Abstract
Background
Late preterm birth is associated with lower rates of breastfeeding and earlier breastfeeding cessation than term birth.
Purpose
The objectives of this secondary analysis were to compare the incidence of exclusive breastfeeding after late preterm and term childbirth and to examine the association between infant feeding outcomes and maternal emotional well-being.
Methods
Participants were 105 mother-infant dyads (54 late preterm and 51 term) at a southeastern U.S. medical center. Face-to-face data collection and telephone follow up occurred during 2009-2012.
Results
Late preterm mothers were less likely to exclusively provide their milk than were term mothers during hospitalization. Feeding at one month did not differ between late preterm and term infants. Among late preterm mothers, (1) formula supplementation during hospitalization was associated with greater severity of anxiety compared to those exclusively providing formula and (2) exclusive provision of human milk at one month was associated with less severe depressive symptoms relative to those supplementing or exclusively formula feeding. Among term mothers, feeding outcome was not related to emotional well-being measures at either time point.
Implications for Practice
Mothers of late preterm infants may particularly benefit from anticipatory guidance and early mental health screening, with integrated, multidisciplinary lactation teams to support these interrelated health care needs
Implications for Research
Prospective research is critical to document women’s intentions for infant feeding and how experiences with childbirth and the early postpartum period impact achievement of their breastfeeding plans.
Keywords: breastfeeding, mothers, preterm infants, anxiety, depressive symtoms
Background and Significance
Late preterm newborns (34-37 gestational weeks) account for 6.8% of births in the United States.1 Late preterm newborns appear similar to term infants after birth,2 yet late preterm infants are less neurologically and physiologically mature.3 Although greater attention and tailored management is being implemented for late preterm infants,4-5 late preterm birth is associated with lower rates of breastfeeding, earlier breastfeeding cessation, and more infant feeding-related morbidities than term birth.6-11 The discrepancy in breastfeeding outcomes include those who prenatally reported intent to breastfeed.12 Exclusive breastfeeding for 6 months and continued breastfeeding for 2 years or beyond is recommended for optimal infant nutrition and development.13-15 Lactation is additionally associated with better short- and long-term maternal health outcomes.16
Women who give birth late preterm have also been found to have greater prenatal and postnatal emotional distress than those who delivered at term.8 Previous research has linked greater maternal emotional distress to poorer breastfeeding outcomes after late preterm childbirth. Zanardo and colleagues10 found that high maternal anxiety, depressive symptoms, and distress after late preterm childbirth were associated with less at-breast feeding at hospital discharge. McDonald and colleagues8 found that, compared to term infants, late preterm infants were less likely to be breastfed within 24 hours of birth and their mothers were more likely to report the first breastfeeding attempt as unsuccessful. In a sample including late preterm and term mothers, greater postpartum anxiety was associated with reduced breastfeeding duration.17 The studies by Zanardo et al.,10 McDonald et al.,8 and Paul et al.17 did not include assessment of women’s breastfeeding intentions, so less is known about whether maternal emotional well-being is related to achievement of individual breastfeeding goals after late preterm childbirth.
Objectives
The objectives of this secondary analysis were to compare the incidence of exclusive breastfeeding after late preterm and term childbirth and to examine the association between infant feeding outcomes and maternal emotional well-being. Further, we explored the relationships among breastfeeding intentions, maternal comfort with the idea of formula feeding, and infant feeding outcomes in a subsample of the mothers of late preterm and term infants.
The first hypothesis was that, because of the lower rates of breastfeeding in late preterm mother-infant dyads reported in the literature, the incidence of the exclusive provision of human milk during hospitalization and at one month postpartum would be lower among the late preterm than in term mother-infant breastfeeding dyads. The second hypothesis was that non-exclusive breastfeeding would be associated with greater maternal emotional distress among both the late preterm and term groups, since previous studies found less at-breast feeding and a shorter duration of breastfeeding were associated with greater maternal emotional distress.8,17 Exploratory analyses examined whether maternal breastfeeding intentions or comfort with the idea of formula feeding were related to infant feeding outcomes during hospitalization and at one month postpartum.
Materials and Methods
This exploratory study was conducted from 2009-2012 as a secondary analysis of a larger ongoing descriptive comparative study. The purpose of the original study was to compare maternal emotional well-being after late preterm and term childbirth,18 with postnatal unit in-person and one-month telephone assessments through an IRB-approved process.
Participants
Mothers delivered their infants in a regional referral birthing center of a southeastern U.S. academic medical center with approximately 3,300 births per year. All of the infants in this study were born and treated at the same hospital, which was not designated as Baby-Friendly.
