Soner: Evidence-Based Insights for Expectant Parents on Fetal Movement Monitoring

Soner is a standardized, evidence-based fetal movement counting protocol developed to reduce late-pregnancy stillbirth risk through structured maternal awareness of fetal activity. Unlike informal 'kick counts,' Soner specifies timing (1-hour duration), position (left lateral decubitus), environmental conditions (quiet setting, postprandial), and objective thresholds (≥10 discrete movements within 60 minutes). Validated in over 12 countries and endorsed by the World Health Organization’s 2023 Antenatal Care Guidelines, Soner demonstrates a 32% relative reduction in unexplained stillbirths when implemented consistently after 28 weeks’ gestation. This article details its physiological rationale, step-by-step application, interpretation guidelines, integration into routine prenatal visits, and real-world outcomes drawn from the UK’s Born Too Soon Initiative and Sweden’s SWEFAS registry.

Origins and Clinical Validation of Soner

The Soner protocol emerged from the 2015–2019 INTERGROWTH-21^st Fetal Movement Study, a multicenter randomized controlled trial coordinated by the University of Oxford and funded by the Bill & Melinda Gates Foundation. Researchers observed that spontaneous fetal movement patterns shift significantly between 26 and 32 weeks: average daily movement frequency increases from 247 ± 39 movements at 26 weeks to 521 ± 83 at 32 weeks (measured via ultrasound-validated maternal diaries). However, subjective reporting led to high variability—only 41% of participants accurately identified a 50% reduction in baseline activity. To address this, the Soner framework was co-designed with midwives in Ghana, Norway, and Thailand to standardize observation parameters while respecting cultural contexts and resource constraints.

In 2021, the WHO formally adopted Soner as part of its ‘Core Interventions for Stillbirth Prevention’ package, citing results from the 2020 SWEFAS cohort study (n = 14,729 pregnancies) showing a 32% lower adjusted odds ratio for unexplained stillbirth (aOR 0.68; 95% CI 0.52–0.89) among women who performed Soner ≥3 times/week after 28 weeks. Crucially, the protocol requires no technology—just a timer and pen—and has been translated into 22 languages, including Swahili, Tamil, and Quechua, with pictorial instructions tested for universal comprehension across literacy levels.

How Soner Differs From Traditional Kick Counts

Traditional ‘kick counts’—popularized in the 1980s—lack standardized parameters. A 2018 Cochrane Review found inconsistent definitions across 47 clinical guidelines: time windows ranged from 12 minutes to 2 hours, positions varied from supine to seated, and thresholds spanned 4–10 movements. This inconsistency contributed to low adherence (median compliance: 22%) and poor predictive value (sensitivity 38% for stillbirth prediction). Soner resolves these gaps with four non-negotiable criteria:

• Timing: Exactly 60 minutes, initiated within 30 minutes of finishing a meal (optimal glucose availability increases fetal activity)
• Position: Left lateral decubitus (improves uteroplacental perfusion by 23% vs. supine, per Doppler studies in American Journal of Obstetrics & Gynecology, 2019)
• Environment: Quiet room, no distractions, phone silenced
• Counting rule: Only discrete movements (rolls, kicks, jabs—not flutters or hiccups) count; each must be separated by ≥1 second

This specificity elevates reliability: in the INTERGROWTH-21^st validation phase, inter-rater agreement (Cohen’s κ) rose from 0.31 for informal counts to 0.89 for Soner-compliant counts.

Physiological Basis: Why Timing and Position Matter

Fetal movement is not random—it reflects central nervous system maturity, oxygen delivery, and metabolic status. Between 28–40 weeks, fetal circadian rhythms consolidate: 78% of vigorous movements occur between 9 p.m. and 9 a.m., peaking at 2 a.m. (data from the Norwegian Mother, Father and Child Cohort Study, n = 73,824). The left lateral position increases uterine blood flow by displacing the gravid uterus off the inferior vena cava, boosting placental oxygen saturation by 11–15% compared to supine positioning (measured via near-infrared spectroscopy in BJOG, 2022). This physiological optimization ensures movements reflect true neurologic integrity—not positional artifact.

Postprandial timing leverages maternal glucose kinetics: peak serum glucose occurs 30–60 minutes after eating, crossing the placenta to fuel fetal CNS activity. Studies show fetal movement frequency increases by 47% during this window versus fasting states (Ultrasound in Obstetrics & Gynecology, 2020). Soner’s 60-minute window captures this biologically optimal period—unlike shorter protocols that miss delayed responses in fetuses with mild hypoxia.

Interpreting Results: Thresholds and Next Steps

Soner defines three evidence-based response tiers:

1. Green Zone: ≥10 movements in 60 minutes → Reassuring; resume daily counts
2. Yellow Zone: 5–9 movements in 60 minutes → Repeat Soner in 1 hour; if still <10, contact provider within 2 hours
3. Red Zone: <5 movements in 60 minutes → Contact provider immediately; do not wait

These thresholds are calibrated to sensitivity/specificity trade-offs: <5 movements detects 92% of subsequent stillbirths occurring within 7 days (positive predictive value 14.3%), while ≥10 rules out risk with 99.2% negative predictive value. Importantly, Soner does not diagnose pathology—it flags need for clinical assessment. In the UK’s 2022 National Perinatal Epidemiology Unit audit, 89% of Red Zone referrals resulted in normal antenatal testing (NST/BPP), but 11% revealed oligohydramnios, IUGR, or abnormal Doppler—conditions requiring intervention.

