Neural maturation of breastfed and formula-fed infants

Background: Human milk provides infants with a full complement of all polyunsaturated fatty acids, including docosahexaenoic acid (DHA) and arachidonic acid (AA). Formula milks only contain the precursors of DHA, AA and linoleic acid, and hence formula-fed infants must synthesize their own DHA and AA. Aim: To evaluate the effect of feeding—whether breastfeeding or formula-feeding—in early infancy upon subsequent neurodevelopment and achievement of optimum brain function. Subjects and methods: The study included 53 normal, healthy infants (30 exclusively breastfed infants and 23 exclusively formula-fed infants) at the age of 1 y (±1 mo). Each infant was subjected to a full physical and neurological examination together with neurophysiological studies including flash visual evoked potential (FVEP), brainstem auditory evoked potential (BAEP) and somatosensory evoked potential (SSEP). Results: There was significant prolongation of P ₁₀₀ wave latency of FVEP in formula-fed infants, together with significant prolongation of absolute latency of waves I, III and V of BAEP in formula-fed infants compared with breastfed infants. There was significant prolongation in inter-peak latencies between cortical and Erb's components in formula-fed infants compared with breastfed infants.

Conclusion: We can conclude that VEP, BAEP and SSEP are more mature in breastfed infants relative to formula-fed infants at 1 y of age, and thus breast milk helps earlier development and maturation of some aspects of the nervous system than milk formulas.     

Effect of early skin-to-skin contact after delivery on duration of breastfeeding: a prospective cohort study

Aim: To study the influence on breastfeeding of skin-to-skin contact after birth. Methods: Using a prospective cohort study design, a group of 1250 Polish children was investigated with 3 y followup. Results: The implementation of the practice significantly increased mean duration of exclusive breastfeeding by 0.39 mo and overall breastfeeding duration by 1.43 mo. The infants kept with the mothers for at least 20 min were exclusively breastfed for 1.35 mo longer and weaned 2.10 mo later than those who had no skin-to-skin contact after delivery. The skin-to-skin contact after birth significantly coexisted with the other hospital practices supportive to breastfeeding, especially rooming-in without separation longer than 1 h per 24 h [relative risk (RR) = 3.18, 95% confidence interval (95% CI): 2.34-4.31] and first breastfeeding within 2 h after birth (RR = 2.94, 95% CI: 2.36-3.67. Multivariate analysis performed by a general linear model with duration of exclusive breastfeeding as the dependent variable indicated skin-to-skin contact and mother education as two independent variables influencing the duration of exclusive breastfeeding. Conclusion: The results indicate that extensive mother-infant skin-to-skin contact lasting for longer than 20 min after birth increases the duration of exclusive breastfeeding.     

Breastmilk feeding for mothers and infants with opioid exposure: What is best?

With rare exception, breastfeeding is the optimal way to feed infants, and has special benefits for women and infants with perinatal opioid exposure. Infants breastfed and/or fed their mother's own breastmilk experience less severe opioid withdrawal symptoms, have shorter hospital stays, and are less likely to be treated with medication for withdrawal. The specific impact of mothers' milk feeding on opioid withdrawal may be related to the act of breastfeeding and associated skin-to-skin contact, qualities of breastmilk, healthier microbiome, small amounts of opioid drug in breastmilk, or a combination of these. Women with opioid use disorder face significant breastfeeding obstacles, including psychosocial, behavioral, concomitant medications, and tobacco use and thus may require high levels of support to achieve their breastfeeding goals. They often don't receive information to make informed infant feeding decisions. Hospital practices such as prenatal education, rooming-in and having a policy that minimizes barriers to breastfeeding are associated with increased breastfeeding rates.     

Are regulatory problems in infancy precursors of later hyperkinetic symptoms?

