1. Introduction
Preterm labor is defined as regular uterine contractions, which result in changes in cervical length before 37 weeks of pregnancy (1). An estimated 15 million preterm births occur each year worldwide, with a global preterm birth rate of 11.1% (among 184 countries). While more than 60% of these preterm births occur in Sub-Saharan Africa and South Asia, preterm labor remains a significant problem in developed countries. Preterm birth rates remain as high as 9% and above for upper middle- and high-income countries. Preterm birth rose from 10.6% in 1990 to a peak rate of 12.8% in 2006 in the United States; however, this rate declined to 11.39% in 2013. Preterm delivery is an important cause of mortality in infants, with the frequency of 5 - 11% (2-5). A worldwide study reported a rising trend in preterm birth during the past decades (6). Complications of preterm birth can cause permanent disability in the survivors (5). On the other hand, increased rate of preterm delivery poses a significant economic burden on the society (6). Psychological disorders during pregnancy are important predicting factors of birth weight and gestational age, and can lead to preterm delivery (7, 8). Some mechanisms for this include: (1) unhealthy coping and life style behavior; (2) stress-dependent hormones; and (3) psycho-immunological factors (9).
Pregnancy affects mothers physically and mentally (10-12). Mental complications of pregnancy include depression, anxiety disorders, and postpartum psychosis. The prevalence of perinatal major and minor depression is up to 20% (13, 14). Compared to the physical aspect, fewer studies have evaluated the psychological aspect of preterm delivery and its effects on pregnancy outcome. In this study, we compared the prevalence of psychological disorders among women with spontaneous preterm versus term delivery.
2. Materials and Methods
In this cross- sectional study, 60 women with spontaneous term delivery and 60 women with spontaneous preterm delivery (gestational age of less than 37 weeks), who referred to Shahid Akbarabadi teaching hospital from April to October 2014 were recruited. The prevalence of psychiatric disorders was compared between the two groups. All participants provided a written informed consent. The ethics committee of Iran University of Medical Sciences approved the study protocol. We provided an informed consent about the aims to the participants. The data file remained anonymous, and the identity of the participants was protected. The inclusion criteria were as follows: Singleton pregnancy, intact membranes at the time of admission, and normal vaginal delivery. The exclusion criteria were incomplete medical documents, history of discharge or symptoms of infection, intrauterine fetal death, and mothers who needed intensive care. To assess the psychological health of the mothers, we asked them to complete the validated Persian version of the questionnaire 12 to 24 hours post-delivery. Literate women filled out the form individually, whereas in the case of illiterate women, another educated person, who accompanied the mother, filled it out. The symptom checklist-90-revised (SCL-90-R) questionnaire has 90 items and nine subscales that measure somatization, obsessive-compulsive, depression, anxiety, phobic anxiety, hostility, interpersonal sensitivity, paranoid ideation, and psychoticism. Score rating is based on a five-point scale and evaluates the individual mental status during the last week (0 = none, 1 = a little, 2 = to some extent, 3 = much, 4 = very much) (Blacker, 2000). Total scores from 90 to 200 represent a significant mental health problem and a need to visit a psychiatrist, and scores more than 200 represent a serious mental health problem, including psychotic and mood disorders. Scores on each of the nine subscales, which are less than 2.5, represent the absence of a disorder; scores from 2.5 to 3 represent the presence of a disorder; and scores higher than 3 represent the presence of a serious disorder. In 1994, Bagheri Yazdi et al. evaluated the reliability and validity of SCL-90-R test, and found that it could successfully be used as a screening tool in studies. Possible confounders, including: height, weight before pregnancy, mother’s birth weight, marital status, and health behavior (smoking, diet, intake of alcohol during pregnancy), were identified from background data and were matched between the two groups.
2.1. Statistical Analysis
The obtained data were entered into SPSS software version 17 (IBM; Chicago, IL, USA). Mean and standard deviation (SD) were used to describe numerical variables, and relative frequency percentage was used to describe the nominal or categorical variables. Chi 2 test was employed to compare qualitative outcomes between the two groups, and independent t-test was utilized to compare the quantitative outcomes between the two groups.
