A Randomized, Controlled Trial of a Behavioral Intervention to Reduce Crying among Infants

Study Population

Mothers of healthy, singleton, newborn infants with a gestational age of 37 to 41 weeks admitted to the normal newborn nursery of a large community hospital and who had the resources to view a VHS tape at home were given a flier inviting them to participate in a study on parenting advice by contacting a research assistant by phone before being discharged. Mothers who did not speak English or were unable to fill out a diary (described below) themselves were excluded. Mothers were recruited between August 2005 and February 2006.

Intervention

The intervention was a 30-minute videotape demonstrating the THB method for calming newborn infants. Caregivers were reminded to first try feeding, holding, and changing their newborn when he/she cried. If none of these was effective, they were encouraged to try the following technique, the basis of which is swaddling. How to swaddle an infant is illustrated in the video, with specific advice to allow the hips to flex and to avoid overheating. If the infant is not consoled with swaddling alone, a series of additional steps is recommended, each added to the other, until the infant is calm. The second step is to place the infant on his/her side or stomach. Caution is given not to do this when babies are put to sleep. The third step is to expose the infant to a loud, harsh, white noise, such as “shushing” in the ear. The fourth step is swinging (rhythmically, jiggling) in rapid, tiny movements. Here caution is given never to shake an infant. The final step is to give the infant a pacifier or otherwise allow the infant to suck.

Control

The control videotape was a 30-minute videotape entitled “Begin with Love” by Civitas (Chicago, IL). It is offered on the Newborn Channel and is available to mothers in many postpartum inpatient settings. This videotape provides 5 standard recommendations for taking care of normal newborns:

1. Take care of yourself.

2. Provide a warm and loving environment.

3. Talk, sing, and read to your baby.

4. Create a predictable world with routines.

5. Respond to your baby's needs; a newborn infant cannot be spoiled.

This videotape provides standard advice for parents of infants who are not consoled with feeding, changing, or holding; namely, never shake your infant, get help to handle the stress, and take heart that it will eventually get better.

Clinical Protocol

Informed consent was obtained by the research assistant. Mothers completed a survey at baseline. The survey included the open-ended question, What do you do to calm your baby when he/she cries? in an effort to determine whether mothers were already using the THB method. All mothers received training on completing a Baby's Day Diary, which is described below.²⁹ Each mother-infant pair was randomized by a randomization table to either the intervention or control group and given a unique code number. The research assistant was initially blinded to participant assignment; however, to assess study compliance, follow-up data were collected with knowledge of group assignment. Mothers were given a videotape in an unmarked jacket to view before discharge and to take home to view as often as she found helpful. All mothers received a lightweight blanket large enough to swaddle a newborn infant, along with the following recommendations:

1. It is safest to put your baby to sleep on his/her back.

2. Never put your baby to sleep with loose blankets.

3. Do not allow your baby to overheat. Check the baby's neck to see if he/she is too hot.

4. When your baby cries, see if he/she needs to be fed, changed, or held.

5. Never shake your baby.

All mothers were contacted by phone during their first week home to assess their understanding of and compliance with the Baby's Day Diary.²⁹ Mothers in the intervention group were also asked open-ended questions to assess their understanding of the intervention both during the first week at home and during the sixth week. Intervention mothers were considered compliant if they answered “yes” to the question, Have you had an opportunity to try the technique taught in the videotape? and also “yes” or “sometimes” to the question, Do you swaddle your infant when you are trying to calm him/her? Compliance was coded as a dichotomous variable: either the parents endorsed some use of the method or none. Control mothers were considered compliant if they provided diaries for week 6.

During the 6th and 12th weeks, all mothers were asked the open-ended questions, What do you do to calm your baby when he/she cries? and Have you ever had to put your baby in a safe place and leave for a few minutes because you could not calm him/her? Mothers were given stamped, self-addressed envelopes and were contacted by phone if the diaries were more than 6 days past due. Mothers received incentives in the form of gift cards for completion of the diaries and surveys ($25 per set of diaries; $75 maximum).

Measures

Mothers completed an Edinburgh Postnatal Depression Scale³⁰ at baseline and during the 6th and 12th weeks. This was done to make sure there was no difference between the groups should maternal depression affect the way mothers completed the diaries or performed the intervention.