Aim: To examine whether regulatory problems in infancy predict later hyperkinetic symptoms in childhood and pre-adolescence. Methods: In a prospective longitudinal study of 319 children at risk of later developmental problems and psychopathology, hyperkinetic behaviour problems were assessed at the ages of 2, 4.5, 8 and 11 y by means of a standardized parent interview. Infant regulatory problems at the age of 3 mo were determined from multiple sources of information. An observational procedure was used to assess the quality of mother-infant interaction. Results: At the age of 3 mo, 17% of the infants (n = 55; 27 boys, 28 girls) suffered from multiple regulatory problems. Compared to a control group (n = 264), these children presented more hyperkinetic symptoms throughout childhood. Negativity in the mother-infant interaction and early family adversity each contributed to later hyperkinetic symptoms. When controlling for family adversity, the association between infant multiple regulatory problems and later hyperkinetic problems was rendered insignificant.

Conclusions: These findings suggest that multiple regulatory problems may not be a key variable for later hyperkinetic problems. The impact of early family adversity factors clearly outweighed that of infant psychopathology on later behaviour disorder.     

A controlled trial of skin-to-skin contact in extremely preterm infants

BACKGROUND: Extremely preterm birth, even in the absence of significant neurological impairment, is associated with altered pain responses and impaired memory and behaviour. Preterm birth increases the risk of maternal depression and may impede the development of the mother-infant relationship, factors that in turn are also associated with impaired infant outcome. Mother-infant skin-to-skin contact has been recommended as a simple means of ameliorating these effects. METHODS: We conducted a pragmatic, prospective, controlled, intention-to-treat trial in two neonatal intensive care units. Infants born below 32 weeks gestation were recruited within the first week after birth and assigned to a control group receiving standard care, or an intervention group in which mothers were encouraged to provide a session of skin-to-skin contact once daily for 4 weeks. We assessed infant behaviour at time of discharge from hospital, responses to immunisation at 4 and 12 months of age, and memory, behaviour and development at 1 year corrected (postmenstrual) age. Indices of maternal depression, stress, anxiety, lactation performance and infant interaction were assessed at time of infant discharge, 4 months and 1 year. RESULTS: No significant difference was identified in any infant or maternal measure at any time point. CONCLUSIONS: Mother-infant skin-to-skin contact after extremely preterm birth results in neither benefit nor adverse consequences. Although there is no reason to dissuade mothers who wish to provide STS contact, we are unable to recommend resource allocation for the implementation of STS programmes for extremely preterm infants in a neonatal intensive care unit setting.     

The effect of the odour of mother's milk on breastfeeding behaviour of premature neonates

AIM: To assess the effects of exposure to the odour of mother's milk on breastfeeding behaviour of premature neonates. METHODS: Thirteen preterm infants born at 30-33 weeks gestational age were tested. Seven infants were randomly assigned to the milk-odour condition, 6 to the water-control condition. During week 35 post-conceptual age, each baby was exposed to the appropriate odour stimulus for 120 sec. on 5 consecutive days immediately prior to a breastfeeding attempt. The breastfeeding bout following the final odour exposure session, and a second breastfeeding session shortly before the baby left the hospital, were analysed. Babies were weighed before and after each feeding session. RESULTS: During each breastfeeding session, babies in the milk-odour condition displayed longer sucking bouts and more bursts composed of >7 sucking movements, and also consumed more milk than the Control infants. The time spent in the hospital was significantly less for the milk-odour condition (median = 43 days vs. 55.5 days for Controls). CONCLUSION: Brief exposure to the odour of mother's milk prior to early breastfeeding trials had a positive effect on sucking behaviour and milk ingestion of preterm babies, which in turn resulted in a shortened stay in the hospital.     

