Table 1.

Characteristics of studies quantifying breast milk feeding parameters in term and preterm infants

Study	Design	Country	Main study aim	Population	Feeding parameter(s)
Aimone et al. (2009)	Longitudinal, randomized controlled	Canada	To examine the impact of feeding human milk containing extra nutrients for 12 weeks after discharge on premature infant bone mineralization, body composition and human milk use up to 1 year.	Thirty‐four preterm infants (born <33 weeks GA, 750–1,800 g; control group: 47% male, intervention group: 74% male) who completed the 12‐week randomized controlled trial by O'Connor et al. (2008) followed until 12 months CA regarding human milk feeding duration, exclusivity and time to introduction of solids.	PBF volume
Amatayakul et al. (1999)	Longitudinal, observational	Thailand	To observe whether or not previous successful breastfeeding has any influence on subsequent breastfeeding behaviour.	Sixty breastfeeding infants (42% male) who were randomly selected from three subdistricts of the rural northern Thai population, received supplementary feeding with premasticated rice within the first month of life. The infant pairs were stratified by whether their mothers were primiparous or multiparous, and were followed until 360 days of age.	PBF volume, PBF frequency
Atkinson et al. (1981)	Longitudinal, non‐randomized controlled	Canada	To examine the adequacy of preterm infant's mother's milk as compared with donor milk or formula for the premature infant.	Of the 24 LBW premature infants (born <1,300 g) selected from all patients admitted to the NICU, eight received pooled breast milk and eight received their mother's own breast milk. The infants were followed for 2 weeks during the NICU stay.	EBF volume, PBF volume
Bandara, Hettiarachchi, Liyanage, Amarasena, and Wong (2015)	Cross‐sectional, observational	Sri Lanka	To measure the human milk intake of infants during the first 6 months of age to assess their adequacy of human milk intake and to document the breastfeeding practices of their mothers.	Forty‐eight exclusively breastfeeding healthy term infants randomly selected from maternal and child health clinics. Infants were stratified across three examined age groups: <2 months, 2 to <4 months and 4–6 months.	EBF volume
Bhutta, Abbass, Wright, and Coward (2004)	Longitudinal, observational	Pakistan	To survey and evaluate the growth pattern, and breast milk and fluid intake patterns of infants in Pakistan.	Twelve term infants who were a subset of the 112 surveyed mother–infant pairs recruited from a hospital medical centre, followed over 6 months.	EBF volume
Borschel, Kirksey, and Hannemann (1986)	Longitudinal, observational	U.S.	To validate the accuracy of the test weighing procedure on volume of formula intakes for formula‐fed infants by comparing the test weighed measured values with those obtained by direct measurement.	Of the 35 healthy term infants of mothers from a university community who were followed for the first 6 months, 15 infants (67% male) were exclusively breastfed and test weighed. The infants were originally part of a larger study investigating vitamin B6 nutrition from consumed breast or formula milk.	EBF volume, EBF frequency
Brown, Robertson, and Akhtar (1986)	Longitudinal, observational	Bangladesh	To describe the amounts of breast milk‐derived macronutrients consumed by marginally nourished Bangladeshi infants and examine their patterns of growth.	Fifty‐eight infants of mothers from an underprivileged semiurban community were followed for 9 months. The infants generally had a lower body weight (approximating the U.S. National left for health Statistics (NCHS) 5th centile during the first 4 months and declining thereafter) than most exclusively breast‐fed North American infants.	EBF volume
Butte, Garza, Smith, and Nichols (1983)	Cross‐sectional, observational	U.S.	To compare the deuterium dilution technique against the test‐weighing method for measuring breast milk intake.	Twenty‐one infants who were breast‐fed exclusively (one infant customarily received water) and assessed at a mean of 3.3 ± 0.4 months of age.	EBF volume
Butte, Garza, Smith, and Nichols (1984); Butte, Garza, Stuff, et al. (1984)	Longitudinal, observational	U.S.	Butte, Garza, Smith, and Nichols (1984): To longitudinally document intakes and growth of breastfed infants to obtain normative data on human milk production and examine potential discrepancies between observed levels of human milk intake and U.S. National Center for Health Statistics (NCHS) nutrient recommendations. Butte, Garza, Stuff, et al. (1984): To examine the influence of maternal diet and body composition on lactational performance in a group of privileged, presumably well‐nourished women to establish energy recommendations during lactation.	Forty‐five exclusively breastfed healthy term infants (born 37–42 weeks GA, 2,560–4,570 g; 60% male) of mothers recruited through a milk bank program, who were observed over the first 4 months.	EBF volume, EBF frequency
