The Greasy, Helpless One-Hour-Old Human New-born
Don’t let anyone tell you that the first hour after birth is not important for mother infant bonding. Don’t let them tell you it is necessary for a mother and infant to be together during that time, either. How can both of these be true? The first statement pertains to our evolutionary legacy as mammals with evolved behaviours that assist in formation of a secure bond that enhances infant survival. The second statement is true because of our legacy as an incredibly flexible species whose dependence on evolved mechanisms for love and attachment is minimal. What is so special about the first hour or two after birth? To understand this, it is important to think about childbirth in the past, before high-tech equipment was available to help the baby adjust to life outside the womb and to facilitate recovery and stabilization of both mother and infant following birth. For much of human history, the mother was the key to infant survival from the moment of birth onward and her presence during the first hour after birth was particularly important.
Infant Helplessness at Birth
Human infants are born with a degree of helplessness not seen in most members of the Primate order. Across species, infant development can be described as precocial or altricial. Precocial infants are those that are well developed at birth, with open eyes and motor skills that enable them to follow or cling to their mothers. Examples include most hoofed mammals and many primates. Altricial infants are helpless at birth, usually do not have open eyes, and must be left in nests or carried by their mothers. Dogs, cats, and a few primate species are altricial. The two degrees of infant development are at one end of a continuum and most species fall somewhere along that continuum rather than at one extreme or another. Human infants are like the precocial monkeys and apes in many ways, but they are ‘‘underdeveloped’’ in other ways. The most obvious is that the brain is only about a quarter of the way through its growth trajectory at the time of birth, so many of the neurological functions that are tied to the immature brain are equally immature. Humans are often referred to as ‘‘secondarily altricial,’’ because of these mixed features of altriciality and precociality. I think of the concept of secondary altriciality as a metaphor for describing the evolutionary history of the human infant. The earliest primates were probably altricial like all of the early mammals. The more recent ancestors that we shared with monkeys and apes probably gave birth to infants that were as developed as monkey and ape infants today, that is, somewhat precocial. We also have milk composition that is more typical of precocial than of altricial species. Based on this evidence, I have argued that our ancestors became more altricial with the evolution of bipedalism and enlarged brains beginning about 2 million years ago, so the helplessness we see today in our infants is ‘‘secondary’’ to having evolved through a more precocial stage in the past. There is further evidence that humans are less developed than would be predicted based on our closest relatives. The degree of bone development seen in macaques at the time of birth is not present in humans until they are several years old. Cranial plates are not as well developed in human infants in comparison to ape and monkey infants. This is advantageous for human birth because the bones of the front part of the skull can slide across one another, making the diameter of the head smaller and easier to deliver. Apes have powerful jaw muscles to enable them to chew the coarse, fibrous foods that make up their diets. If their babies had cranial plates that were as undeveloped as those in humans, their powerful chewing muscles could pull their skulls apart when they started eating solid foods.
Other systems that seem underdeveloped in comparison with other primates include gastrointestinal, immune, and thermoregulatory systems. New-born infants lack enzymes for digesting foods other than colostrum and milk and will not develop them until they are several months old. This is one of the reasons that providing foods like cereals to very young infants can cause digestive problems. The American Academy of Paediatrics recommends not feeding cereals to young infants until they are four to six months old. As we have seen, new-born infant immune systems are immature and will not be fully functioning until the baby is about a year old. Before that time, the infant is dependent on the immune properties acquired from the mother during pregnancy and from breast milk. As we will see, there are several things that happen during and soon after birth that can have a positive (or negative) impact on the infant’s immune function and that reinforce the idea that birth is part of a continuum rather than a discrete event. There are a number of ways in which a mother maintains her infant’s health throughout the prenatal and postnatal period that strengthen the notion that the 15–21 months following conception are a continuum of fatal-like development. For example, during gestation, fatal body temperature is maintained by the mother’s thermoregulatory system. After birth, the new-born infant has a limited ability to maintain a stable body temperature, but the mother can continue to keep him warm with her own body. Paediatrician Jan Weinberg describes the ‘‘nest’’ that the mother creates with her breasts, chest, and arms and notes that this nest provides more warmth to the infant than an artificially warmed hospital cot. Comparing skin-to-skin babies with cot babies, he and his colleagues found that the skin-contact babies were better able to retain adequate blood glucose levels, a very important benefit before milk production kicks in. Skin-contact babies also cry less, which further conserves energy and would have kept the vulnerable mother-neonate dyad from being detected by potential predators in the past. When the infant suckles, the temperature in the mother’s breasts and chests increases, adding to the warmth. Certainly the mother’s ability to help the baby conserve heat and energy was critical to survival in the past, as it still is in many areas of the world today.
