Perceived Sleep Quality and Fatigue in a Population of New Mothers: A Cross-Sectional Study Comparing Relationships with Breastfeeding and Bottle Feeding

Abstract

Introduction:

This study, which used a cross-sectional design, was carried out to examine the factors associated with the way mothers fed their infants such as breastfeeding or bottle feeding, and to compare perceived sleep quality and fatigue levels.

Method:

The study sample consisted of a total of 100 women in the 4th to 16th week postpartum, including 50 women breastfeeding and 50 women bottle feeding their infants. The data of the study were collected in Family Health Centers (FHC) through the face-to-face interview technique using “a Personal Information Form,” “the Pittsburgh Sleep Quality Index-PSQI,” and “the Checklist Individual Strength-CIS.”

Results:

The mothers' total sleep quality (PSQI) score was found to not differ significantly according to the type of infant feeding. Similarly, total scores for fatigue assessment obtained from the CIS did not differ according to the infant feeding type variable. A significant positive correlation was found between total sleep quality and total fatigue level, and subjective fatigue level.

Discussion:

The sleep quality and fatigue levels of mothers are independent of the method of feeding their infants. Midwives should plan initiatives with parents to improve maternal sleep quality and reduce fatigue levels and inform parents that breastfeeding is not a factor that reduces sleep quality or increases fatigue. Clinical Trials.gov ID: 1129/5463.

Introduction

Breastfeeding has been defined as a universally recognized fundamental right under the International Human Rights since 1924 to meet and protect infants' need for safe and nutritious food and to support their growth and development.^1,2 International organizations recommend that breastfeeding of the newborn should start within the first hour following birth, the intake of breast milk should be encouraged, infants should be fed only on breast milk during the first 6 months, and breastfeeding should continue until the age of 2 years and beyond.^1,3

The needs of mothers for night sleep in the postpartum period may increase by 20%.⁴ However indisputable the benefits of breastfeeding are, mothers may have concerns about how their feeding method will affect their sleep.⁵ Mothers may think that they experience sleeplessness and thus fatigue due to breastfeeding at night. Since breast milk is digested more easily than formula, infants tend to get hungry more frequently, so they may want breast milk more often.⁴ Newborns, who are breastfed, are more likely to continue waking up at night.^6,7 Also, the composition of breast milk requires more frequent feeding for the growth of the baby and more frequent stimulation for the continuation of milk production.⁸

The effect of breastfeeding on the mother's sleep has to be considered in relation to the infant's sleep, and the opportunity the mother has (or does not have) to mitigate the effects of normal infant sleep behaviors on her own sleep through taking maternal daytime naps or earlier bedtime, reducing other work burdens,⁷ co-sleeping,^9,10 or sleeping in the same room.⁸ According to studies investigating the effect of feeding methods on maternal sleep, there is little evidence to support the idea that breastfeeding has a negative effect on maternal sleep.¹¹ Gay et al. reported that mothers who breastfed their infant were awake for a longer time during the night, but that the total sleep duration was not different from that of those who fed their infant with formula.¹² In another study, breastfeeding mothers were concluded to sleep 40 minutes more per night.¹³ In a study conducted using home-based polysomnography with mothers breastfeeding their infants in Australia (infant age about 11–12 weeks), the total sleep time of breastfeeding and non-breastfeeding mothers was not different, but mothers who breastfed their infants were found to show lower sleep efficiency and more wake-ups during the night.¹⁴

In the postpartum period, mothers may experience fatigue accompanied by sleeplessness. Postpartum fatigue is defined as a multidimensional condition that causes a woman to feel more negative, uncomfortable, and less competent than normal.¹⁵ It is a short-term health problem that usually resolves spontaneously in the 8 to 24 weeks after birth. Although fatigue is a common and even expected condition after birth, severe postpartum fatigue has adverse effects on women's health and activities, such as deterioration of the mother's health, late return of the mother to daily life activities, quitting breastfeeding early, and delaying the development of the infant. Besides, permanent postpartum fatigue has been associated with postpartum depression.^16–18 Rychnovsky and Hunter (2009) showed that fatigue scores were at the highest level after birth and that high fatigue level was associated with sleeplessness in the United States.¹⁹

