Clinical Lactation

Breastfeeding is a physical function for mothers and infants. The societal relevance ought to be undoubted en as a medical discipline it should belng among the highest ranked, for its population (all newborn children!) is huge. In daily practice the knowledge of human lactation and the counseling of breastfeeding dyads amongst medical and nursing health professionals is on average rather low. Many advices and treatments are not based on scientific evidence, but on tradition, hear-say and the influences of pharmaceutical and infant formula industries. And this is not so for a lack of available  scientific knowledge. Most medical and nursing professional journals do publish about breastfeeding research and even more knowledge surrounding human lactation and breastfeeding counseling is published in specialized peer reviewed lactation journals. Today I would like to highlight some articles from the Fall, 2010 issue of Clinical Lactation. Genna, Walker and Kendall-Tackett are great names in lactation science. They write about breastfeeding as the norm in feeding and caring for infants and young children. Kendall-Tackett addresses sense and non-sense in her article about safe-sleep campaigns, and stresses that it is not sharing a bed with a parent that raises SIDS risks, but other factors, mostly a combination of factors. Walker discusses the special needs late-premature infants have and the special care breastfeeding them is needed for breastfeeding counseling. Genna addresses the importance of maternal and infant positions in order to facilitate the baby to use his hands in finding the breast and latching on.
Kathleen Kendall–Tackett, Zhen Cong, Thomas W. Hale: Mother–Infant Sleep Locations and Nighttime Feeding Behavior; U.S. Data from the Survey of Mothers’ Sleep and Fatigue. Clinical Lactation Vol. 1, Fall 2010
Marsha Walker: Breastfeeding Management for the Late Preterm Infant; Practical Interventions for “Little Imposters”. Clinical Lactation Vol. 1, Fall 2010
Catherine Watson Genna, Diklah Barak: Facilitating Autonomous Infant Hand Use During Breastfeeding. Clinical Lactation Vol. 1, Fall 2010.

Research and development

Research around the health outcome effects of certain interventions follows a certain structure an complicated mathematics to diminish the influence of  ‘’confounding factors’’ on the study findings, in order for the researcher to be sure it is his intervention that made the difference. SES (socio-economic situation) and education level are well known and often used variables used to dim study-results. Result from targeted studies comparing results from developing and developed countries show that these variables are not as stable and sure as they are traditionally accounted for. A large-scaled study by Brion et al Compared results from studies varying countries with different SES and educational structures about the influence of breastfeeding on blood pressure, obesity and diabetes in children. In more developed countries A higher SES was positively correlated to higher breastfeeding rates, but not in less developed countries. In developed countries a clear positive correlation was found between breastfeeding and lower blood pressure, better BMI’s and higher IQ’s, but in less developed countries this was only true for breastfeeding and higher IQ. IQ positively turns out to be not only a matter of inherited benefits, but of infant feeding choices as well. And evenly evident it seems to be that besides and after breastfeeding BMI and blood pressure in later life are influenced by more than infant feeding alone. The COHORTS study revealed amongst others that in the developing countries participating in these studies breastfeeding or not hardly has any measurable influence on blood pressure, obesity and diabetes later in life. The researchers point out that more research, that fine-tunes the categories of ‘’ever or never breastfed’’, duration of breastfeeding and of exclusive breastfeeding might change these findings. In many developing countries breastfeeding incidence is high, but breastfeeding duration and more so duration of exclusive breastfeeding may be quite low.
Brion M-JA, Lawlor DA, Matijasevich A, Horta B, Anselmi L, Araújo CL, Menezes AMB,
Victora CG, Smith GD:  What are the causal effects of breastfeeding on IQ, obesity and blood pressure? Evidence from comparing high-income with middle-income cohorts Int. J. Epidemiol. (2011) dyr020 first published online February 24, 2011
Fall CHD, Borja JB, Osmond C, Richter, Bhargava SK, Martorell R, Stein AD, Barros FC, Victora CG, and the COHORTS group: Infant-feeding patterns and cardiovascular risk factors in young adulthood: data from five cohorts in low- and middle-income countries Int. J. Epidemiol. (2011) 40(1): 47-62 first published online September 17, 2010

