Parenting stress in families with very low birth weight preterm infants in early infancy

Research in Developmental Disabilities 35 (2014) 1748–1756

Contents lists available at ScienceDirect

Research in Developmental Disabilities

Parenting stress in families with very low birth weight preterm infants in early infancy§ Tsu-Hsin Howe a, Ching-Fan Sheu b, Tien-Ni Wang c,d,*, Yung-Wen Hsu e a

Department of Occupational Therapy, Steinhardt School of Culture, Education and Human Development, New York University, New York, NY 10012, United States b Institute of Education, National Cheng Kung University, Tainan, Taiwan c School of Occupational Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan d Division of Occupational Therapy, Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan e Department of Occupational Therapy, National Cheng Kung University, Tainan, Taiwan

A R T I C L E I N F O

A B S T R A C T

Article history: Received 29 October 2013 Received in revised form 14 February 2014 Accepted 19 February 2014 Available online 19 March 2014

Taking care of a premature infant adds an extra burden to already stressed parents. Previous studies have shown that parental stress occurs during the initial hospitalization. However, there is little information on parental stress over time, and the few existing results are conflicting. In addition, many studies have focused on maternal stress but there is little information about a father’s long-term adaptation to stress. The purpose of this study was to examine the degree and type of parenting stress in the families of very low birth weight (VLBW) preterm infants over the first two years of life. We compared parenting stress in families with preterm infants with control families, while also comparing the stress in mothers to that in fathers. Furthermore, we explored the relationship between parenting stress in the preterm group with identified factors that included the infant’s age, medical complications, and parents’ perceived feeding issues after they had been discharged from the hospital. This was an exploratory study with a cross sectional design. Participants included a total of 505 mothers from Tainan, Taiwan; 297 with preterm children (239 mothers, 58 fathers) and 208 with full-term children (181 mothers, 27 fathers). Assessments including the Parenting Stress Index, Neonatal Medical Index and Behavior-based Feeding Questionnaire were used to measure parental distress, infants’ medical complications and parents’ perceived feeding issues, respectively. Results of the study, though not statistically significant, indicated the presence of increased parenting stress in parents of preterm infants as compared to parents of full-term infants. 13.1% of mothers with preterm infants demonstrated total stress levels that warranted clinical intervention. We also found that mothers of preterm infants presented different parenting stress patterns than fathers of preterm infants. Fathers of preterm infants tended to have overall higher stress scores than mothers. On the other hand, mothers of preterm infants tended to report more health related difficulties, more depression, higher social isolation and role restriction, and less support from their spouses, than reported by fathers. Moreover, as time went on, parents with preterm infants continued to experience greater parenting stress than those with full-term infants. Understanding the experiences

Keywords: Prematurity Risk factor Parent distress

§ Grant and financial support: This project was supported in part by the following grants from the National Sciences Council of Taiwan: NSC-101-2314-B-002-001 and NSC-102-2314-B-002-009 to Tien-Ni Wang and NSC-100-2410-H-006-027 to Ching-Fan Sheu. * Corresponding author at: School of Occupational Therapy, College of Medicine, National Taiwan University, No. 17 Syu-Jhou Rd., 4th Floor, Taipei City 100, Taiwan. Tel.: +886 2 3366 8163; fax: +886 2 2351 1331. E-mail addresses: [email protected], [email protected] (T.-N. Wang).

http://dx.doi.org/10.1016/j.ridd.2014.02.015 0891-4222/ß 2014 Published by Elsevier Ltd.

T.-H. Howe et al. / Research in Developmental Disabilities 35 (2014) 1748–1756

1749

of parents with preterm children is important for health care providers while interviewing parents for information regarding their children and designing intervention programs to improve children’s outcomes. ß 2014 Published by Elsevier Ltd.