3. Results
In this study, we studied 120 women: 60 women with spontaneous preterm delivery and 60 with spontaneous term delivery. The mean age of women with preterm delivery was 23.58 ( ± 4.26), and it was 23.90 ( ± 4.71) in women with term delivery, which was not significantly different (P value = 0.22), (Table 1). The mean score of SCL-90-R in women with preterm delivery was 102.21 ( ± 35.81), and it was 59.14 ( ± 22.17) in women with term delivery, which was significantly different (P value < 0.001). The mean scores for each subscale were 2.5 or less in the two groups, but it was significantly higher in the preterm delivery group (P value < 0.03). The mean score of all the nine subscales was higher in the preterm-delivery group. Table 2 demonstrates a summary of the mean score of each of the nine subscales in the two groups. Mental health disorders were only observed in preterm delivery group. Table 3 presents a summary of mental health disorders in the preterm delivery group.
Table 1. Demographic Data
| Term Delivery (%), n = 60 | Preterm Delivery (%), n = 60 | P Value | |
|---|---|---|---|
| Job | 0.083 | ||
| House keeper | 71.7 | 75 | |
| Worker | 28.3 | 25 | |
| Education | 0.075 | ||
| Illiterate | 9.7 | 10.3 | |
| Primary school | 23.6 | 26.4 | |
| Diploma | 45 | 38.3 | |
| Higher levels | 21.7 | 25 | |
| Family income ($) | 0.764 | ||
| Less than 815.66 | 65 | 66.7 | |
| 815.66 - 1631.32 | 21.7 | 25 | |
| More than 1631.32 | 13.3 | 8.3 |
Table 2. The Mean Score of Each of the Nine Subscales in the Two Study Groups
| Delivery | Lowest Score | Highest Score | Mean | SD | P Value | |
|---|---|---|---|---|---|---|
| Psychosis | Preterm | 0.00 | 2.50 | 0.9633 | 0.61671 | < 0.001 |
| Term | 0.00 | 1.50 | 0.5383 | 0.51719 | ||
| Obsessive compulsive | Preterm | 0.00 | 2.50 | 1.0167 | 0.64733 | < 0.001 |
| Term | 0.00 | 1.30 | 0.5683 | 0.43628 | ||
| Paranoid ideation | Preterm | 0.00 | 2.50 | 0.8367 | 0.65146 | < 0.001 |
| Term | 0.00 | 1.40 | 0.6083 | 0.47561 | ||
| Anxiety | Preterm | 0.10 | 2.20 | 1.0733 | 0.56143 | 0.03 |
| Term | 0.00 | 1.90 | 0.5667 | 0.55040 | ||
| Interpersonal sensitivity | Preterm | 0.00 | 2.50 | 1.0517 | 0.59674 | < 0.001 |
| Term | 0.00 | 1.40 | 0.6550 | 0.49143 | ||
| Phobic anxiety | Preterm | 0.00 | 2.20 | 1.1150 | 0.63535 | < 0.001 |
| Term | 0.00 | 1.70 | 0.7333 | 0.50107 | ||
| Hostility | Preterm | 0.00 | 2.20 | 1.0983 | 0.58324 | < 0.001 |
| Term | 0.00 | 1.40 | 0.4700 | 0.48966 | ||
| Somatization | Preterm | 0.00 | 1.30 | 0.5767 | 0.56789 | < 0.001 |
| Term | 0.00 | 1.10 | 0.4987 | 0.48757 | ||
| Depression | Preterm | 0.00 | 1.40 | 1.017 | 0.65479 | < 0.001 |
| Term | 0.00 | 1.10 | 0.8768 | 0.79865 | ||
| Total score | Preterm | 18.57 | 187.14 | 102.2143 | 35.81673 | < 0.001 |
| Term | 10.00 | 108.57 | 59.1429 | 22.17692 | ||
| Global severity index (GSI) | Preterm | - | - | 67.41 | 13.41 | < 0.001 |
| Term | - | - | 50.46 | 8.94 | ||
| Positive symptom distress index (PST) | Preterm | - | - | 22.59 | 13.21 | < 0.001 |
| Term | - | - | 39.54 | 8.94 | ||
| The positive symptom distress Index (PSDI) | Preterm | - | - | 2.43 | 1.04 | < 0.001 |
| Term | - | - | 1.27 | 0.57 |
Table 3. Distribution of Mental Health Disorders in the Preterm and Term Delivery Groups
| Groups | N = 120 | ||
|---|---|---|---|
| Psychosis | Preterm | Yes | 2 (3.3 %) |
| No | 58 (96.7%) | ||
| Term | Yes | 0 (0%) | |
| No | 60 (100%) | ||
| Obsessive compulsive | Preterm | Yes | 1 (1.7 %) |
