Participants
Medically low risk women, who participated in a randomized controlled trial of supplementary prenatal care between April 2001 and July 2004 and agreed to future research, were invited to participate in this follow-up study. Low medical risk referred to women who did not require prenatal care from an obstetrician, and had an uncomplicated pregnancy such that specialist care for fetal or maternal complications was not required. Pregnant women who sought services provided by family physicians at one of three participating Calgary maternity clinics were included in the study. Women were excluded from the study if they were under the age of 18 (due to ethical issues associated with confidentiality and informed consent), had not completed the baseline study prior to their first appointment with the clinic, did not plan to attend the clinic at the time of the first recruitment call, lived outside the Calgary Health Region, were not pregnant, or could not communicate to study interviewers or translators in one of seven languages (English, French, Cantonese, Mandarin, Punjabi, Urdu, or Arabic dialects) (Figure 1).
In the original trial, women who participated were randomized to: (1) current standard of prenatal care; (2) standard of care plus support from a nurse; or (3) standard of care plus support from a nurse and home visitor. Study participants completed 3 computer-assisted telephone interviews over the perinatal period (first trimester, 32–34 weeks gestation, and 8 weeks post delivery). Data on demographics, lifestyle, psychosocial health, resource utilization, network orientation, and history of abuse and neglect were collected. Of the 2,556 women who were eligible for the study, 1,737 (68%) agreed to participate and completed the first questionnaire. Of those who agreed to participate, 78 percent (1,352/1,737) completed all three questionnaires. Non-completion rates did not differ by study group, but women who did not complete the study tended to be younger, non-Caucasian and had lower education than those who completed the study. Demographic and lifestyle characteristics did not differ by study group. Overall, 75 percent of women in the study were of Caucasian ethnicity and 73 percent of women had some college or university level education. A full description of the randomized controlled trial and results are reported elsewhere [20].
In this follow-up study, mothers were contacted by telephone (using their most recent contact information) when their child was approximately three years old, and they were invited to complete a telephone questionnaire. Before completing the questionnaire, respondents were informed by the interviewers that their participation was voluntary, that their responses would be linked to the original trial data, and that information would be kept confidential. Women who miscarried, did not speak English, did not reside in the city of Calgary any longer, or who had an incorrect phone number were excluded. The follow-up study was launched on November 30, 2005 and was completed on March 27, 2006. The study received ethical approval from the Conjoint Medical Bioethics Committee of the University of Calgary and Calgary Health Region.
Questionnaire
The telephone questionnaire took approximately 15–20 minutes to complete and included information on child health and medical care, child development, child care, mother's demographics and lifestyle, mother's emotional and physical well-being, and parenting style. Items were generated by the research team in consultation with community partners over a 6 month period at monthly meetings to address the research question and to ensure potential covariates were considered (eg. access to physician services, child care). If an identified construct could be assessed with standardized tools (eg. child development, parenting, social support, detailed below), the research team reviewed and considered appropriate tools and made decisions by consensus. Criteria for tool selection included the psychometric properties of the scale, reading level and length.
The questionnaire was pilot tested with 20 mothers to assess the length, flow, and comprehension. The questionnaire was revised and shortened based on comments from the pilot test as well as expert consultations. Expert consultants included those with backgrounds in: early child development, speech language development, community service delivery, nursing, social work, epidemiology, survey development, biostatistics, and parenting.
Outcome Measure
The Parents' Evaluation of Developmental Status (PEDS) was used to screen infants for risk of developmental and/or behavioral problems [21]. The PEDS can be used from birth to 8 years of age and is written at a grade 4 to 5 reading level. Validity and reliability has been determined through assessment of more than 771 children in various settings across the US including physician offices, outpatient clinics, day care centers, and schools. In addition, the PEDS has been standardized on 2823 families from a range of economic and ethnic backgrounds.
The PEDS is a 10 item parent report screening measure designed to facilitate parent-professional communication about development and to increase the probability that developmental and behavioral problems in children, birth to 8 years of age, are detected and addressed. This is accomplished by eliciting parental concerns, determining a child's level of risk for problems, and identifying the appropriate next steps. The PEDS classifies children into one of five categories or 'Paths' based on parents' report of concerns: (A) multiple significant concerns are present that are predictive of disability (high risk); (B) one significant concern is present that is predictive of disability (moderate risk); (C) nonsignificant concerns are present that are not predictive of disability but there is elevated risk for behavioral problems (including mental health problems) because of disruption of family functioning, parent-child conflict and/or disciplinary problems (moderate – low risk); (D) parents have problems communicating (moderate risk); or (E) no concerns are present (extremely low – no risk). The PEDS has a sensitivity and specificity that ranges between 70% and 80%, and these percentages increase with repeated administration [21].
Independent Variables
Potential covariates of interest were grouped into four categories: child characteristics, home environment, sociodemographic factors, and pregnancy-related variables.
Child Characteristics
Child health status was based on maternal report (excellent, good, fair, poor, or terrible) and on change in the child's health compared to 1 year ago (about the same, better, or worse). Caregivers reported on health care utilization, routine health examinations, immunizations, having a family doctor, chronic conditions, vision and hearing problems, and referrals.
Home Environment Characteristics
Maternal physical and emotional health status was based on self report (excellent, good, fair, poor, or terrible) [22]. Questions about abuse, social support, and relationship with a partner were asked. Information about parenting was collected and included parenting morale, which was assessed using the Parenting Morale Index [23], and parenting style, which was assessed using two subscales of the National Longitudinal Survey of Children and Youth (hostile/ineffective and aversion) [24].
Sociodemographic Factors
Self-reported information on marital status, education, annual household income, ethnicity, and lifestyle factors (smoking, alcohol, drug use) was collected.
Pregnancy-Related Variables
Several variables measured during the original randomized controlled trial were included in this analysis, including the Kellner Symptom Questionnaire [25], Rosenberg Self Esteem [26], McCubbin Social Support Index [27], Woman Abuse Screening Tool (WAST) [28], Edinburgh Postnatal Depression Scale [29] and Vaux Network Orientation Scale [30].
Statistical Analysis
Data collected from the follow-up study were linked to data from both the original randomized controlled trial using unique research identifiers (to include pregnancy-related variables in the analysis) and to provincial perinatal records (to obtain the most accurate estimate of gestational age of the infant at birth). This resulted in data for mothers at four time points from their first trimester to 3 years post partum.
Bivariate comparisons between the PEDS path and independent variables in the four categories of interest were conducted using a chi-squared test. A multinomial logistic regression model was constructed to explore the relationship between risk of developmental problems and factors associated with this risk, yielding odds ratios and 95% confidence intervals. Statistical significance was set at p < 0.05 for bivariate analyses and was also the criteria for considering variables for regression modeling along with known confounders. Selected predicted probabilities for screening in each PEDS path were also calculated. All statistical analyses were performed using Stata 9/SE version 9.2.