1. Introduction Taking care of an infant who has been born prematurely adds an extra burden to already stressed parents. Previous studies have documented that parental distress occurs during initial hospitalization (Baker, 1994; Carter, Mulder, Bartram and Darlow, 2005; Ho, Chen, Tran and Ko, 2010). During the hospital stay, parents not only have to cope with various stressors from the environment of the neonatal intensive care unit, but also with the medical crisis of their newborn baby, the uncertainty of their baby’s survival, the physical and emotional isolation from their baby, and the normal stresses of parenthood (Baker, 1994; Dudek-Shriber, 2004). Studies have reported that mothers of preterm infants experience increased levels of stress in the neonatal period compared with mothers of full-term infants, and they are more likely to suffer from depression and anxiety at the time of hospital discharge (Carter et al., 2005; Holditch-Davis, Bartlett, Blickman and Miles, 2003; Kaaresen, Rønning, Ulvund and Dahl, 2006). Parents may continue to experience distress as they attempt to care for a biologically fragile infant. After discharge from the hospital and during the first few years, the daily care of preterm infants may be more time consuming and laborious than full-term infants. An estimated 31–45% of preterm infants experience feeding problems in the first two years of life (Hawdon, Beauregard, Slattery and Kennedy, 2000; Rommel, De Meyer, Feenstra and Veereman-Wauters, 2003; Thoyre, 2007). These feeding-related difficulties could persist throughout the first five years of life (Howe et al., 2010). Parents of preterm infants may have to deal with possible feeding difficulties, special nourishment requirements, and increased medical attention. In addition, uncertainties about the future may continue after the neonatal period, as the preterm child grows and encounters new problems, developmentally. While there are a small number of studies on parental outcomes of preterm children beyond the immediate postpartum period, there is little information on the parental stress over time (Kersting et al., 2004), ¨ stberg and Fellman, and the few results are conflicting (Halpern, Brand and Malone, 2001; Singer et al., 1999; Tommiska, O 2002). Some studies have reported that mothers of preterm infants continue to experience depression and anxiety for a long time after their babies are discharged from the hospital (Gray, Edwards, OCallaghan and Cuskelly, 2012; Singer et al., 1999), while others have reported that the increased distress experienced by mothers of very low birth weight (VLBW) preterm infants during the newborn period may diminish over time (Halpern et al., 2001). In addition, most of the studies have focused on maternal stress in general; there is even lesser information about a father’s long-term adaptation (Gray et al., 2012; Kaaresen et al., 2006) or about stress related to feeding problems. The purpose of this study was to examine the degree and type of parenting stress in families of VLBW preterm infants over the first two years of life. We compared parenting stress in families with preterm infants with that in control families; we also compared the stress in mothers with that in fathers. Furthermore, we explored the relationship between parenting stress in the preterm group with identified factors, including an infant’s age, medical complications, and parents’ perceived feeding issues of their infants after discharge from the hospital. 2. Method 2.1. Participants Participants included a total of 505 parents, 297 with infants born premature (239 mothers, 58 fathers) and 208 with infants born full-term (181 mothers, 27 fathers). Parents with preterm infants were recruited from a developmental followup clinic for preterm children at a large urban hospital in the southern region of Taiwan, consisting of referrals of preterm infants from six regional hospitals. 297 parent–preterm infant pairs were invited to participate in this study after being screened for predetermined inclusion criteria. In order to be eligible for the study, parents needed to be at least 18 years old, able to read and complete questionnaires, and involved in the daily care of their babies. All recruited preterm infants had a gestational age of less than 37 weeks, a birth weight equal to or less than 1500 g and no documented congenital anomalies. A convenience sample of 208 parents with full-term infants was recruited from outpatient well-baby clinics at the same hospital as a comparison group. The inclusion criteria were comparable to the studied group except for the infants’ gestational age, which was equal to or greater than 37 weeks. 2.2. Instruments 2.2.1. Parenting Stress Index (PSI)-Chinese version The PSI (Abidin, 1995) is a self-report instrument designed to assess parental perceptions of the degree of stress related to the different dimensions of parenting roles. The Chinese version of PSI was translated from the original PSI and

1750

T.-H. Howe et al. / Research in Developmental Disabilities 35 (2014) 1748–1756

normed based on 1362 Chinese mothers from Taiwan (Yeh et al., 2001). The instrument is a 94-item questionnaire providing a total stress score (PSI-T) and two summary domain scores: parent (PSI-P) and child (PSI-C). The parent domain (PSI-P) consists of 50 items measuring seven parent-related stress factors, reflecting stress arising from selfperceived competence as a parent, feelings of depression about being a parent, social isolation and inadequate spousal support in parenting. The child domain (PSI-C) consists of 44 items measuring six child-related stress factors, measuring stress arising from child-focused attributes such as the child’s ability to reward or reinforce the parent, and the child’s acceptability of his or her parent. Parents were asked to report how strongly they agree with each statement by marking a 5-point Likert scale, ranging from ‘‘strongly agree’’ to ‘‘strongly disagree’’ with higher scores indicating higher levels of stress. Internal consistencies of the PSI-C and PSI-P were both 0.91. According to the manual of PSI-Chinese version, parents who scored PSI-T above 294 (90th percentile) were experiencing clinically significant levels of stress (Yeh et al., 2001). In this study, the Chinese version of PSI was used to measure parenting stress after their babies were discharged from the hospital. 2.2.2. The Neonatal Medical Index (NMI) The Neonatal Medical Index (NMI) (Korner et al., 1993) summarizes preterm infants’ medical course during their NICU stay, including birth history and medical complications, at the time of hospital discharge. It organizes the severity of medical complications of a preterm infant into five levels of categorization. The categorical levels of the NMI range from I to V; with level I describing preterm infants free of significant medical problems and V describing infants with the most serious complications. Previous studies have reported that the NMI has a good concurrent and predictive validity in discriminating the abnormal neurobehavioral outcomes of infants (Franck, Cox, Allen and Winter, 2005; Korner et al., 1993, 1994). In this study, the level of NMI was determined based on each preterm infant’s pertinent postnatal medical history obtained from his or her medical records. The level of the NMI was used as one of the predictors of parenting distress. 2.2.3. Behavior-based Feeding Questionnaire for infants with preterm history The Behavior-based Feeding Questionnaire for Infants with Premature History is designed to assess preterm infants’ feeding behaviors from the primary caregiver’s perspective (Howe and Ho, 2009). This questionnaire consists of 33 questions and is geared to assess issues in six areas: endurance, gastrointestinal related issues, muscle tone, oral motor function, respiration, and sensory regulation. The face and content validity of the questionnaire had been established via expert opinions (Howe and Ho, 2009). Specifically, a panel of experts consisting of 3 nurses, 3 occupational therapists, and 3 physicians (2 neonatologists, and 1 developmental pediatrician) validated the questionnaire. They had an average of 17 years of experience working with preterm infants in different capacities and settings. The expert panel believed that all items in this questionnaire fell under the categories of 3 and 4 (quite relevant to very relevant); and all experts rated the questionnaire in its entirety, very relevant. In this study, the Behavior-based Feeding Questionnaire was used to assess feeding issues perceived by parents and also serve as one of the predictors of parenting stress. 2.3. Procedure Permission for the study was given by the hospital’s ethics committee. Parents attended the developmental follow-up for preterm infants or well-baby clinics were approached to join the study. Signed consents were obtained from the parents prior to administering the questionnaires. Parents were asked to complete two questionnaires: the Behavior-based Feeding Questionnaire and the Parenting Stress Index-Chinese version. Additional data including infants’ gestational age, birth weight and medical history, as well as parents’ demographic information including level of education and family incomes was extracted from the medical records of all participating infants. Educational qualifications were divided into four categories, high school and below (less than 12 years of full-time education), senior high school (12 years), College (13–16 years), and graduate school (>16 years). Annual family income was categorized into four groups, NT$0–500,000 (low income), NT$500,001–1,000,000 (average income), NT$1,000,001–1,500,000 (high income), and $1500,001 (very high income). The average exchange rate was US$1.00 = NT$30.0 and the average family disposable income of 2012 was NT$924,000 (US$30,800) (Directorate-General of Budget, 2013). 2.4. Data analysis All statistical analysis was performed using the SAS/STAT program (Version 9.03 for Windows). Mean comparison of PSI scores including PSI-T, PSI-P and PSI-C between preterm and full-term groups was performed using the multiple comparisons tests (Westfall et al., 2011). Multiple comparisons tests were used during each PSI-P and PSI-C subcategory’s mean comparison between the two groups to avoid possible false positives or type I errors (Cabral, 2008; Dudoit, Van Der Laan and Pollard, 2004). Adjusted P values were used for accepting or rejecting a comparison. P < 0.05 was considered significant. Since the majority of the questionnaires were completed by the mothers of the infants (80% in preterm group and 87% in full-term group), the main analyses were completed based on maternal stress responses. Parenting stress reported by the fathers was analyzed separately and the results were compared with responses obtained from the mothers. Regression

