Effects of breast stimulation for spontaneous onset of labor on salivary oxytocin levels in low-risk pregnant women: A feasibility study

A longitudinal study of the association of epidural anesthesia and low-dose synthetic oxytocin regimens with breast milk supply and breastfeeding rates

Breastfeeding is known to improve maternal and child health. However, epidural anesthesia (EDA) and synthetic oxytocin (synOT) are suggested to have negative effects on breastfeeding. In this study, we aimed to determine the effects of intrapartum synOT and EDA on breast milk supply, breastfeeding rates, and maternal salivary oxytocin levels. Women were recruited during pregnancy or after birth at a single hospital. Data were collected at 3 days postpartum (T1), 1 month postpartum (T2), and 4 months postpartum (T3) on 83 low-risk primiparous women who planned to breastfeed for at least 12 weeks postpartum to avoid dropouts from early discontinuance of breastfeeding. Women with cesarean section, twin pregnancy, premature neonates, and an Apgar score of < 7 at 5 min were excluded. Participants recorded their 24-h milk supply by test weights at 3 days and 1 month postpartum. Additionally, they filled out questionnaires assessing their breastfeeding level and lactogenesis stage II initiation. Salivary oxytocin levels were obtained at 3 days postpartum. Women who delivered using EDA had lower salivary oxytocin levels (P = .055, d = .442), breast milk supply in early postpartum (P = .025, d = .520) and at 1 month postpartum (P = .036, d = .483), and breastfeeding rates at 4 months postpartum (P = .037, V = .236) than women who did not deliver using EDA. There was no association between breastfeeding and the use of intrapartum synOT. In conclusion, this study showed that women who delivered using EDA had lower breast milk supply in the early postpartum period and breastfeeding rates at 4 months postpartum. It also revealed that using synOT at low doses during labor did not affect breastfeeding. Thus, women who deliver using EDA need support for increased breast milk supply in the early postpartum period.Trial registration: UMIN000037783 (Clinical Trials Registry of University Hospital Information Network).

Intrapartum nipple stimulation therapy for labor induction: a randomized controlled external pilot study of acceptability and feasibility

OBJECTIVE

Nipple stimulation is purported as a natural and inexpensive method for inducing labor, but its use is understudied. We aimed to assess whether conducting a large randomized controlled trial comparing intrapartum nipple stimulation therapy versus oxytocin infusion is feasible and acceptable to patients and obstetric care providers.

STUDY DESIGN

This single-center parallel-group randomized controlled external pilot study (NCT04756089) included women with gestations ≥36 weeks who were planned to receive exogenous oxytocin for their labor induction. Those <18 years old, non-English-speaking, or with fetuses at increased risk for neonatal intensive care were excluded. Stratified by parity, women were randomized 3:1 to intrapartum nipple stimulation therapy or immediate receipt of oxytocin. Women assigned to nipple stimulation therapy were asked to stimulate with an electric breast pump or by hand for periods of at least 30 minutes, with breaks as needed for up to 15 minutes at a time, for at least a cumulative two hours prior to considering initiation of oxytocin, and to complete intrapartum diaries. Labor characteristics and outcomes were examined. Validated questionnaires were used to assess the participants' pain level during the intervention, their sense of control during childbirth, and their breastfeeding success. Primary outcome measures were recruitment, adherence to study protocol and follow-up, and cross-over rates.

RESULTS

620 women underwent labor induction from 3/13/21-6/23/21. Of 557 potentially eligible women, 53 were approached by available research staff. 24 (45%) consented and enrolled: 18 randomized to nipple stimulation and 6 randomized to oxytocin. One woman assigned to nipple stimulation withdrew due to delay of clinical care and received oxytocin (cross-over rate of 1/24 (4%)), and one woman assigned to oxytocin did not receive it due to spontaneous labor progress. All other participants followed their assigned intervention. The 17 women who performed nipple stimulation stimulated for a median duration of 198 (IQR 125-291) minutes and required a median of 69 (IQR 21-80) minutes of stimulation prior to achieving at least three contractions in a 10-minute window, averaged over 30 minutes (a.k.a. "adequate" contractions) Among those assigned to nipple stimulation therapy, 15/17 (88%) later received oxytocin infusion prior to delivery. The median time from intervention start to delivery was 16.4 (IQR 0.6-28.2) and 20.6 (IQR 14.2-23.4) hours for women assigned to nipple stimulation therapy versus oxytocin infusion, respectively. 12 (50%) women completed their postpartum study questionnaires.