A lot of the hormonal and physical changes that occur in mothers and infants at the time of and immediately after birth promote not only healthful adaptation to changed circumstances but also the development of a strong mother-infant bond. Humans are not really all that different from other primates and even rats when it comes to the tools available to enhance the ability of mothers to attach to their infants. These tools work to ensure that mothers will be willing to invest the huge amount of time and energy in caring for and raising young that will be dependent directly on them for sustenance and nurturance for several weeks (rats), months (monkeys), or years (chimpanzees and humans). There has been wide-ranging debate about the importance of the first hour after birth (referred to as the maternal sensitive period by some scholars) for bonding, and I will not try to review the extensive literature here. Suffice it to say that birth and the associated changes in physiology, the sights, sounds, and smells, and the presence of the new-born infant all serve to focus the mother’s attention on the infant and it is indefensible to claim that the hour after birth is just like any other hour in a person’s life. Certainly the hormones that lead to attachment in other animals probably contribute to bonding, but it is clear that they are not necessary for bonding to take place. Here is what I wrote about the proposed maternal sensitive period in 1987, and my thoughts about the first hour after birth have not changed in the interim: Consider the intense physical and emotional experience of giving birth and the hormonal actions that accompany the process. The mother has been aware of the existence of this child for several months. She has felt its movements and may have even talked to it. The new-born infant is finally present in living, breathing form, and, like a wrapped package that is explored upon opening, the mother is especially interested in finding out about it....we all know the excitement of unwrapping gifts and the sense of discovery felt upon opening a gift box. We also know the disappointment felt when someone else opens a package intended for us. The value and meaning of the gift itself, in the long run, may not have anything to do with whether or not we actually opened it, but there is added pleasure in doing so. So it is with the new-born infant. The later, long-term relations may have nothing to do with...whether or not the mother and infant were together for the fist hour getting-acquainted period. They missed out, however, on a special period of excitement that in itself is valuable and meaningful.
What do Mothers and Infants do in The First Hour After Birth?
Following routine hospital deliveries in the middle of the 20th century, mothers and infants did not do much of anything together in the first hour after birth, so the question that heads this section would have seemed meaningless to those experiencing or witnessing births. Other animals, however, are known to exhibit behaviours after birth that are called ‘‘species-specific’’ because they are not only predictable for a given species, but are slightly different for each species. Near-universal behaviour seen in mammals is the routine licking of the infant by the mother immediately after birth. Maternal licking of the infant serves a number of functions: removing some of the material that covered the fetus in utero so that it does not inhibit breathing and heat retention; stimulating breathing, digestion, and elimination; removing odours that might attract predators; orienting the infant toward the nipple; learning of infant odours; and facilitating bonding. Observers of maternal licking in mammals report that it seems compulsive and mothers ignore everything else in their environment until the task is completed. This makes sense from a survival stance because infants that are not licked often fail to survive. One important exception to maternal licking of the neonate is the human species. I have been unable to find any report of licking in the anthropological literature and assume that humans are a rare exception to the near-universal mammalian pattern. (Ocean-dwelling mammals, which do not appear to lick their infants, are another exception.) But what human mothers do is use their hands extensively in interacting with their infants in the first hour after birth. In my observations of 66 births that occurred in a homelike setting, I found that mothers engaged in a predictable pattern of touching their infants, beginning with cradling or encompassing the infant very soon after birth and moving on to palmar massaging and finally to finger exploration of face, hands, and extremities. I interpreted these behaviours as enhancing warmth, respiration, and gastrointestinal development, just as licking does in other mammals. The likely promoter of all of these benefits is the hormone oxytocin, the production of which increases when the infant suckles and is in skin contact with the mother. Successful breastfeeding is extremely important for infant survival, so evidence that skin-to-skin contact between mother and infant in the first few minutes after birth is related to significantly greater breastfeeding duration adds credibility to the idea that early postpartum interaction is important to long-term health of both mother and baby.
