Pacifier use modifies infant's cardiac autonomic controls during sleep

doi:10.1016/j.earlhumdev.2004.02.002

Early Human Development

Volume 77, Issues 1–2, April 2004, Pages 99-108

https://doi.org/10.1016/j.earlhumdev.2004.02.002 Get rights and content

Abstract

Objective: The risk for sudden infant death (SIDS) was postulated to decrease with the use of a pacifier and by conditions increasing parasympathetic tonus during sleep. We evaluated the influence of a pacifier on cardiac autonomic controls in healthy infants. Study design: Thirty-four healthy infants were studied polygraphically during one night: 17 infants regularly used a pacifier during sleep and 17 never used a pacifier. Thumb users or occasional pacifier users were not included in the study. The infants were recorded at a median age of 10 weeks (range 6–18 weeks). Autonomic nervous system (ANS) was evaluated by spectral analysis of the heart rate (HR). The high frequency component of HR spectral analysis reflected parasympathetic tonus and the low frequency on high frequency ratio corresponded to the sympathovagal balance. Results: Most infants (63.6%) lost their pacifier within 30 min of falling asleep. Sucking periods were associated with increases in cardiac sympathovagal balance. During non-sucking periods, in both REM and NREM sleep, infants using a pacifier were characterized by lower sympathetic activity and higher parasympathetic tonus compared with non-pacifier users. Conclusions: The use of pacifiers modifies cardiac autonomic controls during both sucking and non-sucking sleep periods. Non-nutritive sucking could regulate autonomic control in infants. These findings could be relevant to mechanisms implicated in the occurrence of sudden infant deaths during sleep.

Introduction

The use of a pacifier (dummy, comforter or soother) was associated with a reduced risk of sudden infant death (SIDS) [1], [2], [3], [4], [5], [6], [7]. The routine use of pacifier [3], [4], [5] or the use during the last/reference night [1], [2], [6], [7] has been reported to be protective for SIDS. When the last or reference sleep periods were compared, infants who died had used a pacifier significantly less frequently than control subjects [1], [2], [4], [5], [6], [7]. Pacifier use was reported to yield odds ratios for SIDS between 0.19 and 0.59 [1], [2], [3], [4], [5], [6], [7].

The protective mechanisms associated with the use of a pacifier are not known. The use of a pacifier could prevent the tongue from sealing off the airways [8], reduce the frequency and duration of gastro-esophageal refluxes [9], decrease the prevalence of prone sleeping [1], [4], favor mouth breathing [10], as well as increase oxygen saturation [11], respiratory drive [12], arousability from sleep [13] and sensory inputs in muscles responsible for the patency of the upper airways [1]. In addition, changes in heart rates (HR) were reported during sucking in both premature [14] and term neonates [15], [16], possibly associated to changes in heart rate autonomic controls.

Changes in autonomic heart rate controls could be associated with the occurrence of SIDS. The study of sleep recordings of infants who eventually died of SIDS revealed an imbalance in cardiac autonomic controls, with an increase in sympathovagal heart rate control [17]. Similar changes were seen in healthy infants submitted to conditions known to increase the risk of SIDS, such as sleeping prone [18], prenatal exposure to cigarette smoke [19], sleep deprivation [20], sleeping in high ambient temperature [21] or with the head covered by bedclothes [22].

It was hypothesized that non-nutritive sucking is associated with changes in cardiac autonomic controls. The study compared the characteristics of autonomic cardiac controls in infants using a pacifier and infants with no pacifier during sleep.