T.-H. Howe et al. / Research in Developmental Disabilities 35 (2014) 1748–1756

1751

analyses were used to examine relationships between parenting stress levels and the characteristics of parents and children, as well as the changes in parenting stress over time. 3. Results 3.1. Characteristics of infants and mothers in preterm and full-term groups The majority of the 505 parents (83%) who participated and had usable data were mothers (239 in preterm group and 181 in control group). The demographic characteristics of infants and mothers of both preterm and full-term groups are summarized in Table 1. The preterm infants in this study consisted of 136 boys and 103 girls with a mean birth weight of 1150.7  247.3 g and a mean gestational age of 29.3  2.6 weeks. A total of 24.9% of these infants had mild medical complications during their NICU stay (NMI levels I & II), 48.4% of them had moderate medical complications (NMI level III) and 26.7% had severe medical complications (NMI levels IV and V). Mothers with preterm infants had a mean age of 31.47  4.3 years old (ranged from 22 to 43 years) and had 13.4  2.1 years of education on average. Of the families with preterm infants, 57.1% of mothers reported themselves as stay-at-home mothers and 45.3% of the families were reported to have income that was categorized as an average Taiwanese household (NT$500,001–1,000,000). The group of full-term infants consisted of 86 boys and 95 girls with a mean birth weight of 3101.6  402.3 g and a mean gestational age of 39.2  1.0 weeks. Mothers with full-term infants had 15.4  2.0 years of education on average. 34.25% of mothers with full-term infants reported themselves as stay-at-home mothers and 41.9% of the families were from average income Taiwanese households. 3.2. Parenting stress in mothers with preterm and full-term infants The results of parenting stress, including group means and standard deviation, measured by PSI, are presented in Table 2. The mean Total Parenting Stress scores did not differ between the preterm and full-term groups. However, mothers with preterm infants reported to have significantly higher mean scores of the child domain, than those of the mothers with fullterm infants (P = 0.046). None of the mean scores of PSI-T, PSI-P, PSI-C and their subscales, in either the preterm or full-term group, were above the clinical cutoff points. That is, neither groups experienced stress that reached the levels of clinical significance. We found that mothers with preterm infants demonstrated significantly higher stress in two out of the seven parentrelated factors, when compared to the full-term group. The two factors were depression, and role restriction. That is, mothers of preterm infants perceived themselves as more depressed and more restricted on personal freedom than mothers with fullterm infants. At the same time, mothers of both preterm and full-term infants experienced similar levels of stress regarding the remaining five parent-related factors: attachment, competence, health, partner or spousal support, and support from their social networks. We also found that mothers with preterm infants demonstrated significantly higher levels of stress than mothers of fullterm infants in two out of six child-related factors. The factors were acceptability, and distractibility. These results reflected that the mothers with preterm infants perceived their children as less acceptable and more distractible than mothers of fullterm infants. However, mothers of preterm infants did not perceive their children as less adaptable, more likely to be demanding and moody, or less reinforcing than their full-term counterparts. Table 1 Demographic characteristics in both full-term and preterm infant groups. Characteristics

Full-term (n = 181)

Preterm (n = 239)

P

Infants Birth weight (g), mean  SD Gestational age (weeks), mean  SD Gender, boys/girls, n (%) Medical complications, I/II/III/IV/V, n (%)

