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Revista chilena de pediatría

versión impresa ISSN 0370-4106

Rev. chil. pediatr. vol.90 no.3 Santiago jun. 2019 


Psychomotor development and cortisol salivary levels in infants that live with their inmate mothers

Gia Haquin Macari1 

Adriana Gallardo Tapia1 

German Iñiguez2 

Gerardo Weisstaub3 

1 Pediatrician Resident, Department of Pediatrics, Faculty of Medicine, Campus Center, University of Chile, Chile.

2 Maternal and Child Research Institute (IDIMI), School of Medicine, University of Chile, Santiago, Chile.

3 Department of Pediatrics, Campus Center, Faculty of Medicine and Institute of Nutrition and Food Technology (INTA), University of Chile, Chile.



In Chile, the prison system has a program that allows inmate mothers to live with their children un der two years of age. This could imply that these children are more exposed to stress conditions and a higher psychomotor developmental delay (PDD) risk.


To compare the PDD and salivary cortisol concentrations (SCC) of children living in prison with their mothers and to compare the results with control children.

Subjects and Method:

Cross-sectional study in 42 infants, 12 of them are children of inmate mothers in the penitentiary center (CPF) of Santiago, and 30 controls from a Primary Care Family Health Center (CESFAM). PDD of infants was assessed through the ASQ-3 questionnaire and salivary cortisol was measured in infants and mothers using radioimmunoassay.


The median salivary cortisol level of the children of CPF and CESFAM mothers was 2.3 ng/ ml (IQR 1.1 to 2.7) and 2.1 ng/ml (IQR 1.6 to 2, 9) respectively. Maternal cortisol was 4.6 ng/ml (IQR 3.8 to 7.3) in the CPF and 3.7 ng/ml (IQR 2.4 to 4.7) in the CESFAM. The PDD deficit was 2.3% and 28.5% for children from the CPF and the CESFAM respectively, without statistical difference (p = 0.06).


There was no difference in the PDD and salivary cortisol between children of both groups.

Keywords: Psychomotor development; stress; infants; cortisol; saliva; penitentiary center; family health center


Psychomotor development (PMD) is the skill set that the child achieves through the maturation of the Central Nervous System and interaction with the en vironment, setting the foundation for children’s futu re learning1. The estimated PMD delay prevalence in Chilean children treated in the public health system is lower than that observed in industrialized countries (11% vs. 12 to 16%, respectively)2,3. It is noteworthy that the data from the Department of Statistics and Health Information (DEIS)obtained from the Monthly Statistical Summaries (REM, Resumenes Estadísticos Mensuales) 2016, show that the prevalence of PMD de lay varies between 2 and 7% in children under 2 years old4. It is possible that there is a sub-register related to the use of PMD screening tests used in our country: Escala de Evaluación del Desarrollo Psicomotor (Psycho motor Development Evaluation Scale; EEDP in Spa nish), and Psychomotor Development Test (TEPSI).

In recent years new screening instruments have been developed based on reports from parents or pri mary caregivers, such as the Ages and Stages Question naires (ASQ), which is being widely used in the USA and other countries. This instrument has also been validated in Chile1,5,6 with the Bayley scale in its Spa nish version. Ages and Stages Questionnaires showed a sensitivity and specificity of 73% and 81% respectively when compared to the Bayley scale, a test considered gold standard5.

On the other hand, it is known that there are diffe rent environmental and social factors that can influen ce the children’s development, one of these is stress, having evident effects on neurodevelopment in the first years of life7,8.

One of the ways to evaluate the stress degree is to measure salivary cortisol levels, a steroid hormone pro duced in the hypothalamic-pituitary-adrenal (HPA) axis that is secreted in saliva as a reaction to stress, for which it has been used as a biomarker of stress in the adult and pediatric population8. There is ample evi dence that the use of salivary cortisol correlates signifi cantly with total cortisol (plasmatic)9,10.

Observational studies suggest that early life stress is associated with cognitive deficits and elevated cortisol levels in children11-13. In addition, there is evidence that young children who maintain high cortisol levels show lower cognitive performance14-16.