Growth, overweight and menarche

According to Kramer c.s. of the large PROBIT study (Belaraus) children who are breastfed show slower growth than those who are not (however it would be more correct to phrase this as ‘’children who are not breastfed will grow faster than breastfed children or even grow too fast). The fact that parents, too, will compare the growth of their breastfed infants with the growth of their formula fed counterparts, may according to the researchers lead to the phenomenon of starting earlier than planned with formula supplements or weaning to formula altogether. ‘’More is better’’ seems to be a well-established adagio in both health care providers and parents, but in the case of body weight this may very well be untrue. Several studies have linked a higher body weight in young girls to early onset of puberty. Early puberty exposes girls to an increased risks of prolonged exposure to estrogens. Duration of breastfeeding and of exclusive breastfeeding, too, are linked to the age at menarche. It is possible that more than breastfeeding per se, the role of breastfeeding in weight gain as infant and the effect of not breastfeeding on obesity in pre-puberal children is the central factor in this theme.
Kramer MS, Moodie EEM, Dahhou M, Platt RW: Breastfeeding and Infant Size: Evidence of Reverse Causality Am. J. Epidemiol. (2011) first published online March 23, 2011
Al-Sahab B, Adair L, Hamadeh MJ, Ardern CI, Tamim H: Impact of Breastfeeding Duration on Age at Menarche Am. J. Epidemiol. (2011) kwq496 first published online March 23, 2011 
Terry MB, Ferris JS, Tehranifar P, Wei Y, Flom JD: Birth Weight, Postnatal Growth, and Age at Menarche Am. J. Epidemiol. (2009) 170(1): 72-79 first published online May 13, 2009

Is breast best?

(Photo: my dog Dora and her first and only litter)

Does breastfeeding make smarter kids? Does breastfeeding cause less infection? Are breastfed children less often and less severe ill? No. Doesn’t breastfeeding have any benefits then? No, that’s right: breastfeeding does not have any benefits. Breastfeeding can not have benefits, because it is the norm for feeding, nurturing and protecting newborns and children in their first years of life. Biologically speaking, humans are mammalians. Most significant feature of mammalians is that the young are fed from the mammae (milk secreting glandular tissue clusters) of their mothers for a certain amount of time following birth. In the course of hundreds of thousands of years of evolution this has become a tried and proven  system, which has led to, amongst others, the great overall success of mammalian species. Part of this perfection is specialization: the lactation process and the composition of milk are fine tuned to the specific needs of the young of each single species. The duration of the lactation period, for example is linked to the eruption of teeth: many mammalians start eating other foods besides milk around the time the first teeth start erupting and drink their last drops of milk around the time the teeth start changing. The composition of milk is related to the way the young are cared for and the needs for developing systems that are crucial for the survival of the species. Species who leave their young in nests provide milk low in water, but very high in energy and protein; carriers on the other hand feed their young with milk high in water and milksugar, but very low in protein. Animals who need to run with the herd get milk with lots of protein and calcium, while species who survive because they’re smarter than others provide their young with nutrients that promote mind-development. Being breastfed by his own mother, or at least a mother from his own species, is essential for every young animal, inclusing the human. Breastfeeding is not an added bonus; non-breastfeeding is the deprivation of a basic need. Non-breastfeeding has disadvantages.

Just milk

Breastfeeding is the most elaborate gift a mother can ive her child: it’s fluid love, food, nurturing and protection; medication and vaccination; developmentl support for body and mind. Throughout history and the world to be breastfed or not could mean life or death. And still, breastfeeding is just a bodily function and a mother’s milk is just milk. Breastfeeding is ultimately special and very normal. Mom’s milk is a magical substance and still just milk. That can make things difficult to understand for moms and others. Breastfeeding extraordinary extra-special and still there this woman is nursing in the train; mom’s milk is almost as sacred as church-wine and still that mom makes pancakes with it. Much has been said about what can or may or should or not be done with human milk and most of it is based on nothing. Guidelines for mom’s milk storage are just the same guidelines used for all protein rich foods and those ignore the magical powers (pro-active pathogen attackers) of fresh human milk. It is ‘’forbidden’’ to cook with mother’s milk, that will destroy the previously ignored protective powers in it, while not taking into account that in the end it’s just milk that can be used in almost every recipe calling for milk. (Note: it is not a good idea to boil all milk a child will have, because than indeed he will suffer from insufficient protection!). Oh, and do remember moms: do not run, twist or jump, because your milk may never been shaken, because that just might break down the proteins. Does anyone worry about broken down proteins in their cappuccino’s?
http://eurolacen.blogspot.com/2011/04/human-milk.html

