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

To the Editor: I applaud McRury and Zolotor¹ for attempting to add a validation study of The Happiest Baby on the Block (THB) video to the growing evidence base evaluating this popular approach to calming babies.

Unfortunately, as the authors state, their study has several critical flaws that weaken any conclusions. There was a small study population and a 30% drop-out rate; there was contamination by advising both the control and intervention group about the use of swaddling; a video was used instead of a digital video disc (DVD; a more user-friendly interface); and parents received no instruction in THB video techniques. The factor that most undermined the reliability of this report is that there was little confidence that the intervention was even viewed or used (mothers said they watched, but they did not refer to THB video in their comments and did not swaddle as was demonstrated in the video).

THB^2,3 is a novel synthesis of several steps that have been shown to calm infant crying and promote sleep. It is based on the hypothesis that babies are born with a suite of previously overlooked neonatal reflexes (the “calming reflex”) that can quickly soothe most fussing during the first months of life.

The goal of finding an effective approach to crying reduction is not trivial. Infant irritability, and the parental exhaustion that it provokes, are primary triggers for many serious problems (eg, child abuse, failure of breastfeeding, marital stress, postpartum depression, excessive visits to an emergency room or doctor, excessive treatment for acid reflux, disturbed bonding, and perhaps sudden infant death syndrome/suffocation).⁴

Numerous peer-reviewed studies⁴ have confirmed the effectiveness of the interventions used in THB video (ie, swaddling, white noise, rhythmic motion, sucking). In addition, a growing body of pilot studies is finding benefits of THB video on early parent–infant interactions.

In 2007, the Department of Public Health in Boulder, CO, reported a study about reducing infant crying. Home-visiting nurses taught THB techniques to 42 at-risk families (teens, drug users, etc) who had fussy babies. Each family was given a THB DVD, compact disc of white noise, and a swaddling blanket. Most families (41 of the 42) reported an immediate, dramatic, and continuing improvement in their ability to calm crying. Many families also reported more than one additional hour of sleep.⁵

A recent randomized controlled trial, funded by the National Institute of Health, was done at Penn State University.⁶ Nurses taught THB techniques to breastfeeding mothers and gave each a THB DVD, a white noise compact disc, and a swaddling blanket. Intervention babies slept an extra ½ to 1 hour per night (P < .05).

A University of Arizona survey (n = 225) showed THB classes significantly boosted parental reports of self-efficacy (P < .001). Before the class, 40% of expectant parents reported moderate, marked insecurity about being able to calm their baby's crying. After the class that dropped to 0.5%.⁷

Today, more than 2000 certified educators teach THB techniques in hospitals and clinics across the United States (including more than 1000 educators in the departments of health of Pennsylvania, Minnesota, Wyoming, Connecticut, and Massachusetts and in numerous regional shaken baby prevention programs). Another 2000 educators are currently in training.

The need to discover an effective intervention to reduce infant crying is especially pressing in light of the recent failure of the highly promoted anti-Shaken Baby Syndrome intervention, Period of PURPLE Crying.⁸ In a large randomized controlled trial, babies whose parents were taught PURPLE reported a 10% increase in irritability. That is of great concern because crying is a primary risk factor for Shaken Baby Syndrome.

Although McRury and Zolotor's¹ study is seriously flawed, other well-designed studies are being planned and conducted to evaluate THB techniques. Hopefully they will yield sufficient information to allow further evaluation of this approach.

Simple, scalable, inexpensive interventions that can reduce infant crying are urgently needed to spare human suffering and reduce the billions of dollars of expenditures resulting from the numerous serious health risks that this stressful experience can trigger.