Butte, Wong, Patterson, Garza, and Klein (1988)	Cross‐sectional, observational	U.S.	To compare the deuterium dilution technique against the test‐weighing method for measuring breast milk intake.	Nine term infants, with five of the infants feeding exclusively on human milk and measured at approximately 1.5, 3 and 4 months of age. The remaining four infants were fed human milk and supplemental foods.	EBF volume
Butte et al. (1990)	Cross‐sectional, observational	U.S.	To combine the doubly labelled water method with conventional indirect calorimetry to explore possible differences in energy utilization between breastfed and formula‐fed infants.	Forty term infants, of which 20 were exclusively breastfed human milk since birth. Ten of the breastfed infants were observed at 1 month, and a second set of 10 infants were observed at 4 months of age.	EBF frequency
Butte, Smith, and Garza (1990)	Cross‐sectional, observational	U.S.	To investigate the energy utilization of breastfed and formula‐fed infants, and determine whether energy utilization was different between the two feeding groups.	Sixty‐five healthy term infants whose mothers were recruited from a milk bank program were observed at 1 and 4 months of age. Of the participating infants, 32 were exclusively breastfeeding (44% male).	EBF volume
Cabrera Lafuente et al. (2018)	Longitudinal, observational	Spain	To describe the intake of mothers' own milk and its composition according to gestational age and postnatal age in preterm infants and to correlate them with neonatal weight, length and morbidities.	One‐hundred‐and‐seventy‐six preterm infants (born <32 weeks GA; 52% male) were included, where the majority of infants received partial feeding of mothers' own milk. The infants were followed at 72 hr, 15 and 30 days and monthly until discharge (90 days).	PBF volume
Carnielli et al. (1996)	Longitudinal, observational	Italy	To determine whether feeding very low birth weight infants exclusively with preterm human milk can ensure constant plasma and red blood cell long chain polyunsaturated fatty acids levels during the first month of life.	Twenty‐two preterm infants (born 750–1,750 g), of which 14 infants received mother's own milk and eight received preterm human milk, were followed for 4 weeks.	EBF volume
Casey, Neifert, Seacat, and Neville (1986)	Longitudinal, observational	U.S.	To report the intakes of milk, energy and some selected nutrients to estimate nutrient intake in the young neonate.	Eleven healthy term infants from mothers with uncomplicated pregnancies, who were put to the breast within two hours of birth and were followed for 5 days. The infants were exclusively breastfed, except for two who were given water or glucose water 3–6 times after breast feeds.	EBF volume
Cohen et al. (1994)	Longitudinal, randomized controlled	Honduras	To examine breast milk intake, total energy intake and infant growth among breastfed infants randomly assigned to receive nutritionally adequate, hygienically prepared complementary foods beginning at 16 weeks or to be exclusively breastfed until 26 weeks.	Fifty healthy term infants whose mothers were recruited from two public hospitals in Honduras. Infants were exclusively breastfed and at 16 weeks were randomly assigned to continue exclusively breastfeeding (control group), to introduce solid foods with ad libitum breastfeeding, or to introduce solid foods with maintenance of preintervention breastfeeding frequency. The infants were followed until 26 weeks of age.	EBF frequency
de Carvalho, Robertson, Merkatz, and Klaus (1982)	Longitudinal, observational	U.S.	To provide normative data for true demand breastfeeding mothers during the first 14 days postpartum, and to determine whether the frequency and duration of breastfeeding affect milk production at 1 month.	Forty‐six term infants (59% male) whose mothers were encouraged to nurse on true demand, were observed during the first 14 days after delivery.	EBF frequency
Dewey, Heinig, Nommsen, and Lonnerdal (1991a, 1991b)	Longitudinal, observational	U.S.	To present data on indexes of functional outcomes to judge whether a particular pattern of intake or growth, particularly for breastfeeding infants, is advantageous in a given environment.	Ninety‐two healthy term infants and their mothers as part of the Davis Area Research on Lactation, Infant Nutrition and Growth (DARLING) study who were followed until 12 months of age.	EBF volume, PBF volume