Protection for mother and child

In this issues some fragments from a Unicef document about the effect of infant feeding choice on the survival chances of children and women’s health. Unicef states: ‘’Breastfeeding Saves More Lives Than Any Other Preventive Intervention’’. And this is not only true in the developing world, but in our rich Western society as well. ‘’Non-breastfed children in industrialized countries are also at greater risk of dying - a recent study of post-neonatal mortality in the United States found a 25% increase in mortality among non-breastfed infants. In the UK Millennium Cohort Survey, six months of exclusive breast feeding was associated with a 53% decrease in hospital admissions for diarrhoea and a 27% decrease in respiratory tract infections.’’ Unicef cooperated with the WHO in formulating recommendations for optimal breastfeeding: ‘’Initiation of breastfeeding within the first hour after the birth; exclusive breastfeeding for the first six months; and continued breastfeeding for two years or more, together with safe, nutritionally adequate, age appropriate, responsive complementary feeding starting in the sixth month.’’ Formula is not an acceptable substitute for breastmilk because formula, at its best, only replaces most of the nutritional components of breast milk: it is just a food, whereas breast milk is a complex living nutritional fluid containing anti-bodies, enzymes, long chain fatty acids and hormones, many of which simply cannot be included in formula.  Furthermore, in the first few months, it is hard for the baby’s gut to absorb anything other than breastmilk. Even one feeding of formula or other foods can cause injuries to the gut, taking weeks for the baby to recover.‘’  The major problems for living up to the recommendations to exclusively breastfeed fo 6 months and continue for 2 years or more are the societal and commercial pressure to stop breastfeeding, including aggressive marketing and promotion by formula producers. ‘’These pressures are too often worsened by inaccurate medical advice from health workers who lack proper skills and training in breastfeeding support. In addition, many women have to return to work soon after delivery, and they face a number of challenges and pressures which often lead them to stop exclusive breastfeeding early.’’ Mothers and children need protection: children by being breastfed and mothers from being pressured to quit breastfeeding and from having to take hurdles and barriers to breastfeed.
http://www.unicef.org/nutrition/index_24824.html

Unwanted ingredients

Although breastfeeding and human milk are the furst choice for the nurturing, protection and feeding of infants, many parents choose to use substitutes to feed and nurture. The infant food industry happily jumps in on this trend by broadly marketing their product to be ‘’even better now’’ and ‘’most like human milk’’ (makes you wonder how inferior the previous variations were). Ingredient after ingredient of human milk is researched and (if not to difficult and pricey to duplicate) added to the human milk substitute. Infant formulas nowadays contain quite some of the hundreds of ingredients of human milk and is more or less suitable to supply the basic nutrition needs of infants. But the basic ingredients used and the methods used also unwanted and not-asked for (and not appearing on the labels) ingredients will end up in the powder. Minerals and spores that need to be in the milk may appear in unwanted-high quantities. A Scandinavian study by Ljung et al found that a serving of human milk substitute contained significant more Fe, Mn, Mo, As, Cd, Pb and U than one feeding of breast milk, but less Ca, Cu and Se. Rice-based products in particular contained elevated As concentrations. Drinking water used to mix powdered formula may add significantly to the concentrations in the ready-made products. Evaluation of potentially adverse effects of the elevated element concentrations in infant formulas and foods are warranted. In Italy, Meucci c.s. studied samples of the leading brands of infant formula milks and meat-based infant foods commonly marketed in Italy to determine the concentrations of zearalenone and its metabolites (zearalenone is a yeast-toxin of the fusarium species, which is slightly toxic, possibly carcinogenic and has estrogenic charateristics). This study shows the presence of mycoestrogens in infant (milk-based and meat-based) food, and this is likely to have great implications for subsequent generations, suggesting the need to perform occurrence surveys in this type of food.
Ljung K, Palm B, Granderm, Vahter M: High concentrations of essential and toxic elements in infant formula and infant foods - A matter of concern. Food Chemistry, 2011, 127(3):943-951.
Meucci V, Soldani G, Razzuoli E, Saggese G, Massart F: Mycoestrogen Pollution of Italian Infant Food. The Journal of Pediatrics, In Press, Corrected Proof, Available online 10 March 2011.