3101.6  402.3 39.2  1.0 86/95 (47.5/52.5) –

1150.7  247.3 29.3  2.6 136/103 (57.1/42.9) 1/52/103/16/41 (0.5/24.4/48.4/7.5/19.2)

<0.001a <0.001a 0.060b

– 15.4  2.0 2 (1.1) 22 (12.2) 120 (66.3) 37 (20.4)

31.47  4.3 13.4  2.1 10 (4.2) 110 (46.0) 111 (46.5) 8 (3.3)

31 75 58 15

93 (39.7) 106 (45.3) 24 (10.2) 11 (4.8)

Mothers Age (years), mean  SD Years of education, mean  SD Less than 12 years, n (%) High school (12 years), n (%) College (13–16 years), n (%) Graduate school (>16 years), n (%) Family income, NT$ (%) NT$ 0–500,000, n (%) NT$ 500,001–1,000,000, n (%) NT$ 1,000,001–1,500,000, n (%) NT$ 1,500,001 and up, n (%)

(17.3) (41.9) (32.4) (8.4)

Note: Severity of medical complications classified by Neonatal Medical Index: level I to V with V indicating highest severity. a Two sample t-test. b Chi-square.

<0.001a

<0.001b

<0.001b

1752

T.-H. Howe et al. / Research in Developmental Disabilities 35 (2014) 1748–1756

Table 2 The results of Parenting Stress Index (PSI) in both full-term and preterm infant groups. Variable

Full-term (n = 181) Mean (SD)

Preterm (n = 239) Mean (SD)

Raw P

Adjusted P

PSI Total Score

236.55 (40.15)

246.98 (44.96)

0.01

0.09

Child domain Acceptability Adaptability Demandingness Distractibility Mood Reinforce parents

106.17 14.55 27.27 22.22 20.91 12.48 8.74

(19.56) (4.97) (5.86) (5.04) (4.39) (3.16) (3.01)

110.96 16.36 28.75 22.80 22.13 12.93 9.13

(22.40) (5.63) (7.42) (5.35) (4.68) (3.43) (3.35)

0.02 <0.01 0.03 0.26 <0.01 0.16 0.22

0.05 <0.01 0.16 0.65 0.05 0.58 0.65

Parent domain Attachment Competence Depression Health Social Isolation Role restriction Spouse support

130.38 13.27 28.26 22.32 11.45 16.22 17.91 20.94

(24.97) (3.32) (6.16) (5.97) (2.59) (4.09) (5.32) (4.93)

133.38 13.96 27.87 24.55 11.73 17.03 19.72 20.70

(26.89) (3.87) (6.26) (6.98) (2.56) (4.16) (5.70) (5.10)

0.05 0.05 0.52 <0.01 0.28 0.04 <0.01 0.62

0.26 0.26 0.76 <0.01 0.65 0.24 0.01 0.76

Note: PSI includes total scores, scores of child and parent domains and scores of subscales under each domain. Multiple comparisons were performed to compare the results between the full-term and preterm groups. P values of both raw and adjusted data were presented in each subscale.

Table 3 Distributions of stress levels (high, normal and low) of mothers in both full-term and preterm groups. Variables

Full-term (n = 181)

x2

Preterm (n = 239)

P

Normal

Low

High

Normal

Low

8.3%

70.2%

21.5%

13.1%

69.9%

17.0%

3.219

0.20

Child domain Acceptability Adaptability Demandingness Distractibility Mood Reinforced parent

6.6% 10.5% 9.9% 9.9% 15.5% 15.5% 7.7%

74.0% 60.8% 70.7% 68.0% 84.5% 66.9% 64.1%

19.3% 28.7% 19.3% 22.1% – 17.7% 28.2%

12.9% 11.1% 19.3% 16.7% 11.5% 19.6% 6.4%

71.1% 71.5% 61.4% 56.7% 88.5% 64.3% 62.1%

15.9% 17.4% 19.3% 26.6% – 16.2% 31.5%

4.759 7.609 7.234 6.369 1.412 1.212 0.704

0.09 0.02 0.03 0.04 0.15 0.55 0.70

Parental domain Attachment Competence Depression Health Isolation Role restriction Spouse

7.7% 6.0% 12.2% 5.5% 13.8% 15.5% 9.9% 13.3%

68.5% 66.9% 71.3% 67.4% 60.8% 65.2% 61.3% 69.1%

23.8% 28.2% 16.6% 27.1% 25.4% 19.3% 28.7% 17.7%

12.2% 6.4% 11.5% 15.0% 15.1% 20.3% 34.2% 13.4%

67.4% 67.5% 68.1% 65.0% 63.4% 65.5% 56.4% 61.9%

20.4% 26.1% 20.4% 20.1% 21.6% 14.2% 9.4% 24.7%

2.482 0.540 0.996 10.620 0.876 2.900 47.203 3.100

0.29 0.76 0.61 <0.01 0.65 0.24 <0.01 0.21

High Total Parental Stress

Note: Total parental stress, child domain (PSI-C), parent domain (PSI-P) and its subscales are presented in this table. Chi-square was used to compare the differences between the two groups.

