Effects of breast pumping on the pharmacokinetics and pharmacodynamics of ethanol during lactation

Infant factors that impact the ecology of human milk secretion and composition-a report from "Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN)" Working Group 3

Infants drive many lactation processes and contribute to the changing composition of human milk through multiple mechanisms. This review addresses the major topics of milk removal; chemosensory ecology for the parent-infant dyad; the infant's inputs into the composition of the human milk microbiome; and the impact of disruptions in gestation on the ecology of fetal and infant phenotypes, milk composition, and lactation. Milk removal, which is essential for adequate infant intake and continued milk synthesis through multiple hormonal and autocrine/paracrine mechanisms, should be effective, efficient, and comfortable for both the lactating parent and the infant. All 3 components should be included in the evaluation of milk removal. Breastmilk "bridges" flavor experiences in utero with postweaning foods, and the flavors become familiar and preferred. Infants can detect flavor changes in human milk resulting from parental lifestyle choices, including recreational drug use, and early experiences with the sensory properties of these recreational drugs impact subsequent behavioral responses. Interactions between the infant's own developing microbiome, that of the milk, and the multiple environmental factors that are drivers-both modifiable and nonmodifiable-in the microbial ecology of human milk are explored. Disruptions in gestation, especially preterm birth and fetal growth restriction or excess, impact the milk composition and lactation processes such as the timing of secretory activation, adequacy of milk volume and milk removal, and duration of lactation. Research gaps are identified in each of these areas. To assure a sustained and robust breastfeeding ecology, these myriad infant inputs must be systematically considered.

Methods of milk expression for lactating women

BACKGROUND

Breastfeeding is important, however not all infants can feed at the breast and methods of expressing milk need evaluation.

OBJECTIVES

To assess acceptability, effectiveness, safety, effect on milk composition, contamination and costs of methods of milk expression.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (21 March 2016), handsearched relevant journals and conference proceedings, and contacted experts in the field to seek additional published or unpublished studies. We also examined reference lists of all relevant retrieved papers.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing methods at any time after birth.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.

MAIN RESULTS

This updated review includes 41 trials involving 2293 participants, with 22 trials involving 1339 participants contributing data for analysis. Twenty-six of the trials referred to mothers of infants in neonatal units (n = 1547) and 14 to mothers of healthy infants at home (n = 730), with one trial containing mothers of both neonatal and healthy older infants (n = 16). Eleven trials compared one or more types of pump versus hand expression and 14 studies compared one type of pump versus another type of pump, with three of these studies comparing both hand expression and pump types. Twenty studies compared a specific protocol or adjunct behaviour including sequential versus simultaneous pumping protocols, pumping frequency, provision of an education and support intervention, relaxation, breast massage, combining hand expression with pumping and a breast cleansing protocol.Due to heterogeneity in participants, interventions, and outcomes measured or reported, we were unable to pool findings for most of the specified outcomes. It was not possible therefore to produce a 'Summary of findings' table in this update. Most of the included results were derived from single studies. Trials took place in 14 countries under a variety of circumstances and were published from 1982 to 2015. Sixteen of the 30 trials that evaluated pumps or products had support from the manufacturers. The risk of bias of the included studies was variable. Primary outcomesOnly one of the 17 studies examining maternal satisfaction/acceptability with the method or adjunct behaviour provided data suitable for analysis. In this study, self-efficacy was assessed by asking mothers if they agreed or disagreed with the following statement: 'I don't want anyone to see me (hand expressing/pumping)'. The study found that mothers who were using the electric pump were more likely to agree with the statement compared to mothers hand expressing, (mean difference (MD) 0.70, 95% confidence interval (CI) 0.15 to 1.25; P = 0.01, participants = 68). Mothers who were hand expressing reported that the instructions for expression were clearer compared to the electric pump, (MD -0.40, 95% CI -0.75 to -0.05; P = 0.02, participants = 68). Descriptive reporting of satisfaction in the other studies varied in the measures used, did not indicate a clear preference for one pump type, although there was satisfaction with some relaxation and support interventions.We found no clinically significant differences between methods related to contamination of the milk that compared any type of pump to hand expression (risk ratio (RR) 1.13, 95% CI 0.79 to 1.61; P = 0.51, participants = 28), manual pump compared to hand expression, (MD 0.20, 95% CI -0.18 to 0.58; P = 0.30, participants = 142) a large electric pump compared to hand expression (MD 0.10, 95% CI -0.29 to 0.49; P = 0.61, participants = 123), or a large electric pump compared to a manual pump (MD -0.10, 95% CI -0.46 to 0.26; P = 0.59, participants = 141).The level of maternal breast or nipple pain or damage was similar in comparisons of a large electric pump to hand expression (MD 0.02, 95% CI -0.67 to 0.71; P = 0.96, participants = 68). A study comparing a manual and large electric pump, reported sore nipples in 7% for both groups and engorgement in 4% using a manual pump versus 6% using an electric pump; and in one study no nipple damage was reported in the hand-expression group, and one case of nipple damage in each of the manual pump and the large electric pump groups.One study examined adverse effects on infants, however as the infants did not all receive their mothers' expressed milk, we have not included the results. Secondary outcomesThe quantity of expressed milk obtained was increased, in some studies by a clinically significant amount, in interventions involving relaxation, music, warmth, massage, initiation of pumping, increased frequency of pumping and suitable breast shield size. Support programmes and simultaneous compared to sequential pumping did not show a difference in milk obtained. No pump consistently increased the milk volume obtained significantly.In relation to nutrient quality, hand expression or a large electric pump were found to provide higher protein than a manual pump, and hand expression provided higher sodium and lower potassium compared to a large electric pump or a manual pump. Fat content was higher with breast massage when pumping; no evidence of difference was found for energy content between methods.No consistent effect was found related to prolactin change or effect on oxytocin release with pump type or method. Economic aspects were not reported.

