Abstract
Abstract
Objective:
This study aimed to determine the relationship between perceived insufficient milk supply (PIMS) and actual insufficient milk supply (AIMS) and the relative contributions of physiological and psychosocial variables on both PIMS and AIMS of first-time breastfeeding mothers.
Participants and Methods:
Data were collected among 123 breastfeeding mothers at a Canadian, French-speaking maternal care hospital. Birth events, breastfeeding practices, infant and maternal capacities, and PIMS and AIMS were collected at 48 hours after birth, postnatal weeks 2 and 6.
Results:
No significant relationship was found between PIMS and AIMS. Maternal breastfeeding self-efficacy and number of feeds were related to PIMS at week 2, and skin-to-skin contact at birth and number of feeds were related to AIMS as measured by 24-hour milk production at week 2.
Conclusion:
Maternal breastfeeding self-efficacy impacts PIMS. Interventions should be directed to increase maternal confidence in breastfeeding, which in turn influences breastfeeding duration.
Introduction
S
Insufficient milk supply
Milk production (or supply) refers to the amount of breast milk transferred to the infant. It relies on three different components: efficacy of baby's sucking, breast capacity to produce milk, and the milk ejection reflex. 7 Any factor undermining this process can decrease the amount of milk transferred to the child and, as such, the child's satisfaction level. 7 Primary insufficiency of breast milk supply is rare and concerns hypoplasia of mammary gland or breast surgery such as breast reduction or Sheehan's syndrome. 8 Secondary insufficiency of breast milk supply or postglandular insufficiency 9 arises when the normal physiological breastfeeding process has been disrupted by factors that limit frequency or efficacy of mammary gland stimulation such as breast milk substitutes at the time of the establishment of lactogenesis stage II, nonoptimal baby suckling, or an insufficient number of feedings. 10
Perception of insufficient milk supply
Maternal perception of insufficient milk supply occurs when the mother believes her breast milk is not enough in quality or in quantity to satisfy her baby.11,12 Indeed, dissatisfaction of the child, expressed by crying, is a major contributing factor to maternal perception of insufficient milk supply. 4 Besides satisfaction of the child, other contributing factors to PIMS are behavior of the infant at the breast and increased or decreased number of feedings. 4 Child capacities also influence the mother's confidence in her capacity to breastfeed, which has been linked to PIMS and breastfeeding exclusivity and duration.4,13,14 However, very few studies have focused on the distinction between PIMS and AIMS. 4 In fact, we cannot confirm if there is a difference between the perception and the reality of milk insufficiency. 15 This limits the development and validation of nursing interventions to prevent, assess, and address both situations. 4 The aim of this study was to determine the relationship between PIMS and AIMS and the relative contributions of physiological and psychosocial variables on both PIMS and AIMS of first-time breastfeeding mothers. The study also aimed at documenting the breastfeeding rates and exclusivity during the first 6 weeks postnatally.
Participants and Methods
This study used a predictive correlational longitudinal design with three time measurements: 48 hours and postnatal weeks 2 and 6. A convenience sample was recruited between June 2012 and January 2014 from the maternity unit at a non-baby-friendly designated Canadian regional hospital averaging 2300 births annually. Inclusion criteria were (1) first-time breastfeeding mothers ≥18 years old, (2) birth of an infant at ≥37 weeks of gestation and with a birth weight of ≥2500 g, and (3) French and/or English language spoken and written. Exclusion criterion was mother–infant separation ≥24 hours after birth because of health conditions of mother or baby. After verification of eligibility, 123 mothers accepted to participate in the study. After signed consent, the mothers were given a questionnaire to complete on day 3. Of the 123 mothers who accepted to participate, 98 (79.7%) completed/returned the day 3 questionnaire to the research assistant and 25 (20.3%) mothers left the hospital without giving back the questionnaire. At week 2, 62 (50.4%) mothers were reached by phone for a home visit appointment and the week 2 questionnaire was completed at the time of the home visit. Sixty-one mothers were not reached by phone after three attempts. In addition, at the time of home visit at week 2, the 24-hour diary of breastfeeding, which includes milk production measurement, was completed by 57 (46.3%) mothers. Reason for noncompletion was cessation of breastfeeding. At week 6, 52 (42.2%) mothers were reached by phone and they answered the breastfeeding practices assessment (Table 1).