Postpartum fatigue, too, can be associated with breastfeeding as sleeplessness is.²⁰ In their study comparing breastfeeding and bottle-feeding women, Callahan et al. found that perceived fatigue did not differ significantly within 2 to 4 days or 6 to 12 weeks following birth in the France.¹⁷ Likewise, Tobback et al. reported that there was no significant difference between women who breastfed (61) and those who bottle-fed (44) their infant (about 6 weeks of age) in terms of subjective fatigue in Belgium.²¹

Carrying out initiatives for evaluating the causes of barriers to breastfeeding in detail and eliminating them can contribute significantly to mother and child health. Although breastfeeding is known to provide important benefits to the mother and infant, sleep and fatigue problems can urge mothers to quit breastfeeding and start formula feeding. This is the first study evaluating sleep and fatigue on mothers only breastfeeding and bottle feeding in Turkey. The study used a cross-sectional design and was carried out to examine the factors associated with the way mothers fed their infants such as breastfeeding or bottle feeding and to compare perceived sleep quality and fatigue levels.

Research questions

Question 1: What are the perceived sleep quality and fatigue levels in women who breastfeed and bottle feed their infant?

Question 2: Does the quality of sleep and level of fatigue differ between mothers who breastfeed and who bottle feed their infants?

Materials and Methods

The data of the study were collected at six Family Health Centers (FHC) in the central county of Konya province, Turkey, between November 2018 and April 2019. The sample frame of the study consisted of women who were in their 4th to 16th week postpartum and registered in FHCs where the study data were collected between November 2018 and April 2019. The interviews were carried out by the researcher in FHC using face-to-face interview technique. Accordingly, 100 women who met the inclusion criteria made up the sample of the study.

The study included women who were in their 4th to 16th week postpartum, only breastfed or bottle-fed their infant, had no communication problems in the Turkish language, and agreed to participate in the study. Women who had an infant requiring hospital care were not included in the study. Babies who were exclusively breastfed were not given any additional food other than breast milk from birth. Infants who were only bottle-fed received other liquids, including water, from the 4th to the 16th week, and there were some infants who were initially breastfed.

The sample size was calculated to be at least 44 individuals for each group on the PASS 11 software package with a power analysis based on 80% power and α = 0.05 error level.²¹ In the study, 50 mothers were enrolled in each group from the sample frame, and the study was completed with a total of 100 mothers.

Ethical approval of Eskişehir Osmangazi University Faculty of Medicine Ethics Committee and Konya Provincial Health Directorate was obtained. Informed written consent of the participants was obtained regarding their participation in the research. All collected forms were filed by the researcher, and the identity information of the participants was kept confidential.

Data collection tools

The study data were collected through the face-to-face interview technique using “a Personal Information Form,” “the Pittsburgh Sleep Quality Index (PSQI),” and “the Checklist Individual Strength (CIS).” Forms were filled out in a room provided in FHC setting by women who presented to FHCs for control, and it took an average of 20 minutes to answer the questions.

The personal information form

This is a 26-item questionnaire that was designed by the researchers following the related literature. It aims to determine the sociodemographic characteristics of the participants (age, education level, employment status, profession, social security, smoking, and income) and the factors related to women and infants that may potentially affect sleep and/or fatigue (number and age of children owned, presence of chronic disease and use of medication, getting help for the infant care, breastfeeding the infant within the first hour after birth, the number and the physical environment of feeding occasions of the infant during the night, and the like).^4,21

The PSQI

PSQI, which was developed by Buysse et al., is a self-report scale that evaluates sleep quality and disorder over the past month. The PSQI scale was used to evaluate the sleep quality and disorder of mothers in the past month. Cronbach's alpha coefficient of the internal consistency of the scale is 0.80 and diagnostic sensitivity is 89.6%. The scale consists of 19 questions and 7 components. These components are subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency (calculated by dividing total sleep time by total time spent in bed), sleep disturbances, use of sleeping medication, and daytime dysfunction.