AUTHORS' CONCLUSIONS

The most suitable method for milk expression may depend on the time since birth, purpose of expression and the individual mother and infant. Low-cost interventions including initiation of milk expression sooner after birth when not feeding at the breast, relaxation, massage, warming the breasts, hand expression and lower cost pumps may be as effective, or more effective, than large electric pumps for some outcomes. Variation in nutrient content across methods may be relevant to some infants. Small sample sizes, large standard deviations, and the diversity of the interventions argue caution in applying these results beyond the specific method tested in the specific settings. Independently funded research is needed for more trials on hand expression, relaxation and other techniques that do not have a commercial potential.

Methods of milk expression for lactating women

BACKGROUND

This is an update of a 2008 Cochrane review. Breastfeeding is important. However, not all infants can feed at the breast and methods of expressing milk need evaluation.

OBJECTIVES

To assess acceptability, effectiveness, safety, effect on milk composition, contamination and cost implications of methods of milk expression.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (March 2014), CINAHL (1982 to March 2014), conference proceedings, secondary references and contacted researchers.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing methods at any time after birth.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed trials, extracted data and assessed risk of bias.

MAIN RESULTS

This updated review includes 34 studies involving 1998 participants, with 17 trials involving 961 participants providing data for analysis. Eight studies compared one or more types of pump versus hand expression and 14 studies compared one type of pump versus another type of pump, with three of these studies comparing both hand expression and multiple pump types. Fifteen studies compared a specific protocol or adjunct behaviour including sequential versus simultaneous pumping protocols (five studies), pumping > 4 times per day versus < 3 times per day (one study), provision of a milk expression education and support intervention to mothers of preterm infants versus no provision (one study), provision of audio/visual relaxation to mothers of preterm infants versus no specific relaxation (two studies), commencing pumping within one hour of delivery versus between one to six hours (one study), breast massage before or during pumping versus no massage (two studies, of which one also tested a second behaviour), therapeutic touch versus none (one study), warming breasts before pumping versus not warming breasts (one study), combining hand expression with pumping versus pumping alone (one study) and a breast cleansing protocol versus no protocol (one study).There were insufficient comparable data on outcomes to undertake meta-analysis and data reported relates to evidence from single studies.Only one of the 17 studies examining maternal satisfaction/acceptability provided data in a way that could be analysed, reporting that mothers assigned to the pumping group had more agreement with the statement 'I don't want anyone to see me pumping' than mothers in the hand expression group and the statement 'I don't want anyone to see me hand expressing' (n = 68, mean difference (MD) -0.70, 95% confidence interval (CI) -1.25 to -0.15, P = 0.01), and that mothers found instructions for hand expression were clearer than for pumping (n = 68, MD 0.40, 95% CI 0.05 to 0.75, P = 0.02). No evidence of a difference was found between methods related to adverse effects of milk contamination (one study, n = 28, risk ratio (RR) 0.89, 95% CI 0.62 to 1.27, P = 0.51), (one study, n = 142 milk samples, MD 0.20, 95% CI -0.18 to 0.58, P = 0.30), (one study, n = 123 milk samples, MD 0.10, 95% CI -0.29 to 0.49, P = 0.61), (one study, n = 141 milk samples, MD -0.10, 95% CI -0.46 to 0.26, P = 0.59 ); or level of maternal breast or nipple pain or damage (one study, n = 68, MD 0.02, 95% CI -0.67 to 0.71, P = 0.96).For the secondary outcomes, greater volume was obtained when mothers with infants in a neonatal unit were provided with a relaxation tape or music-listening interventions to use while pumping, when the breasts was warmed before pumping or massaged while pumping.Initiation of milk pumping within 60 minutes of birth of a very low birthweight infant obtained higher mean milk quantity in the first week than the group who initiated pumping later. No evidence of difference in volume was found with simultaneous or sequential pumping or between pumps studied. Differences between methods was found for sodium, potassium, protein and fat constituents; no evidence of difference was found for energy content.No consistent effect was found related to prolactin change or effect on oxytocin release with pump type or method. Economic aspects were not reported.Most studies were classified as unclear or low risk of bias. Most studies did not provide any information regarding blinding of outcome assessment. Fifteen of the 25 studies that evaluated pumps or products had support from the manufacturers.

