In the first six months of life, between 15-35% of parents report a problem with their infant's sleep [
1‐
3] including difficulties settling their infant to sleep at the start of the night and re-settling them overnight. Such problems disturb parental sleep leading to parental fatigue [
4], reduced ability to care effectively for the infant, and parental depression symptoms [
5]. Persistent infant sleep problems are associated with later child behaviour problems [
6‐
8].
Similarly, around 14-28% of parents report infant crying as a problem in the first few months of life and sleep and crying problems often co-exist. Crying duration exceeding 3 hours/24 hours for at least 3 days for at least 3 weeks is typically known as 'colic' and affects between 9-12% of infants from community samples [
9,
10]. Parents of crying infants may experience frustration and anger towards their infant and parental perception of crying as a problem is the most common proximal risk factor for Shaken Baby Syndrome [
11]. Problem crying is associated with early weaning from breast milk, frequent changes of formulae and parent depression symptoms. Parental
perception that their infant's crying is a problem therefore merits attention, regardless of whether the actual duration of crying meets criteria for 'colic'.
Sleep problems in infants
Approximately two-thirds of infants learn to 'sleep through the night' i.e. experience unbroken sleep between the hours of midnight and 5 am, by 12 weeks of age [
12,
13]. However, up to a third do not [
14] and may also have problems initiating sleep [
15]. Such problems have been consistently linked to parental mood disorder [
16,
17] and when infant sleep problems are treated parental depressive symptoms decrease [
18,
19]. Preventing infant sleep problems may therefore be an acceptable way to reduce rates of parental depression, particularly given that breast feeding mothers are often reluctant to accept pharmacologic treatment for depression [
20].
Infant sleep problems tend to arise when parents actively help their infant to fall asleep [
21,
22]. Infants, like adults, tend to wake briefly several times during the night, but parents are only aware of this if the infant cries out (signals) and wakes the parents. Parents who rock, feed, or remain with their infant while the infant falls asleep, are more likely to report frequent night awakenings and settling problems [
21], as their infants tend to cry out and demand the same attention each time they wake during the night. Conversely, parents who allow their infant to settle to sleep independently with little caregiver interaction, report fewer immediate and long term sleep problems [
23,
24]. Their infants tend to be more successful at falling back to sleep without the caregiver's help throughout the night [
15].
Maternal cognitions about infant sleep are also strongly related to infant sleep problems [
25]. Mothers who have problems resisting their infant's demands, who feel anger and helplessness when faced with their infant's demands, or who feel doubt regarding the adequacy of their parenting, are significantly more likely to report infant sleep disturbance [
25]. In order to cope with these feelings, parents may become 'over intrusive' at bedtime. This may result in the infant learning caregiver dependent sleep associations that in turn lead to more frequent night signaling [
21].
Crying in infants
Around 14-28% of parents report infant crying as a problem [
9,
26,
10]. Infant crying duration peaks at around 6-8 weeks of age at around 2.5 hours per 24 hours, then gradually declines [
27,
28]. 'Colic' refers to crying in excess of 3 hours per day for at least 3 days per week, over a three week period that resists soothing. The cause(s) of colic are unknown. Although long attributed to gastrointestinal upset (e.g. flatulence and gastro-oesophageal reflux) [
29,
30] and organic disturbances such as food intolerance or allergy [
31], medical causes are thought to affect only one in ten infants [
32]. Yet many parents change their own diet (if breast feeding) or the infant's formula, in the belief that a food intolerance underlies the crying problem [
33,
34]. Others seek over the counter medications for reflux or alternative therapists such as chiropractors, both of which have been shown in rigorous trials to have no impact on crying [
35,
36]. Other medications are either ineffective (e.g. simethicone) [
37,
38], associated with serious side effects (e.g. dicyclomine and apnoeas) or may predispose the infant to harm (e.g. acid suppressive medications and eosinophilic oesophagitis)[
39].
Parenting style may also affect the amount of fussy crying (crying that can be soothed) as well as colicky crying (crying that is unsoothable). 'Proximal care' describes a parenting style that typically involves feeding an infant in excess of 14 times per day, holding them for greater than 80% of the day time, and cosleeping (i.e. parent sharing a sleeping surface with the infant). One study compared the impact of this approach on infant sleep and crying with a more structured approach (i.e. feeding infant every 3 to 4 hours, placing them in a cot for sleep and a delayed response to infant demands) and an approach somewhere between the two styles [
40]. Comparison of approaches revealed that proximal care parents had infants with less fussy crying but the same amount of colicky crying as the more structured approach. Proximal care resulted in more frequent waking and crying at night at 12 weeks of age. The authors concluded that a proximal care approach throughout the first few weeks of life may be useful in reducing overall amounts of non-colicky crying, but changing to a structured approach after this time may result in less night waking at 12 weeks of age [
40]. Any program which aims to prevent early infant sleep and cry problems could incorporate this approach.
Interventions for existing infant sleep/cry problems
Behavioural strategies such as graduated extinction (where the parent returns to check on their crying child at increasing time intervals with brief parental reassurance) and positive bedtime routines [
41,
42] have been shown to be the most effective strategies for managing sleep problems in children aged 6 months or older. Despite the effectiveness of such interventions [
43,
44], some parents find techniques involving extinction unacceptable, as they dislike leaving their infant to cry [
25,
42]. Given that these parents may not follow through with strategies, it may instead be preferable to aim to
prevent sleep problems. Prevention may have additional advantages including greater efficacy (as problem is less entrenched) and prevention of associated parental distress.