Each item is evaluated over 0–3 points, and the total score of the 7 components gives the global PSQI score. The total score ranges between 0 and 21. A high score indicates poor sleep quality. A global score of ≤5 indicates “good sleep quality,” whereas a global score of >5 indicates “poor sleep quality.”²² The reliability and validity studies of the scale for the Turkish context were conducted by Agargün et al. using the Cronbach's alpha reliability coefficient, and the scale was determined to be appropriate for the Turkish context. In the same study, Cronbach's alpha value of the scale was found to be 0.79.²³

The checklist individual strength

Developed by Vercoulen, CIS is the most widely applied questionnaire worldwide to evaluate fatigue.²⁴ According to this questionnaire, fatigue is evaluated in terms of four aspects such as the subjective experience of fatigue, decrease in concentration, decrease in motivation, and decrease in physical activity. The questionnaire consists of 20 statements that measure fatigue in the last 2 weeks and a 7-point Likert type scale is used for the responses.

In the study, the cutoff value for the total fatigue score was stated as ≥76. While high scores indicate increased fatigue levels, low scores show decreased levels of fatigue. The reliability and validity studies of the questionnaire for the Turkish context were conducted by Ergin and Yıldırım (2012) using the test-retest method, construct, and criterion-related validity and the questionnaire was determined to be appropriate for the Turkish community. Cronbach's alpha internal consistency coefficient of the scale was found to be 0.87 in the same study.²⁵

Data analysis

The data obtained in the study were analyzed using Statistical Package for Social Sciences for Windows 22.0 software package. Numbers, percentages, and mean and standard deviation (SD) values were used as descriptive statistical methods in the evaluation of data. The association between group variables was tested with chi-square analysis. The t test was used to compare quantitative continuous data between two independent groups. Pearson's correlation analysis was used to evaluate the correlation between sleep and fatigue variables and the number of nighttime feeding occasions of the infant.

Results

Comparison of the sociodemographic characteristics of the mothers according to the way they fed their infants

Table 1 presents the distribution of sociodemographic data of mothers according to whether they breastfed or bottle-fed their infants. There was no statistically significant difference between the mothers who breastfed and who bottle-fed their infants in terms of the distribution of age, marital status, level of education, and perceived socioeconomic level (p > 0.05).

Table 1.

Sociodemographic Characteristics

Sociodemographic characteristics	Total sample (N = 100) n	Breastfeeding mothers (n = 50) n (%)	Bottle-feeding mothers (n = 50) n (%)	p	χ²
Age				0.18	3.39
25 years and younger	33	20 (40)	13 (26)
26–30 age	33	17 (34)	16 (32)
31 years and older	34	13 (26)	21 (42)
Marital status				0.07	5.26
Married	95	50 (100)	45 (90)
Single	5	0 (0)	5 (10)
Level of education				0.55	1.17
Illiterate	1	1 (1)	0 (0)
Literate	4	1 (2)	3 (6)
Primary school	42	24 (48)	18 (36)
Secondary school	17	7 (14)	10 (20)
University	36	17 (34)	19 (38)
Education level of the spouse				0.45	1.58
Primary school	36	20 (40)	16 (32)
Secondary school	28	15 (30)	13 (26)
University	36	15 (30)	21 (42)
Employment status				0.008	6.85
Working	70	41 (82)	29 (58)
Housewives	30	9 (18)	21 (42)
Social security status				0.06	3.40
Yes	88	47 (94)	41 (82)
No	12	3 (6)	9 (18)
Perceived socioeconomic level				0.84	0.34
Lower	14	6 (12)	8 (16)
Middle	72	37 (74)	35 (70)
Upper	14	7 (14)	7 (14)
Smoking habits				<0.001	13.25
Yes	15	1 (2)	14 (28)
No	85	49 (98)	36 (72)
Pre-existing chronic disorder mother				0.50	0.06
Yes	21	11 (22)	10 (20)
No	79	39 (78)	40 (80)
Use of chronic medication mother				0.30	0.58
Yes	19	8 (16)	11 (22)
No	81	42 (84)	39 (78)
Pre-existing psychiatric disorder mother				0.75	0.00
Yes	2	1 (2)	1 (2)
No	98	49 (98)	49 (98)
Use of psychotropic medication mother				0.12	3.09
Yes	3	0 (0)	3 (6)
No	97	50 (100)	47 (94)

Bold values: p < 0.001.