CONCLUSION

Random assignment to intrapartum nipple stimulation therapy versus oxytocin infusion for labor induction is feasible and acceptable to patients and obstetric care providers.

Evaluating the effect of nipple stimulation during labour on labour progression in term pregnant women

This study aimed to assess the effect of nipple stimulation during labour on duration of latent and active phases of labour in the term pregnant women. Pregnant women (222) were divided into two groups of nipple stimulation and control. Duration of latent and active phases of labour, the number of women treated with oxytocin, rate of caesarean section (C-section) and foetal outcomes were compared. The median of the latent phase duration of labour in the intervention and control groups was 3.2 (1.3-6.3) and 4.8 (0.8-3.0) h, respectively (p = .008); however, the median of active phase duration was 2.3 (1.4-3.0) in the intervention group and 2.5 (2.0-3.3) in control group, which was not significantly different (p = .249). Additionally, the number of women treated with oxytocin in nipple stimulation group was significantly (p = .001) less than the control group. More studies are needed to evaluate optimum frequency and duration of nipple stimulation during labour.IMPACT STATEMENTWhat is already known on this subject? In limited studies, nipple stimulation is considered as a low-complication method for stimulating labour at onset.What do the results of this study add? Nipple stimulation can be applied during labour for accelerating latent phase and reducing oxytocin infusion.What are the implications of these findings for clinical practice and/or further research? Nipple stimulation can be applied as a non-pharmacological and non-invasive method allowing patient to control her own labour progression more effectively.

Antenatal breastmilk expression for women with diabetes in pregnancy - a feasibility study

Background

Mothers with diabetes are less likely to achieve successful breastfeeding. Antenatal breastmilk expression (ABE) may facilitate earlier breastfeeding, but feasibility of introducing ABE and its acceptance among Scandinavian women have previously not been investigated.

Methods

This observational trial was conducted between the 1 January 2019 and the 12 March 2020 in Tromsø, Norway. We aimed to determine the feasibility of ABE in terms of practicality and acceptability among women with medically (metformin or insulin) treated diabetes. Women were invited to participate during antenatal visits from 32 weeks gestation. Participants received instruction and started ABE from gestation week 37 + 0. Participants, and their infants, were followed until 6–8 weeks after birth. We collected data on breastfeeding rates, infant hypoglycemia, transfer to the neonatal unit, and the women’s overall experience and satisfaction with antenatal breastmilk expression.

Results

Twenty-eight of 34 (82%) invited women consented to participate. All started ABE from week 37 + 0, and continued until hospital admission. No women reported any discomfort or side effects. Labor was induced at 38 weeks gestation. Twenty-four women brought harvested colostrum to the maternity ward, which was given to their infants during the first 24 h of life. Breastfeeding rates at discharge were 24/28 (86%) and 21/27 (78%) at 6–8 weeks after delivery. Seven (25%) infants were transferred to the neonatal unit; four because of hypoglycemia. Maternal satisfaction assessed 6–8 weeks after delivery revealed that all participants felt positive about the ABE, but one woman would not recommend it to other pregnant women.

Conclusions

Implementing a structured ABE guideline for women with medically treated diabetes was feasible. The intervention was associated with high level of satisfaction among study participants. No obvious side effects were observed, and breastfeeding rates at discharge and 6–8 weeks after delivery were higher than in comparable studies.

Trial registration

The study was registered at the research study registry at the University Hospital of North Norway (Nr 2018/7181).

The Hormonal Milieu by Different Labor Induction Methods in Women with Previous Cesarean Section: a Prospective Randomized Controlled Trial

