The largest ever UK study to examine self-harm risk around pregnancy has shown that most women are generally less likely to self-harm during and after pregnancy.

The University of Manchester team showed that in 1,000 women, four are likely to self-harm over a year and this risk halves in pregnancy to 2, according to the research published in the British Journal of Psychiatry today.

And while women with a diagnosis of psychiatric disorder had a higher background risk of self-harm, their risk more than halved when pregnant.

Even after pregnancy, women over the age of 30 are at lower risk of self-harm. The risk reduction at 3–6 months after pregnancy is 13% for women aged 30 to 34, and 27% for women aged 35 to 45, compared to women of the same age who were not pregnant, reports in the study.

However, mothers under the age of 30 are more likely to self-harm between three and six months after giving birth.

Mums aged 15 to 19 are 66% more likely, 20 to 24 year-olds 40% more likely, and 25 to 29 year-olds 15% more likely to self-harm between three and six months after giving birth compared to women of the same age who were not pregnant, according to the study from The University's Centre for Women's Mental Health.

The study team identified and analyzed almost 58,000 self-harm events in women aged 15 to 45 years between January 1990 and December 2017.

The data were linked to 1.1 million pregnancies and their outcomes, utilizing the Clinical Practice Research Datalink and Pregnancy Register.

Though only a small number of women self-harm during and after pregnancy, the team argue that identifying those at risk will allow doctors to target resources to the women who need them most of all.

They also discovered:

• Overall, there was a small increase in risk of self-harm post pregnancy, but this risk was carried primarily by young women, aged 15 to 29 years.
• Unlike older women, adolescent women aged 15–19 with a history of self-harm are likely to continue to self-harm during pregnancy.

Lead author Dr. Holly Hope said: "This study—which is the largest of its kind—makes important advances in our understanding of how pregnancy and the first year after giving birth affect self-harm risk.

"As we already know, self-harm among young women generally in the UK is increasing and self-harm is associated with up to a 50 times higher risk of suicide in women, that's important.

"Significantly, we find that the risk of self-harm is indeed higher among women under 30 after giving birth, but reassuringly, for women over 30, the risks of self-harm decrease both during and after pregnancy.

"Latterly, women are increasingly likely to wait a few years until they have a baby which could be down to a number of factors, including their education and employment choices.

"Older women may be in a better financial and psychological position to care for themselves and their baby.

"Hormonal changes during pregnancy intended to promote maternal attachment and increase a sense of wellbeing. However, this mechanism might be overridden by other factors in some younger women."

She added: "Older women might also be in a better position to take advantage of health services which do a good job in signposting them to services if they need help.

"This study shows us more clearly than before, in a contemporary population of women becoming pregnant, where the greatest risks of self harm lie which means resources might be more focussed on those at-risk age groups so they can be monitored more effectively and referred for help more efficiently.

"The most deprived neighborhoods where teenage pregnancy is more common might benefit from a similar focus."

Dr. Jo Black, chair of the Perinatal Faculty at the Royal College of Psychiatrists, said: "By highlighting where resources are needed most, the findings could help ensure funding is better targeted to reach those at greatest risk."