A significant relationship was found between the employment status of the mothers and the way they fed their infants (χ² = 6.85; p = 0.008). The proportion showing housewife as occupation was higher among the breastfeeding mothers. There was a significant relationship between smoking habits and the way mothers fed their infants (χ² = 13.25; p < 0.001). Smoking was more prevalent in bottle-feeding mothers.

Comparison of the characteristics of mothers regarding infant and infant care according to the way they fed their infants

Table 2 presents the distribution of mothers' self-reported breastfeeding or bottle-feeding characteristics regarding infant and infant care according to breastfeeding or bottle-feeding mothers. No statistically significant difference was found between breastfeeding or bottle feeding and the distribution of data regarding getting help for infant care, the number of nighttime feeding of the infant, and the presence of a health problem in the infant (p > 0.05). Accordingly, 61.0% of the mothers were found to receive assistance in infant care, and 31.0% were determined to feed their infant four times a night.

Table 2.

Infants and Infant Care Characteristics

Infants and infant care characteristics	Total sample (N = 100) n	Breastfeeding mothers (n = 50) n (%)	Bottle-feeding mothers (n = 50) n (%)	p	χ²
Regarding getting help for infant care				0.34	0.37
Yes	61	32 (64)	29 (58)
No	39	18 (36)	21 (42)
Number of nighttime feeding of the infant				0.19	4.65
2	20	10 (20)	10 (20)
3	24	8 (16)	16 (32)
4	31	16 (32)	15 (30)
5 and over	25	16 (32)	9 (18)
Presence of a health problem in the infant				0.13	2.17
Yes	8	2 (4)	6 (12)
No	92	48 (96)	44 (88)
Breastfeeding the infant within the first hour after birth				<0.001	67.91
Yes	55	48 (96)	7 (14)
No	45	2 (4)	43 (86)
Sleeping arrangement				0.08	4.91
Separate room	7	1 (2)	6 (12)
Same room, not mother's bed	74	41 (82)	33 (66)
Same room, mother's bed	19	8 (16)	11 (22)
Feeding arrangement during the night				0.003	11.59
Separate room	7	1 (2)	6 (12)
Same room, not mother's bed	45	17 (34)	28 (56)
Same room, mother's bed	48	32 (64)	16 (32)

Bold values: p ≤ 0.001.

The average age of the babies participating in the study is 10.5 (SD = 3.57) weeks. A significant relationship was found between breastfeeding the infant within the first hour after birth and the way mothers fed their infants (χ² = 67.91; p < 0.001). The rate of breastfeeding the infant within the first hour after birth was higher among breastfeeding mothers compared to mothers who bottle-fed their infant. Also, there was a significant relationship between where the infant was fed during the night and the way mothers fed their infants (χ² = 11.59; p = 0.003). The rate of feeding the infant in their bedroom during the night among breastfeeding mothers was higher compared to bottle-feeding mothers. Furthermore, 64% of the mothers slept their infants in their beds compared to 32% of bottle-feeding mothers.

Comparison of sleep quality and fatigue levels according to the way the mothers feed their infants

Table 3 gives the comparison of sleep quality (PSQI) and fatigue scores (CIS) of mothers according to the way they fed their infants. The scores of the mothers for subjective sleep quality, sleep latency, sleep duration, habitual sleep efficacy, sleep disturbances, use of sleep medication, and daytime dysfunction subscales and the total PSQI score were found to not differ significantly according to the type of infant feeding (p > 0.05). In both groups, the mean of total sleep quality score was greater than the cutoff value (>5 points), 5.90 (SD = 2.35) for the breastfeeding group and 5.82 (SD = 2.90) for the bottle-feeding group. Global score of >5 indicates poor sleep quality. Also, 54% of the whole sample was found to have a sleep quality score above the cutoff value (>5 points), which denoted poor sleep quality. The mean of the total sleep quality score was 5.86 (SD = 2.63).

Table 3.