Procedure
Both Research Ethics Committees of the university and hospital approved the study. Each day, the research assistant verified about new births in the past 24 hours and mothers' eligibility for participation in the study. Nurses asked eligible mothers if they were interested in participating. When they agreed, the research assistant met them to explain the study and obtain informed consent. At 48 hours postnatal, mothers completed a self-reported questionnaire (duration 15 minutes) that included measures described below. The research assistant also reviewed both mother's and baby's charts for pregnancy and birth events. With the phone number provided at time of recruitment, the research assistant called the mother to plan a home visit at around 2 weeks. At the time of home visit, the research assistant brought a baby weighing scale (precision at 2 g) for breast milk production measurement and explained the use of it as well as the 24-hour breastfeeding journal. Mothers were asked to weigh their baby before and after each breastfeeding session for the next 24 hours (1 day) and to complete the breastfeeding journal accordingly, including baby's urine and stools at diaper change as another indicator of adequate milk supply. 16 The same self-reported questionnaire completed at 48 hours, which included breastfeeding self-efficacy measure, was also filled at that time by the mother (duration 10 minutes). Another home visit was planned for the pickup of the scale. At postnatal week 6, a phone call (duration 5–10 minutes) was made by the research assistant to ask about breastfeeding practices and offer guidance as needed.
Measures
Table 2 summarizes the variables included in this study.
Baseline variable—sociodemographic characteristics
Sociodemographic characteristics were self-reported by the mother in the day 3 questionnaire.
Study variables
Birth events
Data collected through chart review by the research assistant included type of birth (vaginal or cesarean section), baby's birth weight, skin-to-skin contact after birth, and first-hour breastfeeding.
Infant capacities
Infant capacities included at 48 hours and postnatal week 2 questionnaires were as follows:
(1) Infant Breastfeeding Assessment Tool (IBFAT) measures child's capacity to suckle.
17
This instrument assesses four components of effective sucking: eagerness to attach to the breast, sucking reflex, and latch and effective suckling, each element being noted by the mother on a 1 to 3 scale. A score between 10 and 12 indicates optimal child's capacity. Inter-rater reliability index of 91% between mothers' and professionals' ratings has been reported.
17
This instrument was also used to predict breastfeeding cessation in the first 2 weeks postnatal.
17
Cronbach's alpha was 0.71 from a previous study on PIM by the main author.
13
(2) Infant breastfeeding demand: Number of times the mother breastfed in the last 24 hours. This measure was self-reported by the mother at day 3 and week 2 questionnaires by answering the following question: How many times did you breastfeed your baby in the last 24 hours? (3) Irritability during feeds subscale of the Mother and Baby Scale
18
was used to measure infant temperament during feeds. This scale assessed maternal perception of how much her baby fretted and cried during feeds.
19
Examples of items were “My baby's overactivity (kicking, turning head, etc.) has been making it difficult to fix her/him to the breast” or “During feeds, my baby has tended to fuss or cry.” Eight items were assessed on a one-dimensional scale from never apply ( = 0) to very/often apply ( = 5). Higher scores mean a more irritable infant during feedings. Cronbach's alpha was 0.86 among a sample of mothers and babies in the early postnatal period.
18
Maternal capacity as per mother's perception
Maternal breastfeeding self-efficacy was measured at 48 hours and postnatal week 2 questionnaires with the Breastfeeding Self-Efficacy Scale-Short Form (BSES-SF), 20 which has 14 items to measure mother's confidence in her capacity to breastfeed. Mother rates each item on a 5-point Likert scale from (1) not confident to (5) very confident. Score varies from 14 to 70. Elevated score indicates high level of confidence. Cronbach's alpha was 0.94 from a previous study on PIM by the main author. 13
Outcome variables
Perceived and actual insufficient breast milk supply
Perceived and actual insufficient breast milk supply was measured at 48 hours and at postnatal week 2 with questionnaires as follows:
(1) PIMS is defined by the mother as milk being insufficient either in quantity or nutritional quality to meet the needs of her child.