Beginning in 2009 for the ongoing larger study, review of postpartum medical records were used to determine potential eligibility (maternal age at least 18 years, custody of child, no history of HIV, psychosis, or bipolar disease, English speaking, infant singleton). Non-English speaking Hispanic mothers were excluded because the measures of maternal emotional well-being used (see Measures below) have not been validated in this population. Additionally, the research team did not include a Spanish-speaking data collector due to funding constraints. Infant health was not an inclusion or exclusion criterion. The goal of this secondary analysis was to enroll adequate numbers of breastfeeding dyads to examine hospital breastfeeding exclusivity. Therefore, late preterm and term mothers providing their milk to their newborns, as indicated by their postpartum hospital records (mother’s own milk or not), were oversampled from 2010-11. The appropriateness of potential participation was then checked with nursing staff. Term dyads (infants born >37 gestational weeks) were matched to late preterm dyads (infants born 34-37 gestational weeks) on maternal race/ethnicity because demographic characteristics have been found to contribute to the breastfeeding disparity between term and late preterm dyads.19
Mothers (N=105) from the larger study information on their characteristics, completed a questionnaire packet, and described their infant feeding and other perinatal experiences (54 late preterm and 51 term). At one month postpartum, 88 mothers provided questionnaire, feeding, and related data (45 late preterm and 43 term). Questionnaires regarding maternal intentions for breastfeeding duration, breastfeeding exclusivity, and comfort with the idea of formula feeding, described below, were added part way into the larger project (in 2010) by a postdoctoral fellow (K.P.T.) who had just joined the team to provide data for this exploratory study on the relationship of infant feeding outcomes and maternal emotional well-being and to asses maternal plans and practices for infant sleep locations.20 Therefore, these measures were administered to about half of the participants (N=53, 26 late preterm and 27 term).
A set of sensitivity analyses were conducted to compare characteristics of the (1) one month subsample of 88 and (2) breastfeeding intentions and comfort with formula feeding subsample of 53 to those dyads from the total sample of 105 not included in the subsample. Nonparametric tests were conducted within each group (late preterm or term) to evaluate the similarities of the groups across the different analyses (hospitalization, one month, and breastfeeding intentions and formula comfort). Wilcoxon Two-Sample Tests for continuous measures and Fisher’s Exact Tests for categorical measures did not indicate any significant differences (p >.10) in those included and those not included.
Measures
Maternal and Infant Characteristics
Demographic information was recorded on a form completed by the mother. The infant’s medical records were reviewed after enrollment and following hospital discharge to obtain data on obstetric history and medical course. Infant feeding outcomes – exclusive human milk, human milk supplemented with formula, or exclusive formula – were assessed by maternal report.
Measures of Maternal Emotional Well-Being
Four aspects of maternal emotional well-being were each assessed during postpartum hospitalization and at one month postpartum: depressive symptoms (Edinburgh Postnatal Depression Scale, EPDS21), anxiety (State anxiety subscale score of the State-Trait Anxiety Inventory, STAI-S22), post-traumatic stress symptoms (Perinatal PTSD Questionnaire, PPQ23-24), and worry about the child’s health (Child Health Worry Scale, Worry Scale25-26). These variables represent major maternal emotional responses to the birth and hospitalization of preterm infants, and all are related to child development (e.g.,27-28). In this sample, the EPDS had Cronbach’s alphas of .87 at hospitalization and .74 at one month. Cronbach’s alphas for the STAI-S were .94 at hospitalization and .83 at one month. PPQ Cronbach’s alphas were .76 at hospitalization and .73 at one month. Worry Scale Cronbach’s alphas were .89 at hospitalization and .89 at one month.
Breastfeeding Intentions
Maternal intentions for infant feeding were not assessed upon admission to labor and delivery at this hospital. Therefore, during postpartum hospitalization, the Infant Feeding Intentions Scale (IFI29) was used to assess maternal recall of plans for infant feeding. In a previous study, the IFI Scale was correlated with breastfeeding duration.29 Cronbach’s alpha for the IFI Scale in this study was .80.
Comfort with Formula Feeding
Participants were also assessed on their level of “comfort with the idea of formula feeding” during post-partum hospitalization. Mothers reported a score from 1-4, ranging from 1 (very uncomfortable) to 4 (very comfortable) (see30).
Procedure
Following Institutional Review Board approval from Duke University Medical Center, a research team member confirmed potential eligibility and the appropriateness of potential participation with the nursing staff. Mothers who were considered to be well enough to potentially participate in the study by their nurses and who were awake and not engaged with a health professional were approached on the postnatal unit the day after childbirth or later. Directly after a mother provided written informed consent to participate in the study, or at a time during postpartum hospitalization more convenient to the mother, the demographics form and questionnaires were administered. A participant who conveyed significant emotional distress during data collection was referred to a mental health professional. Mothers were paid $10 each time they participated in the questionnaires (during postpartum hospitalization and at one month postpartum).