The Evolutionary Significance of Vernix
A further benefit to the infant of rubbing and massaging is that it spreads the vernix caseosa into the skin, which protects it from drying out, among other functions. Although it has antimicrobial properties, it is usually wiped or washed off immediately after birth in hospital deliveries as part of the process of cleaning the baby and removing unsightly birth fluids. In home births, however, it is seen as an important substance for protecting the baby’s skin and it is often rubbed in. Midwives with whom I have worked are eager to get a dab on their own hands because of its superb moisturizing properties. Vernix is derived from fatal skin cells and is comprised mostly of water, with lipids and proteins at about 10% each. If we assume that ‘‘nature’s cold cream’’ is best for babies, it suggests that the high oil percentages found in creams and oils manufactured for babies may not be ideal moisturizers. Scientists at the Skin Sciences Institute of Cincinnati Children’s Hospital Medical Centre in Ohio are working on developing a moisturizer with a formula similar to vernix for use with premature infants whose skin is poorly formed, and for diaper rashes in infants and eczema and psoriasis in adults. Furthermore, vernix is high in vitamin E and the skin pigment melanin, both of which have antioxidant properties and may help protect the infant’s skin from pollutants and ultraviolet (UV) light. It has an odour and, perhaps, pheromones that are attractive to parents and may contribute to bonding. Additionally, its smoothness may be a magnet for rubbing and massaging. The baby’s skin forms in utero, but the process requires that the top layer on which the new skin is developing be dry. Vernix serves as a barrier to water in the amniotic fluid that enables the new skin to develop. This happens between 25 and 26 weeks of gestation, so an infant who is born before that time will not have the top skin layers. This means that the premature baby will have problems with heat regulation, water loss, and microbe invasion. Medical researchers have even suggested that the skin may be the limiting factor for survival for ever-younger premature births. When a baby is born, its skin is exposed to air, bacteria, and sunlight; the skin is an important mechanism for coping with the cold, dry environment that the baby meets at birth. New-born infants (at least those born in hospitals) are usually covered with various types of bacteria, including Staphylococcus, Bacillus, and E. coli. As noted, neonates have low immunity (except that derived from their mothers) and the vernix seems to serve as a ‘‘complex innate defence barrier’’ as well as a promoter of colonization by useful microbes. It may also protect the fetus from the tar-like ‘‘stools’’ that are sometimes excreted (known as meconium) and the neonate from infectious rash-inducing agents in faeces.