Human milk

(picture: A day's congress attendees' harvest; Ede, NL, 2010)

Today my planned topic was on handling human milk: in what container, how and how long to store; how to thaw, warm and mix; do’s and don’ts, but I just can’t find any research on it. Lots of studies on details (just re-read the Newsflashes under the tags bacterial contamination, flash heating, pasteurization), but not the overall questions. Still, many rules are shared on the storage and handling of expressed and pumped milk: do not ever shake human milk (I really would like to know what has been observed under controlled laboratory circumstances with shaken milk!); place human milk at a certain place in the fridge or freezer for fear of temperature changes (now, really, folks, how are the odds of rising the temperature of cold milk in a container up to dangerous temperatures for bacteria growth by opening the fridge door?); never mix fresh milk with milk already stored (or not until they have the same temperature); never heat human milk up to body temperature twice; don't use human milk after deep-freezing for 4 or 6 months; finish or throw away within an hour of the start of a feed. All these are rules that make human milk feeding difficult. For mothers who do not easily pump, throwing away their milk is hard. And if there was a bit of evidence that these rules really are true hazards, OK, but I can’t find it. Someone?

Biological Nurturing

Since doctors took over labor and delivery women have been lying down to give birth. In the last decennia awareness grew that however convenient these positions are for the physician or midwife delivering the baby, it is not so for mother or child. After all, just imagine how hard it is to push a slightly too big child trough a slightly too narrow curving birth canal while working against gravity. Pioneers like Odent, Gaskin and Smulders recognized that and started working on and promoting vertical birthing positions. In breastfeeding we see something happen that compares to this, but the other way around. Breastfeeding is viewed as learned behavior and mother are instructed how to position themselves and their child, how to support and how to latch on. Most frequently used positions are sitting straight upright. To learn breastfeeding this way is often hard and frustrating for both mother and child and is often accompanied with discomfort and pain for mom. Colson is the pioneer in this area, working on and promoting different breastfeeding positions in order to make breastfeeding easier and increase comfort and enjoyment. In order to achieve enjoyable and comfortable breastfeeding mothers need to recline  to a laid-back position. The positions traditionally used for birthing appear to be working better for breastfeeding and vice versa. A baby who is on his tummy on top of his laid-back mother, is in an optimal position to promote his innate reflexes for searching and finding the breast, latch o and create milk flow. Mothers are way more comfortable and enjoy breastfeeding without or far less pain. It is time we reconsider the ways we teach mothers how to breastfeed.
Colson S., (2005) Maternal breastfeeding positions: Have we got it right? (1) The Practising Midwife 8:10;24-27; (2) The Practising Midwife 8:11; 29-32
Colson S (2008) The Nature – Nurture Debate and breastfeeding competencies. Bringing Nature to the Fore. The Practising Midwife 8(11) 14-19
Colson S: An Introduction to Biological Nurturing – New Angles on Breastfeeding. Hale Publishing, 2010 (Available In Dutch summer 2011).
CW Genna: Facilitating autonomous infant hand use during breastfeeding. Clin Lact, 2010 - media.clinicallactation.org

Mother’s milk substitutes

Almost all mothers can breastfeed successfully, which according to WHO and Unicef includes initiating breastfeeding within the first hour of life, breastfeeding exclusively for the first 6 months and continuing breastfeeding (along with giving appropriate complementary foods) up to 2 years of age or beyond. Exclusive breastfeeding in the first six months of life is particularly beneficial for mothers and infants. Positive effects of breastfeeding on the health of infants and mothers are observed in all settings. Nevertheless, a small number of health conditions of the infant or the mother may justify recommending that she does not breastfeed temporarily or permanently. Whenever stopping breastfeeding is considered, the benefits of breastfeeding should be weighed against the risks posed by the presence of the specific conditions listed. When deciding to interrupt, stop or supplement breastfeeding it should be noted that feeding at breast is first choice, directly followed by alternatively feeding mom’s own milk. If, even after optimizing breastfeeding management and techniques first choice for an alternative is another mother’s milk (donor-milk) or feeding at breast by another mother (cross-nursing). The 4th option, if no human milk in any form is available, is a specialized non-human milk based substitute or formula. Only children who are incapable to digest human or non-human milk the first and only alternative is a highly specialized and adapted milk substitute. This includes children with classic galactosemia, maple syrup urine disease and with phenylketonuria. A very short list of maternal medications contra-indicates breastfeeding for the duration of the therapy. Mothers who have several acute or chronic diseases can breastfeed a long as they are able to handle their child. One true contra-indication is HIV+, but only if formula is AFASS (acceptable, feasible, affordable, sustainable and safe). Other situations like pre- and dysmaturity, increased risk of hypoglycemia need to be addressed with optimized breastfeeding management and techniques, possibly with own mother’s milk supplements, and only if these do not lead to the aimed results supplements of non-human milk based substitute is indicated.
HIV infection1: if replacement feeding is acceptable, feasible, affordable, sustainable and safe (AFASS)
http://www.borstvoeding.com/problemen/medicijnen/medicijnlijst-nl.html
WHO/Unicef: Acceptable medical reasons for use of breast-milk substitutes. WHO/NMH/NHD/09.01. WHO/FCH/CAH/09.01