Analyses
Descriptive statistics were used to summarize the characteristics of the mother-infant dyads, as well as infant feeding outcomes and maternal emotional well-being during postpartum hospitalization and at one month postpartum. Cross-sectional outcome analyses were conducted during hospitalization and at one month. We applied non-parametric methods for this analysis. When statistical significance testing was conducted, the level of significance was set at p<0.05 (two-tailed tests). Statistical analyses were conducted using SAS 9.3.
Outcome analyses
First, infant feeding outcomes between the late preterm and term mother-infant dyads were examined using chi-square tests. Edinburgh Postnatal Depression Scale total scores were dichotomized (total score ≤12 or >12)21 and used as a covariate in the analyses on infant feeding outcomes by late preterm and term participants at hospitalization and one month postpartum, using the Cochran-Mantel-Haenszel Test.
Next, Wilcoxon Two-Sample Tests were used to test for differences between late preterm and term maternal emotional well-being outcome total scores at hospitalization and one month. A Kruskal-Wallis Test was then used to determine if there were differences among the three infant feeding outcome groups, namely (1) exclusive human milk; (2) human milk supplemented with formula; (3) exclusive formula, on the different measures of maternal emotional well-being. When a signficant feeding group difference was demonstrated, a posteriori multiple comparisons were conducted using the Wilcoxon Two-Sample Test to test for pairwise differences on the maternal well-being measures in the different feeding groups.
A Kruskal-Wallis Test was also used to test if the length of infant hospitalization was associated with the infant feeding outcomes during hospitalization. A Wilcoxon Two-Sample Test was used to examine whether infant care (rooming-in only or the infant spent any time in an intensive care unit) was associated with maternal anxiety or depressive symptoms during hospitalization. Then, the Cochran-Mantel-Haenszel Test was used to examine whether infant care (rooming-in only or any intensive care) was associated with the infant feeding outcomes during hospitalization. Within the term group, the Wilcoxon Two-Sample test was also used to test if the length of infant hospitalization was associated with childbirth mode (cesarean section or vaginal delivery). A Fisher’s Exact Test was then used to determine whether childbirth mode was associated with non-exclusive breastfeeding among the term dyads during hospitalization.
Lastly, Wilcoxon Two-Sample Tests were used to test for group (late preterm versus term) differences in the total score of the Infant Feeding Intentions Scale and ratings of Comfort with the Idea of Formula Feeding among the subsample of late preterm and term participants for whom these data were available. For the Infant Feeding Intentions Scale, the analysis of total scores was conducted among those who indicated any intent to provide their milk (total score of >0) in order to compare plans for breastfeeding duration and exclusivity between the late preterm and term mothers who reported that they intended to breastfeed.
Results
In the full sample, late preterm infants had gestational ages at birth of 34 0/7 to 36 6/7 weeks and the term infants had gestational ages of 37 5/7 to 41 6/7 s. The sample was 50.0% White non-Hispanic, 34.6% Black non-Hispanic, and 15.4% English speaking Hispanic women. Participant demographics by late preterm and term childbirth status are provided in Table 1.
Table 1. Characteristics of the Late Preterm and Term Mother-Infant Dyads (N=105).