Vernix is more prolific in babies born by caesarean section, suggesting that the contractions of labour and the tight squeeze through the birth canal in vaginal deliveries results in some of the cream being rubbed into the skin. An early suggestion for the function of vernix was that is served as a ‘‘grease’’ to help the baby pass through the birth canal. The fact that C-section babies have a lot of vernix seemed to support this but the least amount of vernix is seen in babies that are larger and beyond term at birth, ones that presumably would benefit from having the most vernix to grease the passage of their larger bulk. No other mammal is known to have vernix, which suggests that the substance may be related to the relative hairlessness of the human infant. Of course, humans do have hair and while in utero, the fetus is covered with a fine hair known as lanugo, most of which has disappeared by the time of full-term birth. Although the function of lanugo is debated (some even suggest it is an ‘‘evolutionary holdover’’ and has no current function), it may work with the vernix to improve its water repellent properties. The movement of the hairs may also contribute to the development of normal heart rate, which, in turn, enhances growth mechanisms. It is also associated with oxytocin release and it has been suggested that the pleasure experienced by the fetus from the oxytocin motivates fatal movement, which further stimulates growth mechanisms. The process continues in the immediate postpartum period when the mother strokes her infant and rubs the vernix, no longer surrounded by lanugo, into the skin. As noted, vernix protects the fetus from dehydration in utero, but it also serves other prenatal functions. Perhaps most important are the antimicrobial properties that protect the fetus from mild intrauterine infections. Interestingly, the mucus plug that closes the cervix until late in labour has many of the same antimicrobial agents that are found in vernix, suggesting that they serve similar purposes. Because mild infections can initiate labour, the ability to reduce their effects is an important adaptation for ensuring that foetuses are sufficiently mature before labour begins. Another function in utero is that some of the proteins in vernix that are swallowed with the amniotic fluid may help in the maturation of the gastrointestinal system. It appears that the maturing skin and maturing lung interact during late pregnancy to facilitate availability of the amino acid glutamine which is abundant in vernix and required by the rapidly growing cells of the maturing gut. Vernix also contains compounds known as surfactants, which are important for keeping the airway sterile when the baby begins to breathe after birth. In its reported role as a promoter of wound healing, vernix that passes to the mother’s perineum during birth would hasten healing of this region following episiotomy or any other nicks and abrasions that occur. It also serves as a skin cleanser, which is important for both mother and baby at the time of birth.
In summary, this amazing multifunctional substance seems ideally suited for enhancing health and survival of new-born infants and postpartum mothers. An evolutionary perspective argues that something this complex and this useful (skin cleanser, moisturizer, anti-infective, and anti-oxidant) should probably be utilized to its maximum advantage rather than washed away with other seemingly noxious birth fluids. This would be especially important in health-poor countries where technological interventions are limited. The World Health Organization recommends that bathing infants should be delayed until a few hours after birth to minimize heat loss, and certainly other important functions of vernix would be compromised by bathing. The anti-infective properties of vernix are equally important in hospital births where it may protect babies from hospital-acquired infections.
Mothers Soothe and Calm Their Babies Immediately After Birth
Many of the things mothers do within minutes after birth serve to soothe the new-born infant, who often shows signs of stress from the experience of labour and delivery. More than 50 years ago, child psychologist Lee Salk reported that most mothers held their babies on their left sides in the first few days postpartum and proposed that this practice exposed the infant to the mother’s heartbeat (a familiar sound in utero), which, in addition to soothing, promoted weight gain early in infancy. Furthermore, infants seem to prefer to look to the right, which suggests that mothers may be responding to subtle cues from the infants when they decide how to hold them. In my observations of 100 mothers, almost three quarters pulled their infants to their left sides when the babies were first handed to them and more than three quarters held left for most of the first hour after birth. I have even speculated that the tendency to hold infants on the left side, over the heart, may have contributed to the emergence of lateralization and right handedness in hominin evolution. Unlike truly altricial mammals, human infants’ eyes are open at birth and they appear to be able to focus on objects 10–20 inches from their faces—about the distance from the mother’s breast to her eyes when the baby is breastfeeding. Observers note that mothers try particularly hard to place their own faces in a plane with their infants’ faces, a position known as en face. When infants are awake and looking into their mothers’ faces, they tend to remain quiet, as if engaged in the process of learning about the mother.
Mothers all over the world use their voices to soothe their infants and even have a special language known as ‘‘motherese.’’ Vocal interactions between mothers and infants of most animal species also serve to maintain proximity and facilitate individual recognition and nursing. Often the maternal vocalizations are high-pitched, complementing the fact that infants are more able to perceive sounds in the higher ranges. Paediatrician Berry Brazelton suggests that the human neonatal nervous system is better able to respond to the higher pitched female voice. Other observers note that mothers seem to ‘‘instinctively’’ elevate the pitch of their voices when talking to their infants, often switching pitch mid-sentence when they move from looking at adults to looking at their infants. An evolutionary perspective on left-side holding of infants, en face gazing, voice pitch elevation, and patterns of touch suggests that they may be the result of natural selection for behaviours that soothed infants, contributed to energy conservation and weight gain, and facilitated mother-infant bonding. The strong bond and associated behaviours also contribute to successful breastfeeding, surely one of the most important factors influencing infant survival in the past and in much of the world today. If these maternal behaviours in the first hour after birth are indeed part of the behavioural repertoire of the human species, it is not surprising that many women today report frustration when they are not able to be with their infants continuously from the moment of birth onward. Certainly if a challenge to the health of the mother or infant occurs at birth, separation may be warranted. It is difficult to bond to a dead baby, of course, so when reasons of health and survival lead to separation of mother and baby very few people would question that decision. But it seems obvious that mothers and babies benefit for a myriad of reasons from being together after birth when things are going well, so modifying hospital and clinic practices to ensure the togetherness that promotes optimal health and well-being seems appropriate.