Infant feeding and cost of health care: a cohort study

Aim: To compare the use and cost of health care in infants with different feeding patterns. Methods: Observational study on a cohort of 842 infants born in ten hospitals in northern Italy and followed up to age 12 months. Data on feeding gathered through telephone interviews with 24-hour recall. Data on use of health services reported by mothers and checked against records. Data on hospital cost derived from Disease Related Groups codes. Data on cost of other services obtained from maternal reports and available price lists. Results: At three months, 56% of infants were fully breastfed, 17% complementary fed and 27% not breastfed. Infants fully breastfed at three months had 4.90 episodes of illness requiring ambulatory care and 0.10 hospital admissions per infant/year compared with 6.02 and 0.17, respectively, in infants not or not fully breastfed. They had also a lower cost of health care: €34.69 versus 54.59 per infant/year for ambulatory care, and €133.53 versus 254.03 per infant/year for hospital care. Higher cost of health care was significantly associated with having a hospital admission and being a twin; cost of health care decreased with each additional gram of birth weight, each month of delayed return of the mother to work after the third month, and each extra month of breastfeeding. Conclusion: Lack of breastfeeding and higher use and cost of health care are significantly associated.     

Correlates of breastfeeding duration in an urban cohort from Argentina

Aim: To analyse factors associated with the duration of breastfeeding in a representative cohort of mothers and children, including socio-demographic and cultural characteristics, breastfeeding antecedents, perinatal factors and perinatal healthcare practices. Methods: The study was conducted in the city of Cordoba, between 1993 and 1998. Mother-child binomials from all public and private hospitals were asked to participate. Follow-up consisted of home visits at 30 d, 6, 12, 24, 36, 48 and 50 mo. Information was obtained on 650 healthy newborns. Cessation of breastfeeding during the first 24 mo of life was analysed using the Kaplan-Meier method, and factors associated with weaning were studied using Cox's proportional risk regression. Results. The median duration of breastfeeding was 4 mo. Factors associated with weaning were: the introduction of artificial formulas within 30 d postpartum [relative risk (RR) = 2.27; 95% confidence interval (CI) = 1.82-2.82]; breastfeeding of a previous child for less than 6 mo (RR = 1.64; 95% CI = 1.32-2.02); delay in the first mother-child contact for over 90 min (RR = 1.50; 95% CI = 1.17-1.93); mother's having completed primary or partially completed secondary education (RR = 1.40; 95% CI = 1.01-1.92) or completed secondary education or higher (RR = 1.59; 95% CI = 1.14-2.22); primiparous mother (RR = 1.39; 95% CI = 1.12-1.74) and; the mother recalling having been breastfed for less than 6 mo (RR = 1.27; 95% CI = 1.01-1.61).

Conclusions. The purpose of strategies to promote breastfeeding should be to eliminate inappropriate care practices, such as delay in the first mother-child contact, as well as reducing the impact of other factors leading to the introduction of artificial milk. Moreover, mothers need more and better support from professionals and peers.     

Morbidity in children born to women infected with human immunodeficiency virus in South Africa: does mode of feeding matter?

Aim: To examine infant morbidity risks associated with refraining from breastfeeding where it is used in an attempt to prevent mother-to-child transmission (MTCT) of human immunodeficiency virus (HIV). Methods: The population consisted of infants born to HIV-infected women in South Africa who were participating in a vitamin A intervention trial to prevent MTCT of HIV. Women chose to breastfeed or formula feed their infants according to UNAIDS guidelines. Actual feeding practices and morbidity were recorded at clinic follow-up visits at 1 wk, 6 wk, 3 mo and every 3 mo thereafter until 15 mo of age or cessation of breastfeeding. The infant's HIV status was assessed according to a predetermined algorithm. Results: HIV-infected infants who were never breastfed had a poorer outcome than those who were breastfed; 9 (60%) of those who were never breastfed had 3 or more morbidity episodes compared with 15 (32%) of breastfed children [odds ratio (OR) 4.05, 95% confidence interval (95% CI) 0.91-20.63, p = 0.05]. During the first 2 mo of life, never-breastfed infants (regardless of HIV status) were nearly twice as likely to have had an illness episode than breastfed infants (OR 1.91, 95% CI 1.17-3.13, p = 0.006).