| Late Preterm N=54 Mean (SD) or % (n) |
Term N=51 Mean (SD) or % (n) |
|
|---|---|---|
| % White non-Hispanic | 50.9 (27/53) | 49.0 (25/51) |
| % Black non-Hispanic | 34.0 (18/53) | 35.3 (18/51) |
| % Hispanic and Other | 15.1 (8/53) | 15.7 (8/51) |
| % Married* | 65.4 (34/52) | 45.1 (23/51) |
| % Public assistance | 43.1 (22/51) | 41.2 (21/51) |
| % First-time mother | 25.9 (14/54) | 31.4 (16/51) |
| Maternal age in years | 29.3 (6.3) | 28.1 (5.7) |
| Gestational age in weeks*** | 35.8 (0.8) | 39.7 (1.0) |
| % Infant female | 50.0 (27/54) | 41.2 (21/51) |
| Apgar at 1 minute | 7.4 (2.1) | 7.6 (1.9) |
| Apgar at 5 minutes | 8.7 (0.8) | 8.8 (0.8) |
| % Cesarean birth | 51.9 (28/54) | 39.2 (20/51) |
| Head circumference at birth in cm*** | 32.3 (1.8) | 34.1 (1.5) |
| Length at birth in cm*** | 47.1 (2.8) | 50.6 (2.7) |
| Birthweight in grams*** | 2585.1 (470.6) | 3351.3 (428.8) |
| % < 2500 | 48.2 (26/54) | 0.0 (0/51) |
| % 2501-3000 | 33.3 (18/54) | 21.6 (11/51) |
| % > 3000 | 18.5 (10/54) | 78.4 (40/51) |
| % Had any pregnancy complications | 55.6 (30/54) | 41.2 (21/51) |
| % No prenatal care | 3.7 (2/54) | 5.9 (3/51) |
| % Diabetes | 9.3 (5/54) | 0.0 (0/51) |
| % Hypertension | 37.0 (20/54) | 26.5 (13/49) |
| % Antepartum hemorrhage | 3.8 (2/53) | 3.9 (2/51) |
| % Chorioamnionitis | 5.6 (3/54) | 15.7 (8/51) |
| % Rupture of membranes prior to delivery |
67.9 (36/53) | 82.0 (41/50) |
| % Received prenatal steroids* | 15.7 (8/51) | 2.0 (1/51) |
| % Received prenatal antibiotics** | 62.3 (33/53) | 35.3 (18/51) |
| % Only in well baby nursery** | 61.1 (33/54) | 88.2 (45/51) |
| Length of hospital stay in days*** | 7.0 (11.3) | 3.1 (3.6) |
| % Provided human milk at discharge | 48.2 (39/51) | 51.9 (42/51) |
Note. Wilcoxon Two-Sample Tests for continuous measures and Fisher’s Exact Tests for categorical measures were used to test for differences in the late preterm and term samples at enrollment.
p<05;
p<01;
p<.001
During hospitalization, 36 of the 105 (34.3%) mothers exclusively breastfed, 47 (44.8%) of participants fed their milk and supplemented with formula, and 22 (21%) of the mothers exclusively formula fed. There was a significant difference in the proportion of hospital infant feeding outcomes between the late preterm term and term participants (X2=16.79, df=2, p=.0002), with less exclusive human milk provision among the late preterm dyads (see Table 2). The increased likelihood of late preterm mothers using formula during hospitalization remained statistically significant after controlling for the level of maternal depressive symptoms during hospitalization (X2=7.35, df=1, p=.007).
Table 2. Infant Feeding Outcomes during Hospitalization and at One Month Postpartum Among the Late Preterm and Term Mother-Infant Dyads.
| Hospitalization*** | One Month | ||||
|---|---|---|---|---|---|
| n | (%) of Group | n | % of Group | ||
| Exclusive human milk | Late Preterm | 9 | 16.7 | 9 | 20.0 |
| Term | 27 | 52.9 | 15 | 34.9 | |
| Human milk with formula | Late Preterm | 33 | 61.1 | 18 | 40.0 |
| Term | 14 | 27.4 | 13 | 30.2 | |
| Exclusive formula | Late Preterm | 12 | 22.2 | 18 | 40.0 |
| Term | 10 | 19.6 | 15 | 34.9 | |
Note. For Hospitalization, X2=16.79, df=2, p=.0002. For One Month, X2=2.54, df=2, p=.28
p<.001
At one month postpartum, 24 of 88 (27.3%) mothers exclusively breastfed, 31 (35.2%) supplemented with formula, and 33 (37.5%) exclusively formula fed. The one month feeding outcomes of the late preterm and term participants did not differ statistically (X2=2.54, df=2, p=.28), including after controlling for the level of maternal depressive symptoms at one month (X2=0.18, df=1, p=.67, see Table 2). The ways that women fed their infants during hospitalization (exclusive human milk feeding, human milk supplemented with formula, and exclusive formula feeding) were significantly associated with the continuation of these same feeding practices at one month postpartum among both the late preterm (X2=20.94, df=4, p=.0003) and term (X2=17.02, df=4, p=.0002) mothers.
Among the women who supplemented with formula in the hospital, 34 were reached at one-month and eight of these women exclusively provided their milk at one month. There was not a statistically significant difference in the move to exclusive human milk provision between the late preterm (5 of 23, 21.7%) and term (3 of 11, 27.3%) mothers (Fisher’s Exact Test, p=.99). Two mothers (one late preterm and one term) who exclusively formula fed in the hospital provided their milk in combination with formula at one month. Half of the women who exclusively provided their milk in the hospital were doing so at one month.
As previouly reported with a sub-sample of the current study’s sample,18 the late preterm mothers reported significantly more anxiety, worry, and depressive symptoms during hospitalization and at one month than the term mothers.
