Researchers have revealed through a meta-analysis that women with a history of stillbirth are at a greater risk – up to four times the risk – of stillbirth in second pregnancy compared to those who had an initial live birth.
Researchers reveal through the meta-analysis published in The BMJ that though there has been a decline in stillbirth rates across most of Europe, UK is ranked 33rd out of 35 for stillbirth rates among European countries with 3,286 stillborn babies on record in 2013.
Sohinee Bhattacharya and colleagues from the University of Aberdeen, Scotland explains that as stillbirth is one of the most common adverse obstetric outcomes and a traumatic experience for parents, couples who have been through such an experience need to understand why it happened in the first place and what are the risks for future pregnancies.
However, researchers found that there isn’t sufficient information for the clinical management to prevent such traumatic outcome.
This motivated researchers to undertake a systematic review and meta-analysis of 13 cohort and 3 case-control studies from high-income countries including Australia, Scotland, the US, Denmark, Israel, the Netherlands, Norway and Sweden to examine the link between stillbirth in an initial pregnancy and risk of stillbirth in a subsequent pregnancy.
The definition of stillbirth was fetal death at more than 20 weeks’ gestation or a birth weight of at least 400g.
During the meta-analysis, the researchers collected data for 3,412,079 women out of which 3,387,538 (99.3 per cent) women had a previous live birth and 24,541 (0.7 per cent) women had a stillbirth in an initial pregnancy. They found that stillbirths occurred in the subsequent pregnancy for 14,283 women: 606 of 24,541 (2.5 per cent) in women with a history of stillbirth and 13,677 of 3,387,538 (0.4 per cent) in women with no history.
Out of all the studies they looked into, twelve studies assessed the risk of stillbirth in second pregnancies and the analyses showed that women who had a stillbirth in an initial pregnancy had a nearly fivefold increased risk of stillbirth in a second pregnancy. This risk is higher than stillbirth linked with medical conditions such as diabetes or hypertension.
After adjusting for confounding factors such as maternal age, maternal smoking and level of deprivation, the increased risk was up to fourfold higher.
Risks following an unexplained stillbirth may not be increased because there are few studies and the evidence remains inadequate, explain the authors.
Pre-pregnancy counselling services should be provided to women who had a stillbirth, they urge, as well as advice on changing these lifestyle factors such as smoking and obesity that are both linked to an increased risk of stillbirth.
Pregnancies should be closely monitored, and antenatal interventions and care be offered at the first sign of increased risk of distress or danger, they add.
In a linked editorial, experts from St Mary’s Hospital echo calls for additional care in next pregnancy, and for more research on unexplained stillbirths, which can account for around 20% of stillbirths. In addition, they stress the importance of an improved international classification system to determine causes of death, especially as these can be quite complex, so that interventions can be adequately targeted.