AUTHORS' CONCLUSIONS

The most suitable method for milk expression may depend on the time since birth, purpose of expression and the individual mother and infant. Low-cost interventions including early initiation when not feeding at the breast, listening to relaxation music, massage and warming of the breasts, hand expression and lower cost pumps may be as effective, or more effective, than large electric pumps for some outcomes. Small sample sizes, large standard deviations, and the diversity of the interventions argue caution in applying these results beyond the specific method tested in the specific settings.

Methods of milk expression for lactating women

BACKGROUND

This is an update of a 2008 Cochrane review. Breastfeeding is important. However, not all infants can feed at the breast and methods of expressing milk need evaluation.

OBJECTIVES

To assess acceptability, effectiveness, safety, effect on composition, contamination and cost implications of methods of milk expression.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (20 January 2011), CINAHL (1982 to January 2011), conference proceedings, secondary references and contacted researchers.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing methods at any time after birth, and crossover trials commencing at least 28 days after birth.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed trials, extracted data and assessed risk of bias. Data were checked for accuracy.

MAIN RESULTS

We included 23 studies with 10 studies (632 mothers) providing data for analysis.Mothers provided with a relaxation tape produced more milk than mothers who were not (mean difference (MD) 34.70 ml/single expression, 95% confidence interval (CI) 9.51 to 59.89, P = 0.007). A lower milk volume over six days was reported when comparing hand expression to the electric pump (standardised mean difference (SMD) -1.00 ml, 95% CI -1.64 to -0.36, P = 0.002); other studies of the same pump using different measures did not find a significant difference (12 to 36 hours postpartum SMD -0.38 cc, 95% CI -0.86 to 0.10, P = 0.12); day five postpartum SMD -0.62 ml/day, 95% CI -1.43 to 0.19, P = 0.13). No evidence of difference in volume was found with simultaneous or sequential pumping, or between manual and electric pumps studied. One study reported a higher sodium concentration in hand expressed milk compared to a manual pump (SMD 0.59 mmol/L, 95% CI 0.22 to 0.96, P = 0.002) and to an electric pump (SMD 0.70 mmol/L, 95% CI 0.32 to 1.09, P = 0.0003), and lower potassium concentration compared to a manual pump (MD -0.37 mmol/L, 95% CI 0.00 to 0.73, P = 0.05) or to an electric pump (SMD -0.32 mmol/L, 95% CI -0.69 to 0.06, P = 0.10). No evidence of difference was found for energy content, milk contamination or adverse effects. Reports of maternal views were not comparable. Economic aspects were not reported.  

AUTHORS' CONCLUSIONS

The most suitable method for milk expression may depend on the time since birth, purpose of expression and the individual mother and infant. Low cost interventions including early initiation when not feeding at the breast, relaxation, hand expression and lower cost pumps may be as effective, or more effective, than large electric pumps for some outcomes. Small sample sizes, large standard deviations, small number of studies reviewed, and the diversity of the interventions argue caution in applying these results beyond the specific method tested in the specific settings.

Population pharmacokinetics of artesunate and dihydroartemisinin in pregnant and non-pregnant women with malaria

Background

The World Health Organization endorses the use of artemisinin-based combination therapy for treatment of acute uncomplicated falciparum malaria in the second and third trimesters of pregnancy. However, the effects of pregnancy on the pharmacokinetics of artemisinin derivatives, such as artesunate (AS), are poorly understood. In this analysis, the population pharmacokinetics of oral AS, and its active metabolite dihydroartemisinin (DHA), were studied in pregnant and non-pregnant women at the Kingasani Maternity Clinic in the DRC.

Methods

Data were obtained from 26 pregnant women in the second (22 - 26 weeks) or the third (32 - 36 weeks) trimester of pregnancy and from 25 non-pregnant female controls. All subjects received 200 mg AS. Plasma AS and DHA were measured using a validated LC-MS method. Estimates for pharmacokinetic and variability parameters were obtained through nonlinear mixed effects modelling.