Among other environmental factors that can in fluence neurodevelopment is deprivation of maternal contact, poverty, and other social conditions17-19. Early separation due to maternal imprisonment breaks the attachment bond and can have a harmful impact on a developing child, which has been described by some experts as a ‘lasting trauma’20-24.

Currently, in Chile, women represent 10% of the prison population, 95% of them are mothers and 2/3 have underage children25,26. Life in prison is com plex. Women who live there with their children have to adapt to very rigid discipline and often the living conditions are far from being the most adequate (e.g. overcrowding, lack of hot water and heating). In gene ral, these are young women, the vast majority have not completed secondary education and have lived their entire lives with deprivation. Mothers are often expo sed to stressful situations: they cannot accompany their children to the doctor if they become ill, they have to face trial and inspections, and they often have a scarce social support network outside prison27.

In this context, and in accordance with the protec tion and promotion principle of the rights of the child, Chile facilitates contact between mothers in prison and their children in a section of the prison, where mothers are allowed to live with their children during the first two years of life. At the same time, in some centers such as the San Joaquin Penitentiary Center, there is also a Fundación Integra (Chilean foundation, main pre-school education provider) program that provides a nursery system for the children of the inmates. At present, there are no studies that analyze the psycho motor development evaluation of these children. The objective of the study was to describe the PMD and sa livary cortisol concentration (SCC) of children living in prison with their mothers and to compare the re sults with those observed in children who are not on this regimen.

Subjects And Method

Study design

Cross-sectional study that included all children un der 2 years of age without acute pathology who lived with their mothers in the San Joaquín women’s correc tional center (WCC), and a group of children, matched by age, enrolled in the “Padre Vicente Irarrázaval” Pri mary Care Family Health Centre (CESFAM) in the commune of Estación Central, which belongs to the public health system. The exclusion criteria were chil dren who presented pathologies that could negatively influence the PMD, hospitalizations longer than one month, and whose mother did not have a command of the Spanish language.

At the beginning of the evaluation, maternal age, the following data were recorded: time spent in the WCC, perinatal pathologies, drug use during preg nancy, gestational age at birth, breastfeeding, mother’s schooling, and presence of acute illness of the mother and/or child.

The following variables were considered dependent on PMD: salivary cortisol levels in children and varia bles independent of sex, chronological age of the child, level of maternal salivary cortisol concentrations, nu tritional status of the child, educational level reached by the mother and maternal age.

Tools used for measurement

Psychomotor development: ASQ-3 was used to evaluate children’s PMD. This test is a screening ins trument for children from 1 month to 5 years old, which consists of five domains (communication, fine motor skills, gross motor skills, problem solving, and interpersonal relationships). The corresponding test was used according to the chronological age of the children and in the case of preterm infants, according to the corrected age. As for the application of the test, each child was evaluated only once and his/her mother was the one who answered the questions. Explanatory accessory material was used and help was given to an swer the questionnaire when the mother had doubts regarding the milestone reached.

There is no consensus in the literature on what cri teria to use for defining psychomotor developmental deficit. Most of the authors recommend relying on do mains, considering PMD deficit cases that have at least one lowered area with a score lower than -2SD of the average. This proposal was which we considered for ca rrying out our study.

In Chile, the 8, 18, and 30 month questionnaires were validated. In a preliminary analysis, it was de monstrated that the use of cut-off values from the ori ginal USA validation were applicable to our popula tion, so for this study the published cut-off points were used, considering as a PMD deficit risk having at least one area below the cut-off points29,30.

Cortisol measurement: The salivary sample for cortisol measure was taken from children and mothers between 8:00 am and 11:00 am. Mothers confirmed that they and her children had not received food at least one hour before31. The samples were taken with a cotton swab, collected in an Eppendorf tube, and sto red at -20 ° C until they were processed in a blinded fashion. They were thawed and centrifuged for five mi nutes at 3000 rpm, and the supernatant was used to de termine salivary cortisol by radioimmunoassay using a commercial kit (DIAsource ImmunoAssays S.A.). The method sensitivity is 0.5 ng/ml and the intra- and inter-assay variation coefficients are 5.5% and 10.6% respectively. Reference value: 1.2-7.5 ng/ml.