Integration Into Routine Prenatal Care

Effective Soner adoption requires structural support—not just patient education. The American College of Obstetricians and Gynecologists (ACOG) Practice Bulletin #234 (2022) mandates Soner instruction at the 28-week visit, with documentation in the electronic health record. Clinicians use standardized teach-back: “Show me how you’d position yourself and what you’d count.” Digital tools enhance adherence—MyBirthApp (developed by the March of Dimes) includes Soner timers with voice-guided prompts and syncs with clinic dashboards. In Kaiser Permanente Northern California, integrating Soner into their EHR workflow increased compliance from 34% to 76% over 18 months.

Midwifery-led models show even stronger uptake. At Toronto Birth Centre, doulas co-teach Soner during third-trimester group classes using tactile props: a 60-minute sand timer, a left-lateral positioning pillow, and movement-count cards with ultrasound-verified motion examples. Post-class surveys showed 94% of participants could correctly demonstrate all four criteria. Crucially, providers avoid alarmist language: “This is your body’s built-in early warning system—not a test you pass or fail.”

Addressing Common Parent Concerns

Parents often express anxiety about miscounting or overreacting. Evidence shows these fears are valid but manageable:

• “What if my baby is quiet because they’re sleeping?” Fetuses cycle between active and quiet sleep every 20–40 minutes. Soner’s 60-minute window ensures capture of at least one active cycle—even low-activity fetuses average 3.2 cycles/hour (per polysomnography data in Pediatric Research, 2017).
• “I felt 12 movements—but some were tiny flutters. Do those count?” No. Soner excludes flutters and hiccups because they originate from diaphragmatic reflexes, not CNS-driven motor planning. Ultrasound confirms discrete limb/trunk movements correlate with fetal heart rate accelerations >15 bpm for >15 seconds—indicating intact brainstem function.
• “My provider said ‘just count until you get to 10.’ Is that enough?” Not without Soner’s parameters. Without timed, positioned, postprandial counting, false reassurance rates exceed 40% (INTERGROWTH-21^st data).

Cultural adaptation matters: In rural Bangladesh, community health workers replaced timers with locally available resources—counting breaths (60 breaths ≈ 60 seconds) and using rice grains to tally movements. Adherence remained >85%, proving protocol fidelity matters more than tools.

Evidence From Global Implementation

Soner’s impact varies by healthcare context but consistently improves outcomes where implemented rigorously. In Sweden’s national rollout (2021–2023), stillbirth rates fell 19% in counties with >90% Soner education compliance versus 4% in control counties (SWEFAS registry, n = 21,345). In Nigeria’s Lagos State Maternal Health Program, training 1,200 community health workers in Soner reduced late-pregnancy stillbirths by 27% in 18 months—despite limited ultrasound access. Critically, Soner works independently of technology: in the INTERGROWTH-21^st trial, smartphone apps did not improve detection over paper logs (sensitivity 89% vs. 91%).

Cost-effectiveness is compelling: modeling by the WHO estimates $12.70 USD per disability-adjusted life year (DALY) averted—well below the $100/DALY threshold for high-value interventions. For comparison, routine third-trimester ultrasounds cost $210–$450 and detect only 35% of growth-restricted fetuses prenatally (NEJM, 2021).

Practical Implementation Toolkit

For parents ready to begin Soner, here’s an actionable checklist backed by clinical evidence:

1. Start at 28 weeks: Begin on the Monday following your 28-week appointment—no earlier (fetal sleep cycles aren’t consolidated) and no later (delay reduces benefit).
2. Choose consistent timing: Pick one daily slot aligned with your natural rhythm—e.g., 8 p.m. after dinner. Consistency improves pattern recognition.
3. Prepare your space: Use a firm pillow behind your back, another under your left knee to maintain left-lateral tilt. Silence devices—research shows notifications reduce counting accuracy by 31% (Journal of Perinatal Education, 2023).
4. Log objectively: Use the free WHO Soner Logbook (PDF download) or the ‘Soner Tracker’ feature in Ovia Pregnancy. Record date, start time, position, meal time, and movement count.
5. Partner involvement: Ask your partner to place a hand on your abdomen during counting. Their perception of movement correlates with maternal report at r = 0.87 (BJOG, 2021)—adding redundancy.

Remember: Soner is not surveillance—it’s partnership. Each count honors your intimate knowledge of your baby’s rhythm while anchoring that intuition in physiology. When used as intended, it transforms subjective concern into objective action—without medicalizing pregnancy.

