In-Utero and Perinatal Conditions Could Influence Suicide Risk, Meta-Analysis Shows

Massimiliano Orri, PhD

A new meta-analysis found that in-utero and perinatal circumstances might increase the risk of suicide throughout a person’s life.

While causes of increased suicide risk have been studied extensively in the past, this was the first meta-analysis to aggregate data specifically regarding in-utero and perinatal associations with suicide risk.

Using sets of keywords for both suicidal acts and ideation as well as circumstances of birth, the team of investigators collected 42 studies which had published between inception and January 24, 2019 from MEDLINE, Embase, and PsycINFO.

Circumstances which proved statistically relevant to increased suicide risk included: high birth order (fourth-born or later); teenage mothers; single mothers; low maternal and/or paternal education; and low birthweight and/or size.

On the other hand, father’s age; low gestational age; obstetric characteristics (such as caesarean section); and exposure to a condition during pregnancy (such as maternal smoking or hypertensive disease) were proven negligible to the point of irrelevance regarding suicide risk.

In an interview with MD Magazine®, study author Massimiliano Orri, PhD, of the Department of Psychiatry at McGill University—said that children born below 2500 g or born to low-educated parents were 30% more likely to die by suicide. Additionally, children of teenage mothers were about 80% more likely to die by suicide.

“This study is the first summarizing the available evidence on the association of in-utero and perinatal factors with suicide risk,” Orri told MD Magazine©.

Orri hopes that having finally aggregated this previous research in a meta-analysis will prove foundational to future investigations. While former studies are valuable, they were previously sparse, scattered, and often contradictory. Orr cited a 1985 trial which was among the first report associations between early-life characteristics and suicide, in which 52 adolescents and 104 controls made up the data pool.

“Since then, other studies explored the topic owing on the growing availability of large datasets such as the Swedish registers,” Orri said. “These studies mostly came from individual countries or focused on 1 of few risk factors.”

Orri also recommended several specific directions for future research on in-utero circumstances related to suicide risk. First, most of the studies used for the meta-analysis came from high-income countries, so conducting similar research in lower-income countries would broaden the data.

Second, it is difficult to differentiate correlation from causation in a meta-analysis, whereas a quasi-experimental design—based upon genetic information, within-family comparisons, or twin data—would expand investigators’ perspective. Orri cited 2 previous studies (Bjørngaard et al., 2013, and Rostile et al, 2014) as informative, inspirational examples of related research.

Overall, Orri hopes that continued investigation will lead to more effective, targeted intervention earlier in life for those at higher risk of suicide.

“More than treatment of suicidal patients, I think this would call for early-life preventive intervention to reduce vulnerability to suicide later in life,” Orri said. “However, an important step before our findings can inform prevention is to understand the mechanisms linking early-life factors and suicide risk.”

The meta-analysis, “In-utero and perinatal influences on suicide risk: a systematic review and meta-analysis,” was published online in Lancet Psychiatry.