Given the known variability of cortisol secretion, it was used the mean result of two salivary cortisol sam ples obtained from the same subject on different days but in the same hourly range.

Nutritional status of the infant. The weight was recorded in kilograms using a previously calibrated weight scale, and the height in centimeters using a por table stadiometer. Nutritional assessment was carried out using W/A, W/H, and H/A indicators according to WHO reference tables, classifying nutritional status according to international cut-off points32,33.

Sample size. Since the study evaluated all infants who were living in that moment with their mothers in the WCC, and there are no national publications refe rring to salivary cortisol concentration in Chilean in fants, no sample size calculation was performed.

Statistical Analysis

Descriptive data were reported using absolute and relative frequency tables for qualitative variables, and quantitative variables were expressed through median and interquartile range (IQR) or mean, and standard deviation according to their distribution. The Fisher and Mann-Withney tests were used to evaluate the sig nificance of the association, considering significant a p < 0.05 value. Data were processed and analyzed using the STATA 15 Software.

Ethical Committee

This study was authorized by the Metropolitan Re gional Directorate Technical Unit of the Chilean Gen darmerie and approved by the Ethics Committee of the Central Metropolitan Health Service. Each mother sig ned an informed consent form before the application of the study.


Between August and December 2017, 48 children between the ages of 1 and 24 months were recruited. 13 infants entered the case group (1 dropped out of the study), and 30 entered the control group. All the children who entered the study were Chilean, only one mother was Peruvian. The median chronological age of the children was 7 months (IQR 5- 11 months). In 90.5% of the children, the gestational age was higher than or equal to 37 weeks. There was male dominance. All the children in the WCC received breastfeeding at some time and only almost half of the children did so at the CESFAM (100% vs 45.2% respectively, p = 0.01) (Table 1). In terms of the nutritional assessment of children, 71.4% were eutrophic, 23.7% present malnu trition by excess, and only one child was at risk of un dernutrition. We found no differences when analyzing nutritional status provided by both locations.

Table 1 Demographic characteristics of children by group of study. 

Although all mothers could read and write, the educational level was lower among mothers in the WCC (p=0.03). In addition, 30% of mothers had some pathology during their pregnancy which was signi ficantly more frequent (58%) in the WCC mothers (p=0.01). The most frequent pathologies were hyper tensive pregnancy syndrome (9.5%), and gestational diabetes (9.5%) (Table 2).

Table 2 Nutritional status of children by group of study. 

The median salivary cortisol level in children of the sample was 2.1 ng/ml (IQR 1.2 to 1.8), with no significant differences between children of the WCC and those of the CESFAM (2.3 ng/ml IQR 1.1 to 2.7 vs 2.1 IQR 1.6 to 2.9, respectively). Regarding ma ternal salivary cortisol level, the median was 3.8 ng/ ml (IQR 3.0 to 5.3) with no significant difference between inmate mothers and those of the CESFAM (Table 3).

Table 3 Demographic characteristics of mothers by group of study. 

After measuring PMD using ASQ3, we obser ved that 13 children had PMD deficits, 61% of them had more than one altered domain, and the areas at the highest risk were fine and gross motor skills, and problem solving. When performing the PMD analysis, according to the child’s residence, we found that the PMD deficit was more frequent among children living outside the WCC representing 2.3% vs 28.5% respec tively (Fisher Test p = 0.06) (Table 4). Out of the total number of children in the sample, four children were younger than 37 weeks, and only one of these had a PMD deficit.

Table 4 Salivary cortisol concentration by group of study. 

When comparing the salivary cortisol concentra tion of children according to the PMD and the salivary cortisol values of mothers with the PMD, no signifi cant association was found (Table 5). We also found no differences when assessing the relationship between the child’s PMD and maternal educational level, re gardless of the child’s residence.

Table 5 Psychomotor development of children by group of study. 


The main finding of this study is that children li ving with their mothers at WCC have salivary cortisol concentrations similar to those seen at CESFAM. In addition, we think it is important to point out that the PMD deficit was strikingly more frequent in CESFAM children, although the difference was not significant (p = 0.06), it is possible that this is due to the sample size.

