Motivation and emotion/Book/2020/Oxytocin and mother-infant bonding

Oxytocin and mother-infant bonding:
What role does oxytocin play in mother-infant bonding?

Multimedia presentation (3 min)

Overview

Figure 1. Mother-Child^{(capitals needed...?)} face to face

This chapter provides insight into the effect that oxytocin has on a mother-infant bond. This phenomena has been of much interest to many scientists around the world, as it is one of the strongest bonds in both the human and animal kingdom (see Figure 1). This connection is primarily due to the neuropeptide and hormone, oxytocin.

Throughout this chapter we will delve into the physiological aspects of a mother-infant bond. These are generally triggered by the oxytocin neuropeptide, or trigger the release of the hormone. These include labour and vaginal deliveries, skin to skin contact, and breastfeeding. We will also explore the idea of whether this unique bond can be altered or broken. To answer this, the areas of elective vs. non-elective caesarean sections and premature births will be analysed.

These varied situations all occur in the immediate lead up to the infants birth and its first few hours of life. This 'golden hour' and the subsequent release of the oxytocin hormone have a defining effect on the mother's continued emotions throughout their fourth trimester.

Focus questions: What is oxytocin and how does it affect emotions? What role does oxytocin release play in physiological responses? What role does oxytocin play in mother-infant bonding? Can the mother-infant bond be altered by internal and/or external factors?

What is oxytocin?

Oxytocin is a hormone, neuropeptide, and a neurotransmitter. These two forms of oxytocin interact with each other to activate many bodily functions such as labour, lactation, sperm movement, and testosterone production

Oxytocin has receptors in the brain that are expressed via neurons. These receptors are found in the amygdala, ventromedial hypothalamus, septum and brainstem. The firing of these neurons help with social recognition. However, their primary job is to trigger the release of the oxytocin hormone (see Figures 2 and 3).

The oxytocin hormone is produced by the hypothalamus and then secreted by the pituitary gland. This hormone is very significant in forming and maintaining important social interactions. High levels of oxytocin in blood plasma means a higher chance of a richer, trusting bond being created.

Figure 3. Oxytocin outputs

This explains why mothers and infants, as well as romantic partners, exhibit higher oxytocin levels. It is important to note to oxytocin also contributes to relaxation. This is evident in breastfeeding mothers. These women tend to exhibit calmer characteristics than those who bottle feed. Oxytocin being a prevalent part of creating social bonds is (somewhat proven) by a study that stated autistic children tend to have a lack of oxytocin in plasma. This could be a contributing factor to the children’s struggle to form meaningful connections to those around them.

Figure 4. Oxytocin is commonly known as the "love hormone".

A fascinating example of the interaction between the oxytocin hormone and neurotransmitter is that of a labouring mother and her foetus. The oxytocin in the mother’s blood is infused through the placenta and then prompts the infant’s oxytocin neurotransmitters. These neurotransmitters then silence the infant’s brain in preparation for delivery. This subsequently reduces hypoxia brain damage in the infant. It is clear to see that oxytocin is not just ‘the love hormone’ (see Figure 4), but is actually more vital than we think.

Quiz 1 Oxytocin is ... A hormone. A neurotransmitter. A neuropeptide. All of the above; oxytocin is very versatile. 2 Oxytocin helps with ... (select more than one answer) Sperm movement and testosterone production. Fight or flight response Labour, lactation and attachment Muscle development

Oxytocin release and its resulting physiological effects

Mother-to-infant bonding scale The mother-infant bonding scale is a Likert type scale in which mothers self report how connected they feel to their new baby. It consists of eight items, each with a scale ranging from 0 to 3, therefore the whole score ranges from 0 to 24. The lower a mother scores on the scale, the better her bond is with her baby. Anything above a 2 suggests bonding difficulties.

