Maternal mortality in eight European countries with enhanced surveillance systems: descriptive population based study

Abstract

Objective: To compare maternal mortality in eight countries with enhanced surveillance systems.

Design: Descriptive multicountry population based study.

Setting: Eight countries with permanent surveillance systems using enhanced methods to identify, document, and review maternal deaths. The most recent available aggregated maternal mortality data were collected for three year periods for France, Italy, and the UK and for five year periods for Denmark, Finland, the Netherlands, Norway, and Slovakia.

Population: 297 835 live births in Denmark (2013-17), 301 169 in Finland (2008-12), 2 435 583 in France (2013-15), 1 281 986 in Italy (2013-15), 856 572 in the Netherlands (2014-18), 292 315 in Norway (2014-18), 283 930 in Slovakia (2014-18), and 2 261 090 in the UK (2016-18).

Outcome measures: Maternal mortality ratios from enhanced systems were calculated and compared with those obtained from each country's office of vital statistics. Age specific maternal mortality ratios; maternal mortality ratios according to women's origin, citizenship, or ethnicity; and cause specific maternal mortality ratios were also calculated.

Results: Methods for identifying and classifying maternal deaths up to 42 days were very similar across countries (except for the Netherlands). Maternal mortality ratios up to 42 days after end of pregnancy varied by a multiplicative factor of four from 2.7 and 3.4 per 100 000 live births in Norway and Denmark to 9.6 in the UK and 10.9 in Slovakia. Vital statistics offices underestimated maternal mortality by 36% or more everywhere but Denmark. Age specific maternal mortality ratios were higher for the youngest and oldest mothers (pooled relative risk 2.17 (95% confidence interval 1.38 to 3.34) for women aged <20 years, 2.10 (1.54 to 2.86) for those aged 35-39, and 3.95 (3.01 to 5.19) for those aged ≥40, compared with women aged 20-29 years). Except in Norway, maternal mortality ratios were ≥50% higher in women born abroad or of minoritised ethnicity, defined variously in different countries. Cardiovascular diseases and suicides were leading causes of maternal deaths in each country. Some other conditions were also major contributors to maternal mortality in only one or two countries: venous thromboembolism in the UK and the Netherlands, hypertensive disorders in the Netherlands, amniotic fluid embolism in France, haemorrhage in Italy, and stroke in Slovakia. Only two countries, France and the UK, had enhanced methods for studying late maternal deaths, those occurring between 43 and 365 days after the end of pregnancy.

Conclusions: Variations in maternal mortality ratios exist between high income European countries with enhanced surveillance systems. In-depth analyses of differences in the quality of care and health system performance at national levels are needed to reduce maternal mortality further by learning from best practices and each other. Cardiovascular diseases and mental health in women during and after pregnancy must be prioritised in all countries.

Fig 1

Maternal and pregnancy associated mortality ratios up to 1 year after end of pregnancy, in countries with enhanced surveillance systems (listed from lowest to highest maternal mortality ratio up to 42 days). Error bars represent 95% confidence intervals. Pregnancy associated deaths are those occurring within 1 year of end of pregnancy, regardless of their cause. Maternal deaths are those with cause related to or aggravated by pregnancy or its management but not from accidental or coincidental cause. In Norway, Finland, and Italy, pregnancy associated deaths are identified up to 1 year after end of pregnancy, but cases occurring between 43 days and 1 year are not reviewed, which is why late maternal deaths were unavailable. In Denmark and Slovakia, pregnancy associated deaths are identified only up to 42 days after end of pregnancy; accordingly, pregnancy associated deaths up to 1 year and late maternal deaths were unavailable for these two countries. In the Netherlands, results up to 1 year after pregnancy end were considered not reliable as linkage is not used to identify deaths, and they therefore not included. *Maternal deaths between 43 and 365 days after end of pregnancy

Fig 2

Age specific maternal mortality ratios, in countries with enhanced surveillance systems. Maternal mortality up to 42 days after end of pregnancy. MMR=maternal mortality ratio

Fig 3

Maternal mortality ratios by women’s migrant or minoritised ethnic background according to various categorisations, in countries with enhanced surveillance systems. Maternal mortality up to 42 days after end of pregnancy; categories presented are those available in each country. Error bars represent 95% confidence intervals. Because all maternal deaths in Finland and Slovakia occurred in women who were citizens and natives of the country, these countries are not presented in this figure. MMR=maternal mortality ratio

Fig 4

Cause specific maternal mortality ratios, in countries with enhanced surveillance systems. Maternal mortality up to 42 days after end of pregnancy. Countries are listed from lowest to highest all cause maternal mortality ratio (MMR)