This is despite overall decline in rates in recent years
Key causes placental issues and birth defects, but unknown in more than half of cases

Despite an overall decline in stillbirths across the UK in recent years, rates among black and South Asian communities are still around double those of the rest of the population, finds an analysis of monitoring data, published in the open access journal BMJ Open.

Placental issues and birth defects are among the key causes in these groups, but the cause isn’t known in more than half of cases, the findings show.

Stillbirth rates are higher in the UK than in many other comparable high-income countries, and are falling more slowly, despite government targets to cut rates by up to 50%.

Ethnic minorities in the UK are typically more disadvantaged and likely to have poorer health outcomes than their white counterparts. But there’s not much research into ethnic inequalities in stillbirth rates, and little is known about differences in the causes of stillbirth between ethnic groups.

In a bid to plug this knowledge gap, the researchers analysed data from the Mothers and Babies: Reducing Risk through Audits and Confidential Enquiries across the UK (MBRRACE-UK) programme from 2014 to 2019.

MBRRACE-UK collects information on all live and stillbirths, including ethnicity, for mothers resident in each of the 4 UK countries.

Ethnicity is categorised as: white; Indian; Pakistani; Bangladeshi; other Asian; black Caribbean; black African and other black; mixed ethnicities; and other (to include Chinese).

Levels of deprivation were assessed by linking the mother’s residential postcode at the time of the birth to local measures showing the proportion of children living in families either in receipt of unemployment benefits or tax credits, and with a reported household income less than 60% of the national average.

Maternal age, another potentially influential factor, was grouped into 5 year age bands from under 20 to more than 40.

Between January 2014 and December 2019, 4,391,569 singleton babies at or above 24 weeks were born to mothers resident in the UK. Of these, 16,013 ended in stillbirth, giving a rate of 3.65/1000 births: 14,633 occurred before birth (3.33/1000) and 1380 during birth (0.31/1000).

The overall stillbirth rate fell by 18% from 2966 (3.96/1000 births) in 2014 to 2241 (3.24/1000 births) in 2019.

Social and financial disadvantage was associated with a higher stillbirth rate: 4.80/1000 births for the most deprived areas compared with 2.70 for the least deprived.

Age at birth was also associated with higher rates: 4.81/1000 births for mums under 20 and 5.42 for those aged 40 and above.

Information about ethnicity was available for most births: 76% were classified as white: 10% Asian (including Indian, Pakistani, Bangladeshi and other Asian groups); 5% black (including black Caribbean, black African and other black groups); 6% mixed; and 3% other ethnicities.

Black African and black Caribbean mothers experienced an additional 4 stillbirths per 1000 births compared with White mothers; there were an additional 3 stillbirths per 1000 births for Pakistani mothers after adjusting for differences in maternal age and deprivation.

Higher proportions of babies of Bangladeshi (42%), black African (39%), other black (39%) and black Caribbean (37%) ethnicities were born to mothers living in the most deprived areas, compared with 18% of white babies. Living in these areas was associated with an additional risk of 1.5 stillbirths/1000 births.

Higher stillbirth rates due to birth defects were observed among stillborn babies of Pakistani, Bangladeshi, and black African ethnicities, while placental issues were evident among mothers of all black ethnicities.

Across the whole UK population, the cause was unknown in over 40% of cases, but this was even higher for babies of other Asian (60%), Bangladeshi (58%), and Indian (52%) ethnicities.

The researchers acknowledge that they can’t rule out the influence of potentially important risk factors that weren’t universally accounted for, and that ethnicity may have been misclassified.

But the study used high quality population data over a 6-year period, with complete ascertainment of stillbirths from 24 weeks of pregnancy, including terminations, they point out. Few other high-income countries have similar active national stillbirth monitoring programmes.

They conclude: “Improved strategies for investigation of stillbirth causes are needed to reduce unexplained deaths so that interventions can be targeted to reduce stillbirths.”