| No | 59 (98.7 %) | ||
| Term | Yes | 0 (0 %) | |
| No | 60 (100%) | ||
| Paranoid ideation | Preterm | Yes | 2 (3.3%) |
| No | 58 (96.7%) | ||
| Term | Yes | 0 (0%) | |
| No | 60 (100%) | ||
| Anxiety | Preterm | Yes | 0 (0%) |
| No | 60 (100%) | ||
| Term | Yes | 0 (0%) | |
| No | 60 (100%) | ||
| Interpersonal sensitivity | Preterm | Yes | 1 (1.7%) |
| No | 59 (98.7 %) | ||
| Term | Yes | 0 (0 %) | |
| No | 60 (100%) | ||
| Phobic anxiety | Preterm | Yes | 0 (0%) |
| No | 60 (100%) | ||
| Term | Yes | 0 (0%) | |
| No | 60 (100%) | ||
| Hostility | Preterm | Yes | 0 (0%) |
| No | 60 (100%) | ||
| Term | Yes | 0 (0%) | |
| No | 60 (100%) | ||
| Somatization | Preterm | Yes | 0 (0%) |
| No | 60 (100%) | ||
| Term | Yes | 0 (0%) | |
| No | 60 (100%) | ||
| Depression | Preterm | Yes | 0 (0%) |
| No | 60 (100%) | ||
| Term | Yes | 0 (0%) | |
| No | 60 (100%) | ||
4. Discussion
In this study, women with spontaneous preterm delivery had significantly higher scores in all the subscales of the SCL-90-R questionnaire. Bjelanovic et al. reached the same result, using this questionnaire (15). Several studies examined the role of stress on preterm delivery and found that the frequency of preterm delivery increases when more events happen in daily lives of the expecting mothers (16, 17). Some studies on depression and frequency of preterm delivery did not detect any significant relationship (18, 19). Gorsuch et al. and Molfese et al. found a significant relationship between anxiety and frequency of preterm delivery, while some other researchers (19, 20) failed to find such a relationship (20-23). We found a significant association between anxiety (one of the nine subscales) and preterm delivery. Women with spontaneous preterm delivery had higher scores of anxiety. Anxiety and its subsequent psychological response can affect gestational age. Most studies found a significant positive relationship between psychological disorders and the incidence of preterm delivery (24, 25). This could be due to the higher prevalence of cigarette, alcohol and drug use among women with psychological disorders, which affects the age of delivery. In this study, 1 - 2% of women with spontaneous preterm delivery had impairment in four categories of psychosis, paranoia, obsessive-compulsive, and interpersonal sensitivity. Other categories had normal scores similar to women with term delivery. Most of the studies evaluated psychological disorders by means of history taking and based on patients’ explanation. In this study, we used SCL-70-R questionnaire, which is an accurate scale that evaluates psychological disorders in nine different categories. These findings suggest that by reducing stress and psychological distress and through improving social support, it may be possible to enhance the quality of life of these patients.
4.1. Conclusion
Psychological disorders in pregnancy are associated with an increased risk of preterm delivery. Future studies should focus on finding ways to lower psychological disorders in late pregnancy. In addition, psychological disorders were higher in women with spontaneous preterm delivery at any level compared to those with term delivery. Therefore, to prevent adverse outcomes, special care should be provided to those women with psychological disorders. Moreover, proper screening programs and treatment regimens should be designed and implemented to decrease the risk of preterm labor.