Vaginal births

The processes that occur during a vaginal birth are biologically ingrained in our DNA^{(interesting claim: cite)}. Every neuron fired, or hormone released, occurs to set off a certain physiological response that assists both mother and infant in the process of delivery. Through the course of a woman’s pregnancy the expressions of oxytocin receptors increase in the areas of the brain that are generally associated with mood regulation and attachment (Bell, et al., 2014). These receptors are also increased in the uterine muscles. These extra receptors appear because the release of the oxytocin hormone, from the posterior pituitary gland, begins labour by bringing on uterine contractions. As the labour progresses, oxytocin is continually released when the infant hits certain points during delivery. The cervix, vaginal canal, and perineum^{(this sentence is incomplete)} (Kovavisarach & Habanananda, 2012).

This continual fluctuation of hormone release assists with the widening of the cervix and larger contractions, also known as the Ferguson reflex Endorphins are also released alongside oxytocin; these help with the pain management of contractions. Oxytocin is also vital in preparing the infant for delivery. As mentioned above, the oxytocin in the mother crosses the placenta and into the infant’s brain. The oxytocin triggers the infants neuroreceptors and puts the brain into a sleep-like-state, helping reduce the chance of hypoxia brain damage.

Once the infant is born the oxytocin in the mother’s body continues to aid in her recovery. The oxytocin maintains the contractions to facilitate the expulsion of the placenta, as well as reducing any excess bleeding that may occur. Oxytocin has shown itself to be vital in the delivery process, however its effects are also very important in the ‘golden hour’ after birth, as well as the days and weeks following. The higher levels of endogenous oxytocin in mothers that have delivered vaginally prompt her instinctual need to care for her infant, thus the vital early bond is created. This uninterrupted flow of hormones that biologically take place in a birthing mother, ultimately put the mother in a mental state that allows her to bond with her baby. If the flow of natural birth is interrupted, the oxytocin levels in the mother are low and thus the mother is less responsive to the cues of her baby. Much of the oxytocin released through the birthing process assists in the mothers instinctual need to care for her infant, therefore creating a bond between mother and baby that will last a lifetime.

Breastfeeding

Figure 5. Mothers who exclusively breastfeed have significantly higher levels of oxytocin than those who don't.

Breastfeeding (see Figure 5) is an important part of an infant’s growth. The first feed is especially important as it lines the infant’s stomach with colostrum, helping with immunity and promoting growth. Studies have shown that ‘breastfeeding supports interaction and bonding between mother and infant’ (Unväs Moberg, et al., 2020:2/38)^{(not APA)}. Breastfeeding promotes this bond because most of the action is influenced by oxytocin. When the nipples of a new mother are stimulated, a few things happen. Neuroreceptors in the brain are activated, these are located in the areas of the brain which relate to social interaction and attachment behaviour, promoting the bond a mother feels with her infant. Stimulation also produces oxytocin which promotes prolactin release, this is the hormone responsible for milk production. Nipple stimulation also produces oxytocin to assist in milk let-down. (see case study below).

Any intervention in the infant’s birth may also impact the mother’s initial ability to breastfeed, as well as her attempt at continuing. This is due to the oxytocin levels that are evident in her body, and intervention generally disrupts the orchestration of the hormones (Lothian 2005), especially endogenous oxytocin. Oxytocin is measured in the mother’s plasma through the technique of radioimmunoassay (see focus box below for more details). Through this technique it has been noted that oxytocin levels peak in a mother when her infant is sucking. For the first ten minutes of breastfeeding the oxytocin is released in five short pulses (Unväs Moberg, et al., 2020), it then platos after this. Mothers who exclusively breastfed had higher oxytocin levels in their plasma than those who gave supplementary feeds (Uvnäs-Moberg, et al.,1990), however the mothers who gave supplementary feeds had higher levels of oxytocin than those who exclusively breastfed. This is due to the lack of stimulation of the nipples.

Case study It is common to hear about women who are breastfeeding beginning to lactate when hearing any infant cry. This generally happens in the first few months of breastfeeding. It occurs because oxytocin is released in response to the infant’s cry. This oxytocin release triggers milk let down, causing women to ‘leak’ when an infant is crying.