Comparison of Mothers' Sleep Quality, Fatigue Level Scores, and Total Sleep Durations by the Way They Fed Their Infants

PSQI	Total sample (n = 100) Mean (SD)	Breastfeeding mothers (n = 50) Mean (SD)	Bottle-feeding mothers (n = 50) Mean (SD)	T value (DF) = T	p
Subjective sleep quality	0.13 (0.50)	0.12 (0.43)	0.14 (0.57)	(98) = −0.197	0.844
Sleep latency	1.11 (0.97)	0.96 (0.87)	1.26 (1.04)	(98) = −1.552	0.124
Sleep duration	1.20 (0.79)	1.16 (0.79)	1.24 (0.79)	(98) = −0.504	0.616
Habitual sleep efficiency	0.03 (0.17)	0.20 (0.14)	0.40 (0.19)	(98) = −0.581	0.562
Sleep disturbances	0.97 (0.50)	1.06 (0.42)	1.88 (0.55)	(98) = 1.815	0.073
Use of sleep medication	0.95 (1.07)	1.14 (1.10)	0.76 (1.02)	(98) = 1.784	0.077
Daytime dysfunction	1.47 (0.82)	1.44 (0.81)	1.50 (0.83)	(98) = −0.363	0.717
Total PSQI	5.86 (2.63)	5.90 (2.35)	5.82 (2.90)	(98) = 0.151	0.880
Total sleep duration	6.21 (1.18)	6.26 (1.13)	6.16 (1.23)	(98) = 0.421	0.675
Checklist individual strength
Subjective fatigue	36.21 (23.11)	34.84 (11.33)	37.58 (11.89)	(98) = −1.179	0.241
Concentration	20.19 (6.58)	19.62 (6.70)	20.76 (6.47)	(98) = −0.865	0.389
Motivation	15.10 (4.85)	14.72 (5.17)	15.48 (4.53)	(98) = −0.781	0.437
Physical activity	10.32 (4.30)	9.24 (3.67)	11.40 (4.64)	(98) = −2.577	0.111
Total CIS	81.82 (23.11)	78.42 (21.91)	85.22 (24.00)	(98) = −1.479	0.144
Number of nighttime feeding of the infant	3.84 (1.60)	4.00 (1.66)	3.86 (1.53)	(97) = 1.000	0.320

Mean ± SD of the components of the PSQI and CIS.

CIS, Checklist Individual Strength; DF, degree of freedom; PSQI, Pittsburgh sleep quality index; SD, standard deviation.

The scores that mothers obtained from subjective fatigue experience, concentration, motivation, and physical activity subscales and the overall CIS scale did not differ significantly according to the type of infant feeding (p > 0.05). The total fatigue score of both groups was above the cutoff value (>76 points), 78.42 (SD = 21.91) for the breastfeeding group and 85.22 (SD = 24.00) for the bottle-feeding group. Besides, in 66% of the entire sample, the score for the fatigue level was above the cutoff value (>76 points), which denoted a high level of fatigue. Moreover, the mean of the total fatigue score was found to be 81.82 (SD: 23.11) in the entire sample. Total fatigue scores above 76 indicate that both groups have high levels of fatigue.

The Pearson's correlation analysis

Table 4 presents Pearson's correlations between mothers' sleep quality and fatigue levels. A significant positive correlation was found between scores for total sleep quality and habitual sleep efficiency, sleep latency, daytime dysfunction, total fatigue level, and subjective fatigue level (p < 0.01). Besides, a significant positive correlation was found between scores for total fatigue level and subjective fatigue level and physical activity (p < 0.01).

Table 4.