11
This instrument first asks for a yes/no answer on mother's belief that she can produce sufficient milk to meet the needs of her infant. Then, an open question invites mother to explain her yes or no from the previous nominal question. Next five questions are noted on a 5-point Likert scale on the mother's perception of the child's satisfaction. Examples of items assessed were “My baby generally appears satisfied after feedings” and “My breast milk is all the nutrition my baby needs to thrive.” High score indicates high perception of milk sufficiency. Content validity of PIMS was assessed by six breastfeeding experts,
11
and Cronbach's alpha was 0.70 in a study sample of 60 mothers.
11
Cronbach's alpha was 0.80 from a previous study on PIM by the main author of this study.
13
(2) AIMS was measured by the child's weight loss at T1 (birth weight minus weight at 48 hours). More than 7% loss is considered significant.
21
At T2, milk production refers to the volume of milk transferred to the child within 24 hours as measured by baby's weight on a precise scale (2 g precision) before and after each breastfeed.
22
One gram of weight gain is considered equivalent to 1 mL of breast milk intake.
22
Breastfeeding practices
At 48 hours and postnatal weeks 2 and 6, mothers were asked if they were breastfeeding exclusively (no other type of feed, including water), predominantly (includes only one or two feeds other than breast milk), partially (three or more feeds other than breast milk), or not breastfeeding. For analysis purposes, predominant and partial breastfeeding were combined.
Data analyses
Data were entered and analyzed using SPSS, version 23. Descriptive statistical analyses were done. The relationships among sociodemographics, pregnancy, birth events, infant/maternal factors, actual and perceived milk insufficiency, and breastfeeding practices were analyzed. Pearson correlations were used to assess continuous variables. Student's t test analysis was used to assess ratio variables. Analysis of variance was used for categorical variables with multiple comparisons.
Results
Sociodemographic characteristics
Table 2 summarizes the sociodemographic characteristics of participants. The mean maternal age was 28.2 years (standard deviation [SD] = ±0.45 years). In total, 86.5% were married or lived with a partner, and almost 70% were at least college graduates. Two-thirds (65.2%) reported a family annual income of ≥50,000 CDN$. Among the group, 87.5% were Canadian and 82.5% spoke French at home.
Birth events
Table 3 summarizes birth events as well as baby's and mother's capacities. Almost 75% of the mothers gave birth vaginally and had immediate skin-to-skin contact at birth with their baby for as long as 1–2 hours as it is the norm in this hospital for most vaginal births. Most vaginally delivered babies had their first suckling during this period.
T1 = day 3 questionnaire.
Missing response.
SD, standard deviation.
Breastfeeding practices
At 48 hours, almost 70% (68/98) of the mothers breastfed exclusively and 30% supplemented their child with formula supplements (30/98). The most frequently reported reasons for supplementation were not enough milk and painful nipple. At postnatal week 2, 91.9% (57/62) of the mothers were breastfeeding, either exclusively (74%; 46/62) or nonexclusively (18%; 11/62). Most frequent reasons given for introducing formula supplements were fatigue, baby not satisfied, and painful nipples. At postnatal week 6, 88% (46/52) of the mothers were breastfeeding exclusively, 10% (5/52) gave formula or other liquid to their child, and 2% (1/52) stopped breastfeeding. The reason most frequently given for supplements were babysitting needed (Table 4).
Baseline = 24 hours after birth; T1 = day 3 questionnaire, T2 = week 2 questionnaire, and T3 = week 6 phone call.
Missing response.
AIMS, actual insufficient milk supply; IBFAT, Infant Breastfeeding Assessment Tool; PIMS, perceived insufficient milk supply; SD, standard deviation.
Breast milk production, actual and perceived
At 48 hours, the mean baby's weight loss was 6.19% (SD = ±0.21). The mean baby's weight loss for exclusive breastfeeding mothers was 6.469 ± 1.894 g and, for nonexclusive, 5.573 ± 2.244 g. Following Student's t test, this difference in weight loss was found to be statistically nonsignificant.
At 2 weeks, the 24-hour breast milk production was 525.48 mL (SD = 213.97) (Table 4). When asked if they perceived their breast milk production enough to satisfy their newborn, 82% (73/89) of mothers at T1 and 92.5% (49/53) of mothers at T2 answered positively. Reasons most frequently reported for positive perception of milk production were related to baby sleeping well or signs of satiety or adequate urine and stool patterns. 16
At T1 (48 hours), no significant association was found between the baby's weight loss and maternal perception of insufficient milk supply (PIMS) (r = −0.33; NS). At T2 (2 weeks), no significant association was found between 24-hour milk production and PIMS (r = 0.20; NS).
