Plasma concentrations of beta-endorphin and adrenocorticotropic hormone in women with and without childbirth preparation

The combined effects of Lamaze breathing training and nursing intervention on the delivery in primipara: A PRISMA systematic review meta-analysis

BACKGROUND

Lamaze breathing has been widely used as a breathing training method. Nursing intervention including postural nursing, delivery ball, doula nursing, massage and psychological nursing is usually provided by nurses during labor. A number of clinical studies have investigated the effect of Lamaze breathing training combined with nursing intervention on maternal pain relief and outcomes improvement. But there were some scholars who were against it.

METHODS

Randomized controlled trials from January 2000 to November 2019 in PubMed, Cochrance Library, Medline, Web of Science, Embase, Chinese Academic Journals, Chinese Biomedical Literature Database, VIP Database, Wanfang Database were searched. Two researchers independently screened the literature according to the criteria. After extracting the data, the researchers used Cochrane system to evaluate the literature quality. Statistical analyses were performed by using Comprehensive Meta Analysis V2 software.

RESULTS

Twenty-two randomized controlled trials conducted on 7035 primiparas were eligible. The results revealed that Lamaze breathing training combined with nursing intervention increased the rate of natural delivery (relative risk [RR] = 2.97, 95% confidence interval [CI] [2.48, 3.56]), shortened the length of labor (-2.604, 95% CI [-3.120, -2.087]), alleviated labor pain (RR = 0.194, 95% CI [0.115, 0.325]) and reduced postpartum bleeding (-2.966, 95% CI [-4.056, -1.877]).

CONCLUSIONS

Lamaze breathing training combined with nursing intervention was effective for ameliorating the process and outcomes of childbirth in primiparae and deserves to be promoted and applied in clinical practice.

The role of maternal attachment in the experience of labor pain: a prospective study

OBJECTIVE

To examine the influence of attachment dimensions and sociodemographic and physical predictors in the experience of labor pain.

METHODS

Eighty-one pregnant women were assessed during their third trimester of pregnancy and during labor. The perceived intensity of pain in the early stages of labor (3 cm of cervical dilatation) and before the administration of patient-controlled epidural analgesia was measured using a visual analog scale. Pain was also assessed indirectly based on anesthetic doses. Attachment was assessed using the Adult Attachment Scale-Revised.

RESULTS

Attachment anxiety and avoidance were positively and significantly correlated with labor pain and anesthetic consumption. In the multivariate models, attachment anxiety was a significant predictor of higher pain at 3 cm of cervical dilatation (β = 0.36, p = .042) and before the administration of patient-controlled epidural analgesia (β = 0.51, p = .002). Older age (β = 0.31, p = .005), a shorter duration of labor (β= -0.41, p = .001), and attachment avoidance (β = 0.41, p = .004) were significant predictors of higher anesthetic use.

CONCLUSIONS

The study findings suggest that perceived labor pain and anesthetic use are strongly associated with attachment, rather than demographic and physical factors. These data support the importance of understanding the experience of labor pain within an attachment theoretical framework.

[The pain and behavior of women during labor and the different positions for childbirth]

This study evaluated the pain intensity and behavior during labor and delivery, among women who had natural childbirth, without analgesia, in one of the following positions: semi-sitting, lying on the left side, and lithotomy. This is a descriptive, cross-sectional and correlational study. The instruments used were a validated questionnaire that evaluates pain and behavior during labor and childbirth, from the women's perspective, and two pain scales: one analog and one alphanumerical. It was observed that the pain among women who had childbirth in a lithotomy position was significantly smaller compared to those lying on the left side (p=0.003), though women chose the positions. There was an association between pain and behavior. Pain in labor and childbirth were associated among each other, as was the behavior in these two moments. The results point at an association between the position at childbirth and pain, but it was not possible to identify factors to explain this association; therefore, there is a need for longitudinal studies.

Response to delivery stress is not mediated by beta-endorphin (1–31)

OBJECTIVE

The aim of the study was to determine the reaction of the melanotroph and corticotroph-type pituitary proopiomelanocortin (POMC) response to vaginal delivery and caesarean section stress. Furthermore, the relationship between the release of pituitary POMC fragments, gonadotropins and sexual steroids were examined.

STUDY DESIGN

Blood samples were obtained from 10 women in labour on arrival in the birth room (t(A)), at cervix dilatation of 5 cm (t(B)) and immediately after spontaneous delivery (t(C)) and in 16 patients undergoing elective caesarean section before induction of anaesthesia (t(B)) and immediately after delivery (t(C)). Samples were analysed for cortisol, ACTH, authentic beta-endorphin, beta-endorphin immunoreactive material (IRM), acetyl-N-beta-endorphin IRM (NAC), beta-lipotropin (beta-LPH) IRM, oestradiol (E(2)), progesterone (P), prolactin (PRL), FSH and LH.

RESULTS

NAC representing the melanotroph-type pituitary POMC system did not increase during the course of caesarean section or spontaneous labour. In contrast, a significant increase of beta-endorphin IRM, beta-LPH IRM and ACTH were observed, representing an activation of the corticotroph-type POMC system. Highly significant correlations between POMC fragment concentrations during caesarean section and spontaneous labour were also observed. Sexual steroids (E(2) and P) decreased significantly. Except for beta-endorphin IRM and E(2) in course of spontaneous delivery no significant correlation was observed between POMC fragment and gonadotropins or sexual steroids.

CONCLUSION

Caesarean section and spontaneous delivery activated the corticotroph but not the melanotroph POMC system.