Among mothers of late preterm infants, supplementing human milk feeding with formula during hospitalization was associated with more maternal anxiety during hospitalization compared to those exclusively providing formula (see Table 3). The duration of late preterm infant hospitalization was not associated with infant feeding outcomes during hospitalization (X2=1.42, df=2, p=.49). Further, in this group, infant care outside of the well-baby nursery (rooming-in) was positively associated with maternal anxiety (p=.05), but infant care (rooming-in only or any intensive care) was not associated with either maternal depressive symptoms (p=.81) or with infant feeding outcome (p=.80) during hospitalization.
Table 3. Emotional Distress by Infant Feeding Practices Among Mothers of Late Preterm Infants.
| Hospitalization, N=53 | Feeding | n | Mean (SD) | Median | 25th, 75th Percentile |
|---|---|---|---|---|---|
| EPDS Total Score | Exclusive human milk | 9 | 3.8 (3.4) | 3.0 | 2.0, 3.0 |
| Human milk with formula |
32 | 6.7 (5.1) | 6.0 | 2.5, 10.0 | |
| Exclusive formula | 12 | 4.7 (3.4) | 3.0 | 2.0, 7.5 | |
| State anxiety subscale score STAI* |
Exclusive human milk | 9 | 31.2 (10.8) | 26.0 | 21.0, 36.0 |
| Human milk with formula |
32 | 38.2 (11.9) | 37.5 | 29.5, 45.5 | |
| Exclusive formula | 12 | 29.2 (7.1) | 28.0 | 23.0, 36.0 | |
| Perinatal PTSD Total Score | Exclusive human milk | 9 | 1.3 (1.5) | 1.0 | 0.0, 2.0 |
| Human milk with formula |
32 | 2.2 (1.9) | 2.0 | 0.5, 3.0 | |
| Exclusive formula | 11 | 1.5 (1.8) | 1.0 | 0.0, 2.0 | |
| Worry Scale Total Score | Exclusive human milk | 9 | 14.8 (4.7) | 15.0 | 11.0, 17.0 |
| Human milk with formula |
32 | 18.0 (5.8) | 17.5 | 14.0, 21.0 | |
| Exclusive formula | 11 | 14.3 (7.1) | 13.0 | 8.0, 18.0 | |
|
| |||||
| One Month, N=41 | |||||
|
| |||||
| EPDS Total Score*** | Exclusive human milk | 8 | 0.8 (0.9) | 0.5 | 0.0, 1.5 |
| Human milk with formula |
17 | 2.9 (2.6) | 3.0 | 0.0, 4.0 | |
| Exclusive formula | 15 | 6.2 (4.2) | 7.0 | 3.0, 9.0 | |
| State anxiety subscale score STAI |
Exclusive human milk | 8 | 27.3 (5.8) | 26.5 | 22.0, 33.5 |
| Human milk with formula |
18 | 29.7 (7.4) | 29.5 | 23.0, 34.0 | |
| Exclusive formula | 14 | 30.9 (7.6) | 28.0 | 25.0, 34.0 | |
| Perinatal PTSD Total Score | Exclusive human milk | 8 | 0.9 (1.0) | 0.5 | 0.0, 2.0 |
| Human milk with formula |
17 | 1.6 (1.7) | 1.0 | 0.0, 2.0 | |
| Exclusive formula | 15 | 2.6 (3.0) | 2.0 | 1.0, 3.0 | |
| Worry Scale Total Score | Exclusive human milk | 8 | 10.8 (3.0) | 10.5 | 8.0, 12.5 |
| Human milk with formula |
18 | 14.5 (6.4) | 13.0 | 11.0, 16.0 | |
| Exclusive formula | 15 | 14.8 (6.0) | 14.0 | 11.0, 17.0 | |
Note. EPDS=Edinburgh Postnatal Depression Scale; STAI=State-Trait Anxiety Inventory; Perinatal PTSD= Perinatal PTSD Questionnaire; Worry Scale=Child Health Worry Scale. A Kruskal-Wallis Test was used to determine if there were differences among the three infant feeding outcome groups on the different measures of maternal emotional well-being. When a signficant feeding group difference was demonstrated, a posteriori multiple comparisons were conducted using the Wilcoxon Two-Sample Test to test for pairwise differences on the maternal well-being measures in the different feeding groups.
p<.05;
p≤.001
At one month postpartum, exclusive human milk feeding was associated with lower maternal depressive symptom scores in late preterm dyads when compared to those supplementing human milk feeding with formula or those exclusively formula feeding at one month (see Table 3). Further, late preterm mothers supplementing with formula at one month was related to fewer maternal depressive symptoms at one month than those exclusively providing formula (see Table 3).