Is the First Hour a Critical Period for Bonding?
Despite all the wonderful things that go on in the first hour after birth that promote mother-infant bonding, it is not in any way critical for initiating this process. Very strong and successful bonds form even when mothers and infants are separated for hours or days following surgical deliveries, premature births, infant distress, and other complications related to birth. Adoptive mothers and infants form strong bonds without the experience of labour and delivery (for the mother). Parents who are strongly motivated to form an attachment to their infants can overcome almost any imaginable obstacle and are far from dependent on biological mechanisms to do this. But it may have been a critical period for bonding in the past, one that benefited from all of the behaviours that mothers and infants exhibit in their interaction during the first hour or so following birth. Consider that the stroking and massaging that most mothers do with their new-born infants in the first hour after birth serve to stimulate breathing, provide warmth, and rub the vernix (with its antibiotic properties) into the skin. By holding the infant over her heart on the left side of the body and talking to him in a high-pitched voice, a mother soothes and quiets him, thus enabling him to conserve energy at a vulnerable time. In the ancestral past, these behaviours probably greatly enhanced infant survival during the very vulnerable period right after birth. The seemingly inborn urge in the infant to find the mother’s breast may have been one of the most important ways for initiating the hormonal cascade that stimulated contractions following birth, leading to the expulsion of the placenta and shrinkage of the uterus to prevent postpartum haemorrhage. In this way, the infant helped to save its mother’s life, thus ensuring that he retained his source of food, comfort, and very survival. Thus, I have argued that infants remaining with their mothers in the first hour after birth may well have been critical for survival in the past. The biological and behavioural mechanisms that are seen immediately after birth are the products of millions of years of selection to ensure survival of mothers and infants during what is probably the most vulnerable period in one’s lifetime.
Baby Blues and Postpartum Depression
Not every woman who has a baby spends the first hours and days after birth in a state of oxytocin-induced bliss gazing into the eyes of her new-born infant. Perhaps equally often, though it seems to vary across populations, women experience the ‘‘baby blues’’ that may lead to postpartum depression (PPD), characterized by a loss of interest in virtually all activities. Both cultural and biological factors have been implicated in postpartum negative mood. For example, even within the United States, there is ethnic variation in incidence, with Hispanic women reporting the lowest rates and Native Americans the highest. Although anthropologists report a great deal of variation in postpartum negative mood and suggest that cultural factors have a greater impact than biology, at least one group of scholars found that unhappiness following birth was reported in all populations they surveyed, suggesting that the potential for low mood after birth may be there for all women, but that there is extensive variation in how and whether it is manifested. Social factors are often implicated in postpartum negative mood; women who report low social support and marriage problems are particularly at risk. Difficulties during pregnancy, labour, and delivery, and infants who have health problems are also associated with a higher incidence of postpartum negative mood, and the need for social support is even greater in such circumstances. All of this makes sense from an evolutionary perspective because, as has been pointed out frequently, women not only benefit from social support in the early months of their infants’ lives but the survival of their infants and their own reproductive success is greatly enhanced by this support, especially when provided by the father of the child or other relatives, whose own reproductive success benefits when they support the child and mother. When postpartum negative mood is associated with poor health of the infant, it may be part of the ‘‘cut your losses’’ phenomenon that characterized parenting in the past, sad as that may seem. This is not to say that it is acceptable today to abandon or lower investment in a sickly child but just to remind us that circumstances surrounding parenting in the past were likely very different from those we face now, and understanding these feelings may lead to workable solutions to contemporary problems. Anthropologist Ed Hagen has suggested that in many cases, postpartum negative mood may elicit sympathy or assistance from relatives (including the father of the child), adding support to the view that at low levels, negative mood may be advantageous. He proposes that in the past, if the mother gave signs of abandoning her child, those with genes invested in that child would have been more likely to begin contributing time and resources to its care. Thus, she could use negative mood to ‘‘negotiate’’ assistance from members of her social group. Of interest with regard to the proposal that one of the legacies that pregnant women take with them into labour and delivery is a need for emotional support, women who have supportive companions (sometimes referred to as doulas) with them at the time of birth are less likely to report postpartum negative mood.