Conclusion: The significant extra morbidity experienced in the first few months by all never-breastfed infants and at all times by HIV-infected infants who are not breastfed needs to be considered in all decisions by mothers, health workers and policy makers so as not to offset any gains achieved by decreasing HIV transmission through avoiding breastfeeding.     

Randomised trial of infant sleep location on the postnatal ward.

OBJECTIVE: To determine whether postnatal mother-infant sleep proximity affects breastfeeding initiation and infant safety. DESIGN: Randomised non-blinded trial analysed by intention to treat. SETTING: Postnatal wards of the Royal Victoria Hospital (RVI), Newcastle upon Tyne, UK. PARTICIPANTS: 64 newly delivered mother-infant dyads with a prenatal intention to breastfeed (vaginal deliveries, no intramuscular or intravenous opiate analgesics taken in the preceding 24 h). INTERVENTION: Infants were randomly allocated to one of three sleep conditions: baby in mother's bed with cot-side; baby in side-car crib attached to mother's bed; and baby in stand-alone cot adjacent to mother's bed. MAIN OUTCOME MEASURES: Breastfeeding frequency and infant safety observed via night-time video recordings. RESULTS: During standardised 4-h observation periods, bed and side-car crib infants breastfed more frequently than stand-alone cot infants (mean difference (95% confidence interval (CI)): bed v stand-alone cot = 2.56 (0.72 to 4.41); side-car crib v stand-alone cot = 2.52 (0.87 to 4.17); bed v side-car crib = 0.04 (-2.10 to 2.18)). No infant experienced adverse events; however, bed infants were more frequently considered to be in potentially adverse situations (mean difference (95% CI): bed v stand-alone cot = 0.13 (0.03 to 0.23); side-car crib v stand-alone cot = 0.04 (-0.03 to 0.12); bed v side-car crib = 0.09 (-0.03-0.21)). No differences were observed in duration of maternal or infant sleep, frequency or duration of assistance provided by staff, or maternal rating of postnatal satisfaction. CONCLUSION: Suckling frequency in the early postpartum period is a well-known predictor of successful breastfeeding initiation. Newborn babies sleeping in close proximity to their mothers (bedding-in) facilitates frequent feeding in comparison with rooming-in. None of the three sleep conditions was associated with adverse events, although infrequent, potential risks may have occurred in the bed group. Side-car cribs are effective in enhancing breastfeeding initiation and preserving infant safety in the postnatal ward.     

Weekly oral vitamin K prophylaxis in Denmark

Aim: To evaluate oral vitamin K prophylaxis at birth by giving 2 mg phytomenadione, followed by weekly oral vitamin K prophylaxis; 1 mg was administered by the parents until 3 mo of age. Methods: A total of 507 850 live babies were born in Denmark during the study period, November 1992 to June 2000. Of these infants, 78% and 22% received oral and intra-muscular prophylaxis, respectively; i.e. about 396 000 neonates received oral prophylaxis at birth. Weekly oral prophylaxis was recommended for all infants as long as they were mainly breastfed. A survey of possible cases of vitamin K deficiency bleeding (VKDB) was carried out by repeated questionnaires to all Danish paediatric departments and by checking the National Patient Register. Results: No cases of VKDB were revealed, i.e. the incidence was 0-0.9:100 000 (95% CI). The questionnaires were used to evaluate compliance with the regimen. Parents of 274 infants participated. A dose of vitamin K was regarded as having been given if the infant received a drop of vitamin K or was mostly formula-fed that week, and the prophylaxis was regarded as completed if the infant had received at least 9 doses. Compliance was good, with 94% of the infants completing the course of prophylaxis.

Conclusion: Weekly oral vitamin K supplementation during the first 3 mo of life was an efficient prophylaxis against VKBD. Parental compliance with the regimen was good.     