Among mothers of term infants, infant feeding outcomes were not related to measures of emotional well-being during hospitalization or at one month postpartum (see Table 4). For the term participants, the duration of infant hospitalization was associated with formula provision (X2=7.27, df=2, p=.03), such that dyads who exclusively provided their milk were discharged earlier than either those who supplemented human milk with formula or those who exclusively formula fed. Term infant care outside of the well-baby nursery (rooming-in) was positively associated with maternal anxiety (p=.05), but infant care (rooming-in only or any intensive care) was not associated with either maternal depressive symptoms (p=.43) or with infant feeding outcome (p=.17) during hospitalization. Among the term participants, both longer infant hospitalization (p=.002) and non-exclusive breastfeeding during hospitalization (p=.05) were positively associated with cesarean section childbirth (7 of 20, 35.0%, exclusive breastfeeding after cesarean section delivery and 20 of 31, 64.5%, exclusive breastfeeding after vaginal delivery).
Table 4. Emotional Distress by Infant Feeding Practices Among Mothers of Term Infants.
| Hospitalization, N=51 | Feeding | n | Mean (SD) | Median | 25th, 75th Percentile |
|---|---|---|---|---|---|
| EPDS Total Score | Exclusive human milk | 27 | 4.5 (5.4) | 2.0 | 1.0, 6.0 |
| Human milk with formula |
13 | 4.5 (6.0) | 1.0 | 0.0, 9.0 | |
| Exclusive formula | 10 | 1.7 (2.5) | 1.0 | 0.0, 2.0 | |
| State anxiety subscale score STAI |
Exclusive human milk | 27 | 30.1 (12.8) | 27.0 | 21.0, 34.0 |
| Human milk with formula |
14 | 32.4 (10.6) | 30.0 | 24.0, 40.0 | |
| Exclusive formula | 10 | 28.2 (6.2) | 26.7 | 23.0, 34.0 | |
| Perinatal PTSD Total Score | Exclusive human milk | 27 | 1.1 (1.9) | 0.0 | 0.0, 2.0 |
| Human milk with formula |
13 | 3.2 (3.7) | 1.0 | 1.0, 6.0 | |
| Exclusive formula | 10 | 1.6 (1.8) | 1.0 | 0.0, 3.0 | |
| Worry Scale Total Score | Exclusive human milk | 27 | 13.9 (6.7) | 12.0 | 9.0, 17.0 |
| Human milk with formula |
13 | 15.0 (7.9) | 12.0 | 8.0, 19.0 | |
| Exclusive formula | 10 | 16.0 (7.5) | 13.5 | 11.0, 25.0 | |
|
| |||||
| One Month, N=39 | |||||
|
| |||||
| EPDS Total Score | Exclusive human milk | 11 | 2.3 (1.8) | 2.0 | 1.0, 3.0 |
| Human milk with formula |
13 | 1.8 (2.2) | 1.0 | 0.0, 3.0 | |
| Exclusive formula | 14 | 1.0 (2.1) | 0.0 | 0.0, 1.0 | |
| State anxiety subscale score STAI |
Exclusive human milk | 12 | 25.1 (3.5) | 24.5 | 22.5, 27.0 |
| Human milk with formula |
13 | 25.0 (3.2) | 24.0 | 24.0, 26.3 | |
| Exclusive formula | 14 | 25.7 (3.4) | 25.5 | 25.5, 29.0 | |
| Perinatal PTSD Total Score | Exclusive human milk | 12 | 1.9 (1.4) | 2.0 | 1.0, 2.5 |
| Human milk with formula |
13 | 1.7 (2.1) | 1.0 | 0.0, 3.0 | |
| Exclusive formula | 14 | 1.1 (2.4) | 0.0 | 0.0, 1.0 | |
| Worry Scale Total Score | Exclusive human milk | 12 | 11.1 (3.3) | 10.0 | 9.0, 14.0 |
| Human milk with formula |
13 | 9.6 (3.0) | 9.0 | 7.0, 11.0 | |
| Exclusive formula | 14 | 11.6 (7.7) | 9.0 | 7.0, 12.0 | |
Note. EPDS=Edinburgh Postnatal Depression Scale; STAI=State-Trait Anxiety Inventory; Perinatal PTSD= Perinatal PTSD Questionnaire; Worry Scale=Child Health Worry Scale. A Kruskal-Wallis Test was used to determine if there were differences among the three infant feeding outcome groups on the different measures of maternal emotional well-being.
In the subsample with data on infant feeding intentions, mothers of late preterm and term infants did not statistically differ on their breastfeeding intentions reported during hospitalization or in their comfort level with the “idea of formula feeding” (see Table 5).