The physiological pattern of hormonal and signaling molecules associated with labor induction is not fully clear. We conducted a preliminary study in order to investigate hormonal changes during labor induction in women with previous cesarean section. Eighty-seven women at term, with previous cesarean section, were randomized to undergo induction of labor by breast stimulation or intracervical balloon and compared with spontaneous labor (controls). Maternal serum levels of oxytocin, prostaglandin F2α, prostaglandin E2, prolactin, estradiol, and cortisol were analyzed at 0, 3, and 6 h post-induction initiation. Fetal umbilical cord hormones were measured. No significant difference was found in the induction-to-delivery time or mode of delivery between the induction groups. Maternal serum oxytocin levels decreased to a lesser extent in the breast stimulation group vs. the control group (p=0.003, p<0.001). In the breast stimulation and control groups, prostaglandin E₂ levels increased as labor progressed (p=0.005, 0.002, respectively). Prostaglandin F2α levels decreased over time in the balloon group (p=0.039), but increased in the control group (p=0.037). Both induction methods had similar outcomes. The hormonal studies ascertained the hypothesized mechanisms, with oxytocin level higher during breast stimulation and lower in balloon induction. These observations could help clinicians determine the appropriate method for cervical ripening in women with previous cesarean section. Larger future studies are needed to examine the effect of these hormonal trends on the rate of successful labor induction and complications, such as uterine rupture, in women with previous uterine scars. ClinicalTrials.gov Identifier NCT04244747.

Touch-induced emotional comfort results in an increase in the salivary antioxidant potential: A correlational study

A pleasant touch reduces psychoemotional stress via the oxytocin mechanism due to its anti-inflammatory and antioxidant effects. Our research is aimed to reveal the correlations between the subjectively perceived pleasantness of touch, the antioxidant potential of saliva, and salivary oxytocin. A total of 56 healthy volunteers aged 18-38 years participated in the study. The control group consisted of 24 volunteers. The participants were subjected to tactile stimulation using a specially designed protocol. They ranked the touch pleasantness on a scale from 1 to 10. Heart rate variability and low-frequency/high-frequency ratios from the power spectral density of ECG were determined to assess psychoemotional relaxation. Salivary oxytocin and antioxidant capacity were quantified before and after the touch test. We found a significant increase in salivary antioxidant potential and oxytocin after pleasant tactile stimulation for the participants compared to the control group. The difference in antioxidant capacity values before and after the test positively correlated with mean pleasantness in the touch test (r = 0.57) and the difference in heart rate variability (r = 0.67); it negatively correlated with the difference in low-frequency/high-frequency ECG band ratio (r = -0.59). Oxytocin ratio positively correlated with the difference in antioxidant capacity values (r = 0.47). As a result of tactile stimulation, a significant increase in the antioxidant capacity of saliva and salivary oxytocin was found in the test group compared to the control group. These findings support further studies of the effects of pleasant touch on hormonal and oxidative metabolism.

Oxytocin Facilitates Dentinogenesis of Rat Dental Pulp Cells

INTRODUCTION

Oxytocin (OT) is a neurohypophysial hormone that plays a role in lactation and parturition and exerts diverse biological actions via the OT receptor. Recently, several studies have reported that OT stimulates bone formation by osteoblasts in osteoporosis. We focused on OT and hypothesized that OT can stimulate the differentiation of odontoblasts as well as osteoblasts. The aim of this study was to verify whether OT is an essential factor in dentinogenesis; we examined the effects of OT on dentinogenesis using a long-term culture system of rat dental pulp cells.

METHODS

Using a culture system of rat dental pulp cells with Otr knocked out by CRISPR-Cas9 genome editing, we examined the effects of OT on odontoblastlike cell differentiation as reflected by dentin formation.

RESULTS

We confirmed that OT stimulated mineralized nodule formation and the expression of both dentin sialoprotein and bone Gla protein messenger RNAs (mRNAs) in the culture system. Interestingly, the cultured cells treated with OT also exhibited an increase of both Wnt10a and Lef-1 mRNA. The Otr knockout cells showed inhibition of nodule formation and mRNA expression, and these phenomena remained despite OT treatment. These results indicate the following: OT regulates odontoblastlike cell differentiation via the OT receptor, it stimulates dentin formation, and the Wnt canonical pathway is closely related to these effects.

CONCLUSIONS

The present results suggest that OT can promote odontoblastlike cell differentiation, resulting in increased dentin formation, and that OT could be an important factor for dentinogenesis.