Correlations Between Mothers' Sleep Quality and Fatigue Levels

	2.	3.	4.	5.	6.	7.	8.	9.	10.	11.	12.	13.	14.	15.
1. Total PSQI	0.19	0.56^**	0.52^**	0.30^**	0.50^**	0.65^**	0.68^**	0.38^**	0.45^**	0.28^**	0.20^*	0.18	0.5	−0.01
2. Subjective sleep quality		−0.05	−0.06	−0.04	−0.06	0.04	0.11	0.01	0.03	0.04	−0.07	−0.01	0.02	0.02
3. Sleep latency			0.05	0.34^**	0.23^*	0.12	0.23^*	0.16	0.17	0.09	0.14	0.09	−0.13	0.15
4. Sleep duration				0.25^*	0.06	0.21^*	0.32^**	0.09	0.18	0.01	−0.01	−0.00	0.31^**	0.05
5. Habitual sleep efficiency					0.01	0.06	0.04	0.18	0.19^*	0.12	0.13	0.12	−0.01	0.05
6.Sleep disturbances						0.25^**	0.37^**	0.34^**	0.36^**	0.34^**	0.22^*	0.10	−0.06	−0.18
7. Use of sleep medication							0.22^*	0.16	0.18	0.09	0.08	0.15	−0.01	−0.17
8. Daytime dysfunction								0.48^**	0.53^**	0.39^**	0.27^**	0.20^*	0.06	0.03
9. Total CIS									0.92^**	0.87^**	0.76^**	0.66^**	−0.10	0.14
10. Subjective Fatigue										0.74^**	0.56^**	0.48^**	−0.10	0.11
11. Concentration											0.62^**	0.46^**	−0.13	0.08
12. Motivation												0.48^**	−0.08	0.07
13. Physical activity													−0.00	0.25^*
14. Number of nighttime feeding of the infant														−0.10
15. Feeding method

The numbers in the row and column in the table indicate the same item.

Bold values: p < 0.05; p < 0.01.

p < 0.05.

p < 0.01.

Discussion

In our study, the perceived sleep quality and fatigue levels in mothers did not differ according to the type of infant feeding. Likewise, Tobback et al. found that mothers' sleep quality did not differ according to the breastfeeding or bottle feeding of the infant.²¹ This result was consistent with our study finding. However, unlike our findings, breastfeeding women were reported to have better subjective sleep quality, but lower habitual sleep efficiency in this study. On the other hand, there was no difference between the subscales in our study. In our study, total sleep quality scores of breastfeeding and bottle-feeding mothers were found to be 5.9 and 5.8, respectively. Also, 54% of the entire sample group was found to have poor sleep quality. The scores in Tobback et al. were 7.3 and 7.6, respectively, and 65% of the entire sample group was determined to have poor sleep quality. According to results of both studies, even though more than half of the mothers exhibited poor sleep quality, the sleep quality was better for both groups in our study results.

In our study, mothers' poor sleep quality may be associated with the immature and evolving sleep of infants. In the first 12 months of life, there are significant changes in the sleep behavior of babies.²⁶ At the same time, some cultural factors²⁷ and the feeding method of infants can affect sleep behaviors and maternal sleep and fatigue. It is reported that infants who are especially breastfed in the first 6 months wake up more frequently at night.⁸ This is explained by the fact that babies need to be fed more frequently, as it is easily digested due to the composition of breast milk. It also allows for close mother-infant contact and bonding day and night, which is necessary for the healthy development of babies.²⁸

Breastfeeding mothers can use some strategies to improve sleep quality and reduce fatigue; for example, they can take daytime naps or go to bed early, reduce other work burdens, and prefer co-sleeping with the infant or sleeping in the same room. In our study, the sleep duration of infants was not evaluated. Studies that evaluate the sleep times of infants together with the sleep quality of the mothers are recommended.

In our study, the mean sleep duration was determined as 6.26 and 6.16 hours in breastfeeding and bottle-feeding mothers, respectively. Although the need for sleep varies by age and gender, 7–8 hours of sleep a day is recommended for adults.²⁹ Based on this information, the sleep duration of mothers was observed to be not at the desired level.

Montgomery-Downs et al. investigated the effect of the infant feeding type on mothers' sleep and daily life and reported that they did not find any difference between the sleep measurements of mothers who only breastfed their infant, those who gave only formula, and those who used both forms of feeding.¹¹ Also, Kendall-Tackett et al. examined the effect of infant feeding type on the sleep duration of mothers and they reported that the feeding method significantly affected the sleep duration of mothers; mothers who only breastfed their infants slept more and that there was no difference between the mean sleep duration of mothers who used a mixed-feeding method and those who only gave formula to their infant. In addition to these, they stated that the mean daily sleep duration was 6.61 hours in mothers who only breastfed their infant, 6.41 hours in those who used a mixed-feeding method, and 6.3 hours in those who fed their infant with only formula.³⁰ Doan et al. found that there was no difference between mothers who only breastfed and those who used formula in terms of daytime sleep, night sleep interruptions, and subjective sleep disturbance during 1 month postpartum and that only breastfeeding mothers slept more at night.³¹

Accordingly, the results of our study and other studies are consistent with research showing that the sleep quality of mothers is independent of the type of infant feeding. Besides, the majority of studies support the findings that the sleep duration of mothers who breastfeed their infants was higher than those who bottle feed them. Our research finding will contribute to clarifying discussions about the assumption that bottle feeding is associated with better sleep quality in mothers.

