Participant characteristics

The characteristics of the LPT twins and their mothers in the longitudinal cohort study (hereafter referred to as the quantitative phase) and in the interview study (hereafter referred to as the qualitative phase) are presented in Table 1. The LPT twin groups were comparable in both studies; apart from that, more multiparas and mothers of boys were in the qualitative sample.

Table 1 Characteristics of the participating mother and twins in the quantitative study (63 / 126) and qualitative study (14 / 28)Breastfeeding rates

The breastfeeding rates (any and exclusive) in mothers of LPT and term twins are presented in Fig. 2 and Table 2.

Fig. 2

Proportion of any breastfeeding at the breast and exclusive breastfeeding at the breast in term twins (n = 80) and late preterm twins (n = 42)

Table 2 Comparison of breastfeeding progression, interventions, and behavior of late preterm twins (n = 44) and term twins (n = 82)

The analysis of the LPT twin s’ mothers’ experiences and the synthezation of the quantitative and qualitative data, resulted in two main categories and nine subcategories, which describe and illuminate the influencing factors on LPT twins’ breastfeeding progression (Table 3).

Table 3 The categories and subcategoriesThe first month – a complex and strenuous phase where task-oriented feeding regimes were followed

The quantitative and qualitative findings on the LPT twins’ mothers’ experiences during the first month are presented in six subcategories, which describe influencing factors on breastfeeding.

Initiation

The quantitative data showed that the breastfeeding initiation rate was high in both twin groups, as 100% of the LPT twins and 96% of the term twins were breastfed at the hospital after birth (p >  0.05). The first attempt at breastfeeding within the first 6 h after birth occurred for 52% of the LPT twins versus 89% of the term twins (p <  0.001). All mothers in the qualitative study had the intention before birth to breastfeed, but many of them experienced that their infants’ or their own health and / or mother / infant separation hindered breastfeeding. A mother who had a cesarean section said:

“They were born, and [infant’s name], the smaller one, he was sort of taken right away and put into the incubator, but [other twin’s name], he got to stay for a short time with us. But then he was also taken to the incubator in the NICU. [Dad’s name] went with them, and I was there [in the delivery suite] to recover.” (M4)

Immature breastfeeding behaviors

Significantly more mothers of LPT twins than term twins reported a weak suck during the first week at home and when the infants were at 1 month of age. Little stamina while breastfeeding was more often reported by mothers of LPT twins than mothers of term twins, both during the first week home and at 1 month of age. Significantly more mothers of LPT twins also reported that they always needed to wake their infants for breastfeeding during the first week at home (Table 2).

In the interviews, mothers highlighted that the LPT infants’ weak suck, little stamina, and sleepiness affected breastfeeding progression considerably during the first month. The mothers described their twins as not interested in feeding, always falling asleep at the breast, always needing to be woken up, and not sucking at all or sucking poorly when put to the breast. As one mother noted, “You know they sucked a little and then just went to sleep; they were so tired.” (M6). Thus, because of the infants’ immature breastfeeding behavior, breastfeeding and feeding were regarded as strenuous and took considerable time.

Mothers’ health

Some mothers experienced anxiety and / or depression during the year before birth. At 1 month, only one mother of twins in the LPT group and no mothers in the term group had an EPDS score of ≥ 13. However, the mean EPDS score of the LPT twins’ mothers at 1 month was significantly higher than the mean score of the term twins’ mothers (Table 1).

Mothers experienced that their health problems affected breastfeeding; some had complications lasting for weeks or months after a cesarean section, whereas others recovered quickly. Pregnancy-related morbidity, like preeclampsia and hyperemesis, was also relatively frequent. A mother with severe preeclampsia explained why she did not breastfeed her twins much during the first days after birth: “I was in bed, and I had a catheter and could not walk or talk. I was sort of out of it for about two days after birth, and I could not see my children,” (M2). Fatigue and exhaustion during the first days and weeks after birth was also common and affected breastfeeding:

“I had some kind of severe exhaustion. It came after a few days, perhaps on day four or five, and I thought I was getting sick. I had flu-like symptoms every day. It happened late in the day, about five o’clock, and I just fell asleep and could not control it. I just fell asleep, and [husband’s name] had trouble waking me up to breastfeed. This just happened over and over again.” (M4).