Perceived pleasantness of gentle touch in healthy individuals is related to salivary oxytocin response and EEG markers of arousal

Affective touch plays an important role in human social bonding, affiliative behavior, and in general emotional well-being. A system of unmyelinated low-threshold mechanosensitive C-type afferents innervating hairy skin (C-tactile or CT system) is postulated to provide the neurophysiological background of affective touch perception. C-tactile afferents respond optimally to soft and slow strokes, and this response correlates positively with pleasure ratings of tactile stimuli. As gentle touch is consistently associated with oxytocin release further promoting prosocial behavior, it has been suggested that this effect is mediated by the response of C-tactile afferents. This study assesses a possible link between CT-optimal touch, its subjective pleasantness, EEG indices of cortical arousal, and peripheral oxytocin response. EEG was recorded in 28 healthy volunteers during resting state and tactile stimulation[gentle slow brush strokes on forearm (CT-targeted touch) and palm (non-CT-targeted touch)]. Saliva samples were collected before and after the touch stimulation. Oxytocin concentration increase was significantly associated with greater subjective ratings of CT-targeted touch but not of non-CT-targeted touch, and with lower peak alpha frequency values indicating decreased cortical arousal. The findings suggest that CT-targeted stimulation triggers oxytocin release but only when the touch is perceived at an individual level as having clearly positive affective salience. This corresponds to previous studies reporting that oxytocin response to touch can be related to different personality factors, and bears important implications for planning touch-based interventions in social and medical care.

The Effects of Essential Oil on Salivary Oxytocin Concentration in Postmenopausal Women

Objectives: The aim of this study was to find essential oils that have increased the oxytocin concentration in postmenopausal women. Methods: Fifteen postmenopausal women participated in this study and the effects of 10 different essential oils were investigated. The essential oils included rose otto, sweet orange, lavender, neroli, frankincense, jasmine absolute, ylang ylang, roman chamomile, clary sage, and Indian sandalwood. The subjects were exposed to the control first for 20 min, followed by exposure to an essential oil for 20 min. Each subject received exposure to only a single kind of essential oil per day. Saliva was collected four times for each patient: immediately before and immediately after control exposure, and immediately before and immediately after essential oil exposure. The oxytocin concentration in the saliva was measured using a competitive ELISA kit. Results: The results showed that salivary oxytocin concentrations increased significantly more after exposure to lavender, neroli, jasmine absolute, roman chamomile, clary sage, and Indian sandalwood than after exposure to the control odor. Conclusions: The aroma of certain essential oils may elicit increased secretion of oxytocin in postmenopausal women. This study suggests that olfactory stimulation with any of a number of essential oils increases salivary oxytocin concentrations, which may inhibit aging-induced reduction in muscle mass and function in women.

Oxytocin levels in low-risk primiparas following breast stimulation for spontaneous onset of labor: a quasi-experimental study

Background

Breast stimulation is performed to self-induce labor. However, there are apparently no reports on hormonal evaluation during stimulation for consecutive days in relation to induction effect. We evaluated the salivary oxytocin level following 3 consecutive days of own breast stimulation for 1 h each day compared with no breast stimulation.

Methods

We used a quasi-experimental design. The participants were low-risk primiparas between 38 and 39 gestational weeks. Eight saliva samples per participant were collected at preintervention and 30, 60, and 75 min postintervention on the first and third days. The primary outcome was change in the salivary oxytocin level on the third day after 3 consecutive days of breast stimulation for 1 h each day compared with no breast stimulation. The secondary outcomes were the rate of spontaneous labor onset and negative events including uterine hyperstimulation and abnormal fetal heart rate.

Results

Between February and September 2016, 42 women were enrolled into the intervention group (n = 22) or control group (n = 20). As there were differences in the basal oxytocin levels between the 2 groups, to estimate the change in the oxytocin level from baseline, we used a linear mixed model with a first-order autoregressive (AR1) covariance structure. The dependent variable was change in the oxytocin level from baseline. The independent variables were gestational weeks on the first day of intervention, age, education, rs53576 and rs2254298, group, time point, and interaction of group and time. After Bonferroni correction, the estimated change in the mean oxytocin level at 30 min on the third day was significantly higher in the intervention group (M = 20.2 pg/mL, SE = 26.2) than in the control group (M = − 44.4 pg/mL, SE = 27.3; p = 0.018). There was no significant difference in the rate of spontaneous labor onset. Although there were no adverse events during delivery, uterine tachysystole occurred in 1 case during the intervention.

Conclusions

The estimated change in the mean oxytocin level was significantly higher 30 min after breast stimulation on the third day. Thus, consecutive breast stimulation increased the salivary oxytocin level. Repeated stimulations likely increase the oxytocin level.

Trial registration

UMIN000020797 (University Hospital Medical Information Network; Prospective trial registered: January 29, 2016).