As a society, we talk a lot about what happens during pregnancy, and as a whole, we are obsessed with the materialistic side of things. The pregnancy announcements, baby showers, nursery must-haves… All of this is fun and exciting! But what about the marathon itself? How do we really prepare for the birth day?
Let’s back up and start by talking about prenatal stress and how important a regulated nervous system is during pregnancy for fetal development. Then we will transition to what this means for the actual birth day. Research shows that maternal stress directly impacts a baby’s developing nervous system even before birth. Moms who are stressed about work, relationships, baby showers, or pregnancy may have babies who reflect the same stress patterns. This highlights a crucial biological link between a mother’s nervous system and her baby’s neurological development.
Conventional prenatal care often overlooks this connection. Fortunately, there are specific techniques and tools you can implement, rather than just vague advice to “reduce stress.” Understanding the mechanics of how your stress affects your baby can empower you with tools and hope for supporting both your and your baby’s nervous system development during pregnancy. We just have to start at the foundation, which really is the nervous system. This system is the air traffic control for your and your baby’s bodies, so we want to make sure it’s functioning correctly for both of you, especially leading up to birth!
Your baby’s nervous system is being shaped right now. Let’s make sure it’s being shaped well.
How Stress Hormones Cross the Placenta
When you experience stress—a work deadline, a fight with your partner, financial worry, pregnancy anxiety—your body releases cortisol.
Cortisol is your body’s main stress hormone. In small, temporary doses, it’s helpful. It mobilizes energy, sharpens focus, and helps you respond to challenges. But chronic, unrelenting stress means chronic, unrelenting cortisol.
Here’s the mechanism: cortisol crosses the placenta. It reaches your developing baby. Your baby’s brain, still forming, still incredibly vulnerable, gets stress hormones.
This affects your baby in several specific ways:
The HPA axis—your baby’s hypothalamic-pituitary-adrenal stress response system—gets programmed in utero. If it’s developing while exposed to high levels of maternal cortisol, it learns to operate in high-alert mode. The gas pedal gets set to a higher baseline. The brake pedal develops weakly.
Structures within the brain that are critical for emotional regulation can become altered when the body is under immense stress. Research shows that the amygdala (a fear center) can enlarge, while the hippocampus (a region involved in memory and emotional processing) can show reduced volume. These aren’t abstract changes; they have real consequences for how your child will handle stress throughout their life.
Prenatal stress also affects vagus nerve development. When the developing vagus nerve is exposed to chronic stress hormones, its function becomes compromised. This explains why babies born to highly stressed mothers often show feeding difficulties, digestive issues, and poor self-regulation from birth.
This isn’t about occasional stress from a hard day. This is about chronic, unrelenting stress your body can’t regulate away. The kind that keeps you awake at night, that sits in your chest all day, that your nervous system can’t escape.
What “Nervous System Regulation” Actually Means
Your Autonomic Nervous System runs everything your body does automatically—heartbeat, breathing, digestion, immune response, sleep, stress reactions. You don’t think about making your heart beat. Your autonomic nervous system handles it.
This system has two main parts. Think of your nervous system like a car. The Sympathetic Nervous System is your gas pedal; it gets you moving when you need to respond to something. Fight-or-flight mode. The Parasympathetic Nervous System is your brake pedal. It helps you rest, digest, sleep deeply, heal, and regulate emotions.
When everything’s working right, you press the gas when needed and the brake when needed! But here’s what happens to so many pregnant moms: chronic stress keeps the gas pedal floored. Work stress, relationship tension, financial worry, pregnancy anxiety, and sleep deprivation. The sympathetic nervous system gets stuck “on.” The brake pedal barely functions anymore.
This state is called sympathetic dominance or dysautonomia. And when your developing baby’s nervous system is learning from yours, they’re learning to live with the gas pedal stuck down, too.
The Importance of Nervous System Regulation Before and During Birth
Now that we’ve learned about the Autonomic Nervous System, gas and brake, and how nervous system stress can impact a baby during pregnancy, let’s explore the nervous system during birth.
The process of birth is, at its core, a beautiful sequence of nervous system shifts. Labor begins in a parasympathetic-dominant state — often called the “brake pedal” side of the Autonomic Nervous System. Research shows that oxytocin, the hormone responsible for initiating and sustaining labor contractions, is released most effectively when the mother feels safe, calm, and supported. Oxytocin’s release is directly linked to parasympathetic activity, which promotes uterine contractility, cervical softening, and rhythmic labor patterns. In this early stage, the body prioritizes smooth muscle coordination, pain modulation, and hormonal balance, all of which depend heavily on a regulated parasympathetic tone. Without this calm baseline, the body has much more difficulty triggering the hormonal cascade that initiates labor. Making nervous system regulation and accessing the brake pedal are the most important steps in initiating birth. You could try the hot sauce, dates, teas, pineapple, and curb walking… But for any of these to work, you need a calm and safe nervous system.
As labor progresses into the active pushing phase, the nervous system must shift gears. This is where the sympathetic “gas pedal” comes online — but only at the right time. The sympathetic system provides the strength, power, and coordinated musculoskeletal contraction required to push baby through the birth canal. Heart rate increases, respiratory rate rises, blood flows to the large skeletal muscles, and catecholamines like adrenaline surge in controlled amounts. This sympathetic activation is not a stress response; it is a purposeful physiological mobilization response that helps mom meet the physical demands of birth. Once baby is born and placed on the mother’s chest, both mom and baby transition back into parasympathetic dominance — a state that stabilizes baby’s temperature, breathing, and heart rate, while also supporting maternal bonding, breastfeeding initiation, and postpartum recovery. This return to parasympathetic tone is what allows oxytocin and prolactin to rise again, reinforcing uterine healing and the neurobiological foundation of attachment.