Negative postpartum feelings can range from mild to severe, and they provide another example of ways in which we can view health challenges as defects or defences. According to Randy Nesse, some negative feelings may have adaptive value, unless they reach a level at which the person is completely debilitated or unable to function. A mild state of blueness after birth may lead a mother to focus all of her thoughts and energy on the task most immediate and, for fitness, most important: caring for her infant. While she is feeling blue, she may not be interested in going out shopping or to social engagements or back to work. These feelings may not be helpful today, but in the past their expression in new mothers may have resulted in babies that received more focused attention from their mothers and thus were more likely to survive. Clearly when the sadness reaches levels that prevent her engaging with her infant at all or compromise her own health, they become maladaptive and warrant treatment. A practice that is widespread across cultures is seclusion of mothers and infants for a period of time after birth, ranging from a few to 40 days. This practice probably affords the mother time to recover from labour and delivery, time to initiate and further develop successful breastfeeding, and time to bond with her infant. Related to this idea of lower activity levels in women after birth contributing to better infant care, anthropologist Barbara Piperata reports a cultural practice of food restriction for women in the Amazon, known as resguardo, that lasts for 40–41 days and is associated with reduced overall energy expenditure. Postpartum restrictions on mothers’ activities are common worldwide and seem to function to ensure health of the mother and infant who are vulnerable at this time. Perhaps mildly low mood after birth in Western societies serves the same function, especially where cultural practices have not been preserved to sustain the woman at this time. Another evolutionary take on postpartum low mood is related to the argument that in the past, if a baby was born under conditions in which survival was unlikely (if it had defects or was sickly, or if there was no one to help the mother and infant), it may have been advantageous to abandon the infant soon after birth. Low postpartum mood may have interfered with bonding at this stage and enabled the mother to act on what may have been in the best interests of her long-term fitness. Related to this argument is the proposal that the high levels of prolactin associated with lactation in the first few weeks following birth contribute to heightened feelings of hostility toward others that may, in the past, have enabled women to be more protective of their new infants once they decided they were worth investing in. Sarah Hrdy calls this ‘‘Lactational aggression’’ and notes that it is even manifested in mild negative feelings toward spouses in the few months following birth. Despite arguments that there may be advantages to mild low mood following birth, when postpartum depression becomes moderate to severe, it is likely to have negative effects on the mother-infant relationship that may extend beyond the first year of life. It can interfere with breastfeeding, which we will see is one route to lifelong compromised health for both the mother and infant. All other things being equal today, it is probably not particularly helpful for mothers to feel blue after birth, but in the past women who had mildly low mood may have been able to provide better mothering.