3.3. Parenting Stress Index percentage of high risk scores in both preterm and full-term groups Further analysis was completed to evaluate the within-group risk, by calculating the percentage of scores at or above the high-risk cut-offs identified by the PSI manual (Abidin, 1995; Tam, Chan and Wong, 2006) (Table 3). According to the manual of PSI-Chinese version, parents who scored PSI-T above 294 (90th percentile) were identified as those who experienced clinically significant levels of stress and were considered as high risk and warranting referral (Yeh et al., 2001). The majority of the mothers in both preterm and full-term groups demonstrated normal level of distress according to the PSI manual (preterm group ranged from 56.4% to 88.5%, full-term group ranged from 60.8% to 84.5%). However, mothers of preterm infants tended to have higher percentage of high stress levels than mothers of full-term infants (preterm group: 6.4–34.2%; full-term group: 5.5–15.5%). Specifically, mothers with preterm infants demonstrated a significantly higher percentage of high stress levels score in the child domain subscales, including acceptability (11.1%), adaptability (19.3%), demandingness (16.7%) and parent domain subscales including depression (15.0%) and role restriction (34.2%). On the other hand, lower frequency of ‘‘at-risk’’ scores in PSI-T (8.3%), PSI-P (7.7%) and PSI-C (6.6%) were found in the control group.

T.-H. Howe et al. / Research in Developmental Disabilities 35 (2014) 1748–1756

1753

Table 4 The results of perceived feeding issues in both full-term and preterm groups. Perceived feeding issues were measured by Behavior-based feeding Questionnaire. Characteristics

Full-term (n = 181)

Preterm (n = 239)

Endurance Gastro-intestinal Muscle tone Oral motor Regulation Respiration

0.43 0.33 0.16 0.25 0.22 0.08

0.50 0.44 0.21 0.30 0.33 0.07

Total score

1.47 (0.64)

(0.24) (0.21) (0.22) (0.12) (0.13) (0.16)

t

P

(0.33) (0.29) (0.23) (0.19) (0.17) (0.16)

2.396 3.976 1.974 2.556 7.086 0.955

0.017 <0.001 0.049 0.011 0.000 0.340

1.85 (0.91)

4.612

<0.001

Table 5 Multiple stepwise regression analyses of the contribution of medical complications presented by the NMI and feeding problems measuring by Behaviorbased Feeding Questionnaire in parent domain parenting stress (PSI-P) and child domain parenting stress (PSI-C) in group of mothers with preterm and group of mothers with full term infants. Variables

Preterm group (n = 230)

b PSI-P Block 1: Age ME Block 2: NMI Block 3: FQ Final model PSI-C Block 1: Age ME Block 2: NMI Block 3: FQ Final model

t

–

– 0.082

1.274

Full term group (n = 181) P

R2 change

– 0.204

0.010

–

–

–

0.165

2.562

0.011

R2 = 0.028

F = 4.460

P = 0.013

–

–

– 0.058

0.123

1.905

–

–

–

0.104

1.607

0.109

R2 = 0.028

F = 3.443

P = 0.034

b

T

P

R2 change

0.243

3.345

0.001

0.054**

R2 = 0.054

F = 11.187

P = 0.001

0.018*

0.016 0.162

0.216 2.330

0.829 0.021

0.034*

0.011

0.371

4.955

<0.01

0.118**

R2 = 0.151

F = 10.526

P < 0.01

0.027*

Abbreviations: ME, maternal education; NMI, Neonatal Medical Index; FQ, Feeding Questionnaire. * P < 0.05 indicated significant predictor. ** P < 0.01 indicated significant predictor.

3.4. Perceived feeding issues reported by mothers with preterm and full-term infants The results of the survey for perceived feeding issues, including group means and standard deviation, measured by a Behavior-based Feeding Questionnaire, are presented in Table 4. There were significant differences between the preterm and full-term groups in the total mean scores as well as in all six subcategories of feeding issues, including endurance, gastrointestinal, muscle tone, oral motor, regulation, and respiration. Mothers of preterm infants were reported to experience significantly more feeding related issues than those of full-term infants. 3.5. Factors associated with parenting stress Multiple stepwise regression analyses were used to examine relationships between parenting stress levels and certain characteristics of parents and children. These characteristics included an infant’s age, medical complications; parents’ perceived feeding issues after their infant being discharged from the hospital; and the mother’s total years of education. Table 5 summarizes the predictive models for parenting stress levels, including parent and child domains (PSI-P and PSI-C), in both preterm and full-term groups. For the group of mothers with preterm infants, the results indicate that perceived feeding issues, measured by the Behavior-based Feeding Questionnaire, were significantly associated with the parental stress levels in the parent domain of the PSI, after controlling for the infant’s biological and social factors. The highest maternal education year was a significant social factor in predicting a preterm infant’s PSI-C regression model. The R2 values of the PSI-P and PSI-C models were 0.028 and 0.028, respectively, in preterm group, indicating a 2.8% variance of parental stress could be explained by the predictors in multiple linear regression models (P values < 0.05).

