The profound connection between mother and fetus is deeper than most think.
While mother and child don’t share blood, the placenta provides a connection between the two, allowing for the exchange of nutrients, wastes, and gasses. The placental wall acts as a barrier, albeit an extremely porous one. Substances consumed by the mother permeate the placental wall and enter the fetus’ circulation, providing nutrients from food the mother eats, liquids she consumes, and air she breathes.
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But the shared substances don’t stop at what is necessary for the fetus’ growth and survival. Alcohol and drugs – both prescription and illicit – are also able to permeate the placenta, often causing congenital disabilities, behavioral changes, and even death.
Women comprise 40 percent of those with lifetime drug use disorders. Additionally, the risk of developing such disorders increases during reproductive years, putting women who are pregnant or soon to become pregnant at an increased risk for substance abuse.
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) defines substance use disorder as the impulsive use of substances despite negative consequences. It is diagnosed by the presence of 11 different criteria.
While a disorder can range from mild to severe, any use of substances can negatively impact both mother and child.
The most commonly used illicit substances among pregnant women are nicotine, alcohol, marijuana, and cocaine. According to the latest data collected in the United States, 5.9 percent of pregnant women use illicit drugs, while 8.5 percent drink alcohol, and 15.9 percent smoke cigarettes.
However, consistent with the rise in opioid use in America and subsequent overdoses, opioid use among pregnant women has also increased in the past decade.
Given the ethical dilemmas associated with researching drug and alcohol effects on fetuses and pregnant women, there are many gaps in the scientific literature. Still, risk factors and adverse consequences for both fetus and mother, pre- and postnatal, are widely documented.
Despite the fact tobacco use through cigarette smoking is decreasing dramatically in the United States, it continues to be the leading preventable cause of disease among pregnant women.
Women with lower socioeconomic standing and decreased education are more likely to smoke during pregnancy. Still, 13 percent of overall women have reported smoking cigarettes during the last three months of pregnancy.
Direct tobacco inhalation is not the only way for a fetus to be affected, however.
Secondhand smoke has been found to negatively impact anyone exposed to it, fetuses included. When a mother is exposed to smoke within the environment, the carcinogens passed to the fetus can result in preterm birth, low birth weight, and childhood cancer.
Compared to indirect or involuntary exposure, direct tobacco exposure through a mother’s voluntary smoking habits are more likely to negatively impact a fetus and result in long-lasting consequences.
Adverse birth outcomes associated with maternal smoking include:
- Infant death.
- Preterm birth.
- Low birth weight.
- Poor intrauterine growth.
- Respiratory problems and infections.
Adverse physical effects are only part of the equation, though.
Prenatal smoking also increases the risks of child behavioral problems, along with cognitive and neurological deficits postpartum.
A fetus exposed to nicotine in the womb is at an increased risk of growing up to exhibit aggressive and hyperactive behavior, prolonged periods of verbal or physical aggression and/or socially undesirable behavior. These behavioral effects can develop into conduct disorders and delinquency throughout childhood.
Other effects of maternal smoking also may not be evident during prenatal stages but can surface during later development.
As a nicotine-exposed baby develops, deficits in fine and gross motor skills will become apparent.
Issues in language acquisition and mental development may also occur, delaying use of language to three years of age and affecting IQ scores and academic performance through late childhood and teenage years.
With alcohol being a legal substance for those over the age of 21 in America, and certain types like wine being found to provide health benefits, consuming alcohol during pregnancy has been a questionable offense.
While there has been a long-standing “no alcohol” policy for pregnant women, news outlets have jumped to the conclusion that an occasional drink while pregnant won’t harm a fetus. This is due to new research finding low-to-moderate consumption only slightly increases the risk of having a baby who is small for gestational age.
Even though alcohol has been an established teratogen, or a substance that causes malformation of an embryo, since the 19th century, it is estimated that 15 to 20 percent of pregnant women continue to consume alcohol while pregnant.
Women who are homeless or living in poverty, surrounded by others who use substances, or who used prior to conception are at an increased risk of using alcohol while pregnant.
Risk factors also include a secondary psychiatric illness and history of physical or sexual abuse. Between 56 to 92 percent of alcohol users have been diagnosed with a psychiatric illness, and around 70 percent experienced abuse in childhood.
Although alcohol is absorbed into the bloodstream, and blood is not shared between mother and fetus, it has the ability to cross the placental wall and affect fetal development.
Due to fetuses having less alcohol dehydrogenase, or a decreased ability to metabolize alcohol, the fetus remains exposed to alcohol longer than the mother, increasing the negative effects.
This already prolonged exposure can be increased if the mother also smokes cigarettes.
Exposure to alcohol in the womb, specifically in the first trimester, increases the risk for spontaneous abortion. Through continued consumption of alcohol during pregnancy (even just 1 to 2 drinks per week), the risk of the fetus developing Fetal Alcohol Syndrome increases exponentially.
Fetal Alcohol Syndrome is characterized by physical developmental deficits, including:
- Microcephaly (head circumference below the 5th percentile on the growth chart).
- Small palpebral fissures.
- Flat nasal bridge.
- Smooth or indistinct philtrum.
- Thinned upper lip.
- Flattening of the midface.
Fetal Alcohol Syndrome is the most recognized disorder associated with alcohol use during pregnancy, but the development of other disorders is also possible.