Newborn skin temperature two days postpartum during breastfeeding related to different labour ward practices

AIM: To investigate (1) the skin temperature pattern in newborns two days after birth in connection to breastfeeding and to examine (2) if the administration of epidural analgesia (EDA) and oxytocin (OT) infusion during labour influences this parameter at this point of time. METHOD: Forty-seven mother-infant pairs were included in the study: nine mothers had received OT stimulation during labour (OT group), 20 mothers had received an EDA and OT during labour (EDA group), while 18 mothers had received neither EDA nor OT stimulation during labour (control group). A skin temperature electrode was attached between the newborn's shoulder blades. The newborn was placed skin-to-skin on the mother's chest and covered with a blanket. The temperature was recorded immediately after the newborn was put on the mother's chest and at 5, 10, 20 and 30 min. RESULTS: The temperature measured when the newborns were put skin-to-skin on their mothers' chest was significantly higher in the infants of the EDA group (35.07 degrees C) when compared to the control group (34.19 degrees C, p=0.025). Skin temperature increased significantly (p=0.001) during the entire experimental period in the infants belonging to the control group. The same response was observed in infants whose mothers received OT intravenously during labour (p=0.008). No such rise was observed in infants whose mothers were given an EDA during labour. CONCLUSION: The results show that the skin temperature in newborns rises when newborns are put skin-to-skin to breastfeed two days postpartum. This effect on temperature may be hampered by medical interventions during labour such as EDA.     

Trans fatty acids in human milk in Poland and their association with breastfeeding mothers' diets

Aim: To determine the content of trans fatty acids in human milk in relation to breastfeeding mothers' diet. Methods: Samples of milk were collected from 100 breastfeeding mothers and 7-d dietary records and anthropometry from 69 mothers were obtained. Results: The following total trans fatty acids contents (median (lower-upper quartile); % wt/wt) in milk samples were determined: 1) data for Spring: colostrum—1.37 (1.00-2.00), mature milk at 5-6 wk of lactation—2.59 (1.49-3.34) and at 9-10 wk of lactation—2.36 (1.55-3.92); 2) data for Autumn: colostrum—1.80 (1.42-2.48), mature milk at 5-6 wk of lactation—2.41 (1.79-4.31) and at 9-10 wk of lactation—2.77 (1.53-4.18). The major sources of trans fatty acids in mothers' diets were bakery products, confectionery and snacks. Mothers who had high level of trans isomers in their milk consumed significantly higher amounts of these products.

Conclusions: Bakery products, confectionery and snacks are a major source of trans fatty acids in maternal diet in Poland. The levels of trans fatty acids in human milk may reflect the current diet of the mother as well as the diet consumed early in pregnancy.     

Breastfeeding the infant with congenital diaphragmatic hernia post extracorporeal membrane oxygenation

Infants born with congenital diaphragmatic hernia (CDH) often require extracorporeal membrane oxygenation (ECMO). Infants on ECMO may experience a long period of being nothing by mouth (NPO) while receiving parenteral nutrition. Once the infant with CDH is repaired and off ECMO, human milk should be used to initiate enteral feedings. Human milk provides immunologic, developmental, and nutritional protection for these highrisk infants and may be crucial in decreasing morbidities commonly associated with post-ECMO survivors. These mother-infant dyads require extensive lactation support to ensure maintenance of milk supply and successful transition to direct breastfeeding. Three case studies are presented as exemplars to demonstrate how breastfeeding success can be achieved even in the most vulnerable infants.     

Effects of sociodemographic factors on adherence to breastfeeding and other important infant dietary recommendations

Aim: To examine in an affluent and healthy population the association between sociodemographic factors and the adherence to key infant dietary recommendations. Methods: In a longitudinal prospective study, healthy newborns were selected randomly in maternity wards around Iceland and their diet recorded every month for one year (n=124). In addition, a 48-hour-weighed-record, including information on added sugar, fruits, vegetables and the use of A and D vitamin drops was completed by 91 (73%) mothers at 9 and 12 months. Information about the mothers' education, smoking, age, parity, and family income was collected (n=98; 79%). Results: Regression analyses, including sociodemographic factors, showed exclusive breastfeeding to be positively associated with more education (P=0.022) and non-smoking (P=0.013) explaining 22% of the variance, and total breastfeeding (exclusive + partial) with non-smoking (P=0.006). Multiple regression also showed children's intake of added sugar from 9-12 months to be positively associated with mother's smoking (P=0.022) and negatively with age (P = 0.026), explaining 30% of variance. Sociodemographic factors were associated with children's fruit and vegetable consumption but not with the administration of AD-vitamin drops. However, when tested for significance between groups, younger mothers with fewer children seemed less likely to give AD-vitamin drops.