1754

T.-H. Howe et al. / Research in Developmental Disabilities 35 (2014) 1748–1756

Table 6 The comparison of parenting stress between mothers and fathers in preterm group. Variables

Father (n = 58) Mean (SD)

Mother (n = 239) Mean (SD)

Raw P

Adjusted P

PSI Total Score

252.85 (43.24)

246.98 (44.96)

0.35

0.88

Child domain Acceptability Adaptability Demandingness Distractibility Mood Reinforce parents

116.35 17.19 28.81 23.44 23.35 13.61 9.95

(21.13) (5.54) (6.55) (5.04) (4.21) (3.02) (2.92)

111.96 16.36 28.75 22.80 22.13 12.93 9.13

(22.40) (5.63) (7.42) (5.35) (4.68) (3.43) (3.35)

0.16 0.30 0.96 0.40 0.06 0.15 0.08

0.62 0.85 1.00 0.91 0.37 0.62 0.43

Parent domain Attachment Competence Depression Health Isolation Role restriction Spouse

136.50 15.40 29.40 23.87 11.71 16.69 19.05 20.37

(25.24) (3.51) (7.99) (5.98) (2.12) (3.31) (5.31) (4.20)

135.38 13.96 27.87 24.55 11.73 17.03 19.71 20.70

(26.89) (3.87) (6.26) (6.98) (2.56) (4.16) (5.70) (5.09)

0.77 0.01 0.10 0.48 0.97 0.55 0.40 0.64

0.98 0.08 0.50 0.93 1.00 0.95 0.91 0.96

Similar results were found in the group of parents with full-term infants. The extent of feedings issues that parents perceived, was significantly associated with parental stress levels, after controlling for social factors. The highest maternal education year and feeding related issues were significantly associated with the parental stress levels in the full-term PSI-C models. The R2 values of the PSI-P and PSI-C models in full-term infants were 0.054 and 0.151, respectively, indicating that a 5.4% and 15.1% variance of parental stress, could be explained by the predictors in multiple linear regression models (P values < 0.05). 3.6. Relationship between parenting stress and age A regression analysis was also used to investigate whether parenting stress changes with increasing infant age in fullterm and preterm groups. The results demonstrated that there were no significant changes of parenting stress with increased age in either group (P = 0.564). That is, mothers with preterm infants continued to experience higher stress levels than those with full-term infants, and this stress neither increased nor decreased as their child got older. 3.7. Comparison of parenting stress levels between fathers and mothers in both preterm and full-term groups In order to explore any potential stress differences between mothers and father, additional analyses were conducted for both preterm and full-term groups. First, we compared parenting stress levels between fathers and mothers in the preterm group (Table 6). There were 239 mothers and 58 fathers who completed the Parenting Stress Index questionnaire. Fathers of preterm infants tended to have higher mean scores than mothers, including PSI-T, PSI-C and PSI-P, though there is no statistical significance. Higher mean scores on the child domain and parent domain subscales indicated that fathers of children with preterm history perceived their children, as well as themselves to be the source of stress, more than mothers. Fathers scored higher in all subscales of child-related stress and in the subscales of attachment and competence of parentrelated stress, while mothers have higher stress scores in the subscales of depression, health status, social isolation, role restriction and spouse support in parent-related stress. Secondly, we found that there were no significant differences between mothers and fathers in the full-term group (181 mothers and 27 fathers) when comparing mean scores of PSI-T, PSI-P, PSI-C and their subscales; except for one subscale of PSI-P: health. However, fathers of full-term infants tended to have higher mean scores than mothers in the child domain, which indicates that fathers with full-term children perceive their children as the source of stress more than mothers. On the other hand, mothers of full-term children perceived themselves as the source of stress more than the fathers did. Mothers in the full-term group experienced significantly higher stress in health, than did the fathers (no table). 4. Discussion In this study, we evaluated the levels of parenting stress in parents with preterm infants. The results failed to identify group differences between the mothers of preterm and full-term infants and the overall levels of parenting stress experienced during early infancy. However, a higher percentage of mothers with preterm infants experienced clinically significant levels of parenting stress, as compared to their full-term control counterparts. Furthermore, the mothers of preterm infants in our studied sample demonstrated more intense parenting stress in child-focused domains, indicating that mothers of preterm infants displayed many more adjustment difficulties related to their children than mothers with full-