English (1985)	Longitudinal, observational	Australia	To report the milk production of a mother post‐partum, while considering the observed production against weight changes and activity of the mother, and breast milk intake of the infant.	One fully breastfed term infant followed for 13 weeks since birth.	EBF volume
Ettyang, van Marken Lichtenbelt, Esamai, Saris, and Westerterp (2005)	Cross‐sectional, observational	Kenya	To evaluate the association between maternal body composition and intake of breast milk in infants in Kenya.	Ten exclusively breastfed infants aged 2–4 months, from a pastoral community living in West Pokot, Kenya. The infants were a randomly selected subset of a larger longitudinal study to determine the prevalence of undernutrition, low iron stores and vitamin A deficiency during the third trimester of pregnancy and at 4 months after birth.	EBF volume
Evans, Evans, Royal, Esterman, and James (2003)	Longitudinal, observational	Australia	To determine the effect of caesarean section on breast milk transfer to the normal term infant over the first week of life.	Of the 185 mother–infant pairs, 88 term infants (50% male) from mothers who had a normal vaginal delivery were exclusively breastfed.	EBF volume
Ferris et al. (1993); Neubauer et al. (1993)	Longutidinal, observational	U.S.	Ferris et al., 1993: To examine whether differences in prenatal care and maternal health, perinatal management of lactation and infant birth outcome among women with IDDM compared with control and reference women explain the duration of human lactation and breastfeeding pattern in women with IDDM. Neubauer et al., 1993: To report the composition of breast milk from mothers with IDDM and their intake from their infants longitudinally.	Thirty‐three infants with mothers with IDDM, 33 control infants from mothers without IDDM and matched by demographic characteristics to the IDDM group, and 11 healthy reference infants followed until 84 days postpartum. Of the 11 term infants with volume of intake data, 10 infants at 7 days and nine infants at 14 days, were exclusively breastfeeding.	EBF volume, EBF frequency
Forsum and Sadurskis (1986)	Longitudinal, observational	Sweden	To examine the interactions between growth and body composition of infants, and the amount of breast milk these infants consume during the first 8–10 weeks of life.	Twenty‐two healthy breastfed infants (59% male) during the first 10 weeks of life.	EBF volume
Hendrickse et al. (1984)	Longitudinal, observational	U.K.	To describe the weight gain and calorie intake of LBW infants who were either fed predominantly on fresh raw breast milk or commercially available LBW formula.	Of the 24 preterm infants (born <33 weeks GA, <1500 g), 10 were fed predominately their own mother's fresh unpasteurized expressed breast milk and followed for their first 6 weeks of life at the NICU.	EBF volume
Hofvander, Hagman, Hillervik, and Sjolin (1982)	Cross‐sectional, observational	Sweden	To compare the amount of breast milk and breast milk substitutes consumed by 1–3 month‐old infants fed ad libitum, and living under similar conditions in their homes.	Of the 150 singleborn, healthy, term infants 75 were exclusively breastfed infants (25 infants studied per age group: at approximately 1, 2 and 3 months of age) were recruited following discharge from randomly sampling mothers from records at a maternity ward.	EBF volume
Hornell, Aarts, Kylberg, Hofvander, and Gebre‐Medhin (1999)	Longitudinal, observational	Sweden	To elucidate the variations in three components of breastfeeding pattern (frequency of feeds, suckling duration and longest interval between two consecutive feeds) in exclusively breastfed infants, while analyzing factors influencing the duration of exclusive breastfeeding and total duration of breastfeeding.	Five‐hundred‐and‐six infants were followed up from the first week after delivery until their mother's second menstruation postpartum or until a new pregnancy. At 26 weeks of follow up, seven of the original 506 infants remained exclusively breastfed. The study was part of a larger, multicentre study of duration of lactational amenorrhea in relation to breastfeeding practices in seven countries.	EBF frequency
Houston, Howie, and McNeilly (1983)	Longitudinal, observational	U.K.	To examine whether minimal intrusion by one, or at the most two, test‐weighs using an electronic balance in 24 hr would give assessments of 24‐hr feed volumes for sufficient accuracy.	Eighteen term infants (born >38 weeks GA, >2,500 g) of breastfeeding mothers were followed for the first 6 postpartum days of life.	EBF frequency
Howie et al. (1981)	Longitudinal, observational	U.K.	To report on the effect that the introduction of supplementary food may have on the frequency and duration of suckling and the resumption of ovarian activity after childbirth.	Twenty‐seven term infants who were exclusively breastfed, and had supplementary food first introduced between 3 and 24 weeks postpartum, were followed up until 40 weeks after delivery.	EBF frequency, PBF frequency
