Women who experience any form of domestic violence during pregnancy are twice as likely to give birth to a premature baby or a baby with low birth weight, according to a new meta-analysis that adds to the evidence linking intimate partner violence to a range of adverse health consequences.
Researchers from the University of Iowa analyzed the results of 50 previously-published studies that looked at the effects of domestic violence–including physical, sexual, financial, psychological or emotional abuse–on pregnancy outcomes, evaluating data from over 5 million women in 17 countries.
The study, published in BJOG: An International Journal of Obstetrics and Gynaecology, found that domestic violence doubled the risk of both preterm birth and low birth weight. This risk was increased even further for women who experienced two or more types of domestic violence during their pregnancy.
“Domestic violence by a partner or ex-partner is of particular concern during pregnancy when not one, but two lives are at risk,” Dr. Audrey Saftlas, the study’s lead author and a professor of epidemiology at the University of Iowa, said in a press release.
‘The detrimental effects of abuse on pregnant women are very clear’
According to the Centers for Disease Control and Prevention, about one in four U.S. women will experience domestic violence in her lifetime. Unfortunately, being pregnant does not protect women against this violence; in fact, research indicates that the severity and frequency of abuse often increase during pregnancy, as does the incidence of intimate partner homicide.
In the U.S., domestic violence is the leading cause of injuries and death among women of childbearing age, and, with at least 324,000 pregnant women victimized each year, domestic violence is also the most common health problem experienced during pregnancy. In addition to poorer overall physical and mental health, pregnant women who are victims of abuse have been shown to have a higher risk of pregnancy complications and adverse birth outcomes such as cervical and uterine infections, preterm birth, low birth weight, and miscarriage.
This latest analysis strengthens that line of evidence, finding that the negative effects of domestic violence on pregnancy outcomes are consistent across studies of women from around the world. While previous meta-analyses have demonstrated a relationship between domestic violence and an increased risk of both preterm birth and low birth weight, the new meta-analysis — which looked at more recent evidence and a greater number of studies overall — found that the magnitude of this relationship was significantly stronger than past estimates.
“Although rates of domestic violence differ across the world, the detrimental effects of abuse on pregnant women are very clear,” Dr. Saftlas said.
Mechanisms of action
While the underlying causes are not entirely understood, evidence suggests that domestic violence can affect a growing fetus in a number of ways.
Most obviously, physical assaults during pregnancy can lead to injuries causing complications such as premature labor, rupture of membranes, and placental abruption, all of which can lead to preterm birth, low birth weight, and even miscarriage and stillbirth. Physical and sexual violence have also been shown to increase the incidence of infections of the kidneys, urinary tract, cervix, and uterus, which in turn can cause intrauterine growth restriction and preterm birth.
However, the effects of domestic violence can also be much more insidious, occurring through a complex web of indirect mechanisms.
One of the primary indirect ways that domestic violence is thought to influence pregnancy outcomes is through chronic psychological stress and elevated levels of stress hormones such as GABA and cortisol, which wreak havoc on the body, increasing the risk of complications ranging from gestational diabetes and hypertension to preterm labor.
Women who are in abusive relationships are also more likely to receive late and/or inadequate prenatal care, and some may also turn to unhealthy coping behaviors such as smoking cigarettes or eating a poor diet. Furthermore, abused women have significantly higher rates of unintended pregnancies (linked to reproductive coercion and sexual violence), which are known to be connected with poor birth outcomes.
‘Pregnancy is a very wonderful but vulnerable time for both mother and child’
Dr. Saftlas said she hopes that these new findings will encourage OBGYNS and general practitioners to do more to screen pregnant women for signs of abuse, so they can get access to appropriate resources. This includes routinely asking pregnant women direct questions about their past and current experiences with any forms of abuse, as well as evaluating psychosocial factors and clinical indicators that can serve as reliable markers of domestic violence risk.
Research has shown that inquiring about domestic violence multiple times throughout pregnancy significantly improves the detection rates, as does asking specifically about different types of abusive behavior.
Routine screening can also help identify pregnant women who are most at risk of fatal partner violence. For instance, research shows that abused women whose partners have access to a firearm experience are significantly more likely to experience very severe violence, and about six to eight times more likely to be killed than abused women whose partners do not have access to guns.
“Domestic violence during pregnancy can have fatal or long term consequences for both mother and baby. These pregnant women have very complex needs and do not necessarily know about the support that is available to them,” Dr. Lesley Regan, Vice President for Strategic Development for the Royal College of Obstetricians and Gynaecologists (RCOG), said in a statement.
“Healthcare professionals have an important role to play in tackling the problem and are often the first and only point of contact that the isolated and vulnerable victim reaches out to. All of us working in health and social services need to be trained to recognize the signs of domestic violence and abuse and know how to act and who to refer to, to ensure the woman’s safety.”