T.-H. Howe et al. / Research in Developmental Disabilities 35 (2014) 1748–1756

1755

term infants. Our findings are consistent with previous research, that while no significant differences in overall parenting stress are found in mothers of preterm infants when compared to mothers of full-term infants, mothers with preterm infants tend to have higher levels of stress and perceived their children as the source of distress (Gray et al., 2012; Singer et al., 1999). When investigating the relationships between age and parenting stress, our results were different from previous studies. Previous studies claimed that parenting stress would decrease as infants grew older (Macey et al., 1987). Macey and her colleagues argued that early interaction between mothers and preterm infants may be less optimal than that of mothers and full-term infants; mothers of preterm infants work harder in the first few months of life to engage with their infants. As the infant matures, behaviorally and physiologically, and is able to communicate better in ways other than crying, and as mothers are given time to learn to read their baby’s signals, it is likely that some of the differences between full-term and preterm mother–infant dyads would disappear (Macey et al., 1987). However, our study found that the age of the child was not a significant predictor of stress, and that the stress levels of mothers with preterm infants did not change significantly over time. Their perceived parenting stress remained higher than mothers with full-term infants, even when their children reached two years of age. These results supported Kersting et al.’s hypothesis that the birth of a preterm infant is a complex, long-lasting traumatic event (Kersting et al., 2004). Thus, mothers of preterm infants may be confronted each day with a stressful reality while caring for their infants (Franck et al., 2005; Macey et al., 1987; Singer et al., 1999). Our results also supported Gray et al.’s findings, (Gray et al., 2013Gray et al., 2013) that parenting stress in mothers of preterm infants at one year of age, remained higher in comparison to the full-term infants and extend their findings to infants at 2 years of age. In our case, the daily stressful reality that parents are facing could be represented by infants’ feeding issues. Our study found that feeding issues perceived by the mothers of preterm infants could be one of the significant sources of parenting stress. Our study identified ‘‘parent perceived feeding issues’’ after infants had been discharged home, as the most consistent predictor of child-focused parenting stress, after controlling for demographic differences. Clinical experience suggests problematic feeding patterns might not only have a negative impact upon the physiologic and emotional health of these children but also on their parents’ physical and psychological heath (Feeley et al., 2007). Our findings have important clinical implications. Research on mothers who have preterm infants with feeding issues has focused mainly on attachment and mother–infant relationships. This study advocates the use of a validated tool such as the PSI to interpret aspects of parenting stress perceived by mothers on a routine basis. Further studies are warranted to investigate feeding issues related to preterm infants and how mothers react to the perceived feeding issues of their infants. Previous studies reported that parenting stress is related to the child’s health status. Parents with high-risk or sick preterm infants tend to score significantly higher in PSI compared to low-risk, healthy preterm or full-term infants (Gray et al., 2013). Research involving low-risk preterm infants indicated that the increased amount of distress initially experienced by the mothers, diminishes over time to levels comparable to that experienced by mothers of healthy, full-term infants (Franck et al., 2005). In our study, we demonstrated the significant differences in child-focused parenting stress levels between mothers of preterm infants and those of full-term infants over time. However, no significant differences were found within the group of preterm infants, with and without severe medical complications, using the NMI as a categorizing criterion. One possible explanation could be that our data collected from the developmental follow-up clinic for preterm infants started around the infants’ adjusted age of 6-months-old. Therefore, parenting stress was not measured during the NICU stay or right after the infant’s discharge in our study. Mothers of preterm infants might have adapted to their child’s medical complications at that point. This speculation on early interaction and parents’ stress responses needs to be studied further in the future. Carter et al., 2005 reported fathers of preterm infants experience increased depressive symptoms during their NICU stays. There has not been much information about the father’s adaptation after that period. In this study, we were able to collect responses from a small sample of fathers. Our findings demonstrated that not only do fathers experience high stress level beyond the NICU period, but also that their stress levels are comparable to mothers in both parent-related and child-related distress. While mothers of preterm infants tended to perceive themselves, the parents, as a source of stress, fathers experienced overall higher stress than mothers did. Equal levels of parenting stress reported between mothers and fathers, in both full-term and preterm groups prompts us to keep in mind that even though taking care of young children remains the primary responsibility of Taiwanese mothers (Ho et al., 2010; Hsieh and Leung, 2013), one should not assume parenting stressors are applicable only to the mothers. 5. Conclusion Investigations of parenting stress are important as they provide a framework to identify key variables that may contribute to the experience of stress. Child behavioral outcomes are known to be related to parental psychological status and coping strategies, which have been shown to be affected by a premature birth. Understanding these experiences of parents of premature children and what contributes to stress, will lead to more targeted interventions to support families, facilitate family functioning and improve child outcomes (Hayes and Watson, 2013). References Abidin, R. R. (1995). Parenting Stress Index: Professional manual, (3rd ed.). Lutz, FL: Psychological Assessment Resources. Baker, D. B. (1994). Parenting stress and ADHD: A comparison of mothers and fathers. Journal of Emotional and Behavioral Disorders, 2(1), 46–50.