Breastfeeding, and its subsequent oxytocin release leads to sleepy, relaxed and calm feelings within a mother, this then acts as a long-term stress buffer, making the mothers first few months with her baby easier and less nerve wracking. The statements, ‘Oxytocin release during breastfeeding influences maternal psychology in a way that facilitates motherhood’ and ‘Oxytocin release associated with breastfeeding contributes to the development of maternal experiences, psychological skills and physiological adaptations’ (Unväs Moberg, et al., 2020), quite clearly state that breastfeeding facilitates the attachment security a mother feels with her infant. The amount of oxytocin released whilst breastfeeding has a very positive effect on the mother-infant bond.

Radioimmunoassay Radioimmunoassay, or RIA, is a technique used to test the levels of an antigen (oxytocin) concentration in a blood sample, through the use of antibodies. RIA relies on the principle of comparative binding. There is a radioactive antigen as well as a non-radioactive antigen (the sample). These two compete for a fixed number of receptors. The more prevalent the antigen is in the sample, the less the radioactive antigen is detected.

Skin to skin contact

Studies conducted on animals show that the neuropeptide oxytocin plays a critical role in the bond between the mother and her infants. This is due to their immediate and continual contact and grooming. As animals, it is understood that this reaction also occurs in humans (Feldman, et al., 2010). Skin to skin contact is vital for the bonding process between a mother and infant (see Figure 6), especially if the infant is pre-term. Through salivary samples from different experiments, it is evident that oxytocin plays an important role in forming the bond through skin to skin contact. In the study conducted by Cong, et al. (2015) salivary samples collected both before and after skin to skin contact showed a release of oxytocin into the bloodstream. This activation of oxytocin reduced stress and anxiety in both the mother and infant. This reduced stress and high levels of oxytocin then facilitates the synchronous process. This process is vital for the mother-infant bond as it means the harmonious coordination of the mother and infant and thereby allows the mother to predict and take care of her infants needs.

A later study conducted by Vittner, et al. (2017) not only confirmed Cong’s theory, but expanded upon it. Salivary samples were taken 15 minutes before skin to skin contact, during the 60 minutes of skin to skin contact and 45 min after. These samples showed a significant increase of oxytocin in the bloodstream both during and after skin to skin contact, and again, showed a decrease in cortisol, which meant reduced stress and anxiety. The study also showed that skin to skin contact greatly benefitted the infant’s health by stabilising its temperature and heartrate, as well as promoting brain development and encouraging better mental and motor development. Unlike breastfeeding, the oxytocin release in mother’s and infant’s is a protracted release, meaning the results of its release can be felt for hours afterwards. Skin to skin contact is vital in the ‘golden hour’ after birth to enhance the chances of synchrony (Nissen, 1995).

Skin to skin is an evidence based holding strategy increased mother-infant immediacy as well as providing an ongoing interactive environment for the infant which, as stated above, is known to enhance the infants physiological stability and effect the closeness between a mother and infant (Vittner, et al., 2017). The oxytocin release that is activated encourages stress reduction, which then leads to an increased chance of synchronism being built, thereby creating and maintaining the mother-infant bond.

Quiz 1 How often is oxytocin released during a vaginal childbirth? Only once, when labour begins. Around five times, at every stage of labour. Never. Twice, when contractions begin and once the baby is born. 2 The process used to measure oxytocin levels called radioimmunoassay True False 3 Skin to skin contact is shown to improve and regulate the health of infants False True 4 Oxytocin levels in plasma were evident in skin to skin contact studies in ... The entire time skin to skin occurred The 15 minutes leading up to skin to skin contact Up to 3 hours after skin to skin contact Up to 45 minutes after skin to skin contact

Can the bond be altered?

Case study A textbook pregnancy generally leads the mother to believe that her birth will be the same. However, an issue, such as an infection, can lead to the body shutting down labour and the mother ended up delivering via non-elected caesarean. This sudden change of plan can lead to emotional distress, due to the mother’s perception of ‘not being able to do it herself’. This non-elected caesarean, as well as the mother’s mental state means a reduction of oxytocin release. This results in the mother finding breastfeeding too difficult and having a lack of connection with her baby. (Based on a personal experience)

Figure 7. A typical caesarean section birth

Caesarean section birth

Caesarean sections have been used in childbirth for nearly to two centuries. In recent times, the caesarean section option has become a more popular mode of delivery. Generally, with a caesarean section birth, the mother is awake and a local anaesthetic is administered, the infant is then cut from the mother's uterus. The baby is taken to the ward whilst the mother goes into recovery and is stitched up (see Figure 7). The question must be asked, what effect does this invasive form of childbirth have on the physiological processes of labour, and therefore, the mother-infant bond.

