Comparison of nutrient intake, life style variables, and pregnancy outcomes by the depression degree of pregnant women

Pregnant women have been exposed to depression during pregnancy not only because of physical changes due to pregnancy but also because of changes of roles, emotion, and psycho-social characteristics [1]. Kwon [2] supported the stress-vulnerability model of high-risk pregnant women for depression. It has been suggested that risk factors associated with depression during pregnancy include socioeconomic level, occupation, and age of pregnant women [2], and it also has been reported that the mental stress and depression during pregnancy affect the delivery of low birth weight [1] or postpartum delivery [3]. In the study of Kim and Lee [4], factors inducing stress during pregnancy included anxiety for baby, anxiety for health, economic difficulties, depressive feeling, and family relations, and less stress was observed in case of having occupation and more stress in case of larger family size. In addition, higher intakes of energy, fat, phosphorus, potassium, and cholesterol increased the risk for the incidence of pregnancy stress while the intakes of proteins, carbohydrates, dietary fiber, and vitamin B2 decreased the risk for stress. Higher pregnancy stress was observed in pregnant women with higher educational level, and higher stress for physical symptoms of pregnant women and for fatal health were observed in pregnant women with occupation [5]. Park and Lee [6] reported that pregnant women under lots of stress have higher risk for gestational hypertension and pernicious vomiting of pregnancy, and higher stress negatively affected maternal weight gain.

Bodnar et al. [7] observed the positive correlation between BMI and depression during pregnancy, and reported that this affected gestational weight gain. Also, pre-pregnancy overweight has been reported to have a strong correlation with the possibility for depression. In a study of women with the experience of abortion, the subjects underwent very stressful daily life during 3 months before abortion and experienced social difficulties [8], and negatively stressful life events were reported as being related to spontaneous abortion [9]. Also, the administration of ω-3 fatty acid to pregnant women with depression, aged 18~40 years, at 16~32 weeks of pregnancy decreased BDI (Beck Depression Inventory), HAM-D (Hamilton Rating Scale for Depression), and EPDS (Edinburgh Postnatal Depression Scale) [10]. On the other hand, several studies on the relationship among daily life stress, risk of preterm delivery, and short gestational period during 16~30 weeks of pregnancy showed that there is no consistent results on the effect of psychosocial stress on preterm delivery and gestational period [11]. Although the risk of stress and depression during pregnancy has been suggested, there are not enough studies done yet on depression and dietary intakes in pregnant women in the country. Therefore, this study was performed to compare socio-cultural factors, nutrient intake, and pregnancy outcome of pregnant women, according to degree of depression and to prevent depression during pregnancy and to utilize the results as basic data for maternal infant nutrition research.

This study was performed to investigate the differences in the lifestyle, nutrient intakes, iron nutrition indices, and pregnancy outcome in pregnant women depending on the depression score. Depression score was significantly different by the number of pregnancy (P < 0.05), showing lower depression score in primipara and higher score in multipara. Hong and Kim [5] reported that pregnant women with occupation had higher stress for physical symptoms of pregnant women and for fetal health, which is rather different from the results in this study.

The lifestyles of pregnant women were not significantly different, but LS group tended to have more women practicing exercise than HS group. The frequency of exercise was also higher in LS group than in HS group. This is similar to the results of Kim and Lee [4] in which the group with less stress during pregnancy practiced light activities and regular exercise than the group with higher stress. Also, a study of pregnant women in Daegu area [12] reported that primipara group exercised more regularly than multipara group, suggesting that primipara group exercises regularly with less stress during pregnancy. Bovbjerg et al. [13] reported that exercise during pregnancy reduced the risk for Cesarean section. It is thought that proper exercise can relieve the stress in pregnant women and lead to desirable pregnancy outcomes. Pre-pregnancy alcohol intake was higher in HS group with higher frequency too (P < 0.05). Sayal [14] in England reported that more than 4 glasses/day alcohol intake in pregnant women increased the risk for fetal behavior and mental health, and that daily drinking before pregnancy increased the risk for hyperactivity and attention deficit. Also, Yang et al. [15] observed that alcohol intake during pregnancy strongly affected abruption placenta (premature separation of placenta). There were no pregnant women who drank alcohol during pregnancy among the subjects in this study but pre-pregnancy drinking frequency was higher in HS group, and thus it is necessary to provide nutrition education and promotion for the lifestyle of not drinking alcohol during pregnancy.

In case of coffee intake frequency, the pre-pregnancy coffee intake ratio was significantly higher in HS group (P < 0.01). In the study on the risk for neural tube damage in pregnant women and their infants with caffeine intake [16], the risk for spina bifida in infants was increased in the group of pregnant women who had more than 10 mg/day caffeine through coffee, tea, soda beverages or chocolate before pregnancy. Thus it is noticeable that pre-pregnancy lifestyle of pregnant women can influence the emotional state of pregnant women and lead to undesirable pregnancy outcomes.

