HISTORICAL reductions in maternal mortality could be “reversed” by increasing levels of Caesarean deliveries and births by older and obese women, according to research.

A study led by Edinburgh University found that a previous C-section delivery was associated with a 52 per cent increase in the risk of severe illness or complications in a subsequent pregnancy.

Being obese - classed as a BMI over 30 - was associated with a 13% increase when compared to mothers of a healthy weight, rising to a 32% increase for expectant mothers who were severely obese.

Women over 40 had a 44% increased risk of complications compared to pregnant women aged 25 to 29, with those aged 35 to 39 at 22% increased risk.

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Overall, the incidence of "severe maternal morbidity" - serious, but usually non-lethal, sickness and complications during pregnancy - increased from nine per 1000 pregnancies in 2012 to 17 per 1000 pregnancies in 2018.

However, the study authors cautioned that this may be an overestimate due to changes in the recording of puerperal sepsis - an potentially fatal blood infection which can occur in the days immediately after childbirth. Clinical coding for puerpural sepsis increased substantially after 2012, but previous evidence suggests it is "unreliable".

The findings, published in the journal Anaesthesia, are based on an analysis of more than 760,000 pregnancies in Scotland over a 14-year period from January 2005 to the end of December 2018.

In total, 41 women died during pregnancy or up to 42 days after delivery. This translated to a maternal mortality rate of 1.6 per 100,000 pregnancies in healthy mothers, but rose to 365 per 100,000 for those who experienced one of 26 severe morbidities included in the study.

As well as sepsis - the most commonly recorded complication - these covered a broad range of medical interventions and events, such as an admission to critical care during pregnancy, a cardiac event, an obstetric-related blood clot, acute kidney failure, or severe psychosis.

The Herald: the rates of 26 severe maternal morbidities per 1000 pregnancies, conditions (red) and procedures (blue). The black line is the cumulative proportion for all severe morbidities (Source: 'Severe Maternal Morbidity in Scotland', Anaesthesia)the rates of 26 severe maternal morbidities per 1000 pregnancies, conditions (red) and procedures (blue). The black line is the cumulative proportion for all severe morbidities (Source: 'Severe Maternal Morbidity in Scotland', Anaesthesia)

The authors stress that the number of women dying in pregnancy and childbirth in the UK is at an "all-time low", but that the "increasing prevalence" of obesity, older age, and previous caesareans - which their analysis indicate increase the risk of severe maternal morbidities - "might reverse the historical reductions in mortality and will increase healthcare during pregnancy and childbirth".

According to the most recent 'Births in Scotland' report, a record 36% of single infant deliveries in the year ending March 2021 were performed by C-section, compared to fewer than 10% in 1976.

The Herald: (Source: Public Health Scotland)(Source: Public Health Scotland)

In the same year, more than a quarter (25.9%) of the women who gave birth were obese and 23.4% were over 35, up from 3.5% in the year to March 1991.

The proportion of pregnancies in Scotland involving twins, triplets or more has also increased, from 1.8% in the mid-1970s to 2.9% now.

The Herald: (Source: Public Health Scotland)(Source: Public Health Scotland)

The Edinburgh University analysis found that this more than doubled the risk of severe maternal morbidity.

The study was led by Dr Nazir Lone, a senior lecturer in critical care at Edinburgh University, in collaboration with colleagues including the highly-respected obstetrician, Professor Fiona Denison, who took her own life in January this year following lengthy battle with health problems triggered by Covid infection.

The authors noted: “The reality today is that the increasing complexity of healthcare needs of women during pregnancy means that they may need greater levels of care during pregnancy and delivery.

"The fact that maternal mortality has stalled, rather than increased, suggests maternity services are adapting to these many challenges.

"However, our study may allow us to develop better systems to identify women at risk of severe maternal morbidity, so that maternity services can provide more personalised care targeted to those at higher risk.”

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Birte Harley-Lam, executive director at the Royal College of Midwives, said: “All UK governments must ensure that maternity services have the right numbers of staff, with the right training and in the right places to ensure all women get the personalised and tailored care they need and deserve.

"This includes specialist services and care for more vulnerable women and those with complex pregnancies. Midwives and their colleagues are doing this now, often against the odds."