Got milk?

Universally mothers (and those around them) fear not to be able to make enough milk for their children. The vast majority of those worry without an cause: humanity as species would not have survived in such abundance if many mothers wouldn’t be able to sustain their offspring. A body capable to conceive, carry and birth a child will also be able to feed and protect the child after birth. Still, often mothers do indeed make not enough milk to feed their babies. Generally the reason will not be that mom’s body can’t do it, but that said body is not instructed well. Milk production is a matter of letting hormones do their job and providing good instruction to the body. Good instructions are: having a baby feed often and accurate at breast and empty the breasts well in order to tell how much milk he needs. And: a baby in close bodily contact with mom to let her body know that the baby is still there, will be there some time more and will be needing milk while he hangs out. Those mothers who even with good instructions do not make enough milk (and of course that is possible, but not as frequent as often thought) aids do exist. Based on frequent and adequate breastfeeding and emptying of the breasts (preferably by the baby, but if needed by pumping as well) there are medications and herbs to increase milk production. Each culture developed their own preference for galactogoge herbs. In Chinese medicine acupuncture is another possibility.  In a randomized trial He et al (2008) showed that both traditional herbal tea and acupuncture led to a similar increase in milk volume. Lu et al (2010) found in his randomized trial that mothers who received both instruction and acupuncture had significantly higher prolactin levels than mothers who only got instruction. The researchers He and Lu did use different acupuncture points (Tanzhong and Tuina respectively).
He JQ, Chen BY, Huang T, Li N, Bai J, Gu M, Yu M, He XP, Wang HY: [Randomized controlled multi-central study on acupuncture at Tanzhong (CV 17) for treatment of postpartum hypolactation][Article in Chinese]. Zhongguo Zhen Jiu. 2008 May;28(5):317-20.
LU Ping, QIU Jin, YAO Fei, ZHENG Juan-juan: Effect of acupoint Tuina on lactation amount for parturient. Chinese Acupuncture & Moxibustion, 2010-09.

Dummies, pacifiers, and substitutes

Mothers sometimes sight about feeling a dummy/pacifier when their little one wants to breastfeed over and over again, even he ‘’can’t be hungry’’. Of course, this is the world turned around: it is the dummy that is the substitute, not the mother. The pacifier is the soother (in earlier ages literally when dipped in sugar water or liquor) if mom herself is not available. Breastfeeding experts and the WHO discourage the use of pacifiers/dummies in breastfed children, because these devices limit the tme spend at breast and could negatively influence breastfeeding exclusivity and duration. Expert from other fields point out that dummies pose other risks as well (increased risk of abnormal dental development abnormal breathing patterns and difficulties in speech development). Yet other experts feel strongly that dummies are a powerful tool in the war on SIDS (however, in this use they are a substitute for breastfeeding as well). Al kinds of research is performed to sort out for once and always if all those claims pro or con pacifiers and their impact on breastfeeding are true or false. And, as expected, this fails completely, because all studies keep each other quite leveled. Some things just can not be proven not denied the Golden Scientific Truth way (prospective, double-blinded, randomized trial). And why would one even want to proof that the original is superior to the substitute? No matter how many George Clooneys are lined up, coffe-substitutes never will taste ike freshly brewed. Not even with all Nestle’s superb marketing tricks.
Lindsten, Rune; Larsson, Erik: Pacifier-sucking and Breast-feeding: A comparison between the 1960s and the 1990s. Journal of Dentistry for Children, 2009, 76(3):199-203(5)
O’Connor NR, Tanabe KO, Siadaty MS, Fern R. Hauck FR: Pacifiers and Breastfeeding; A Systematic Review. Arch Pediatr Adolesc Med. 2009;163(4):378-382.
Karabulut E, Yalçin SS, Ozdemir-Geyik P, Karaağaoğlu E.: Effect of pacifier use on exclusive and any breastfeeding: a meta-analysis. Turk J Pediatr. 2009 Jan-Feb;51(1):35-43.