The results of the only study conducted in a po pulation similar to ours differ somewhat from those found by us. Morales M. found in a children sample obtained from the same WCC (n=15), after evaluating the PMD through EEDP, that 25% of children had al tered PMD18. Since the time of this work publication, there have been changes, such as the creation of the nursery, which could be responsible for the differen ces found. We believe that the contact of children with their mothers and the stimulation that they received in the WCC kindergarten, could influence the observed results. We think it is important to emphasize that the mentioned kindergarten has, in addition to the regular staff in this type of facility, a psychomotor specialist and weekly psychological consultation which could enhance the maternal care impact. We also notice the high breastfeeding frequency in WCC children (100%) which could be favored because children sleep with their mothers, a situation promoted by the government program Crececiendo Juntos34 (Growing Together). Regarding the breastfeeding impact on PMD, Chui et al. have shown that there is a linear “dose-response” asso ciation between breastfeeding duration and motor and cognitive development35. On the other hand, the PMD deficit observed in children treated at CESFAM (28%) is similar to that found in national studies (30%).36

The salivary cortisol concentration detected in both groups of children in the study is within the nor mal range. Tollenaar et al. analyzed the morning sali vary cortisol concentration in a cohort of 300 infants by measurements at six weeks, five months, and 10-12 months of age showing that normal ranges in infants younger than one year of age are between 1.59 and 9.05 ng/ml37. Another study carried out by Albers et al. measured salivary cortisol in 64 infants under one year of age in a nursery, determining that normal con centrations were between 1.92 and 4.34 ng/ml12.

Cortisol, under normal conditions, shows a marked circadian rhythm in adults and children. Cortisol levels are highest in the morning, followed by an abrupt drop immediately after awakening38-41. It is believed that in fants develop this cortisol circadian rhythm during the first year of life, but exactly when, it has not yet been established. The concentration variability of this hor mone, when measured repeatedly, is not clear. A pioneering study by Ivars et al. describes that most infants begin their circadian rhythm at four months of age; however, they describe a significant individual variabi lity of these levels, as shown in our study42. It is known that cortisol concentration varies widely in the same subjects at different times of the day and according to age40. Other factors, depending on the sampling stan dardization, could also explain the above-mentioned variation. In our study, the necessary fasting period before sampling (1 hour)43 was evaluated by question naire, which could also explain some of the observed variability.

Regarding the limitations of our study, the small number of evaluated children in the WCC is one of the factors that could explain the lack of significant diffe rences found in our work. Another aspect to consider is that the study design does not allow for causality associations. A future study should consider a con trol group of children living with their mothers in a penitentiary center without a nursery. We believe that it is also necessary to follow up the evaluated children to explore whether PMD and stress are affected in the long term.

It should be noted that this is the first study in Chile that measure the stress level of mothers and children in a penitentiary center, which includes an interdisci plinary nursery, and its association with the PMD that these children have living under these conditions.

As a conclusion, we believe that our study is a con tribution that should be considered when evaluating the benefit of the coexistence between infants and their mothers in penitentiary centers of the country, having the obligation to respect the rights of children.

Ethical Responsibilities

Human Beings and animals protection: Disclosure the authors state that the procedures were followed ac cording to the Declaration of Helsinki and the World Medical Association regarding human experimenta tion developed for the medical community.

Data confidentiality: The authors state that they have followed the protocols of their Center and Local regu lations on the publication of patient data.

Rights to privacy and informed consent: The authors have obtained the informed consent of the patients and/or subjects referred to in the article. This docu ment is in the possession of the correspondence author.

Financial Disclosure: Authors state that no economic support has been asso ciated with the present study.

Conflicts of Interest: Authors declare no conflict of interest regarding the present study.

Acknowledgement: The authors thank the women who participated in the study and the valuable contributions of staff who work in the kindergarten and Primary Care Center “Padre Vicente Irarrázaval”.


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Received: April 05, 2018; Accepted: December 15, 2018

Correspondence: Gerardo Weisstaub. E-mail:

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