The subjective fatigue experience of mothers, concentration, motivation, physical activity subscales, and total scores obtained from the overall CIS scale did not differ according to the infant feeding type variable. In addition to this, the fatigue levels of the mothers were found to not show a difference according to the way the mothers fed their infants.

Tobback et al. reported that the fatigue level of mothers did not show a difference according to the infant feeding type. They found the total fatigue level scores as 82.1 in the breastfeeding group and 79.0 in the bottle-feeding group. Besides, they determined that 61% of the whole group showed a high level of fatigue and that the average fatigue level score of the group was determined as 80.8%. According to the results of both studies, mothers were found to show a high level of fatigue.²¹ Likewise, Callahan et al. examined the effect of the way mothers fed their infant on their fatigue levels and compared the perceived fatigue scores on the second and fourth days and in the 6th and 12th weeks postpartum between mothers who breastfed and bottle-fed their infants. As a result, similar to the findings of our study, they reported no difference between the groups.¹⁷ Besides, Montgomery-Downs et al. found that there was no difference between the fatigue levels of mothers who only breastfed, who only gave a formula, and who used both models.¹¹ To sum up, the results of our study and other studies, in general, show that the fatigue level of the mother is independent of the infant's diet. Accordingly, we think that the findings of our research will help elucidate discussions about the supposition that breastfeeding increases the fatigue level of mothers.

Our study found that breastfeeding mothers had a higher prevalence of initiating breastfeeding within an hour of birth. Bottle-feeding mothers who smoked or who were employed at the time of the survey, despite the availability of paid maternity leave, also had a higher percentage. These results point to key physiological and social factors that may create barriers to exclusive breastfeeding of newborns in Turkey, as well as factors that influence the sleep quality and fatigue levels of new mothers independent of infant feeding mode at the time of the survey.

Conclusion

In conclusion, the quality of sleep, sleep duration, subjective fatigue experience, concentration, motivation, physical activity, and the level of fatigue were found to show no difference among women who were between their 4th and 16th week postpartum and who only breastfed or only bottle-fed their infant.

Based on the results of our study, we would like to make some recommendations. First of all, postpartum sleeplessness and fatigue should not be shown as a reason for women to quit breastfeeding their infants. Given the numerous benefits of breastfeeding for the mother and the infant, mothers should be encouraged to start breastfeeding their infants immediately after birth, they should be supported, and the mother should be motivated to share the same room with the infant in the early postpartum period.

Second, mothers working in the postpartum period should be provided appropriate conditions to ensure proximity and frequent feeding so that they can breastfeed their infants easily. Next, mothers should be informed about the adverse effects of smoking. Strong evidence has shown that nicotine is passed from mothers to breastfed infants by way of breast milk. The researchers suggest that babies may refuse to feed once the mother returns to smoking because the breast milk composition is altered or that the nicotine transfer causes restlessness in babies, which may be interpreted as a sign of insufficient milk by mothers, leading them to supplement with artificial feeding.³² Last, but not least, midwives should plan initiatives together with parents to improve maternal sleep quality and reduce fatigue and inform parents that breastfeeding is not a factor that reduces sleep quality and increases fatigue.

Limitations of the study

In the study, data about sleep quality and duration were determined based on the perceptions and reports of the participants, which did not allow an objective measurement. No information has been collected on the status of bottle-fed infants receiving human milk in the bottle. Besides, the study had limitations regarding research methodology as it used a cross-sectional research design and the size of the self-selected sample, small sample size.

Footnotes

Acknowledgments

The authors express their gratitude to the women in the sample for participation in the study.

Disclosure Statement

No competing financial interests exist.

Funding Information

No funding was received for this article.

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