1756

T.-H. Howe et al. / Research in Developmental Disabilities 35 (2014) 1748–1756

Cabral, H. J. (2008). Multiple comparisons procedures. Circulation, 117(5), 698–701. http://dx.doi.org/10.1161/CIRCULATIONAHA.107.700971 Carter, J., Mulder, R., Bartram, A., & Darlow, B. (2005). Infants in a neonatal intensive care unit: Parental response. Archives of Disease in Childhood-Fetal and Neonatal Edition, 90(2), 109–113. Directorate-General of Budget, Accounting and Statistics, Executive Yuan, Republic of China. (2013). Report on the survey of family income and expenditure, 2012, Taipei, Taiwan: Directorate-General of Budget, Accounting and Statistics, Executive Yuan, Republic of Chinahttp://win.dgbas.gov.tw/fies/doc/result/101.pdf. Retrieved from. Dudek-Shriber, L. (2004). Parent stress in the neonatal intensive care unit and the influence of parent and infant characteristics. American Journal of Occupational Therapy, 58(5), 509–520. Dudoit, S., Van Der Laan, M. J., & Pollard, K. S. (2004). Multiple testing, Part I. Single-step procedures for control of general type I error rates. Statistical Applications in Genetics and Molecular Biology, 3(1), 1–69. http://dx.doi.org/10.2202/1544-6115.1040 Feeley, N., Gottlieb, L., & Zelkowitz, P. (2007). Mothers and fathers of very low-birthweight infants: Similarities and differences in the first year after birth. Journal of Obstetric, Gynecologic, and Neonatal Nursing, 36(6), 558–567. Franck, L. S., Cox, S., Allen, A., & Winter, I. (2005). Measuring neonatal intensive care unit-related parental stress. Journal of Advanced Nursing, 49(6), 608–615. Gray, P. H., Edwards, D. M., O’Callaghan, M. J., & Cuskelly, M. (2012). Parenting stress in mothers of preterm infants during early infancy. Early Human Development, 88(1), 45–49. http://dx.doi.org/10.1016/j.earlhumdev.2011.06.014 Gray, P. H., Edwards, D. M., O’Callaghan, M. J., Cuskelly, M., & Gibbons, K. (2013). Parenting stress in mothers of very preterm infants – Influence of development, temperament and maternal depression. Early Human Development, 89(9), 625–629. http://dx.doi.org/10.1016/j.earlhumdev.2013.04.005 Halpern, L. F., Brand, K. L., & Malone, A. F. (2001). Parenting stress in mothers of very-low-birth-weight (VLBW) and full-term infants: A function of infant behavioral characteristics and child-rearing attitudes. Journal of Pediatric Psychology, 26(2), 93–104. Hawdon, J. M., Beauregard, N., Slattery, J., & Kennedy, G. (2000). Identification of neonates at risk of developing feeding problems in infancy. Developmental Medicine and Child Neurology, 42, 235–239. Hayes, S. A., & Watson, S. L. (2013). The impact of parenting stress: A meta-analysis of studies comparing the experience of parenting stress in parents of children with and without autism spectrum disorder. Journal of Autism and Developmental Disorders, 43(3), 629–642. Ho, H.-Z., Chen, W.-W., Tran, C. N., & Ko, C.-T. (2010). Parental involvement in Taiwanese families: Father–mother differences. Childhood Education, 86(6), 376–381. Holditch-Davis, D., Bartlett, T. R., Blickman, A. L., & Miles, M. S. (2003). Posttraumatic stress symptoms in mothers of premature infants. Journal of Obstetric, Gynecologic, and Neonatal Nursing, 32(2), 161–171. http://dx.doi.org/10.1177/0884217503252035 Howe, T.-H., & Ho, S.-H. (2009). Development of a behavior-based feeding questionnaire for infants with premature history. Journal of Occupational Therapy, Schools and Early Intervention, 2(3), 150–158. http://dx.doi.org/10.1080/19411240903392368 Howe, T.-H., Hsu, C.-H., & Tsai, M.-W. (2010). Prevalence of feeding related issues/difficulties in Taiwanese children with history of prematurity, 2003–2006. Research in Developmental Disabilities, 31(2), 510–516. Hsieh, M.-O., & Leung, P. (2013). Attitudinal and behavioral indicators influencing employment decisions among married and single mothers in Taipei, Taiwan. International Social Work, 0(0), 1–25. http://dx.doi.org/10.1177/0020872812461045 Kaaresen, P. I., Rønning, J. A., Ulvund, S. E., & Dahl, L. B. (2006). A randomized, controlled trial of the effectiveness of an early-intervention program in reducing parenting stress after preterm birth. Pediatrics, 118(1), 9–19. Kersting, A., Dorsch, M., Wesselmann, U., Lu¨dorff, K., Witthaut, J., Ohrmann, P., et al. (2004). Maternal posttraumatic stress response after the birth of a very lowbirth-weight infant. Journal of Psychosomatic Research, 57(5), 473–476. Korner, A. F., Stevenson, D. K., Forrest, T., Constantinou, J., Dimiceli, S., & Brown, B. W. (1994). Preterm medical complications differentially affect neurobehavioral functions: Results from a new Neonatal Medical Index. Infant Behavior and Development, 17, 37–43. Korner, A. F., Stevenson, D. K., Kraemer, H. C., Spiker, D., Scott, D. T., Constantinou, J., et al. (1993). Prediction of the development of low birth weight preterm infants by a new Neonatal Medical Index. Journal of Developmental and Behavioral Pediatrics, 14(2), 106–111. Macey, T. J., Harmon, R. J., & Easterbrooks, M. (1987). Impact of premature birth on the development of the infant in the family. Journal of Consulting and Clinical Psychology, 55(6), 846–852. Rommel, N., De Meyer, A., Feenstra, L., & Veereman-Wauters, G. (2003). The complexity of feeding problems in infants and young children presenting to a tertiary care institution. Journal of Pediatric Gastroenterology and Nutrition, 37, 75–84. Singer, L. T., Salvator, A., Guo, S., Collin, M., Lilien, L., & Baley, J. (1999). Maternal psychological distress and parenting stress after the birth of a very low-birthweight infant. JAMA: The Journal of the American Medical Association, 281(9), 799–805. Tam, K. K., Chan, Y. C., & Wong, C. K. M. (2006). Validation of the Parenting Stress Index among Chinese mothers in Hong Kong. Journal of Community Psychology, 22(3), 211–223. Thoyre, S. M. (2007). Feeding outcomes of extremely premature infants after neonatal care. Journal of Obstetric, Gynecologic, and Neonatal Nursing, 36(4), 366–375. http://dx.doi.org/10.1111/j. 1552-6909.2007.00158.x. quiz 376, PII: JOGN158 ¨ stberg, M., & Fellman, V. (2002). Parental stress in families of 2 year old extremely low birthweight infants. Archives of Disease in Childhood-Fetal Tommiska, V., O and Neonatal Edition, 86(3), 161–164. Westfall, P. H., Tobias, R. D., & Wolfinger, R. D. (2011). Multiple comparisons and multiple tests using SAS, SAS Institute. Yeh, C. H., Chen, M. L., Li, W., & Chuang, H. L. (2001). The Chinese version of the Parenting Stress Index: A psychometric study. Acta Paediatrica, 90(12), 1470–1477.