Maternal Obesity During Pregnancy and Premature Mortality
Maternal Obesity During Pregnancy and Premature Mortality
Objectives. To determine whether maternal obesity during pregnancy is associated with increased mortality from cardiovascular events in adult offspring.
Design. Record linkage cohort analysis.
Setting. Birth records from the Aberdeen Maternity and Neonatal databank linked to the General Register of Deaths, Scotland, and the Scottish Morbidity Record systems.
Population. 37,709 people with birth records from 1950 to present day.
Main Outcome Measures. Death and hospital admissions for cardiovascular events up to 1 January 2012 in offspring aged 34-61. Maternal body mass index (BMI) was calculated from height and weight measured at the first antenatal visit. The effect of maternal obesity on outcomes in offspring was tested with time to event analysis with Cox proportional hazard regression to compare outcomes in offspring of mothers in underweight, overweight, or obese categories of BMI compared with offspring of women with normal BMI.
Results. All cause mortality was increased in offspring of obese mothers (BMI >30) compared with mothers with normal BMI after adjustment for maternal age at delivery, socioeconomic status, sex of offspring, current age, birth weight, gestation at delivery, and gestation at measurement of BMI (hazard ratio 1.35, 95% confidence interval 1.17 to 1.55). In adjusted models, offspring of obese mothers also had an increased risk of hospital admission for a cardiovascular event (1.29, 1.06 to 1.57) compared with offspring of mothers with normal BMI. The offspring of overweight mothers also had a higher risk of adverse outcomes.
Conclusions. Maternal obesity is associated with an increased risk of premature death in adult offspring. As one in five women in the United Kingdom is obese at antenatal booking, strategies to optimise weight before pregnancy are urgently required.
The obesity epidemic, with its attendant risk of cardiovascular and other chronic disease, has become a global threat to population health and a major public health burden. The prevalence of maternal obesity has risen rapidly in the past two decades. In the United States, about 64% of women of reproductive age are overweight and 35% are obese, with a similar pattern in Europe. The link between an adverse intrauterine environment and disease in later life is well documented, with many studies showing associations between low birth weight (a surrogate measure of intrauterine growth) and subsequent death from cardiovascular disease. Evidence from animal models and emerging data from humans suggest that maternal obesity also creates an adverse in utero environment, with long term "programmed" detrimental effects for the offspring. Several studies have shown associations between maternal obesity and obesity in the offspring, whether it is assessed in the neonatal period or in adulthood, independent of current lifestyle and shared familial (genetic and environmental) factors. Recent studies have reported associations between higher maternal weight before pregnancy and biomarkers of future atheromatous disease in the offspring, including higher blood pressure and dyslipidaemia, in childhood and in young adulthood. Whether this translates into a long term increased risk of cardiovascular disease and death for the offspring is unknown. This is largely because of a lack of suitable cohorts with available data on maternal weight during pregnancy and with long enough follow-up of the offspring. To our knowledge there has been only one small published study reporting increased death from coronary heart disease in 3302 Finnish men who were thin at birth and whose mothers had a high body mass index (BMI) during pregnancy, with the finding restricted to mothers who were of short stature.
We hypothesised that maternal obesity is associated with increased risk of death from cardiovascular events in their adult offspring. To test this we examined hospital admissions for cardiovascular events (including both coronary events and other vascular events) and death rates in 37,709 individuals aged 34-61 whose mothers’ BMI was recorded in pregnancy. We used a large database of pregnancy data, the Aberdeen Maternity and Neonatal Databank (AMND), linked to national death and morbidity records to generate 1,323,275 person years of follow-up.
Abstract and Introduction
Abstract
Objectives. To determine whether maternal obesity during pregnancy is associated with increased mortality from cardiovascular events in adult offspring.
Design. Record linkage cohort analysis.
Setting. Birth records from the Aberdeen Maternity and Neonatal databank linked to the General Register of Deaths, Scotland, and the Scottish Morbidity Record systems.
Population. 37,709 people with birth records from 1950 to present day.
Main Outcome Measures. Death and hospital admissions for cardiovascular events up to 1 January 2012 in offspring aged 34-61. Maternal body mass index (BMI) was calculated from height and weight measured at the first antenatal visit. The effect of maternal obesity on outcomes in offspring was tested with time to event analysis with Cox proportional hazard regression to compare outcomes in offspring of mothers in underweight, overweight, or obese categories of BMI compared with offspring of women with normal BMI.
Results. All cause mortality was increased in offspring of obese mothers (BMI >30) compared with mothers with normal BMI after adjustment for maternal age at delivery, socioeconomic status, sex of offspring, current age, birth weight, gestation at delivery, and gestation at measurement of BMI (hazard ratio 1.35, 95% confidence interval 1.17 to 1.55). In adjusted models, offspring of obese mothers also had an increased risk of hospital admission for a cardiovascular event (1.29, 1.06 to 1.57) compared with offspring of mothers with normal BMI. The offspring of overweight mothers also had a higher risk of adverse outcomes.
Conclusions. Maternal obesity is associated with an increased risk of premature death in adult offspring. As one in five women in the United Kingdom is obese at antenatal booking, strategies to optimise weight before pregnancy are urgently required.
Introduction
The obesity epidemic, with its attendant risk of cardiovascular and other chronic disease, has become a global threat to population health and a major public health burden. The prevalence of maternal obesity has risen rapidly in the past two decades. In the United States, about 64% of women of reproductive age are overweight and 35% are obese, with a similar pattern in Europe. The link between an adverse intrauterine environment and disease in later life is well documented, with many studies showing associations between low birth weight (a surrogate measure of intrauterine growth) and subsequent death from cardiovascular disease. Evidence from animal models and emerging data from humans suggest that maternal obesity also creates an adverse in utero environment, with long term "programmed" detrimental effects for the offspring. Several studies have shown associations between maternal obesity and obesity in the offspring, whether it is assessed in the neonatal period or in adulthood, independent of current lifestyle and shared familial (genetic and environmental) factors. Recent studies have reported associations between higher maternal weight before pregnancy and biomarkers of future atheromatous disease in the offspring, including higher blood pressure and dyslipidaemia, in childhood and in young adulthood. Whether this translates into a long term increased risk of cardiovascular disease and death for the offspring is unknown. This is largely because of a lack of suitable cohorts with available data on maternal weight during pregnancy and with long enough follow-up of the offspring. To our knowledge there has been only one small published study reporting increased death from coronary heart disease in 3302 Finnish men who were thin at birth and whose mothers had a high body mass index (BMI) during pregnancy, with the finding restricted to mothers who were of short stature.
We hypothesised that maternal obesity is associated with increased risk of death from cardiovascular events in their adult offspring. To test this we examined hospital admissions for cardiovascular events (including both coronary events and other vascular events) and death rates in 37,709 individuals aged 34-61 whose mothers’ BMI was recorded in pregnancy. We used a large database of pregnancy data, the Aberdeen Maternity and Neonatal Databank (AMND), linked to national death and morbidity records to generate 1,323,275 person years of follow-up.