Itabashi et al. (1999)	Longitudinal, observational	Japan	To investigate the nutritional intake of ELBW infants to propose an advisable and practically feasible nutritional intake from Japanese infants with smaller average gains in body weight, head circumference and length than infants from Western countries.	Sixteen ELBW preterm infants (born 26–33 weeks GA) who were admitted to the NICU and were mainly fed preterm milk during the first 4 weeks, gradually reducing to 60% of total milk intake by the 13th week, were followed until 12 weeks of postnatal age.	PBF volume
Janas, Picciano, and Hatch (1985)	Longitudinal, observational	U.S.	To determine the relationships among specific parameters of protein, nitrogen and amino acids of term infants fed either human milk, a whey‐predominant formula, or a cow's milk formula.	Thirty‐seven term infants whose mothers were recruited at prenatal classes or immediately following their infants' birth in the hospital, were followed until 16 weeks of age. Eleven of these infants (27% male) received human milk and were introduced supplementary food after 8 weeks of age.	EBF volume
Jia et al. (2018)	Longitudinal, observational	China	To conduct a longitudinal study on tracing the growth of exclusively breastfed infants and combining human milk analysis to support breastfeeding and to achieve optimal development of infants.	Of the 130 term infants who were enrolled from seven cities in China, 59 infants (51% male) were exclusively breastfed and followed up until 6 months of age.	EBF frequency
Kent et al. (2013)	Longitudinal, observational	Australia	To assess the reproducibility of measures of breastfeeding behaviour and breast milk intake, and to provide clinicians with evidence‐based information to inform parents' expectations of their infants' breastfeeding behaviour and breast milk intake from 1 to 6 months of exclusive breastfeeding.	Fifty‐two healthy term infants who were exclusively breastfed on demand, where mother–infant pairs participated in one of four larger longitudinal studies on energy balance of lactating women, the effect of a progesterone‐only contraceptive pill on lactation, prolactin concentrations in milk and blood and the rate of milk synthesis, and breast volume and milk production during exclusive breastfeeding.	EBF frequency
Krebs, Reidinger, Robertson, and Hambidge (1994)	Longitudinal, observational	U.S.	To determine the growth pattern of normal infants who were fed human milk exclusively for at least 5 months and investigate the relationship of growth to milk intake and whether the growth was related to zinc intake from human milk.	Seventy‐one healthy term infants who were exclusively human milk fed for at least 4.5 months and were randomly assigned to receive 15‐mg zinc supplementation or placebo at 2 weeks of age (milk output between the groups were not significantly different). Of the infants, 43 continued in the study through 9 months of age.	EBF volume, PBF volume
Martinez and Chavez (1971)	Longitudinal, observational	Mexico	To obtain longitudinal data on breast milk yields of mothers from a poor rural community of the Mexican plateau under conditions of strict control and standardization.	Seventeen full term infants who were not breastfed in the first 48–72 hr of life, and were instead fed sugarless leaf infusions or donor milk. Infants were allowed to be fed on demand, including water and other supplementary foods. The mother–infant pairs were part of a larger project to understand the relationship between infant nutrition and its physical, mental and social development.	PBF volume, PBF frequency
Matheny and Picciano (1986)	Longitudinal and cross‐sectional, observational	U.S.	To determine the existence, extent and nature of relationships among nursing frequency, quantity of milk consumed and growth characteristics of exclusively breastfed infants.	Fifty healthy term infants with anthropometric measurements, milk intake and nursing frequency data acquired from three different conducted studies. Milk intake and nursing frequency data were obtained for up to 16 weeks of age.	EBF frequency
Michaelsen et al. (1994)	Prospective, observational	Denmark	To describe the nutritional role of breastfeeding and provide a detailed description of the intake, protein, fat, carbohydrate, and energy of human milk, and potential influencing factors.	Ninety‐one infants (46% male) were followed until 12 months of age and were grouped as EBF or PBF. The infants were part of a larger study, The Copenhagen Cohort study on Infant Nutrition and Growth.	EBF volume, EBF frequency, PBF volume, PBF frequency