Elected

Caesarean section interrupts the natural course of childbirth. The process, as stated in the ‘Vaginal Births’ section, is a flow on effect, one stage leads to another. This process is headed by oxytocin. By deciding, pre-labour, to have a caesarean section as a mode of birth, these processes do not even begin to occur. Therefore, the lack of hormonal activation may affect whether the mother recognises her infant’s cues, creating a lack of bond. Another factor which effects the mother-infant bond is the early mother-baby separation. This alters the oxytocin release and may affect both mother and baby short and long term (Forti-Buratti, et al., 2017). However, it is important to note that with an elected caesarean, early skin to skin contact is made more often than an unplanned caesarean, and generally a family member is present in the room. These two factors can contribute to a more calming effect and reduce the cortisol in the mother’s system, so a strong bond can still be formed with her baby.

Elected caesarean sections lead to a lack of oxytocin release in the mother, raising her stress levels and causing some of her babies cues to go unrecognised, leading to a lack of bond between mother and infant.

Non-elected

An emergency caesarean section, or unplanned caesarean section, generally occurs due to a medical emergency whilst the mother is labouring. This could foetal distress, labour not progressing or decline in the mother’s health. This has different effects on both the physiology of the mother as well as her mental health. As we know, the oxytocin release begins contractions, this means that the physiological process of labour has begun for the mother and baby. When this is suddenly interrupted, the subsequent reactions that lead to an attachment being formed are inhibited. As well as a disrupted physiological response, the mentality of being a failure and being unable to complete such an important motherly instinct can affect the mother-infant bond. Initially the bond might not be as strong as a vaginal delivery, however, the oxytocin has been released, and therefore, breastfeeding may come more naturally. This fact can promote a stronger bond to be developed over time.

Emergency caesarean sections allow for the natural physiological process of labour to begin, however, can lead to greater mental health issues with the mother (see case study above). Therefore, the bond between a mother and her infant is altered.

Premature births

In most cases of pregnancy, the oxytocin neurons are kept dormant through inhibitory mechanisms to prevent pre-term births. However, it is evident that this doe not always happen. A pre-term birth is categorised between 23- and 37-weeks’ gestation. The reasons that pre-term births occur is generally unknown, as it could be a myriad of genetic, medical, environmental, or iatrogenic reasons. Globally, around 11% of all babies are born prematurely (Walani, 2020).

If a baby is born premature, there is a greater chance of medical intervention. This medical intervention means placing the infant in the Neonatal Intensive Care Unit (NICU). By placing the infant here, generally in an incubator, skin to skin contact is dramatically decreased. Most of the studies used in Skin to skin contact, were on the effects skin to skin contact has on the health of premature babies. We can deduce that if an infant is born pre-term, and skin to skin contact reduced, thereby interfering with certain physiological processes, such as oxytocin release. This interference has been shown to affect the mother-infant bond in both short-term and long-term instances, causing increased anxiety in both mother and infant (Fort-Buratti, et al., 2017). By starting the relationship of in stressful circumstances, and distorted interaction, it is inevitable that the processes that activate oxytocin release occur less, and therefore, the bond between a mother and her infant is altered.

Another interesting aspect of premature births is that of multiple pregnancies. In the USA, 60% of multiple pregnancies ended with a premature labour, therefore all multiple pregnancies are classified as high risk (Prior, et al., 2012), A lot is unknown about the oxytocin levels in mother’s that are carrying multiple babies, however, due to increased stretch of the uterus and surrounding skin, greater levels of oxytocin receptors are found. This has the potential to cause early labour, however, again, there is not a lot of evidence supporting this, and a lot can be put down to speculation.