Primary and Secondary Outcome Measures

The primary outcome measure was the mean hours per day of total infant crying (fussing, crying, and unsoothable crying) as recorded in the Baby's Day Diary²⁹ by their mothers 3 days per week during the 1st, 4th, 6th, 8th, and 12th weeks of age. The diary was a printed sheet with the 24-hour day divided into 4 timelines of 6 hours each. The timelines were further divided into 5-minute intervals. Mothers recorded their baby's activity by filling in the behavior, represented by marks for each activity according to a code included on the sheet: sleep, awake and content, awake and fussy, awake and crying, unsoothable crying, feeding, or cannot remember. The frequency and duration of crying recorded on the Baby's Day Diary²⁹ has been found to have a moderately strong correlation with simultaneous audio-taped recordings^29,31 and is commonly used in studies of infant crying. Secondary outcome measures included the mean hours per day of sleep and the mother's level of stress as measured using the PSI, which was administered to the mother during the infants’ 6th and 12th weeks of age. The PSI was developed to assess stress in the parent-child relationship in parents of children 1 month to 12 years of age.³²

Statistical Methods

Statistical analyses were done using the SAS software (SAS, Inc., Cary, NC). The primary outcomes were analyzed as continuous variable with either a Wilcoxon 2-sample test or a student t test. Shapiro Wilk tests for normality were used to make decisions between parametric and nonparametric statistical tests. Fisher exact tests were used when expected cell counts were <5. P < .01 was interpreted as indicating a statistically significant difference caused by multiple testing. P < .05 was considered suggestive of a statistically significant difference.

Diaries

Mean daily total crying time included time spent crying, fussing, and crying that was unable to be soothed. For each day, the sum of these 3 behaviors was calculated; the mean of the 3 daily sums at each specific age was then calculated, yielding the mean daily total crying time. Mean daily total sleep time was, similarly, the mean of 3 daily sleep times reported at each age. Diary data that had more than 3 hours not recorded or recorded as “can't remember” were excluded from analysis. If fewer than 3 diaries were completed for a given time period (ie, one or 2 of the days was missing or had more than 3 hours unrecorded), then the means of only the completed diaries were used.

The PSI was scored according to the manual.³² Total stress scores can range from 131 to 320 (less stress to more), with a score of 222 being the 50th percentile.

Institutional review board approval was obtained from Nationwide Children's Hospital and Riverside Methodist Hospital (both in Columbus, OH). During the 6th and 12th weeks, mothers were asked the open-ended question, Have you taken the baby to the doctor for any visits other than regularly scheduled check-ups since he/she was born? All Edinburgh Postnatal Depression Scales were scored as they were received and the mother was notified to contact her physician for evaluation if her screen was positive for depression (a score of ≥12).³⁰

Participant Drop Out

Of the 51 participants enrolled, 16 (31%) did not complete the study and were excluded from statistical analyses (Figure 1). These 16 participants (9 from the intervention group and 7 from the control group) did not complete any of the diaries or data collection instruments beyond baseline. Because crying and sleeping scores were not available, an intention-to-treat analysis including these participants was not possible. Demographic characteristics of these 16 participants were compared with the 35 who completed the study. Those who did not complete the study had significantly lower levels of education compared with those who did complete it, but were not different on any of the other demographic variables.

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Figure 1.

Flow of participant progress. NICU, neonatal intensive-care unit.

Group Differences at Randomization

Demographic and baseline characteristics of the intervention and control participants were compared (Table 1). There were no statistically significant differences between groups, indicating successful randomization. Edinburgh Postnatal Depression Scale scores were not significantly different between groups at baseline or at weeks 6 or 12.

Mean Daily Total Crying

There were no statistically significant differences between control and intervention groups with respect to mean daily total crying (fussing, crying, and unsoothable crying) at any of the 5 age points (Table 2). Daily total crying time was recalculated to include only crying and unsoothable crying (“awake and fussy” was excluded). Again, there were no statistically significant differences between the control and intervention groups. During the eighth week, mean daily total crying time for infants in the intervention group was greater than the control group (mean difference, 0.7 hours), but the difference did not reach statistical significance (P = .04) and the direction of the effect was opposite to the hypothesized direction.

Mean Daily Sleep

There were no statistically significant differences between the control and intervention groups with respect to mean daily sleep at any of the 5 age points (Table 2). Analysis was repeated using the definitions of compliance noted above. Of the 18 intervention participants, 15 were compliant with swaddling during the sixth week (2 did not answer the question and one said “no”). Of the 17 controls, 16 were compliant. There were no differences between the groups in average daily total crying or sleeping.

Parenting Stress Index

The total stress scores on the PSI are presented in Table 3. During the 12^th week, the intervention group had higher scores compared with controls (P = .01).

Questions to Mothers

In response to the question, What do you do to calm your baby when he/she cries?, there were no answers specifically referring to the THB method or the videotape. However, mothers in each group reported behaviors such as “swaddle,” “bounce,” “swing,” and “pacifier,” both at baseline and on the surveys during the 6th and 12th weeks. There were no positive responses to the question, Have you ever had to put your baby in a safe place and leave for a few minutes because you could not calm him/her? There were no responses of “colic” or “crying” to the question, Have you taken the baby to the doctor for any visits other than regularly scheduled check-ups since he/she was born?