Few randomised controlled trials (RCTs) have evaluated interventions for colicky infant crying. Most have involved changes to diet or use of medication, with results mostly suggesting no effect over and above placebo and additionally, the methodological rigor of these trials has been questioned [
45]. Increased carrying of the infant has been shown in one trial to prevent crying [
46] but did not reduce established crying in another trial [
47]. Keefe [
48] has proposed a model to explain infant colic as a psychobiological disturbance in infant behaviour regulation due to increased sensitivity to the environment. Disruptions or inconsistencies in parenting or the surrounding environment overstimulate the infant resulting in crying that the infant does not yet have the maturity to regulate. With this in mind Keefe and colleagues [
48] conducted a RCT of an intervention for colicky infants aged two to six weeks. In the intervention group (n = 64), nurses visited families four times over one month to provide support to parents, make modifications to infant care (with an emphasis on consistency of routines) and educate parents on reducing overstimulation in their infant. The control group (n = 57) received usual care. Compared with the control group, intervention infants had a significantly higher number of resolved crying problems (61.8% vs. 28.8%, p = 0.03) as well as shorter total crying time/day (1.29 vs. 2.94 hours, p = 0.02) at approximately 13 weeks of age (exact mean age not given in manuscript). This suggests that intensive parental support, modification of environment and provision of structured care can reduce crying.
Can we prevent infant sleep and cry problems?
Only four RCTs have examined the impact of prevention programs on infant sleep problems. No RCTs have aimed to prevent both infant sleep
and cry problems. In a small RCT of middle-class first time parent couples (intervention n = 29, control n = 31), Wolfson and colleagues [
24] provided parents with two prenatal and two postnatal group sessions that taught parents about normal infant sleep/wake patterns and the importance of establishing an independent sleep routine so that the infant can self-settle. Infants of parents who attended these group sessions slept for longer amounts of time, and demonstrated better sleep patterns than infants of control group parents at one, two and three weeks of age.
Kerr, Jowett & Smith's [
49] RCT aimed to prevent infant sleep problems by providing parents with information on settling methods and the importance of routine via a booklet and a home visit (intervention n = 86 and control n = 83). Information was provided at three months of age and follow up data were collected at nine months. Compared with control group infants, intervention group infants had significantly fewer settling difficulties (21% vs. 39%, p = 0.03), significantly fewer night awakenings (23% woke two or more times per night vs. 46%, p = 0.02) and significantly better cumulative sleep scores overall (22% met criteria for a severe sleep problem vs. 39%, p = 0.03).
In a three-armed RCT that aimed to prevent infant sleep problems in infants aged 8 to 14 days [
23], families were allocated to receive either (1) a structured behavioural program (n = 205), (2) an education oriented group (n = 202), or (3) the usual care provided by UK health services (n = 203). Parents in the behavioural group were asked to allow their infant to settle to sleep independently, to only respond to the infant when genuinely crying (as opposed to fussing or fretting), to keep stimulation low during the night, and after three months of age, to gradually increase the time between night feeds. Parents received the information via a flyer which a researcher also discussed with the parents. Parents in the education oriented group received the same information in a ten page booklet and the information was suggestive rather than prescriptive. By 12 weeks of age, significantly more behavioural group infants were sleeping through the night (having uninterrupted sleep from 12 am-5 am) than the other two groups. Behavioural but not education group parents tended to access significantly fewer health services for their infant's sleep in the following six months. In a post hoc analysis [
50], infants receiving in excess of 11 feeds per day at one week of age were more likely to wake during the night at 12 weeks of age. The data of infants who met this criterion, from both the behaviour group, and the control group, were then compared. By 12 weeks of age, 80% of these 'at risk' infants in the behaviour program, compared to 60% in the control group, were sleeping through the night. Thus a behavioural program may be particularly useful for preventing sleep problems in infants who feed frequently in the first week of life.
In another RCT that aimed to prevent infant sleep problems, parents recruited via birth notices in the local newspaper were randomly allocated to receive either a 45 minute consultation with a nurse accompanied by written information at infant age three weeks (intervention group, n = 137), or usual care (control group, n = 131) [
51]. Intervention group parents were taught about the cyclical nature of sleep and the benefits of parent-independent sleep cues. Parents were recommended to leave the infant to settle for five minutes before responding if the infant was crying and to extend this response time by five minutes for each subsequent visit. All parents completed a 7 day infant behaviour diary at 12 weeks of age. Intervention infants were significantly more likely to have at least 15 hours of sleep per 24 hours than control infants (62% vs. 36%, respectively,
p < 0.001). The sample was predominantly middle-upper class thereby limiting the generalisability of the findings.
Prior research has been limited by the use of population sampling that is self-selected [
51,
24], excludes unmarried parents [
24] or fails to collect data on compliance with intervention strategies [
49,
51,
24]. Despite strong links between infant sleep and crying problems and parental depression [
16,
17], parent well being has rarely been included as an outcome [
49,
24]. Data from fathers is often lacking despite the increasing role fathers play in infant care [
52] and the protective role they can play in prevention of postnatal depression in mothers [
53‐
55]. Therefore, involvement of fathers in trials that have a specific focus on infant and mother wellbeing is paramount.
In summary, an infant demand style of approach in the first few weeks of life may reduce overall crying, but changing to a more structured style of care after these first few weeks, may result in less night waking at 12 weeks of age [
40]. A program that implements elements of both approaches and provides parents with information about normal sleep and cry patterns and ways to reduce stimulation and provide a predictable environment in the first few months of life, may be able to prevent both infant sleep and cry problems [
14,
48]. Reduction in these problems is likely to have positive flow on benefits for parent wellbeing [
18,
19], and could lead to reduced health service use for both parent and infant wellbeing [
23]. This paper presents the study protocol of a randomised controlled trial of a universal parenting program designed to prevent both infant sleep
and cry problems, and improve parental wellbeing. The recruitment phase of this trial is currently complete and intervention delivery and follow up assessments are ongoing.