Sinead Brophy, Kelly Morgan – NCPHWR, Swansea University; Mark Atkinson, Muhammad Rahman – FARR Institute Swansea
Affecting around 1 in 20 women in Wales, obesity in pregnancy is a rising public health problem that has an impact on both maternal and child health and cost to the NHS. It is associated with heavier infants, more birth interventions, poorer health of the baby and greater likelihood that the infant will grow up to be overweight or obese.
In a two part study which looked independently at the health service use of obese mothers during their pregnancy and later at the health service use of the child during their first year, it was found that both obese mothers and their children had a significant increase in health service use than mothers of a healthy weight and their children.
The average cost to the NHS per obese pregnancy were 37% higher than mothers of a healthy weight, with the average cost of care for the first year of a child’s life who has been born to an obese mother 72% higher than children born to mothers of healthy weight.
When calculating the combined cost of increased health service use by both the mother and child, the research showed that interventions costing less than £2,310 per obese mother could be cost effective if they reduce healthcare usage among these women to levels equivalent to that of a woman of healthy weight.

Study 1 – Obesity in pregnancy and the effect on maternal health service use
This research project estimated the direct healthcare cost of being overweight or obese in pregnancy to the NHS in Wales. The study examined the direct healthcare cost with an aim to inform the amount that could be spent on public health intervention and still be cost saving.
Working with SAIL Databank, which is totally anonymised to comply with all data protection rules, data was extracted and linked from GP records, hospital admissions, questionnaires, maternal pregnancy notes and the child health record (red book).
During 2011 – 2012, 484 women took part in the study and were categorised into two groups: normal body mass index (BMI) and overweight/obese.
Costs were calculated as costs of the mother (not the infant) and were related to health service usage throughout the pregnancy and two months following the birth.
The research showed that there is a strong association between healthcare usage cost and BMI, with costs being higher both among obese women and overweight women compared to those mothers of normal weight.
The study found costs to the NHS per pregnancy were 23% higher for overweight women and 37% higher for those classed as obese. Obese women spent on average 30% more days in hospital, and had between 15 – 20% greater usage of all healthcare services. The study also showed an increase in caesarean section deliveries and poor health of both mother and baby.
When applied to the NHS across the UK, the additional cost of overweight and obese women added up to between £105m and £286m.
The research concluded that interventions costing less than £1171.34 per person could be cost effective if they reduce healthcare usage among obese women to levels equivalent to that of normal weight women – saving the NHS money, and also giving better health outcomes for both mother and baby.
Study 2 – Obesity in pregnancy and the effect on child health service use in their first year
A follow up study ‘Obesity in Pregnancy: Infant Health Service Utilisation and Costs on the NHS’ looked to estimate the direct healthcare cost of infants born to overweight or obese mothers to the NHS in the UK. The study examined the direct healthcare cost with an aim to inform the amount that could be spent on public health intervention and still be cost saving.
Working with SAIL Databank, data was combined and linked on a group of mother-child pairs enrolled on the ‘Growing Up in Wales: Environments for Healthy Living Study.
Participants were made up of 609 pregnancies with available health service records and antenatal maternal body mass index (BMI). Infants were categorised as healthy, overweight or obese according to the mothers early pregnancy weight (BMI).
Costs were calculated in the year 2012-2013 as cost of the infant (not the mother) for health service usage from birth to age 1 year. The results of the research showed that there is a strong association between healthcare usage cost and BMI.
The findings showed a significant increase in health service use and associated costs for infants born to obese mothers. The average costs to the NHS were 72% higher among children born to obese mothers compared to infants born to healthy weight mothers. Infants born to obese mothers cost an estimated £1138.11 more than infants born to healthy weight mothers.
The Impact
Both the studies add an economic dimension to the importance of promoting healthy weights among women of child bearing age. The findings can help to inform policy makers and stimulate cost effective interventions to prevent maternal obesity.
Taking forward the result from these 2 studies, NCPHWR researchers at Swansea University are part of the team evaluating “Bump Start”. The Bump Start project run by Cwm Taff University Health Board offers obese women at booking visit one- on- one health lifestyle and midwife dietician sessions. This new study will evaluate the weight gain, birth and infant health for women offered these sessions compared to a control group who have treatment as usual. This work will examine the cost of these sessions compared to any cost savings from improved birth and health for the baby and the mother.