Protection and pathogens

(Photo: Louis Pasteur, inventor of pasteurisation) 

A primary function of breastfeeding is protection against infection. Human milk contains both pathogens and protective properties. Protection works best if baby breastfeeds directly at breast, followed closely by drinking untreated, freshly pumped milk that was not chilled nor heated. But direct breastfeeding or consuming fresh milk is not always possible, so some milk may need to be stored and heated. Many professionals feel it should be pasteurized as well. Any kind of storage and all temperature changes will cause some alteration in the protective function of human milk. Multiple studies investigated different ways to pasteurize and store milk. The most common method of pasteurization (Holder pasteurization, 62.5°C, 30 min) turned out to be not only an effective way to destroy all pathogens tested, but also the vast majority of protective factors. Modified pasteurization (57°C, 30 min) in the Czank c.s. study showed to be as effective in the termination of pathogens, but kept far more protection intact. Akinbi et al found that not only  heat treatment, but also storage at −20°C for 4 weeks did lower protective properties, but not as much as heating. Marin c.s. on the other hand did not find significant differences in protective properties after storing milk samples at -20°C for 6 weeks. A remarkable result they did find, however, was that in all milk samples obtained by pumping bacterial counting was higher than in all samples obtained by hand expression.
Akinbi H, Meinzen-Derr J, Auer C, Ma Y, Pullum D, Kusano R, Reszka K, Zimmerly K: Alterations in the Host Defense Properties of Human Milk Following Prolonged Storage or Pasteurization. Journal of Pediatric Gastroenterology & Nutrition: 2010, 51(3):347–352
CZANK, CHARLES; PRIME, DANIELLE K.; HARTMANN, BEN; SIMMER, KAREN; HARTMANN, PETER E.: Retention of the Immunological Proteins of Pasteurized Human Milk in Relation to Pasteurizer Design and Practice. Pediatric Research: 2009, 66(4):374-379
Marín, María L; Arroyo, Rebeca; Jiménez, Esther; Gómez, Adolfo; Fernández, Leonides; Rodríguez, Juan M: Cold Storage of Human Milk: Effect on Its Bacterial Composition. Journal of Pediatric Gastroenterology & Nutrition: 2009, 49(3):343-348

Sleep, baby, sleep

Sleep of both new parents and infants is a much debated and researched topic. The completely differing sleep patterns of newborns and young babies cause sleep problems, sleep deprivation and daytime fatigue in their parents. Often the blame for ‘’sleep problems in infants’’ (which, in fact, of course, are parents’ sleeping problems) is put on breastfeeding and there is a widely-held believe that formula fed babies sleep better, but multiple studies have denied these theories. All kinds of programs and methods have been developed to coerce infants lightly or more strongly into not making themselves heard at night times.  A mostly overlooked point in al discussions, studies and programs is that is a fact that young babies do have other patterns and needs for a reason; for instance that wakening regularly at night will protect from SIDS, and will ensure continuing feeding, in order to prevent low glucose levels and uninterrupted brain development. Other studies (check Newsflash archives for ‘’co sleeping’’, ‘’bed-sharing’’, and ‘’night time breastfeeding’’) show that the closer a mother sleeps to her sleeping child, the more her sleep cycles mimic those of the child, which makes her loosing less sleep and waking up more refreshed. Co-sleeping (in the same bed, with a co-sleeper or ‘’side-car’’) benefits breastfeeding. Prenatal (and perhaps even pre-conception) education should include information on normal infant sleeping patterns (which are not linked to the chosen infant feeding method!), that differ from those of parents and how parents can work with that knowledge in order to have everybody get the rest they need.
Montgomery-Downs, Hawley E., Clawges, Heather M., Santy, Eleanor E: Infant Feeding Methods and Maternal Sleep and Daytime Functioning. Pediatrics 2010 126: e1562-e1568
Hunter LP, Rychnovsky JD, Yount SM: A Selective Review of Maternal Sleep Characteristics in the Postpartum Period. Journal of Obstetric, Gynecologic, & Neonatal Nursing. 2009, 38(1):60-68.