Due to the continual intervention of premature births, it can be concluded that the oxytocin release is inhibited and therefore the bond between mother and infant is altered.

Cascade of Intervention Every situation above is the result of the ‘cascade of intervention’. This is when different types of maternity care lead to unintended effects during labour and birth (National partnership for women and families, n.a.). Generally, the problem that is being ‘solved’ by an intervention, was caused by a previous intervention. Interventions include, inducing labour by using Pitocin (synthetic oxytocin), artificially breaking membranes, and pain relief (epidural). These interventions cause problems as they interrupt the body’s natural physiological response to childbirth by interrupting the natural release of hormones (oxytocin) and leaving the risk of infection prevalent. One of the biggest interventions is the epidural analgesia, used for pain relief from contractions. The epidural is a spinal tap that numbs the nerves below the hips. This can lead to difficulties pushing, and movement, prolonging the labour. This intervention cascades because Pitocin is then used to strengthen contractions and forceps/vacuum is used to pull the baby out. This can potentially have flow on effects into the babies first hours of life, altering the bond between mother and child.

Quiz 1 What is the benefit of having an elected caesarean over an emergency caesarean? Being able to prepare for the exact time of birth. Having a family member around. More chance of immediate skin to skin contact, increasing the chance of a bond being created. It hurts less. 2 What is a factor in an emergency caesarean that can inhibit the bond between a mother and her infant? The mother's hormones are jumbled. The mother's change in mental health due to sudden, unplanned nature of the caesarean. The scar the mother will now have There are no factors that inhibit the mother-infant bond. 3 What are the amount of weeks gestation that classify a premature baby? 23-37 weeks 25-33 weeks 23-39 weeks 4 What percent of multiple pregnancies lead to a premature birth? 40% 5% 60% 100%

Conclusion

Oxytocin has a huge effect on the mother-infant bond. Oxytocin is released in every aspect of labour, as well as any skin to skin contact between a mother and her infant and continual breastfeeding. The release of oxytocin causes the mothers emotions to settle and allow her to feel calm, stress free and happy. It also helps with synchrony between a mother and infant which facilitates a greater bond. Medical interventions such as caesarean sections and incubation of premature babies effects the amount of oxytocin released, and thereby effects the bond created between a mother and infant. The bond created can change overtime but is initially and specifically created because of oxytocin.

This chapter also suggests further research in the hopes that more light can be shed on the internal and biological influences on the mother-infant bond.

Take home messages 1. Oxytocin is not just the 'love hormone', it has a very important role in the physical aspects of childbirth. 2. Any interruption in the natural course of childbirth may lead to a weaker bond between mother and infant due to the disruption of hormones. However, this does not mean a bond is not created, or the bond is less than that of a mother who delivered vaginally. 3.Everything that occurs within hours of childbirth can effect breastfeeding, and a bond between a mother and her infants, months and years into the future. Oxytocin is not just an immediate, short-term response.

See also

• Cesarean section (Wikipedia)
• Oxytocin (Wikipedia)
• Oxytocin and Emotion (Book chapter, 2013)
• Hormones and Emotion (Book chapter, 2017)
• James-Lange Theory (Wikipedia)
• Attachment theory (Wikipedia)

References

Bell, A. F., Erickson, E. N., & Carter, S. C. (2014). Beyond labour: the role of natural and synthetic oxytocin in the transition to motherhood. Journal of Midwifery Womens Health, 59(1), 35-42. doi: 10.1111/jmwh.12101

Borghini, A., Pierrehumbert, B., Miljkovitch, R., & Muller-Nix, C., et al. (2006). Mother’s attachment representations of their premature infant at 6 and 18 months after birth. Infant Mental Health Journal, 27(5), 494-508. doi: 10.1002/imhj.20103

Bystrova, K., Ivanova, V., Edhborg, M., & Matthiesen, A-S., et al. (2009). Early contact versus separation: effects on mother-infant interaction one year later. Birth Issues in Perinatal Care, 36(2), 97-109. https://doi.org/10.1111/j.1523-536X.2009.00307.x