Covered by the umbrella term “Fetal Alcohol Spectrum Disorders” (FADs), other possible disorders include Partial Fetal Alcohol Syndrome, Alcohol-Related Birth Defects (ARBD), Alcohol-Related Neurodevelopmental Disorder (ARND), and Neurobehavioral Disorder Associated with Prenatal Alcohol Exposure (ND-PAE).
Despite the US Surgeon General’s warnings surrounding alcohol use during pregnancy, 7.6 percent of pregnant women continue to drink while pregnant, and 1.4 percent binge drink.
For the children who grow up to develop a disorder under FADs, they often receive treatment to improve long-term outcomes. While these treatments have been effective in addressing neurological based problems, there is no cure for any symptoms they may experience.
Cannabis is the most commonly used illicit drug in developed countries, specifically among women of childbearing age.
Statistics on women using cannabis during pregnancy is lacking. However, of the data collected, some studies found 2.6 to 5 percent of pregnant women use cannabis, while others found rates of cannabis use as high as 10 to 20 percent.
The study where 5 percent of pregnant women reported use during pregnancy found no significant association between cannabis use and prenatal death, need for special care, birth weight, birth length or head circumference.
However, another study found cannabis use during pregnancy to result in babies, on average, weighing 375 grams less, having a lower gestational age, shorter body length, and a greater likelihood of being admitted to the neonatal intensive care unit (NICU)
Through the use of both human and animal studies, researchers have been able to accumulate data supporting the use of cannabis causing various negative congenital disabilities, including:
- Low birth weight.
- Intrauterine growth retardation.
- Presence of congenital abnormalities.
- Perinatal death.
- Delayed time to commencement of respiration.
Seeing as this area of research is both ethically challenging and often reliant on self-report data, the findings are bound to be conflicting.
Regardless of small sample sizes and conflicting findings, cannabis use during pregnancy impacts the fetus and weight of the newborn. It’s the degree and associated risk that is yet to be determined.
Other Illicit Drugs
In the late 1970s to 1990s, cocaine use among women in their reproductive years accelerated dramatically.
In the late 1900s, when cocaine use first spiked, studies on children born to cocaine-using mothers found that these infants were born with lower birth weight, shorter gestation, and smaller head circumference than average infants.
While cocaine use has severe adverse effects on infants,
leading to the term “crack-baby” being coined in the 1980s, mothers using crack cocaine during pregnancy also experience adverse effects.
Maternal cocaine use was found to increase the risk of the mother experiencing preeclampsia, placental abruption, gestational diabetes, and preterm labor.
Although most women successfully deliver healthy babies and fully recover from preeclampsia, some have complications. Many of these complications can become life-threatening to the mother and/or baby. Placental abruption can also pose life-threatening risks to both mother and baby, with the potential of shock from blood loss or issues with blood clotting.
Opioid use in the United States has reached epidemic proportions, and the dramatic increase in use can also be seen among pregnant women.
From 1999 to 2014, the number of pregnant women with opioid use disorder (OUD) at labor and delivery more than quadrupled. However, the rise in maternal opioid use is significantly higher than the rate of neonatal abstinence syndrome (NAS), suggesting the adverse effects associated with maternal opioid use can vary.
For example, in 2012, rates of NAS reached 5.63 per 1,000 hospital births. This is a stark increase from the 1.19 per 1,000 hospital births in 2000.
Neonatal abstinence syndrome is postnatal drug withdrawal specifically exhibited by infants exposed to opioids in the womb.
The syndrome is characterized by hyperactivity of the central and autonomic nervous system and gastrointestinal disturbances, with symptoms including:
- Excessive crying.
- Poor sleep.
- Increased muscle tone.
- Loose stools.
- Nasal stuffiness.
While less common, 2 to 11 percent of infants with NAS also experience seizures.
Along with NAS, complications like intrauterine growth restriction, placental abruption, preterm delivery, oligohydramnios, stillbirth, and maternal death are also associated with opioid use during pregnancy.
Studies tracking the development of opioid-exposed infants found an increased risk of attention deficit disorder (ADD), disruptive behavior, and the need for comprehensive psychiatric referrals in exposed children.
The Food and Drug Administration (FDA) classify most prescription opioids as harmful to fetuses (except oxycodone). Still, opioids are often prescribed to pregnant women to treat lower back and pelvic pain, along with joint pain and migraines.
Even with substantial evidence outlining the adverse effects of prescription opioid use during pregnancy, the number of women fulfilling opioid prescriptions while pregnant has been increasing for the past decade.
Rates of substance abuse differ between sexes, and despite increasing rates in females, men continue to be two to three times more likely to have a drug abuse or dependence disorder.
Etiology, progression, and treatment needs are different between sexes, yet treatment programs reflecting these differences are lacking.
For example, substance abuse among women is more likely to stem from traumatic events in one’s life, specifically physical or sexual violence. Due to the history and lack of specialization to women’s needs, programs that treat men and women together can have difficulty attracting and retaining female clients.
With few programs specifically targeted to women in general, finding treatment as a pregnant woman can be even more difficult.
However, in the 1990s, the Federal Center for Substance Abuse Treatment (CSAT) created protocols for treating substance abuse in women and specifically pregnant women. These documents put together advice from medical experts, experts on substance abuse treatment and experts in social services, outlining programs that would best benefit pregnant women suffering from substance abuse disorders.
According to the gathered information, pregnant women should seek family-centered, comprehensive programs staffed by an interdisciplinary team of professionals.
Through an environment that is free of judgment, free of punishment, and approached through nurture, the mental health of pregnant women can be addressed to ensure a safe transition away from substance use.