Section snippets

Patients

Thirty-four healthy infants were recorded polygraphically during one night. There were 17 pacifier users, defined as infants who used a pacifier every day and night during sleep, and 17 non-users, defined as infants who never used a pacifier. The infants were selected successively from a larger group of infants recruited for a research program on sleep-related behavior if they met the following inclusion criteria for study entry. Thumb users or occasional pacifier users were not included in the

Sleep and breathing characteristics

The infants of the two groups could not be differentiated by gender (7 boys with no pacifier, 10 with a pacifier), birth weight (median of 3300 g for the infants with no pacifier, 3140 g for the infants with a pacifier, range values: 2300–4350 g), age at study (median of 10 weeks for both groups of infants, range values: 6–18 weeks), gestational age (median of 40 weeks for both groups of infants, range values: 37–41 weeks), number of infants small for gestational age (1 infant in both groups)

Discussion

Infants who slept with a pacifier had, compared to infants with no pacifier, significant increase in parasympathetic activity and decrease in sympathovagal heart rate controls during both REM and NREM sleep. The differences in cardiac control were seen during non-sucking periods, mainly during the first part of the night, when the use of pacifier was the most frequent. Sucking, that occurred mainly during REM sleep, was associated to increases in sympathovagal cardiac controls. As already

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Citation Excerpt :
Because of the PNS’s involvement in both emotion regulation and a range of functions involved in feeding (e.g., sucking, swallowing, and breathing), the gustatory-vagal hypothesis posits that nutritive sucking may be an early regulatory strategy that establishes the neurophysiological architecture necessary for social regulation (Porges & Lipsitt, 1993; Porges & Furman, 2011). Several studies have found infants to experience decreases in PNS tone (Lappi et al., 2007; Portales et al., 1997; Suess et al., 2000) and possible increases in SNS tone (Franco, Chabanski, Scaillet, Groswasser, & Kahn, 2004; Zimmerman & Thompson, 2016) while sucking, indicating mechanically-, rather than cortically-, driven physiological mobilization. Because of the unique neuromuscular action involved in breastfeeding (Brown, 2007), the infant vagus may be uniquely exercised by this form of sucking, which may train the PNS for efficient reactivity during non-feeding social interactions (Quigley, Moore, Propper, Goldman, & Cox, 2016).
Cardiac autonomic balance (CAB), defined as the relative influences of the sympathetic (SNS) and parasympathetic (PNS) nervous systems on the heart at rest, is a well-established biomarker of mental and physical health in adulthood (Kemp & Quintana, 2013). SNS and PNS functioning that, jointly, determine CAB, mature and stabilize between gestation and age five (Alkon, Boyce, Davis, & Eskenazi, 2011), co-developing with capacity to regulate distress during challenge and social engagement (Porges & Furman, 2011). This review integrates existing work in developmental, clinical, and medical sciences to propose a theoretical model of CAB development from gestation through early childhood and its putative relations with later functioning. By age five, CAB may reflect biological embedding of regulatory strategies that lay the groundwork for risk or resilience: The same profiles of SNS and PNS functioning associated with limited regulatory support in infancy and exposure to early adversity predict poor mental and physical health problems in adulthood (e.g., Beauchaine, 2001; Oosterman et al., 2010; Suurland, van der Heijden, Smaling, et al., 2017). In three key questions, we identify areas of consensus and remaining gaps in existing work to guide the next generation of research on early CAB development as a possible pathway from early experiences to mental and physical health outcomes.
The effects of dummy/pacifier use on infant blood pressure and autonomic activity during sleep
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Citation Excerpt :
Importantly, a higher LF HRV together with a higher LF/HF suggests that sympathetic activity is increased during active sucking. Our HRV findings are consistent with a previous study, which also showed that LF and LF/HF HRV were higher during active sucking [23]. The rise in sympathetic tone during sucking episodes also appeared to be present in the vasculature, as evidenced by a higher LF and LF/HF BPV at 5–6 months (Fig. 4G and I).
Dummy/pacifier use is protective for sudden infant death syndrome (SIDS); however, the mechanism/s for this are unknown. As impaired cardiovascular control may be the underlying cause of SIDS, we assessed the effects of dummy/pacifier use on cardiovascular control during sleep within the first 6 months of life.
Term infants, divided into dummy/pacifier users and non-dummy/pacifier users, were studied at 2–4 weeks (n = 27), 2–3 months (n = 35) and 5–6 months (n = 31) using daytime polysomnography. Heart rate, blood pressure (BP), heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) were measured in triplicate 1–2-min epochs during quiet and active sleep in the supine and prone positions.
Overall, during the non-sucking periods, in the prone position, the BP was higher (10–22 mmHg) in dummy/pacifier users compared to non-users at 2–4 weeks and 5–6 months (p < 0.05 for both). HRV and BRS were higher in dummy/pacifier users compared to non-users at 2–4 weeks (p < 0.05). Active sucking increased HRV and BPV, consistent with increased sympathetic activity in dummy/pacifier users.
Higher BP and HRV in dummy/pacifier users indicate increased sympathetic tone, which may serve as a protective mechanism against possible hypotension leading to SIDS; however, these effects were not apparent at 2–3 months, when the risk of SIDS is highest.
Sudden death in infants during sleep
2011, Handbook of Clinical Neurology
Citation Excerpt :