Carter, C. S., Williams, J. R., Witt, D. M., Insel, T. R. (1992). Oxytocin and social bonding. Annals of the New York Academy of Sciences. 652, 204-211. doi: 10.1111/j.1749-6632.1992.tb34356.x

Carter, F. A., Frampton, C. M., & Mulder, R. T. (2006). Cesarean section and postpartum depression: a review of the evidence examining the link. Psychosomatic Medicine, 68(2), 321-330. doi: 10.1097/01.psy.0000204787.83768.0c

Cong, X., Ludington-Hoe, S., Hussain, N., Cusson, R., Walsh, S., & Vazquez, V. et al. (2015). Parental oxytocin responses during skin-to-skin contact in pre-term infants. Early Human Development, 91(7), 401-406. doi: 10.1016/j.earlhumdev.2015.04.012

Feldman, R., Gordon, I., Schneiderman, I., Weisman, O., & Zagoory-Sharon, O. (2010). Natural variations in maternal and paternal care are associated with systematic changes in oxytocin following parent–infant contact. Psychoneuroendocrinology, 35(8), 1133-1141. doi: 10.1016/j.psyneuen.2010.01.013

Forti-Buratti, M., Palanca-Maresca, I., Fajardo-Simón, L., Olza-Fernández, I., Bravo-Ortiz, M., & Marín-Gabriel, M. (2017). Differences in mother-to-infant bonding according to type of C-section: Elective versus unplanned. Early Human Development, 115, 93-98. doi: 10.1016/j.earlhumdev.2017.09.020

Fuchs, A-R., Romero, R., Keefe, D., & Parra, M., et al. (1991). Oxytocin secretion and human parturition: pulse frequency and duration increase during spontaneous labor in women. American Journal of Obstetrics and Gynecology, 165(4), 1515-1523. https://doi.org/10.1016/S0002-9378(12)90793-0

Kosfeld, M., Heinrichs, M., Zak, P. J., Fischbacker, U., & Fehr, E. (2005). Oxytocin increases trust in humans. Nature, 435, 673-679. https://doi.org/10.1038/nature03701

Kovavisarach, E., & Habanananda, T. (2012). Natural Birth. Thai Journal Of Obstetrics And Gynaecology, 20, 87-94. https://he02.tci-thaijo.org/index.php/tjog/article/view/2950/2819

Matthiesen, A-S., Ransjö-Arvidson, A-B., Nissen, E., & Uvnäs-Moberg, K. (2001). Postpartum maternal oxytocin release by newborns: effects of infant hand massage and sucking. Birth, 28(1), 13-9. doi: 10.1046/j.1523-536x.2001.00013.x

Matthiesen, A-S., Ransjö-Arvidson, A-B., Nissen, E., & Uvnäs-Moberg, K. (2001). Postpartum maternal oxytocin release by newborns: effects of infant hand massage and sucking. Birth issue in perinatal care, 28(1), 13-19. https://doi-org.ezproxy.canberra.edu.au/10.1046/j.1523-536x.2001.00013.x

Nissen, E., Uvnäs-Moberg, K., Svensson, K., & Stock, S., et al. (1996). Different patterns of oxytocin, prolactin but not cortisol release during breastfeeding in women delivered by caesarean section or by the vaginal route. Early Human Development, 45(1-2), 103-118. https://doi.org/10.1016/0378-3782(96)01725-2

Nissen, E., Gustavsson, P., Widström, A-M., & Uvnäs-Moberg, K. (2009). Oxytocin, prolactin, milk production and their relationship with personality traits in women after vaginal delivery or caesarean section. Journal of Psychosomatic Obstetrics & Gynecology, 19(1), 49-58. https://doi.org/10.3109/01674829809044221

Nissen, E., Gunilla, L., Widström, A-M., & Uvnäs-Moberg, K. (1995). Elevation of oxytocin levels early post partum in women. Acta Obstetricia et Gynecologica Scandinavica, 74(7), 530-533. https://doi.org/10.3109/00016349509024384

Prior, E., Santhakumaran, S., Gale, C., & Philipps, L. H., et al. (2012). Breastfeeding after cesarean delivery: a systematic review and meta-analysis of world literature. The American Journal of Clinical Nutrition, 95(5), 1113-1135. https://doi.org/10.3945/ajcn.111.030254