Motil, Sheng, Montandon, and Wong (1997)	Longitudinal, observational	U.S.	To investigate the differences in nitrogen and energy utilization between breast‐ and formula‐fed infants by measuring longitudinally the differences in body composition and protein and energy intakes who were fed either human milk or a commercial formula.	Twenty term infants, of which ten were breastfed, were followed until 24 weeks postnatal age.	EBF volume
Neville et al. (1988)	Longitudinal, observational	U.S.	To perform a longitudinal study in highly motivated lactating women, focusing particularly on the first 14 days postpartum to gain a better understanding of the relationship between milk transfer during the initiation of lactation and later lactational performance.	Thirteen term infants who were breastfed, with solids introduced between 4 and 9 months of age and with formula used occasionally after 4 months in three mother–infant pairs.	EBF frequency
Nielsen et al. (2011)	Longitudinal, observational	Scotland	To test whether and how human lactation and breastfeeding practices can adapt to fulfil infant energy requirements during exclusive breastfeeding for 6 months.	Of the 47 infants, 36 infants provided data at 15.4 ± 1.3 weeks, and 38 infants at 24.5 ± 1.3 weeks. At the second time point, six infants were reported to have received complementary foods, however, there were no statistically significant differences in milk intake between these infants and those who were exclusively breastfed.	EBF volume, EBF frequency
Nommsen et al. (1991)	Longitudinal, observational	U.S.	To examine factors, including maternal anthropometric indicators, dietary intake data from a subgroup of the participants, and mother–infant variables such as nursing frequency, feed duration and milk volume, that are potentially related to interindividual differences in the amount of protein, lactose, lipid and energy in milk.	Ninety‐two mother–infant pairs were initially recruited, of which 73, 60, 50 and 46 term infants provided data at 3, 6, 9 and 12 months postpartum, respectively. Mothers of the infant had planned not to introduce solid foods before 4 months of age, or to feed >120 ml/day of other milk or formula throughout the first 12 months. The mother–infant pairs were part of the larger Davis Area Research on Lactation, Infant Nutrition and Growth (DARLING) study, designed to document total nutrient intakes and growth patterns of breastfed and formula‐fed infants during the first 18 months of life.	EBF frequency, PBF frequency
Novotny and Mata (1983)	Cross‐sectional, observational	Costa Rica	To examine the breast milk consumption and anthropometric status of rural Costa Rican infants.	Twenty term breastfeeding infants, of which ten infants were fully breastfed and the remaining ten infants were partially breastfed. Data from the infants were collected at a range of ages, including 2 to 103 days and 26 to 184 days, for the fully breastfed and partially breastfed infants, respectively.	EBF volume, EBF frequency
O'Connor et al. (2008)	Longitudinal, randomized controlled	Canada	To determine whether mixing a multinutrient fortifier to approximately one half of the human milk fed each day for a finite period after discharge improves the nutrient intake and growth of predominately human milk‐fed LBW infants through a pilot study.	Thirty‐nine preterm infants (born <33 weeks GA, 750–1,800 g; control group: 47% male, intervention group: 74% male) randomly assigned to the control group where infants were discharged from the NICU on unfortified human milk (n = 20), or to the intervention group receiving half their volume of human milk as nutrient‐enriched feedings after hospital discharge (n = 19). Infants were followed on study day 1, and 4, 8 and 12 weeks after discharge; and 6 and 12 months CA in a follow‐up study by Aimone et al. (2009).	PBF volume
Oras et al. (2015)	Longitudinal, observational	Sweden	To describe breastfeeding patterns in preterm infants up to 1 year of CA.	Eighty‐three exclusively breastfed preterm infants (born 28–33 weeks GA, 740–2,920 g; 63% male) who along with their mothers, were part of a larger study on kangaroo mother care, where a breastfeeding diary was sent home after discharge from hospital, and at 2, 6 and 12 months of the infant's CA.	EBF frequency, PBF frequency
Pao et al. (1980)	Longitudinal, observational	U.S.	To describe milk consumption and total dietary intake of completely and partially breast‐fed infants and identify factors related to these patterns.	Of the 22 term infants studied at 1, 3, 6 and 9 months, seven infants were completely breastfed at 1 month, one infant was completely breastfed at 3 months, and three infants were partially breastfed at 9 months.	EBF frequency, PBF frequency