Results

A simultaneous parent-metabolite model was developed consisting of mixed zero-order, lagged first-order absorption of AS, a one-compartment model for AS, and a one-compartment model for DHA. Complete conversion of AS to DHA was assumed. The model displayed satisfactory goodness-of-fit, stability, and predictive ability. Apparent clearance (CL/F) and volume of distribution (V/F) estimates, with 95% bootstrap confidence intervals, were as follows: 195 L (139-285 L) for AS V/F, 895 L/h (788-1045 L/h) for AS CL/F, 91.4 L (78.5-109 L) for DHA V/F, and 64.0 L/h (55.1-75.2 L/h) for DHA CL/F. The effect of pregnancy on DHA CL/F was determined to be significant, with a pregnancy-associated increase in DHA CL/F of 42.3% (19.7 - 72.3%).

Conclusions

In this analysis, pharmacokinetic modelling suggests that pregnant women have accelerated DHA clearance compared to non-pregnant women receiving orally administered AS. These findings, in conjunction with a previous non-compartmental analysis of the modelled data, provide further evidence that higher AS doses would be required to maintain similar DHA levels in pregnant women as achieved in non-pregnant controls.

Breast pumping and lactational state exert differential effects on ethanol pharmacokinetics

Prior research revealed that breast stimulation altered the way the lactating body handles alcohol. Its effects depended upon when it occurred relative to drinking. The goal of the present study was to determine whether breast pumping works independently of the physiological and metabolic changes that accompany lactation. To this end, we tested 12 women when they were exclusively breastfeeding 3-5-month-old infants and then again several months after lactation had ceased. Subjects were randomly assigned to one of two groups that differed in the timing of breast pumping relative to drinking a 0.4g/kg dose of alcohol: one group breast pumped 0.6h after drinking (pumped after group) and the other pumped 1h before drinking (pumped before group). For each reproductive stage, subjects were tested on 2 separate days, consuming a standardized meal 1 h before drinking during 1 test day and remaining fasted during the other. Breath alcohol concentrations (BrAC) and temperature readings were obtained before and at fixed intervals after drinking. Pumping before drinking significantly decreased BrAC during both reproductive stages, whereas pumping after drinking resulted in different BrAC time curves during lactation when compared with after lactation. That is, levels were significantly lower during the descending phase of the time curve during than after lactation. The interactions between pumping and reproductive stage were most apparent during fed condition. Furthermore, women were more sensitive to hypothermic effects of both fasting and drinking alcohol during lactation. These findings add to the growing literature that lactating women metabolize alcohol differently, in part, due to the frequent breast stimulation during breastfeeding and the pronounced physiological changes that accompany one of the most energetically costly mammalian activities.

Interference of ethanol and methylmercury in the developing central nervous system

Studies involving alcohol and its interactions with other neurotoxicants represent the focus of several works of research due to the fact that the use of alcohol can sometimes leads to serious health problems. Fetal exposure to alcohol and mercury has a high incidence in some regions of Brazil, where there are pregnant women who are alcoholics and live in mining areas. This work was conducted to examine the effects of combined exposure to ethanol (EtOH) and methylmercury (MeHg) in rats during the development of the central nervous system (CNS). Experimental behavioral animal models/tests were used in order to examine locomotion, anxiety, depression and memory. Pregnant rats received tap water or EtOH 22.5% w/v (6.5 g/kg per day), by gavage) during pregnancy and breast-feeding. On the 15th day of pregnancy, some groups received 8 mg/kg of MeHg (by gavage). The groups were as follows: control, EtOH, MeHg and EtOH+MeHg. The experimental results showed that the EtOH, MeHg and EtOH+MeHg groups reduced the percentage of frequency and time spent in the open arms entries of the elevated plus-maze (EPM) test, when compared to the control group. This result suggests an anxiogenic behavioral response. The MeHg group increased locomotor activity in the arena and the immobility time in the forced swimming test, suggestive of depression-like behavior. The EtOH+MeHg group showed greater reductions in the percentages of frequency and time spent in the open arms entries in the EPM test, suggesting a sedative-behavior since the frequency of enclosed arm entries was affected. In the inhibitory avoidance task, the EtOH+MeHg group reduced the latency of the step-down response onto the grid floor, suggesting a cognitive and behavior dysfunctions. Taken together, the results suggest that EtOH and/or MeHg intoxication during the developing CNS may be a risk for deficits related to locomotor impairment, anxiety, depression and neurocognitive functions. There is a possibility that EtOH may prevent some of the MeHg responses, but the precise mechanism of action involved in this process needs to be considered for future research.