Psych Central Staff, W. (2018). About Oxytocin. Psych Central. <https://psychcentral.com/lib/about-oxytocin/#:~:text=Oxytocin%20is%20a%20hormone%20that,a%20neurotransmitter%20in%20the%20brain.&text=It%20is%20not%20a%20bliss,and%20orgasm%20in%20both%20genders.>

Silver, R. K. & Gibbs, R. S. (1987). Predictors of vaginal delivery in patients with a previous cesarean section, who require oxytocin. American Journal of Obstetrics and Gynecology, 156(1), 57-60. https://doi.org/10.1016/0002-9378(87)90202-X

Stuebe, A., Grewen, K., & Meltzer-Brody, S. (2013). Association Between Maternal Mood and Oxytocin Response to Breastfeeding. Journal Of Women's Health, 22(4), 352-361. doi: 10.1089/jwh.2012.3768

Turton, P., Neilson, J. P., Quenby, S., & Burdyga, T., et al. (2009). A short review of twin pregnancy and how oxytocin receptor expression may differ in multiple pregnancy. European Journal of Obstetrics and Gynecology and Reproductive Biology, 144(1), S40-S44. https://doi.org/10.1016/j.ejogrb.2009.02.011

Uvnäs-Moberg, K., Ekström-Bergström, A., Buckley, S., & Massarotti, C., et al. (2020). Maternal plasma levels of oxytocin during breastfeeding – a systematic review. Plos One. https://doi.org/10.1371/journal.pone.0235806

Uvnäs-Moberg, K., & Prime, D. K. (2013). Oxytocin effects in mothers and infants during breastfeeding. Infant, 9(6), 201-06. http://www.infantjournal.co.uk/journal_article.html?RecordNumber=6635

Uvnäs-Moberg, K., Ekström-Bergström, A., Bukley, S., Massarotti, C., et al. (2020). Maternal plasma levels of oxytocin during breastfeeding – a systematic review. Plos One, https://doi.org/10.1371/journal.pone.0235806

Uvnäs-Moberg, K., & Eriksson, M. (1996). Breastfeeing: physiological, endocrine and behavioural adaptations caused by oxytocin and local neurogenic activity in the nipple and mammary gland. Acta Paediatrica, 85(5), 525-530. https://doi.org/10.1111/j.1651-2227.1996.tb14078.x

Uvnäs-Moberg, K., Widström, A., Werner, S., Matthiesen, A., & Winberg, J. (1990). Oxytocin and Prolactin Levels in Breast-Feeding Women. Correlation with milk Yield and Duration of Breast-feeding. Acta Obstetricia Et Gynecologica Scandinavica, 69(4), 301-306. doi: 10.3109/00016349009036151

Vittner, D., McGrath, J., & Robinson, J., et al. (2017). Increase in oxytocin from skin-to-skin contact enhances development of parent-infant relationship. Biological Research for Nursing, 20(1), 54-62. https://doi.org/10.1177/1099800417735633

Walani, S. R. (2020). Global burden of preterm birth. International Journal of Gynaecology and Obstetrics, 150(1), 31-33. https://doi.org/10.1002/ijgo.13195

You and Your Hormones from the Society for Endocrinology. (2015). https://www.yourhormones.info/hormones/oxytocin/

Zak. P. J. (2005). Oxytocin is associated with human trustworthiness. Hormones and Behavior. 48(5), 522-527. https://doi.org/10.1016/j.yhbeh.2005.07.009

External links

• Netflix Documentary Series - Babies, Part 1, Episode 1 - Love, 2020. This episode of the recent Netflix documentary series 'Babies' discusses the role that oxytocin plays in both maternal and paternal bonds with the new infant.
• TED Talk - Paul Zak: Trust, morality -- and oxytocin? 2011. What drives our desire to behave morally? Neuroeconomist Paul Zak shows why he believes oxytocin (he calls it "the moral molecule") is responsible for trust, empathy and other feelings that help build a stable society.