Paul et al. (1988)	Longitudinal, observational	U.K.	To measure the growth, energy and nutrient intake longitudinally throughout infancy and to investigate the factors influencing breast milk intake. Additionally, to explore the relationship between breast milk intake and growth and provide fuller details of breast milk intake and anthropometry from 2 to 10 months of age.	Forty‐eight term infants (58% male) who received breast milk up until at least 4 months of age. At approximately 7, 8 and 10 months of age, all infants were no longer exclusively breastfed and were partially feeding.	EBF frequency, PBF frequency
Quandt (1986)	Longitudinal, observational	U.S.	To determine the range of variation in individual breastfeeding behaviours known to have biological and cultural significance, and whether these behaviours are patterned; if patterns exist, whether individual mothers maintain a similar pattern through the early lactation period; and whether patterns of breastfeeding behaviours are associated with outcomes such as duration of exclusive breastfeeding and time of weaning.	Sixty‐two term infants who showed evidence of well‐established exclusive breastfeeding were selected, who were followed at 4 and 8 weeks of age.	EBF frequency
Salmenpera, Perheentupa, and Siimes (1985)a	Longitudinal, observational	Finland	To evaluate the growth of infants exclusively breastfed and compare the growth with infants who weaned early and/or were given complementary foods.	One‐hundred‐and‐ninety‐eight term infants (born 37–42 weeks GA; 53% male) were followed up to 12 months of age.	EBF volume
Sievers, Oldigs, Dorner, and Schaub (1992); Sievers, Oldigs, Santer, and Schaub (2002)	Longitudinal, observational	Germany	To examine whether breastfed infants are able to adapt to zinc intakes that are lower than the recommended dietary allowance; what differences may exist between zinc intake, excretion and retention in breastfed infants and formula‐fed infants, and to compare zinc balances from term breastfed infants with those of term and preterm infants who were formula‐fed.	Of the breastfed and formula‐fed infants enrolled in the study, 7, 10, 9, 9 and 10 infants were of term birth and breastfed at 17, 35, 57 85 and 113 days, respectively.	EBF volume
Stuff and Nichols (1989)a	Longitudinal, observational	U.S.	To determine whether the ad libitum addition of solid foods to the diet of exclusively human milk‐fed infants will increase energy intake and reverse the decline in weight‐for‐age percentiles observed during the exclusive breastfeeding period.	Forty‐five healthy term infants who were exclusively breastfed for as least 16 weeks, where three groups emerged during the transition to monthly mixed feedings of human milk and solid foods. The groups were categorized according to introduction of mixed feeding at Group 1, 20 weeks; Group 2, 24 weeks; and Group 3, 28 weeks.	EBF volume, PBF volume
van Steenbergen et al. (1991)	Cross‐sectional, observational	Indonesia	To describe the feeding practices, breast milk intake and the consumption of additional food during infancy.	Seventy‐seven PBF infants providing cross‐sectional data at 37–56 weeks were studied from three villages along the island of Madura in East Java, Indonesia. Infants were given supplementary foods, such as mashed banana, and solid foods such as egg and fish, as the infants aged.	PBF frequency
van Steenbergen, Kusin, and van Rens (1981)a	Cross‐sectional, observational	Kenya	To report on breastfeeding behaviour, breast milk yield and breast milk composition from mothers living in a rural highland area.	Eighty‐five infants with mothers at different stages of lactation who were examined according to season. The participants of this study were part of two cross‐sectional studies on food intake of infants and toddlers by the Joint Project Machakos. Most infants began to be supplementally fed with some cow's milk at 3 months of age.	EBF volume, PBF volume
Yamauchi and Yamanouchi (1990)	Longitudinal, observational	Japan	To investigate the factors contributing to the frequency of breastfeeding during the first 24 hours after birth and the neonatal response to breastfeeding frequency.	Two‐hundred‐and‐ten healthy term (born 37–44 weeks GA, 2,525–4,030 g; 44% male) breastfed newborns who were observed during the first 24 hr after birth at their hospital stay.	EBF frequency

Abbreviations: CA: corrected age; EBF: exclusively breastfeeding; ELBW: extremely low birth weight; GA: gestational age; IDDM: insulin‐dependent diabetes mellitus; LBW: low birthweight; NICU: neonatal intensive care unit; PBF: partially breastfeeding.

^aData not originally available from the studies were supplemented with data presented in the review by Arcus‐Arth et al., 2005.