The average daily energy intake of the subjects in this study was 1840.81 ± 774.5 kcal, which is 97~80% of 1,900~2,350 kcal, the EER for pregnant woman in KDRIs (Dietary Reference Intakes for Koreans) [17]. Protein intake was 149% KDRIs (EAR) in LS group and 125% KDRIs in HS group, and most nutrients except vitamin A and sodium tended to have higher intake in LS group compared to HS group. This is similar to the results that energy and protein intakes were higher in low-stress group than in high-stress group [18]. Kim and Lee [4] reported that nutrient intakes were similar in both low-stress group and high-stress group. Total calcium, plant calcium, plant iron, potassium, total folate and dietary folate intakes were significantly higher in LS group than in HS group, respectively (P < 0.05, P < 0.05, P < 0.01, P < 0.001, P < 0.05, P < 0.01), but total calcium & total folate intakes of both groups were under the EAR of the KDRIs. Choi et al. [19] studied the relationship between stress by trimester and nutrient intakes and reported that potassium and vegetable calcium intakes in the early pregnancy were decreased as stress became higher, which is similar to our results. Also, birth weight of infants from pregnant women with stress was lower than that without stress, and apgar score was also lower in the group with stress than that without stress. Czeizel et al. [20] reported that the administration of 0.8 mg/day folate starting from one month before pregnancy reduced the risk for congenital cardiac anomalies and neural tube defects in infants. Also in the study on the intakes of vegetables, fruits, and vegetable oils in pregnant women and the risk for toxemia [21], the higher intake of vegetables reduced the risk for toxemia.

The analysis for iron nutrition indices in pregnant women showed that all values except RBC, HGB, and HCT were in the normal range and no significant differences were observed between LS group and HS group. HGB was 11.75 ± 1.27 g/dl in LS group and 11.34 ± 1.24 g/dl in HS group, and HCT was 34.87 ± 3.5% in LS group and 33.63 ± 3.76% in HS group. These are lower than the normal ranges of HGB and HCT in female adults, 11.5~16.9 g/dl and 36~46%, respectively, but not the level of anemia by WHO criteria, HGB < 11.0 g/dl and HCT < 33.0%, for anemia in pregnant women [22].

For pregnancy outcome, no significant differences in birth weight, birth length, apgar score, total maternal weight gain, and gestational period were observed between two groups. In case of delivery type, the ratio for Cesarean section was significantly higher in HS group compared to LS group (P < 0.01). Liston et al. [23] observed that Cesarean section, when compared to normal spontaneous vaginal delivery, increased the hypo-function and risk for respiratory condition at birth and thus increased the risk for respiratory distress syndrome and transient tachpnoea of the newborn. That is, the possibility for Cesarean section can be increased in pregnant women with higher depression score and affect negatively on pregnancy outcomes. In this study, the gestational period was analyzed as a significantly influential factor on birth weight (P < 0.01).

In the study on the birth weight changes of normal birth in the past 5 years in Korea [24], the average birth weight per gestational period was decreased in the order of 37 weeks, 38 weeks, and 39 weeks and the decrement became smaller as the gestational age increased, suggesting that the maintenance of normal gestational period is important for desirable pregnancy outcomes.

Hedegaard et al. [11] in Denmark reported that the living environment that induced higher stress increased the risk for short gestational period and preterm delivery. Bae [25] also reported lower birth weight from shorter gestational periods, and Maconochie et al. [26] reported that the stress was one of the causes of miscarriage and could be reduced by taking vitamin supplements and eating fresh fruits and vegetables everyday. Thus it is considered that proper lifestyle management including nutritional management is needed for pregnant women because the living environment of a pregnant woman can affect negatively on pregnancy outcome in relation to stress.

The analysis of factors for affecting delivery type in this study showed that only depression score had significant differences (P < 0.01). Olusanya and Solanke [27] reported that delivery type was related to age, occupation, social status, number of pregnancy, and income level, and emergency Cesarean section had apgar score at 5 minutes of less than 7 points and special protective care was needed for infants. Thus it is suggested that the risk for Cesarean section became lower as the depression score decreased (Odds ratio: 0.22, 95% CI; 0.07~0.7).

In this study, LS group tended to have higher exercise frequency compared to HS group, and proper exercise during pregnancy decreased the risk for Cesarean section. In addition, LS group showed lower alcohol and coffee intakes compared to HS group, suggesting the relationship between the lifestyle of pregnant women and desirable pregnancy outcomes. Like this, HS group showed fewer exercise frequency during pregnancy and higher intakes of alcohol and coffee before pregnancy compared to LS group. That is, higher depression score was related to undesirable lifestyle and highly related to negative pregnancy outcomes such as Cesarean section.

Therefore, it is thought that the degree of depression during pregnancy can have important influence on pregnancy outcome. By considering the recent reality of higher childbearing age and lower birth rate faced by our society, it is more important than anything to educate pregnant women and promote proper lifestyle during pregnancy to induce desirable pregnancy outcome, in the aspect of ensuring better human resources.