Inflammation, Hormones, and Baby Blues
A search for underlying biological factors that predispose or are protective against postpartum low mood and depression has yielded conflicting results, but there is little doubt that these factors exist and, with psychosocial and environmental factors, influence risk for postpartum low mood. Childbirth has a direct effect on the immune response and on the hormones that regulate stress response and there is increasing evidence that many physical and psychological ills that humans face are due to infection and inflammation. In support of the proposal of an infectious link to postpartum low mood, some researchers found higher inflammatory response in women who had postpartum blues. Thus, anything that can reduce inflammation can, presumably, reduce the chances of experiencing postpartum depression. Women who breastfeed are less likely to suffer from depression, suggesting another possible connection to infectious agents. The probable mechanism linking these is that women who have recently given birth are more susceptible to inflammation due to a number of factors, including hormonal changes, pain, sleep disturbances, and other stressors. All of these can increase the likelihood of depression, but breastfeeding (unless it causes pain and stress itself) can attenuate it by countering stress and thus the inflammatory effects. Depressed mothers often stop breastfeeding, a decision that may perpetuate the depression. Because breastfeeding is so ubiquitous in traditional cultures, this may partially explain the low reported incidence of postpartum blues in those cultures. Kathleen Kendall-Tackett, a health psychologist, claims that inflammation is not just one of the factors that influence postpartum mood, but is the factor. She argues that rather than acting directly on mood, all other variables that seem to be related to postpartum feelings (pain, sleeplessness, trauma, lack of social support, marital difficulties, infant illness, low income, a history of trauma) act to increase inflammation which, in turn, increases risk for depression. Developing ways to deal with the inflammatory response to these stressors may be the best hope for intervention efforts and prevention of postpartum low mood and depression. Getting a good night’s sleep may be difficult for new mothers, but it is probably one of the best ways of ameliorating postpartum blues, just as it is for many other physical and psychological ailments. Add breastfeeding to the prescription and postpartum depression may be avoided by most new mothers. Kendall-Tackett also suggests that anything a woman can do to reduce inflammation will also improve postpartum mood. This includes consuming anti-inflammatory agents such as long chain omega-3 fatty acids.
Unfortunately, because depression often leads to sleep deprivation, there is a vicious cycle that is difficult to overcome in the early postpartum days. It is the same with pain: pain increases stress and inflammatory response, which in turn, lowers the threshold for pain and leads to low mood. Almost all women report some level of pain in the postpartum period. Interestingly, anthropologists Jim McKenna and Thom McDade report that what may be considered to be disrupted sleep seen in women who co-sleep with their infants does not seem to be related to increased pain, suggesting that co-sleeping may be protective against low mood. Women who sleep with their infants also tend to breastfeed and they do not usually have to get up in the night to feed, so their overall sleep may be better than that of a mother who arises every hour or two to breastfeed her infant. Finally, I return to the evidence that hormones of pregnancy reach much higher levels in women in health-rich nations than they do in women in health poor populations. Thus, the changes that occur at the end of pregnancy and the withdrawal of high levels of estrogens and progesterone may have more profound impacts on health-rich women and thus lead to low mood. It seems that we can blame more and more of the ill effects of modern civilization on factors that increase lifetime exposure to high levels of reproductive hormones. If those of us who work in the field of evolutionary medicine made recommendations, here is what we might say mothers should do to reduce the chances of developing more serious mood disorders of the postpartum period: (1) prepare for childbirth so that its physical and emotional stressfulness is reduced, especially by having a supportive companion with the mother at delivery; (2) eat plenty of omega-3 fatty acids throughout pregnancy and postpartum; (3) breastfeed the infant for at least a year; (4) get as much sleep as possible, even if it means sleeping with the infant (in a safe manner) so as to minimize the disruption caused by breastfeeding; (5) reduce stresses from as many sources as possible, even if it means some form of (nondrug) therapy to deal with ones that cannot be controlled; (6) get plenty of exercise, because it counteracts both inflammation and stress (but do not start doing vigorous exercise in pregnancy if exercise has not been routine); (7) keep potentially stressful infant crying to a minimum by breastfeeding frequently and responding to cries as quickly as possible. Even if none of these works to prevent baby blues, they enhance overall health of mothers and infants, so I have no hesitation in proffering them. I have demonstrated that a lot of interesting and important things go on in the first hour after birth and that in the evolutionary past, mother-infant contact during this time was probably critical to infant survival. Given what is going on in the first year or two of life, it may seem strange that an entire article has been given over to what is essentially only a single hour. Perhaps I have paid too much attention to this tiny bit of time, but as noted earlier, it is probably one of the most significant hours in a person’s life, and what happens in that time can potentially have a great deal of impact on how that life unfolds. It certainly had great importance in the evolutionary past. All of this happens under the watchful eyes of mothers and other caretakers, but the most crucial component is breastfeeding.