Table 5. Breastfeeding Intentions and Comfort with Formula Feeding Among Mothers of Late Preterm and Term Infants.
| Group | n | Mean (SD) | Median | 25th, 75th Percentile |
|
|---|---|---|---|---|---|
| Infant Feeding Intentions Scale Total Score (N=53) |
Late Preterm | 26 | 13.0 (3.7) | 15.0 | 10.5, 16.0 |
| Term | 27 | 12.1 (3.7) | 12.5 | 10.0, 16.0 | |
| Comfort with the idea of formula feeding (N=50) |
Late Preterm | 22 | 3.1 (1.0) | 3.0 | 3.0, 4.0 |
| Term | 28 | 2.7 (1.1) | 3.0 | 2.0, 3.5 |
Note. Wilcoxon Two-Sample Tests were used to test for group (late preterm versus term) differences in the total score of the Infant Feeding Intentions Scale and ratings of Comfort with the Idea of Formula Feeding.
Discussion
This exploratory study assessed the relationship between infant feeding outcomes and maternal emotional well-being among both late preterm and term mother-infant dyads during postpartum hospitalization through the first postpartum month. The mothers of late preterm infants reported less exclusive breastfeeding during hospitalization. In the subsample of participants reporting their feeding intentions, late preterm and term mothers reported similar breastfeeding intentions and comfort with the idea of formula feeding. Results from our study suggested that mothers of late preterm infants were at-risk for deviating from their breastfeeding plans and experiencing emotional distress through at least the first postpartum month.
Non-exclusive breastfeeding for the late preterm dyads was associated with greater maternal anxiety during hospitalization and with more severe maternal depressive symptoms at one month postpartum. Our findings do not demonstate cause-effect, but are consistent with the previous study findings of greater maternal anxiety among late preterm mothers,8,31 and that higher maternal anxiety is associated with poorer breastfeeding outcomes.32 Depressive symptoms are known to be common in postpartum women33 and to negatively affect breastfeeding (e.g.,34). Mothers of late preterm infants may particularly benefit from anticipatory guidance and early mental health screening, with integrated, multidisciplinary lactation support teams as recently described by Bunik et al.35 Bunik and colleagues35 used a Trifecta Breastfeeding Approach that involves a pediatrician, lactation consultant, and clinical psychologist providing comprehensive evaluation and contextualized support for mother-infant dyads. The Association of Women’s Health, Obstetric and Neonatal Nurses (AWHONN) position statement on breastfeeding36 recommends that late preterm dyads receive additional monitoring and support from nurses so that families can realize their breastfeeding goals. AWHONN recommendations37 to prevent or ameliorate inadequate feeding among late preterm mothers and their infants includes promotion of kangaroo care, observation of feeding sessions, education on infant behavioral cues for feeding, and validation of women’s knowledge about effective breastfeeding. Multidisciplinary guidelines for facilitating late preterm breastfeeding and maternal mental health screening are also detailed by the National Perinatal Association5 and the Academy of Breastfeeding Medicine.38
Mothers who deliver late preterm infants may become distressed due to breastfeeding challenges, their emotional distress may hinder early breastfeeding, or, most likely, their infant feeding practices and emotional well-being are reciprocal processes. In our study, late preterm mothers who were exclusively breastfeeding were less distressed than those providing formula in addition to their milk or those who were exclusively formula feeding. This finding is consistent with the work of Ystrom,39 who found that among term and preterm mothers, supplementing human milk feeding with formula was correlated with greater maternal anxiety and depressive symptoms at 6 months postpartum. Late preterm mothers may therefore benefit from providers who are experienced in tailoring lactation support to enable exclusive human milk provision..Management guidelines such as put forward by Meier et al.4 may be a useful resource for this population. Although early supplementation of breastfed infants is currently common in the U.S.,40 formula supplementation may coincide with maternal emotional distress. Poor breastfeeding outcomes among late preterm dyads may reflect of a lack of appropriate support for parental negotiation of the physiological, metabolical, and developmental obstacles associated with late preterm childbirth.41-42
The infant feeding outcomes of the term group did not correlate with the measures of maternal emotional well-being. However, the low rates of exclusive breastfeeding we observed warrant further investigation. In particular, in the term group, non-exclusive breastfeeding during hospitalization was associated with both cesarean section childbirth and a longer duration of infant hospitalization. Breastfeeding obstacles after cesarean section include maternal mobility limitations, positioning difficulties, and frustration at the need for assistance.43 In addition to Baby-Friendly accreditation44 and tailored breastfeeding support for the population of dyads who experience operative childbirth, improved maternal access to infants while rooming-in with bassinets that attach to the maternal bedframe has been identified as a way to potentially facilitate breastfeeding and maternal satisfaction after cesarean section.45
Only half of the women who exclusively breastfed on the postnatal unit exclusively provided their milk at one month. In the U.S., most mothers stop breastfeeding earlier than they desire.46 The breastfeeding rates we observed were less than the Healthy People 2020 goal of at least 46.2% of infants being exclusively breastfed at 3 months postpartum.47 Additional prospective research is critical to document women’s intentions for infant feeding and how experiences with childbirth and the early postpartum period impact achievement of their breastfeeding plans. In future studies, larger sample sizes would permit within-group testing of factors associated with infant feeding outcomes among mothers of late preterm and term infants.