The Effects of a Dysregulated Nervous System in Birth
However, this beautifully timed sequence can be disrupted when the “gas pedal” turns on too early. When a mother does not feel safe due to environmental stressors like bright hospital lights, unfamiliar staff rotations, loud noises, frequent interruptions, or a history of trauma, the sympathetic nervous system takes over prematurely. Elevated stress hormones like cortisol and norepinephrine can inhibit oxytocin release, slow cervical dilation, and dysregulate contraction patterns. This is why stressful environments are associated in research with longer labor, more interventions, and increased pain perception. When mom is already stuck in a defensive sympathetic state, her nervous system is less able to shift cleanly into the parasympathetic phases labor relies on. This dysregulation also impacts the baby. A newborn’s first form of nervous system regulation is co-regulation with the mother through skin-to-skin contact, eye contact, warmth, nursing, and the rhythm of her heartbeat and breath. If mom and baby are separated immediately after birth due to NICU procedures, medical complications, or routine practices, that co-regulatory loop is interrupted. Studies show that newborns separated from their mothers experience elevated heart rate, lower HRV, more difficulty stabilizing temperature and glucose levels, and higher stress hormone levels — all signs of a dysregulated autonomic state in the baby.
Ultimately, our goal is not to control every variable of birth, because birth is inherently unpredictable, but to help mothers enter the experience with a nervous system that is regulated, resilient, and adaptable. A well-regulated nervous system can fluidly shift between parasympathetic and sympathetic states without getting “stuck” in either one. This adaptability is what allows a mother to stay grounded during contractions, move into empowered activation during pushing, and then settle into deep connection during postpartum bonding. Regulation does not mean eliminating stress; it means the nervous system can respond rather than react, mobilize when needed, and return to calm when the moment has passed. When we support mothers in cultivating this adaptability throughout pregnancy with Neurologically-Focused Chiropractic Care, that’s when all of those regulation tips, such as breathwork, supportive environments, and intentional preparation, will work during labor. The nervous system has to be repaired first before it will regulate, and then we can encourage and allow the autonomic nervous system to do exactly what it was designed to do during birth.
Prenatal Stress and Baby Outcomes
Science confirms what we see in practice.
A 2017 study found that infants born to mothers with the highest stress levels showed 22% higher stress reactivity compared to infants whose mothers reported the lowest stress levels. These babies startled more easily, took longer to calm down, and showed reduced exploratory behavior.
Research on Heart Rate Variability reveals even more. Babies born to mothers who experienced higher stress levels show measurably lower HRV at birth—indicating reduced parasympathetic activity and poor nervous system regulation right from the start. Their brake pedals don’t work well because they were never properly installed during development.
Long-term high prenatal stress correlates with increased risk for:
- Anxiety and depression in childhood
- ADHD and attention difficulties
- Behavioral problems and emotional dysregulation
- Altered brain structure visible on imaging
- Reduced cognitive abilities in early childhood
The research also shows something fascinating about maternal stress perception. It’s not just objective life circumstances—it’s how your nervous system handles stress. Two women can experience similar situations, but if one has a well-regulated nervous system that can process and recover from stress while the other stays stuck in sympathetic dominance, their babies develop differently.
Here’s what this means for you: your nervous system state during pregnancy matters. A lot. But conventional prenatal care offers no tools to actually assess or improve nervous system function. You get generic advice to “reduce stress” without any way to measure whether your nervous system is actually regulated, needs some extra repair, or is stuck.
What You Can Do Right Now
Standard prenatal care monitors your baby’s growth. Tracks development. Screens for complications. All essential work that OB/GYNs do. What’s missing isn’t bad intentions; it’s the scope of practice.
There’s usually no assessment of your nervous system function. No measurement of maternal stress impact on fetal nervous system development. No intervention to improve regulation during this critical window.
This is where Neurologically-Focused Chiropractic Care makes the difference.
Measurable Proof—INSiGHT Scans
INSiGHT Scans provide objective measurement of nervous system function through Heart Rate Variability, EMG, and thermal scanning.
The Thermal Scan acts like a stress thermometer for your neurospinal system. It measures your Autonomic Nervous System balance—essentially showing whether you’re stuck in stressed-out, sympathetic fight-or-flight mode or able to access that calm, parasympathetic rest-and-digest state. For pregnant moms, this reveals whether your body is in survival mode or thriving mode.
The Surface EMG (Electromyography) reveals the physical patterns of stress in your nervous system. Think of it as showing us where you’re “holding” your tension—those spots where stress literally gets stuck in your body. During pregnancy, these patterns can indicate how much energy your nervous system is wasting on tension instead of using for growing your baby.
The Heart Rate Variability (HRV) scan is considered the gold standard for measuring adaptability. It shows your vagal tone—basically, how resilient and flexible your nervous system is under stress. A healthy HRV means you can roll with the punches; a compromised one suggests you’re white-knuckling through pregnancy.
In practice, we consistently see this pattern: moms under care show stress within their scans, improving to regulated patterns. Energy returns. Sleep improves. Emotional balance restored. And then they have their baby! After birth, when baby gets scans, we usually see the scans often mirror mom’s nervous system health. In newborns, the nervous system isn’t fully stabilized or developed, so we could see dysregulated scans, which means mom’s nervous system has to be ready to teach baby’s nervous system how to grow and develop. Regulated moms usually have regulated babies. This is co-regulation.
Your Next Step
Find a PX Docs certified pediatric and Perinatal Chiropractor in your area through our directory. Start with INSiGHT Scans to assess your current nervous system function. Begin gentle, Neurologically-Focused adjustments. Track changes through re-scans to see objective progress.
Earlier in pregnancy is better. But it’s never too late to start supporting your nervous system and your baby’s development.