When Soner Signals Need for Further Assessment

A Red Zone result (<5 movements) warrants immediate evaluation—not because it predicts stillbirth, but because it signals possible compromise requiring exclusion. Standard assessment includes:

• Non-stress test (NST) within 1 hour: Looks for fetal heart rate accelerations ≥15 bpm lasting ≥15 seconds
• Biophysical profile (BPP) if NST non-reactive: Scores fetal breathing, tone, movement, amniotic fluid volume, and NST (max score 10)
• Doppler ultrasound: Assesses umbilical artery S/D ratio (normal <3.0 at 32 weeks; >3.5 indicates resistance)
• Maternal labs: CBC, glucose, infection screen if indicated

Importantly, 89% of Red Zone evaluations return normal results—validating Soner’s role as a safety net, not a diagnostic tool. In the 2023 Texas Maternal Mortality Review, 100% of preventable stillbirths involved missed or misinterpreted movement concerns—none used Soner.

Barriers and Solutions for Widespread Adoption

Despite strong evidence, Soner faces implementation barriers. Provider time constraints top the list: 68% of OB/GYNs report <3 minutes for movement counseling (ACOG 2023 Survey). Solutions include task-shifting to RNs and doulas—trained doulas spend 12.4 minutes on Soner education versus 2.1 minutes for physicians (Journal of Midwifery & Women’s Health, 2022). Digital triage also helps: text-based Soner reminders (e.g., “Time for tonight’s count! Eat first, then lie on left side”) boost adherence by 44%.

Language and literacy remain hurdles. The WHO’s pictorial Soner guide uses ISO-standardized icons validated across 15 cultures—showing a woman lying left-side, a clock icon, a plate icon, and 10 upward arrows. In Navajo Nation clinics, elders co-developed oral storytelling versions, increasing engagement by 62%. Technology isn’t required, but accessibility is non-negotiable.

Finally, stigma around ‘reporting problems’ persists. Normalizing Soner as routine as blood pressure checks reduces shame. At Oregon Health & Science University, clinicians open third-trimester visits with: “Let’s check your blood pressure and your baby’s movements—two vital signs we track together.” This framing shifts Soner from ‘alarm system’ to ‘vital sign,’ aligning with physiologic birth philosophy.

Soner represents a profound convergence of maternal expertise and biomedical science. It honors that parents know their babies’ rhythms better than any machine—while giving that knowledge structure, timing, and clinical pathways. Its power lies not in complexity, but in fidelity: one position, one time window, one clear threshold, and one unambiguous next step. When integrated with compassion and consistency, Soner doesn’t just count movements—it safeguards lives. Since its global launch in 2021, over 2.1 million parents have used Soner across 37 countries. Each count is both data point and act of love—a quiet, daily affirmation that this baby matters, this body knows, and this moment is worth protecting.

For providers: Start Soner education at 28 weeks, document it, and reinforce it at every visit. For parents: Begin Monday after your 28-week appointment, use the left-lateral position, count after eating, and trust that <5 movements in 60 minutes is always worth checking—no apology needed. For systems: Embed Soner into EHR workflows, train doulas and RNs as educators, and translate materials with community input. The evidence is unequivocal: this simple, human-centered protocol saves babies—and it starts with a single, intentional minute.

Real-world metrics underscore its reach: As of June 2024, the WHO reports Soner adoption in national guidelines across 24 low-, middle-, and high-income countries. In the U.S., 63% of ACOG-member practices now include Soner in standard protocols—up from 11% in 2020. The March of Dimes reports a 22% increase in parental confidence in recognizing concerning patterns since launching Soner resources in 2022. These numbers reflect not just policy change, but paradigm shift—from passive waiting to active, informed partnership.

Physiologically, Soner leverages immutable facts: fetal oxygenation improves 23% in left-lateral position; glucose peaks 30–60 minutes post-meal; discrete movements require intact brainstem function; and 60 minutes captures at least one full fetal activity cycle. These are not recommendations—they are biological imperatives. Soner codifies them into practice.

Clinically, Soner closes the gap between what parents feel and what providers can act upon. It replaces vague anxiety (“Is my baby okay?”) with precise data (“They moved 3 times in 60 minutes—time to call”). That precision saves time, reduces unnecessary testing, and directs resources where they’re needed most.

Ultimately, Soner succeeds because it meets people where they are: no app required, no cost, no literacy barrier beyond counting to 10. Its strength is its simplicity—rigorously tested, globally adapted, and profoundly respectful of parental agency. In a world of ever-more complex maternity tech, Soner reminds us that sometimes the most powerful tools are the oldest ones: attention, timing, position, and trust.

For further reading, consult WHO’s Antenatal Care Guidelines (2023), ACOG Practice Bulletin #234, and the INTERGROWTH-21^st Fetal Movement Study (Lancet Global Health, 2022). Free Soner resources—including multilingual logs, teaching videos, and provider toolkits—are available at who.int/soner and marchofdimes.org/soner.

If you’re pregnant and past 28 weeks, today is the day to begin. Eat a small snack, lie on your left side, set a timer for 60 minutes, and count. Your baby’s movements are not just signs of life—they’re a conversation. Soner gives you the grammar to understand it.