Factors associated with breast milk production, actual or perceived
Factors related to actual breast milk production at T1 (baby's weight loss) were skin-to-skin contact (t = −3.359, p = 0.001) and breastfeeding at birth (t = −3.652, p < 0.01) and at T2 (24-hour milk production) were skin-to-skin contact at birth (t = 2.336, p = 0.023) and number of breastfeeds/24 hours (r = 0.33, p < 0.05). Factors related to PIMS at T1 were IBFAT (r = 0.538, p < 0.01), I-MABS (r = −0.45, p < 0.01), and BSES-SF (r = 0.38, p < 0.01) and for PIMS at T2 were BSES-SF T1 (r = 0.308, p < 0.5) and BSES-SF T2 (r = 0.725, p < 0.01) and number of breastfeeds per 24 hours (r = 0.499, p < 0.01).
We further compared these variables among mothers who reported breastfeeding exclusively versus nonexclusively (predominant + partial) at both 48 hours and postnatal week 2. Mothers who breastfed exclusively (68/92) were more likely than mothers who introduced breast milk substitutes (24/92) to perceive their breast milk production as sufficient (21.46 ± 4.04 versus 18.63 ± 4.46; t = 2.87, p = 0.005). Mothers who breastfeed exclusively at 48 hours (65/85) compared with mothers who introduced breast milk substitutes (20/85) were also significantly different in terms of breastfeeding self-efficacy (52.17 ± 10.06 versus 45.45 ± 10.11; t = 2.61, p = 0.01). At postnatal week 2, mothers who did not breastfeed exclusively (11/57) were more likely to perceive milk insufficiency than mothers who breastfed exclusively (19.45 ± 3.42 versus 23.28 ± 1.72; t = 3.63, p = 0.004). They were also more likely to breastfeed less frequently than mothers who breastfed exclusively (7.45 ± 1.29 versus 9.6 ± 1.87; t = 3.04, p = 0.004).
Discussion
This study aimed to determine the relationship between PIMS and AIMS and the relative contributions of physiological and psychosocial variables on both PIMS and AIMS. To our knowledge, this is the first study that documents, at the same time points, PIMS and AIMS. 4 We also intended to report breastfeeding and its exclusivity rates.
Maternal perception of insufficient milk supply was not related to actual milk supply. Indeed, at both time frames, more than 80% of the mothers at 48 hours and more than 90% at postnatal week 2 believed their breast milk supply was enough to satisfy their infants. Actual milk production, both at 48 hours and at postnatal week 2, was within expected and published results. The mean percentage of baby's weight loss was 6.19% (SD = ±0.21) at 48 hours, which parallels the results of a systematic review where mean weight loss from 11 studies ranged from 5.7% to 6.6% (SD = ±2%). 23 Our findings also correspond to the expected result of less than 7% of weight loss between 3 and 5 days. 21 The 24-hour milk production at 2 weeks was 525.48 mL (±213.97 mL), which is similar to published results of normal breast milk production during the first postnatal month. 8
Factors associated with PIMS at 48 hours were both infants' ability to suckle effectively and maternal breastfeeding self-efficacy. Mothers who perceive positively both mother and child breastfeeding capacities are more likely to perceive their supply as sufficient to satisfy their infants. At 2 weeks, mothers who perceive positively their own breastfeeding capacity and who breastfeed often perceive their breast milk supply as adequate to satisfy their infant. These findings confirm previous results not only on the importance of child's capacity to suckle effectively for optimal milk transfer but also its impact on mother's breastfeeding confidence.4,7,13,14 Maternal evaluation of the dyad's capacity contributes to her perception of breastfeeding self-efficacy and is determinant to her intention to pursue and to maintain her breastfeeding practice and the actions required for its success. 24 Perception of a satisfied infant provides a feeling of security to the mother and enhances her breastfeeding self-efficacy. 25 Mother's confidence in her breastfeeding capacity influences her interpretation of the infant's demands and cues in a positive way.25,26
Factors associated with actual breast milk production were different than for the perceived breast milk production at 48 hours, but partly similar at 2 weeks. Skin-to-skin contact at birth, followed by an early breastfeeding session, was associated with baby's reduced weight loss at 48 hours. This is in line with evidence from the literature. It has been demonstrated that immediate and uninterrupted skin-to-skin contact at birth positively influences the initiation of breastfeeding as baby is more inclined to attach spontaneously to the breast if not forced to suckle and oxytocin level is increased by this contact; feedings are also more effective when skin-to-skin contact lasts at least 1 hour without interruption.27–34 When baby suckles spontaneously within the first 2 hours, it is linked with more feeding episodes at days 3 and 4, more milk production, more milk ingested, and less engorgement.27,35,36 There is also a demonstrated link between immediate and uninterrupted skin-to-skin contact at birth and exclusivity of breastfeeding at discharge and later on.27,37
