WOMEN are up to four-times more likely to experience stillbirth if they have had a stillbirth in a previous pregnancy.
Poor fetal growth, placental problems (such as placental abruption), birth defects, infections, and chronic health conditions among mothers are some of the clear causes of stillbirth. However, according to study author Dr Sohinee Bhattacharya and colleagues from the University of Aberdeen, Aberdeen, UK, the cause of stillbirth is often unclear, and they stressed the importance of building a better understanding of factors that may contribute to elevated risk of stillbirth.
To investigate the impact of stillbirth history on experiencing stillbirth in subsequent pregnancies, the team analysed data from 13 cohort and 3 case-controlled studies involving 3,412,079 women from high-income countries including the Netherlands, Australia, and the USA. Of these women, 99.3% had a live birth in an initial pregnancy, while 0.7% had a stillbirth in an initial pregnancy, defined in the study as the death of a fetus after 20 weeks of pregnancy or a weight of ≥400 g at birth.
The researchers found 14,283 stillbirths in a subsequent pregnancy. Of these, 2.5% and 0.4% were among women who had experienced stillbirth in a previous pregnancy and who had no history of stillbirth, respectively. After adjusting for possible confounders, including maternal age, smoking status during pregnancy, and socioeconomic status, the team determined that women who experienced a stillbirth in a previous pregnancy were up to four-times at greater risk compared with women with no history of stillbirth.
The authors reported that just two studies included in their analysis involved women with a history of unexplained stillbirth, and therefore the subsequent risk of stillbirth among these women was unclear.
However, the team said that their data support previous research indicating a history of stillbirth as a significant risk factor for stillbirth recurrence, which may strongly affect clinical practice. They added: “Current management of pregnancies should take account of pregnancy history and make use of pre-pregnancy counselling services.
“Based on the available evidence identified by this review, a stillbirth in an initial pregnancy was associated with an increased risk of a subsequent stillbirth, and pregnancies after a stillbirth should be closely monitored with a view to intervene at the first sign of fetal compromise.”