Increases in sympathovagal controls have been measured following prenatal exposure to cigarette smoke (Franco et al., 1999), prone sleep (Franco et al., 1996; Galland et al., 1998), previous sleep deprivation (Franco et al., 2003), sleeping in high ambient temperatures (Franco et al., 2000b), or with the face covered by a bed sheet (Franco et al., 2002a). Pacifier use and sleeping supine in swaddling conditions during sleep, two factors associated with a lower risk for SIDS, were characterized by a reduction of the heart rate sympathovagal ratio (Franco et al., 2004a, 2004c). It has been reported that increased sympathetic activity reduced the electrical stability of the heart and precipitated ventricular fibrillation and sudden cardiac death (Lown and Verrier, 1976; Schwartz et al., 1984).
Sudden infant death syndrome (SIDS) is defined as the sudden death of an infant less than 1 year of age that remains unexplained after a complete postmortem examination, including an investigation of the death scene, and a review of the case history. A complete pathologic examination is required for the diagnosis of SIDS, including microscopic, toxicological, microbiological, immunohistochemical, molecular, and metabolic exams. Case-control reviews on sleeping position and SIDS showed that the relative risk for SIDS increased 4–9 fold when infants sleep prone than when they sleep supine. The chapter discusses the various mechanisms to explain the association of prone sleeping and SIDS. The chapter presents the three basic mechanisms to cause SIDS: the breathing control hypothesis; the autonomic control hypothesis; and the sleep and arousal hypothesis. An infant could be vulnerable for SIDS because of a deficiency in cardiorespiratory controls during sleep, favoring the development of recurrent episodes of hypoxemia.
Cardiovascular control during sleep in infants: Implications for Sudden Infant Death Syndrome
2010, Sleep Medicine
Citation Excerpt :
Dummy or pacifier use has been shown to enhance arousal from sleep and modify cardiac ANS regulation [132] and these have been the mechanisms suggested for the increased protection against SIDS [130,131,133]. Franco and colleagues [132] demonstrated that periods of sucking increased cardiac sympathovagal balance, while non-sucking sleep periods were associated with lower sympathetic activity and high parasympathetic tone in term infants studied at 10 weeks of age [132]. Furthermore, pacifier sucking has also been shown to elicit increases in BP in quietly awake or asleep term infants when assessed prior to feeding [134].
In infants the cardiorespiratory system undergoes significant functional maturation after birth and these changes are sleep-state dependent. Given the immaturity of these systems it is not surprising that infants are at risk of cardiorespiratory instability, especially during sleep. A failure of cardiovascular control mechanisms in particular is believed to play a role in the final event of Sudden Infant Death Syndrome (SIDS). The “triple risk model” describes SIDS as an event that results from the intersection of three overlapping factors: (1) a vulnerable infant, (2) a critical development period in homeostatic control, and (3) an exogenous stressor. This review summarises normal development of cardiovascular control during sleep in infants and describes the association of impaired cardiovascular control with the three overlapping factors proposed to be involved in SIDS pathogenesis.
Pacifier Use: A Systematic Review of Selected Parenting Web Sites
2008, Journal of Pediatric Health Care
The purpose of this study was to explore and describe content related to pacifier use on parenting Web sites.
Sixteen parenting Web sites met the inclusion criteria of the study. Two checklists were used to evaluate and describe different aspects of the Web sites. The first checklist provided a quality assessment of the Web sites. The second checklist was constructed to identify content categories of pacifier use.
The majority of sites met quality assessment criteria. Eleven content categories regarding pacifier use were identified. Nine of the 16 sites contained eight or more of the 11 content areas. The most common types of Web pages containing pacifier information included pacifier specific (articles), questions and answer pages, and related content pages.
Most of the parenting Web sites met the quality measures for online information. The content categories reflected the current controversies and information regarding pacifier use found in the expert literature. The findings of this study suggest the need to establish pacifier recommendations in the United States to guide parents and health care providers with decision making.
Effects of nutritive and non-nutritive sucking on infant heart rate variability during the first 6 months of life
2007, Infant Behavior and Development
The effects of eating on heart rate variability (HRV) differ between adults and newborns. This may reflect the impact of suckling on the overall psychophysiological and autonomic nervous system maturation. The purpose of the present study was to explore whether the reactions of HRV during feeding change towards the adult pattern during the first 6 months of life. In addition, the effects of non-nutritive and nutritive sucking on heart rate (HR) and HRV were compared. The participants were 23 infants on whom recordings were performed as newborns and at 6, 12 and 24 weeks old. Nutritive sucking caused an increase in HR and a decline in HRV. The results were consistent with previous reports of a decrease in high frequency components of HRV during feeding in newborns, reflecting a decrease in parasympathetic activity. This response was apparent in all four ages studied, and remained similar throughout the 6-month period. However, age as an independent factor seemed to influence both HR and HRV. Pacifier sucking had no significant effects on HRV at any age. The results demonstrate the physical strain that sucking imposes on the baby, with a specific autonomic nervous system response involved. We consider this response an essential part of the overall psychophysiological maturation of infants.