At postnatal week 2, skin-to-skin contact and number of breastfeeds were still associated with 24-hour milk production. This finding adds to previous results that the frequency of breast stimulation among nonsupplementing mothers was related to milk production in the first 3 weeks postpartum. 22 However, it seems that frequency of breastfeeds is often reported as an issue by breastfeeding mothers; they expressed difficulty in determining how often they should breastfeed their baby. 38 In this study, mothers with PIM were less likely to breastfeed frequently as they believed it meant their baby was not satisfied. Although informed by health professionals to breastfeed on baby's demand, mothers expressed difficulty in interpreting baby's cues.26,38 If mothers have skin-to-skin contact immediately at birth and are supported early on to recognize their baby's demand and to immediately respond to it, mothers seem less preoccupied by the frequency of feeds.
Limitations
There are a few limitations to this study. First, it is a convenience sample, therefore self-selection might have occurred. The sociodemographic characteristics of participants were comparable with regional sociodemographic data except for family income, educational level, and marital status, which are slightly higher than average for the area. These characteristics have been associated with breastfeeding exclusivity and duration. Lack of variability in our sample of breastfeeding mothers might have influenced the nonsignificant relationship between perceived and actual breast milk supply. Indeed, mothers who experienced breastfeeding difficulties might have been less likely to participate in this study or might have stopped breastfeeding or have introduced breast milk substitutes early. Therefore, mothers with a successful breastfeeding experience might have been overrepresented.
Second, the breastfeeding assessment measures were self-administered, obviously subjective in nature. Validity and reliability of the measures of actual milk supply might have influenced the results as well as the small sample of mothers who did measure their milk production at 2 weeks. Not all mothers provided 24-hour milk production and these missing data might not have been random. It is also possible that some measurement error occurred even though actions were taken to minimize this bias by selecting a precise baby scale—the research assistant explained the functioning to the mother. It might also be the case for actual breast milk production measure such as percentage of baby's weight loss. This measure was taken from baby's chart at 48 hours. We could not exclude that some babies might have continued to lose weight when back home.
Conclusion
The aim of this study was to determine the relationship between PIMS and AIMS and the relative contributions of physiological and psychosocial variables on both PIMS and AIMS of first-time breastfeeding mothers. To our knowledge, this is the first study documenting at the same time points maternal perception and actual insufficiency of milk supply. In this sample of primiparous mothers, maternal perception of not having enough milk was not associated with an actual insufficiency of milk supply as measured by baby's weight loss or 24-hour milk production. Indeed, factors associated with maternal perception versus actual insufficiency were deemed different. First-time breastfeeding mothers with higher breastfeeding self-efficacy were less likely to perceive their infant as nonsatisfied. Therefore, interventions should be directed toward promoting early, optimal, and frequent feedings. Professional support should be directed to inform and guide parents toward optimal latch-on and signs to recognize that baby's suckling is efficacious, as well as resources available if experiencing breastfeeding difficulties.
Footnotes
Acknowledgments
The authors would like to thank all mothers who participated in this study. They thank Drissa Sia, PhD, for his participation in statistical analyses. They also thank the “Naissance-Renaissance Outaouais,” the regional breastfeeding mother-to-mother group, for their support with renting the baby's scale.
Disclosure Statement
No competing financial interests exist.
