Childhood trauma affects the timing of motherhood, a new study finds.
A team of researchers from the University of Turku and the University of Helsinki said that women who have experienced childhood trauma become mothers earlier compared to those who have a more stable childhood environment. They added that the trauma girls experience from natural disasters, epidemics, and living in war zones can have unexpected effects that will resurface later in their lives.
Childhood trauma and reproductive timing
In the abstract of their study, which appeared in the journal Nature Communications, lead author Robert Lynch and colleagues explained that it is a considerable cross-disciplinary interest to understand how conditions experienced by kids during their development years can affect their reproductive schedules. Life history theory, which is an analytical framework designed to study the diversity of life-history strategies, has predicted that organisms accelerate reproduction when the future is uncertain. Applying the theory to humans, it could be triggered by early exposure to mortality. However, previous studies were inconclusive because there are several factors likely to affect reproduction.
Exposure to elevated mortality rates
For their research, the team used records of Finnish women in World War II. They found that young girls who served in the paramilitary organization wait less time to reproduce, have shorter inter-birth intervals, and gave birth to more kids compared to their non-serving sisters or peers. This supports the hypothesis that being exposed to elevated mortality rates during development years can result in accelerated reproductive timing. The findings also add to their understanding of how participation in warfare affects women.
Lynch also told medical research platform Medical Xpress that if we can measure the effects of trauma on basic things, including the timing of motherhood, then it almost certainly also has major effects on our other important behaviors, like the pace of sexual development, sociality, and the overall aversion to risk.
Senior author John Loehr moreover pointed out that their findings are “groundbreaking” as it overcomes many of the problems in research that made it difficult to understand whether trauma is the fundamental cause of starting a family at a younger age.
Adjusting reproductive strategies despite environmental stress
The team said that although adversity and environmental stress are usually seen as a detriment to the fitness of individuals during development, the models from the life history theory show that people will also adaptively adjust their reproductive strategies in response to the conditions they experience during their development years.
The extensive dataset on Finnish women who aid in the war effort as part of the Finnish voluntary auxiliary paramilitary organization for women Lotta Svärd made it possible for the researchers to compare women before and after the war. Lynch and colleagues also took into consideration the family backgrounds of the women subjects and compared them to their sisters. All these offered strong evidence to support the idea that childhood trauma can affect women’s reproductive timing.
The relevance of the study
The study has clear importance for the millions of adults and kids worldwide who experience trauma through wars. Furthermore, the significance may also likely apply to other sources of trauma, like natural disasters and the current pandemic. If we are to base the findings on evolutionary theory, it also predicts that people who experienced an unstable environment with a high mortality rate would risk reproducing sooner than not having the opportunity later. Nevertheless, scientific online publication Our World in Data shares that the global fertility rate has fallen so rapidly from 5.05 children per woman in 1950 to 2.49 in 2015.
University of Turku’s Academy Professor Virpi Lummaa, who co-authored the study, explains that there seems to be a sensitivity window from childhood that extends into early adulthood where behaviors of people adjust to match the circumstances they experienced. Even after the situation already stabilizes, the consequences of the trauma can be so far-reaching that it can influence their adult lives, like the time they get pregnant.
Many children are exposed to traumatic life events. A traumatic event is one that threatens death, injury, or the physical integrity of self and others and causes helplessness, terror, and horror at the time it occurs. According to Recognize Trauma, a group of public and private agencies, individual mental health care providers, 26% of children in the US will witness or experience a traumatic event before they turn four. Also, four of every 10 children in the US say they experience a physical assault during the past year with one in ten receiving an assault-related injury.
People who have experienced trauma are 15 times more likely to attempt suicide, 4 times more likely to develop a sexually transmitted disease, 4 times more likely to become alcoholic, 4 times more likely to inject drugs, 3 times more likely to use antidepressant medication, 3 times more likely to experience depression 3 times more likely to have serious job problems, 2.5 times more likely to smoke, and 2 times more likely to have a serious financial problem.
The group said that people don’t need to become therapists to help kids and adolescents deal with traumatic events. There are several steps adults can take that can lead to recovery after trauma. Controlling their emotions is one and this is an important step to handle a traumatic event.
After trauma, a sudden change in mood can be especially upsetting. If that happens, adults should let their kids know that they are reacting to a memory that it is not their fault. For kids who go through a traumatic event, they are often more sensitive to loud noises. This is why one should avoid slamming doors or raising their voice to help the kid deal with a traumatic event.
The new study provides strong support for the hypothesis that women's reproduction is sensitive to the local mortality rates during development. It will also have general relevance to better understand how inequality in crime rates, war, and healthcare and differences in exposure to mortality rates are connected to the patterns of declining fertility, postponement of first reproduction, and teen pregnancies across the world.