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Pacifier use modifies infant's cardiac autonomic controls during sleep

Abstract

Introduction

Section snippets

Patients

Sleep and breathing characteristics

Discussion

Appl. Nurs. Res.

J. Pediatr.

J. Pediatr.

J. Pediatr.

Lancet

Dummies and the Sudden Infant Death Syndrome

Arch. Dis. Child.

Environment of infants during sleep and risk of the Sudden Infant Death Syndrome: results of 1993–5 case-control study for confidential inquiry into stillbirths and deaths in infancy

BMJ

Is the use of dummy or carry-cot of importance for sudden infant death?

Eur. J. Pediatr.

Risk and preventive factors for cot death in the Netherlands, a low-incidence country

Eur. J. Pediatr.

Dummy use, thumb sucking, mouth breathing and cot death

Eur. J. Pediatr.

Pacifier use and Sudden Infant Death Syndrome: results from the CESDI/SUDI case control study

Arch. Dis. Child.

Sleep environment and the risk of Sudden Infant Death Syndrome in an urban population: the Chicago Infant Mortality Study

Pediatrics

Possible mechanisms of pacifier protection against SIDS

J. Pediatr.

Effects of non-nutritive sucking on infant gastroesophageal reflux

Pediatr. Res.

Clinical observations on response to nasal occlusion in infancy

Arch. Dis. Child.

Carbon dioxide concentrations in the environment of sleeping infants

J. Paediatr. Child Health

The effect of nonnutritive sucking on heart rate in preterm infants

Dev. Psychobiol.

Blood pressure increases in response to feeding in the term neonate

Dev. Psychobiol.

Cardiovascular responses to pacifier experience and feeding in newborn infants

Dev. Psychobiol.

Polysomnographic study of autonomic nervous system in potential victims of Sudden Infant Death Syndrome

Clin. Auton. Res.

Sleep position, autonomic function and arousal

Arch. Dis. Child., Neonatal Ed.

Influence of maternal smoking on autonomic nervous system in healthy infants

Pediatr. Res.