[Corticotrophin hormone serum levels of parturients submitted to nonpharmacologic anxiety and pain relief method during labor]

This study aimed to analyze the plasma ACTH levels and the correlation between the ACTH levels and pain and anxiety during parturition. Seventeen parturients received routine nursing care (control group--CG) and nineteen (Experimental Group--EG) were stimulated and guided to perform respiration and relaxation techniques. ACTH levels, pain intensity and state-trait anxiety were evaluated. ACTH levels were lower at the beginning of labor, peaked at the end and decreased again in the immediate postpartum period. There was no significant statistical difference between the groups. Lower ACTH levels and partial stress relief in the EG suggest the interference of breathing and relaxation techniques; ACTH levels did not show any correlation with anxiety or pain in any of both groups.

Maternal and fetal hypothalamic-pituitary-adrenal axes during pregnancy and postpartum

The principal modulators of the hypothalamic-pituitary-adrenal (HPA) axis are corticotropin-releasing hormone (CRH) and arginine-vasopressin (AVP). Corticotropin-releasing hormone is not exclusively produced in the hypothalamus. Its presence has been demonstrated at peripheral inflammatory sites. Ovulation and luteolysis bear characteristics of an aseptic inflammation. CRH was found in the theca and stromal cells as well as in cells of the corpora lutea of human and rat ovaries. The cytoplasm of the glandular epithelial cells of the endometrium has been shown to contain CRH and the myometrium contains specific CRH receptors. It has been suggested that CRH of fetal and maternal origin regulates FasL production, thus affecting the invasion (implantation) process through a local auto-paracrine regulatory loop involving the cytotrophoblast cells. Thus, the latter may regulate their own apoptosis. During pregnancy, the plasma level of circulating maternal immunoreactive CRH increases exponentially from the first trimester of gestation due to the CRH production in the placenta, decidua, and fetal membranes. The presence in plasma and amniotic fluid of a CRH-binding protein (CRHbp) that reduces the bioactivity of circulating CRH by binding is unique to humans. Maternal pituitary ACTH secretion and plasma ACTH levels rise during pregnancy-though remaining within normal limits-paralleling the rise of plasma cortisol levels. The maternal adrenal glands during pregnancy gradually become hypertrophic. Pregnancy is a transient, but physiologic, period of hypercortisolism. The diurnal variation of plasma cortisol levels is maintained in pregnancy, probably due to the secretion of AVP from the parvicellular paraventricular nuclei. CRH is detected in the fetal hypothalamus as early as the 12th week of gestation. CRH levels in fetal plasma are 50% less than in maternal plasma. The circulating fetal CRH is almost exclusively of placental origin. The placenta secretes CRH at a slower rate in the fetal compartment. AVP is detected in some neurons of the fetal hypothalamus together with CRH. AVP is usually detectable in the human fetal neurohypophysis at 11 to 12 weeks gestation and increases over 1000-fold over the next 12 to 16 weeks. The role of fetal AVP is unclear. Labor appears to be a stimulus for AVP release by the fetus. The processing of POMC differs in the anterior and intermediate lobes of the fetal pituitary gland. Corticotropin (ACTH) is detectable by radioimmunoassay in fetal plasma at 12 weeks gestation. Concentrations are higher before 34 weeks gestation, with a significant fall in late gestation. The human fetal adrenal is enormous relative to that of the adult organ. Adrenal steroid synthesis is increased in the fetus. The major steroid produced by the fetal adrenal zone is sulfoconjugated dehydroepiandrosterone (DHEAS). The majority of cortisol present in the fetal circulation appears to be of maternal origin, at least in the nonhuman primate. The fetal adrenal uses the large amounts of progesterone supplied by the placenta to make cortisol. Another source of cortisol for the fetus is the amniotic fluid where cortisol converted from cortisone by the choriodecidua, is found. In humans, maternal plasma CRH, ACTH, and cortisol levels increase during normal labor and drop at about four days postpartum; however, maternal ACTH and cortisol levels at this stage are not correlated. In sheep, placental CRH stimulates the fetal production of ACTH, which in turn leads to a surge of fetal cortisol secretion that precipitates parturition. The 10-day-long intravenous administration of antalarmin, a CRH receptor antagonist, significantly prolonged gestation compared to the control group of animals. Thus, CRH receptor antagonism in the fetus can also delay parturition. The HPA axis during the postpartum period gradually recovers from its activated state during pregnancy. The adrenals are mildly suppressed in a way analogous to postcure Cushing's syndrome. Provocation testing has shown that hypothalamic CRH secretion is transiently suppriently suppressed at three and six weeks postpartum, normalizing at 12 weeks.

Maternal hypothalamic-pituitary-adrenal axis in pregnancy and the postpartum period. Postpartum-related disorders

During pregnancy, placenta-derived CRH increases exponentially in the plasma. Circulating levels of CRH-binding protein decrease considerably in the last trimester of pregnancy, resulting in further elevation of bioavailable plasma CRH. The adrenal glands during pregnancy gradually become hypertrophic because of the increase in ACTH, which parallels that of CRH. Thus, pregnancy is a transient period of relative hypercortisolism. The activation of the hypothalamic-pituitary-adrenal axis during pregnancy has been proposed to function as a biological clock. In this model, the placenta is perceived as a stress-sensitive organ and placental CRH as a timing starter, determining a preterm, term, or postterm labor. During pregnancy, as well as during the immediate postpartum period, the hypothalamic maternal CRH secretion is suppressed, because of the circulating levels of cortisol. Hypothalamic CRH secretion normalizes within 12 weeks. This transient postpartum maternal hypothalamic CRH suppression, together with the steroid withdrawal that follows parturition, might be causally related to the mood disorders and the vulnerability to autoimmune diseases such as thyroiditis or rheumatoid arthritis often observed during the postpartum period.