Limitations
Although our sample was diverse and infant health was not an inclusion or exclusion criterion, the relationship of infant degree of illness and maternal emotional distress was not assessed. The sample was limited by the exclusion of families with multiples and of non-English speaking Hispanic mothers. Maternal history of recreational drug abuse or use of any pharmacological agents that are contraindicated in breastfeeding were also not assessed. Generalizability is further limited by lack of aggregate data from the population of late preterm and term dyads in this community, which would have enabled a comparison of between those who enrolled and those who did not participate. Additionally, other geographical areas may coincide with different levels of maternal emotional distress following childbirth and/or infant feeding intentions. Further, prenatal maternal emotional distress was not assessed, which McDonald et al.8 found to be greater among mothers who went on to deliver late preterm infants, rather than term infants. Finally, maternal recall of infant feeding intentions while on the postnatal unit may have been biased from experiences that occurred between birth and study participation.
A strength of the study was that maternal race and ethnicity was matched between the late preterm and term mothers since preterm birth is more common in African American women48 and U.S. breastfeeding outcomes vary systematically by maternal ethnicity.49 Further, In the subsample, mothers of late preterm and term infants did not differ in their breastfeeding plans or comfort with the idea of formula feeding. These findings suggests that the less exclusive breastfeeding and greater maternal distress among mothers of late preterm infants are not an artefact of the demographic characteristics of the sample. However, breastfeeding intention and formula comfort data were limited to half of the participants in this study. Although the characteristics of the subsample did not differ statistically from the remainder of the sample, future research would benefit from more comprehensive documentation of maternal breastfeeding plans. Future research would benefit from the additional postpartum data collection points of 6-months and beyond to determine how maternal emotional well-being and breastfeeding goals can be most effectively supported over time.
Conclusions
Mothers of late preterm infants are at-risk for suboptimal infant feeding outcomes and maternal emotional distress. Mothers of term infants may experience unplanned formula supplementation after cesarean section childbirth and during longer postpartum hospital stays. More comprehensive breastfeeding support for the mothers of both late preterm and term infants is warranted.
What this Study adds.
Among mothers of late preterm infants, supplementing human milk feeding with formula during hospitalization was associated with more maternal anxiety during hospitalization compared to those exclusively providing formula
At one month postpartum, exclusive human milk feeding was associated with lower maternal depressive symptom scores in late preterm dyads when compared to those supplementing human milk feeding with formula or those exclusively formula feeding at one month
Among mothers of term infants, infant feeding outcomes were not related to measures of emotional well-being during hospitalization or at one month postpartum
What we know
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Late preterm birth is associated with poorer breastfeeding outcomes than term birth
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Exclusive and continued breastfeeding is recommended for optimal infant nutrition and development
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Women who give birth late preterm have greater prenatal and postnatal emotional distress than those who delivered at term
What needs to be studied
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Discontinuation of exclusive and any breastfeeding during transition home and in the early weeks
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More comprehensive documentation of maternal breastfeeding plans, prenatal maternal emotional-well bring, and how these interrelated aspects of women’s health can be most effectively supported over time
What we can do today
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Provide late preterm mothers with tailored breastfeeding support
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Assess the emotional-well being of all mothers during the prenatal and early postpartum periods
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Integrate mental health and lactation support on the postpartum unit and in the community
Acknowledgments
Source of Funding
This research was supported by 2KR251106 from the North Carolina Translational and Clinical Science Institute awarded to Kristin P. Tully and Duke University School of Nursing support to the other 3 authors. The Eunice Kennedy Shriver National Institute for Child Health and Human Development Training Grant T32HD007376 funded Kristin P. Tully. The authors thank Richard Sloane for statistical support.
Footnotes
Conflict of Interest Statement
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Contributor Information
Kristin P. Tully, Center for Developmental Science and Carolina Global Breastfeeding Institute, University of North Carolina at Chapel Hill, 100 East Franklin Street, Suite 200, Chapel Hill, NC, 27599.
Diane Holditch-Davis, School of Nursing, Duke University, 307 Trent Drive, DUMC 3322, Durham NC 27710.
Susan Silva, School of Nursing, Duke University, 307 Trent Drive, DUMC 3322, Durham NC 27710.
Debra Brandon, School of Nursing, Duke University, 307 Trent Drive, DUMC 3322, Durham NC 27710.
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