birthweight in grams, parity, smoking, pre-eclampsia and diabetes. MAIN OUTCOME MEASURES: Placental weight, birthweight and placental weight/birthweight ratio. RESULTS: The mean placental weight increased with maternal age: 647.1 g in women below the age of 20 years and 691.3 g in women aged 45 years or older. Among the oldest group of women (≥45 years) 15.8% of placentas were in the highest decile of placental weight z-score, whereas this was true for just 7.0% of women below the age of 20 years (Wald test, P < 0.001). Using women younger than 20 years of age as a reference, the odds ratio for having a placenta in the highest decile of placental weight z-score was 2.50 (95% CI 1.92-3.26) for women aged 45 years or older, after adjustment for offspring birthweight, parity, maternal smoking, pre-eclampsia and diabetes. CONCLUSION: We found an association between increased placental weight and maternal age, and this finding may be important in understanding the causes of adverse events associated with high maternal age.
OBJECTIVE: To study the association of maternal age with placental weight, birthweight and placental weight/birthweight ratio. DESIGN: Population-based study. SETTING: Medical Birth Registry of Norway. POPULATION: All singleton births in Norway in the period 1999-2008 (n = 536,954). METHODS: Z-scores of placental weight and birthweight were calculated and divided into deciles. The proportions with a small or a large placenta were calculated within each maternal age group. Also, the odds ratios of having a small (lowest decile) and a large (highest decile) placenta, according to maternal age, were estimated, with and without adjustment for birthweight in grams, parity, smoking, pre-eclampsia and diabetes. MAIN OUTCOME MEASURES: Placental weight, birthweight and placental weight/birthweight ratio. RESULTS: The mean placental weight increased with maternal age: 647.1 g in women below the age of 20 years and 691.3 g in women aged 45 years or older. Among the oldest group of women (≥45 years) 15.8% of placentas were in the highest decile of placental weight z-score, whereas this was true for just 7.0% of women below the age of 20 years (Wald test, P < 0.001). Using women younger than 20 years of age as a reference, the odds ratio for having a placenta in the highest decile of placental weight z-score was 2.50 (95% CI 1.92-3.26) for women aged 45 years or older, after adjustment for offspring birthweight, parity, maternal smoking, pre-eclampsia and diabetes. CONCLUSION: We found an association between increased placental weight and maternal age, and this finding may be important in understanding the causes of adverse events associated with high maternal age.
Authors: Sandra Larsen; Camilla Haavaldsen; Elisabeth Krefting Bjelland; Johanne Dypvik; Anne Marie Jukic; Anne Eskild Journal: Int J Epidemiol Date: 2018-08-01 Impact factor: 7.196
Authors: Pasi Huuskonen; Maria R Amezaga; Michelle Bellingham; Lucy H Jones; Markus Storvik; Merja Häkkinen; Leea Keski-Nisula; Seppo Heinonen; Peter J O'Shaughnessy; Paul A Fowler; Markku Pasanen Journal: Reprod Toxicol Date: 2016-05-14 Impact factor: 3.143