Pregnancy is an important life experience for all mothers. As a susceptible group to anxiety, pregnant women are more likely to induce prenatal anxiety when their neuroticism or mental level is too high during pregnancy, and thus produce negative coping styles and lead to psychological damage[17]. The neurophysiological pathogenesis of prenatal anxiety remains unclear. Studies have shown that persistently high estrogen levels during pregnancy can attenuate the number and function of S-HT1A receptors and increase the number of S-HT2A receptors, which in turn can lead to prenatal anxiety[18]. Secondly, fluctuations in neurohormone levels can cause mood changes in pregnant women during pregnancy[19]. In addition, increased release of adrenocorticotropic hormone and plasma cortisol during pregnancy and inhibition of central norepinephrine synthesis may induce prenatal anxiety. However, prenatal anxiety often causes fear of childbirth[20].
Fear of childbirth has been reported to affect the mode of delivery[21, 22]. The possible reason for this is that many women are full of fear of the pain caused by childbirth, they are not confident in their ability to handle the labor process, and they will want to escape the pain of childbirth. Many pregnant women will worry about some birth accidents during childbirth, will be afraid of switching to emergency cesarean section due to the failure of vaginal delivery, and will be afraid of damage to themselves and the fetus due to childbirth, so they will choose elective cesarean section to terminate the pregnancy[21]. The possible reason for some emergency cesarean section is that the fear of childbirth felt by pregnant women will make certain changes in the internal environment of the uterus, so that the secretion of adrenaline in pregnant women will increase, which will lead to metabolic acidosis in pregnant women, and cause intrauterine hypoxia in the fetus, and at the same time will lead to neurological disorders in pregnant women, and uterine atony will occur during childbirth and cause dystocia[23, 24]. In addition, pregnant women with prenatal anxiety often have poor sleep and appetite, and cannot get enough rest and adequate nutrition, which will also affect the delivery situation, and in severe cases, it will cause fetal delay during delivery, thereby increasing the incidence of emergency cesarean section[25].
Fear of childbirth is often accompanied by feelings of anxiety[26]. Severe anxiety can lead to physical symptoms and sleep problems such as difficulty falling asleep and waking up early. Long-term poor sleep will reduce the vitality of pregnant women, and frequent nocturia and other problems will make it difficult to maintain uninterrupted sleep at night, affecting physical recovery, resulting in a series of physical symptoms such as body pain, numbness, and fatigue[27, 28, 29]. Studies have shown a high correlation between fear of childbirth and physical symptoms[30]. Somatic symptoms are a condition in which a patient feels unwell and cannot explain the symptoms after a series of tests. In this study, the term somatic symptoms are non-specific somatic symptoms and have the same connotation as functional somatic discomfort, somatic discomfort disorder, functional somatic symptoms, and somatic symptom disorder. Severe or long-term physical symptoms may cause distress or stress to the pregnant woman[31], which can affect the outcome of childbirth. The results of this study also imply this important information. The results of this study suggest that PHQ-15 score has a strong correlation with pregnancy outcomes. Early detection and prevention of maternal fear of childbirth are of great significance for improving pregnancy outcomes. Fear of childbirth is often difficult to detect and diagnose as a change in the psychological state of pregnant women during pregnancy, and the PHQ-15 questionnaire used in this study is expected to be an effective tool for early detection and early diagnosis.
In this study, multiple linear regression analysis showed that family economic pressure, family relationship status, mother-in-law and daughter-in-law relationship, and pregnant women's own personality were correlated with PHQ-15 questionnaire scores. It has been reported that family economic pressure[32], family relationship status[33], and mother-in-law and daughter-in-law relationship[32] will affect the sleep quality of pregnant women, thereby affecting prenatal depression. That is in line with the results of this study. Financial stress has a global impact on a woman's mood and sleep during pregnancy. Raising children can bring new challenges to low-income families, causing worries about the future, resulting in bad moods and poor sleep quality. Pregnant women who understand social support, especially family support, and improve marital happiness are protective factors for prenatal depression. The study found that good family relationships were significantly lower than bad family relationships in pregnant women with antenatal depression[34]. Drastic changes in hormone levels during pregnancy increase emotional sensitivity in pregnant women. The results of the study not only suggest that pregnant women need to actively pay attention to their own psychological conditions, and that their partners and families need to be patient and companionship, but also remind women to pay attention to the quality of family relationships when choosing marriage. The personality of pregnant women may affect the different subjective feelings and environmental interactions of pregnant women towards the family environment. Good psychological counseling before childbirth can improve the depression, anxiety and physical health of pregnant women[35]. Other contributing factors to somatic symptoms include continued work after pregnancy. Pregnant women who continued to work after pregnancy scored lower somatic symptoms than those who took leave or quit their jobs after pregnancy, probably because work diverted tension during pregnancy, which also reflected the importance of psychological counseling during pregnancy.
For pregnant women with anxiety or even depression during pregnancy, early detection and early intervention are crucial. Many families are not aware of the serious impact of the abnormal emotions of pregnant women, and the pregnant women themselves lack the awareness of seeking help, which eventually leads to increasing psychological pressure and affects the quality of life of the fetus. Studies have shown that timely intervention and alleviation of psychological problems during pregnancy can prevent the birth of many malformed fetuses, and can also bring a relatively smooth birth process to pregnant women, which has a beneficial impact on improving the birth experience of pregnant women during pregnancy and improving the quality of life of newborns[35, 36]. The PHQ-15 questionnaire used in this study can indicate the nervousness and anxiety of pregnant women early through a series of somatic symptom scores. Targeted prenatal education and corresponding nursing for nervous and anxious pregnant women can effectively help mothers eliminate anxiety, further enhance their confidence in childbirth, and avoid adverse emotions or other psychological problems affecting childbirth, so as to achieve the purpose of improving their delivery outcomes.
Finally, there are still some limitations in this study, such as insufficient sample representation and selection bias in the face of force majeure factors and research confounding factors. The participants in the study were from the same hospital and at the same time period of low-risk third trimester women, which is not representative of the overall situation of low-risk third-trimester women in other regions, other hospitals, and other years. Due to the limitation of sample size, some of the results of the study may differ from the conclusions of the existing studies, and it is necessary to expand the sample size and carry out in-depth research in the future.