Conclusions: In a group of mothers getting regular antenatal care and giving birth to healthy infants, sociodemographic factors can predict which mothers need special guidance concerning recommendations about diet in infancy. These were mothers with less education, who smoked, were younger and were having their first or second child.     

Skin-to-skin contact may reduce negative consequences of "the stress of being born": a study on temperature in newborn infants,subjected to different ward routines in St. Petersburg

AIM: To evaluate how different delivery-ward routines influence temperature in newborn infants. METHODS: A total of 176 newborn mother-infant pairs were included in a randomized study. The babies were kept skin-to-skin on the mother's chest (Skin-to-skin group), held in their mother's arms, being either swaddled or clothed (Mother's arms group), or kept in a cot in the nursery, being either swaddled or clothed (Nursery group). Temperature was measured in the axilla, on the thigh, back and foot at 15-min intervals at from 30 to 120 min after birth. RESULTS: During this time period the axilla, back and thigh temperatures rose significantly in all the treatment groups. The foot temperature displayed a significant fall in the babies in the Nursery group and this decrease was greatest in the swaddled babies. In contrast, foot temperature rose in the babies in the Mother's arms group and in particular in babies in the Skin-to-skin group. Foot temperature remained high in the Skin-to-skin group, whereas the low temperature observed in the Nursery group gradually increased and two days after birth the difference was no longer significant. CONCLUSION: The results show that delivery-ward routines influence skin temperature in infants in the postnatal period. Allowing mother and baby the ward routine of skin-to-skin contact after birth may be a "natural way" of reversing stress-related effects on circulation induced during labour.     

Randomized study of nasal continuous positive airway pressure in the preterm infant with respiratory distress syndrome

Aim: To evaluate whether very preterm babies can be extubated successfully to nasal continuous positive airway pressure (nCPAP) within one hour of birth after receiving one dose of surfactant in the treatment of respiratory distress syndrome (RDS). Methods: Forty-two infants of 25 to 28[Formula: See Text] wk of gestation were intubated at birth and given one dose of surfactant. They were then randomized within one hour of birth to either continue with conventional ventilation or to be extubated to nCPAP. Results: Eight out of 21 (38%) babies randomized to nCPAP did not require subsequent reventilation. (Ventilation rates of 62% vs 100%, p = 0.0034). The smallest baby successfully extubated weighed 745 g. There were also significantly fewer infants intubated in the nCPAP group at 72 h of age (47% vs 81%, p = 0.025). There was no significant difference between the two groups in the number of babies that died, developed chronic lung disease or severe intraventricular haemorrhage.

Conclusion: A significant number of very preterm babies with RDS can be extubated to nCPAP after receiving one dose of surfactant. nCPAP is a potentially useful modality of respiratory support even in very premature infants.     

Clinical experience with preterm formulas in very low birthweight infants

Infants below 1500 g at birth were randomly assigned to receive one of two preterm infant formulars: S26 Low Birthweight (S26-LBW, 25 infants) or Enfalac Premature (EPF, 24 infants). They were either exclusively formula-fed (13 infants) or the formula was used to supplement their own mother's fresh breast milk (36 infants). The mean age when milk feeds were commenced was 7 days and the mean age when birthweight was regained was 12 days. The mean age when 2000 g was reached was 45 days at which time 10 (20%) infants were below the tenth centile on the intrauterine growth chart. None of the above variables were significantly different between the S26-LBW and EPF groups. However, the S26-LBW group established full enteral feeding significantly earlier compared to the EPF group (42 versus 64 d) and the number with adverse gastrointestinal effects was lower (4 versus 10 infants). Both preterm infant formulas supported a growth rate in excess of that in utero without stressing the infants' metabolic system. The growth rate of infants fed preterm breast milk supplemented with preterm infant formula was quantitatively similar to those exclusively fed preterm infant formula.     

Postnatal and postprandial changes in plasma concentrations of glicentin in term and preterm infants

Aim: To examined the changes in basal plasma concentrations of glicentin in developing children and the postnatal and postprandial changes in plasma glicentin levels in infants. Methods: Glicentin, an active component of enteroglucagon, is considered to have a significant trophic action on the intestinal mucosa. Fasting plasma concentrations of glicentin in healthy children and in term and preterm infants were measured before and 30 min after feeding during the first 14 d of life. Results: Plasma basal concentrations of glicentin in children under 1 y of age were significantly higher than those in children aged 1 to 15 y. Plasma basal concentrations of glicentin at 5 or 6 d (2496 and 2190 pg/ml) and at 14 d (2987 and 2817 pg/ml) after birth were significantly higher than those at 1 or 2 d (1098 and 1240 pg/ml) after birth in normal birthweight (NBW) and low-birthweight (LBW) infants. There was no significant difference in the glicentin level between infants at 1 or 2 d (1864 pg/ml) and at 5 or 6 d (1910 pg/ml) after birth in very-low birthweight (VLBW) infants, but the levels at 14 d (3310 pg/ml) after birth were significantly higher than either of those levels. Plasma glicentin concentrations after feeding were significantly higher than those before feeding at 1 or 2 d and at 5 or 6 d after birth in NBW and LBW infants, but a significant increase in the plasma glicentin level after feeding was first observed at 14 d after birth in VLBW infants. There were no significant differences in the basal plasma (2401 and 2718 pg/ml) and postprandial (3007 and 3912 pg/ml) glicentin levels between breastfed and formula-fed infants.

Conclusion: The results of the study suggest that glicentin may play an important role in intestinal mucosal growth in the early period of life, although its role in VLBW infants should be further investigated.     

PCDDs, PCdfs and Co-PCBs in human breast milk samples collected in Tokyo, Japan

Aim: To observe the distribution of PCDD/Fs and Co-PCBs in samples of human breast milk collected in Japan. Methods: Using high-resolution gas chromatography, milk samples for polychlorinated dibenzo-p-dioxins (PCDDs; 14 congeners), polychlorinated dibenzofurans (PCDFs; 15 congeners) and coplanar polychlorinated biphenyls (Co-PCBs; 12 congeners) from 240 mothers residing in Tokyo were analysed. There were 120 donors each of primiparae and secundiparae, each group including 60 donors aged 25 to 29 y (“the younger group”) and 60 aged 30 to 34 y (“the older group”). Individual milk samples (about 50 ml) were obtained 30 d after delivery in 1999 and in 2000. Results: The mean toxic equivalent (TEQ) level of PCDD/Fs (the sum of PCDDs and PCDFs) was 14.9 pg TEQ/g fat, of Co-PCBs 10.6 pg TEQ/g fat, and the total sum of PCDD/Fs and Co-PCBs was 25.6 pg TEQ/g fat. The mean TEQ levels of PCDD/Fs, Co-PCBs, and total PCDD/Fs and Co-PCBs were higher in primiparae than in secundiparae. In each of these, the levels were higher in the subgroup of older mothers. In the secundiparae, the mean levels were lower in the group of mothers who had breastfed their first babies than in those who bottle-fed or partly bottle-fed their first born.

Conclusions: The concentrations of PCDD/Fs and Co-PCBs in the breast milk of Japanese women were slightly lower than those described in previous studies conducted in Japan and other countries; and the concentrations of PCDD/Fs and Co-PCBs in the breast milk were influenced mainly by the mother's age and nursing history.