Milk expression

The use of a breast pump for expressing breast milk and establishing milk production was significantly more common among mothers of LPT twins compared to mothers of term twins (Table 1). All mothers of LPT twins expressed breast milk after birth, but the time of initiation, frequency, and effectiveness varied. Some had their breasts hand expressed shortly after birth: “She [the midwife] came right away and worked hard on me to get the colostrum out to give to them [her twins]” (M3). All mothers used the breast pump to establish milk production alongside breastfeeding at the breast, with the goal to pump for a short time and to only breastfeed at the breast later on, as described by a mother:

“After every feeding for many weeks after birth, I used the breast pump to get more milk. The plan was always to breastfeed exclusively. Even though deep down, I knew it was highly unlikely that I could do that. But I thought, let’s try it.” (M1).

Not having enough breast milk was common for all the twins’ mothers, with no difference between the mothers of LPT and term infants (Table 2). Some of the interviewed mothers experienced an insufficient milk supply only during the first week after birth, as described by a mother who pumped every 3 h after birth: “.. . I was pumping full time. .. always. .. I was pumping for every feeding but had to give extra. .. They got perhaps 40% formula; the rest was breast milk.” (M3) Many mothers continued to struggle with milk production and breastfeeding and supplemented with infant formula:

“Breastfeeding twin B was a struggle. I never knew if [infant’s name] would take the breast. But both of them got better, and I thought we were almost there [breastfeeding exclusively]. So yeah, but it never happened. I did not have enough milk.” (M10)

The burden of insufficient milk production and / or having to use a breast pump at the same time as focusing on establishing breastfeeding were challenging for the mothers and impacted their experiences and actions:

“We always hoped for exclusive breastfeeding, but it never happened. .. perhaps partly because I had such limited time to use the breast pump. .. I got so confused in all this [breastfeeding at the breast and expressing] that sometimes I just forgot why I was doing all this.” (M1)

Focus on weight-scheduled feedings, set amounts of milk, and test-weighing

The mothers experienced major concerns for their LPT twins’ weight gain during the first weeks. These concerns motivated the mothers to use numerous feeding regimes related to the infants’ breast milk intake and breastfeeding (Table 2). The timing of breastfeeding was predetermined by scheduled feeding times, the amount of milk in a feed was prescribed as a fixed number of milliliters, and test weighing was used as a method to determine the infant’s milk intake. As a consequence, breastfeeding became “robotic” and “instrumental” during the first month, where the mothers used the words “military camp” and “boot camp” to describe the experience. The mothers would start breastfeeding at a set time, and then the mother, or partner, would bottle feed afterward with a fixed amount of milk. Thus, feeding became a task: “We were just working on getting them to gain weight. .. That was what life was all about. .. Yes, yes, this was a task.” (M1). The mothers did not talk about the infants’ cues but talked much about the standardized schedules assigned by health professionals and ways to ensure that their infants got enough milk during feeds.

“I was so stressed about this [weight gain]. I focused so much on making sure, and therefore I was never careless about this [breastfeeding]. The schedule was three hours, and even if I was tired during the nights, I just thought, ‘no, I must get out of bed,’ and they [her twins] must do it [breastfeed]. Although they were lazy, I never gave up, and I was like, ‘You are not finished!’ This is what it was like, but when I saw that they had gained weight—they gained a lot—the weight curve was just straight to the ceiling, and I became calmer.” (M4)

Further, test-weighing was commonly used by the mothers to assess the intake of breast milk (Table 2). One mother who test-weighed her LPT twins for 6 weeks described her experiences:

“We rented a scale that we placed on this table and weighed them. We wrote down how much they weighed and, of course, calculated how much they needed in addition to breastfeeding. After four days, we felt this was insane.” (M1).

In addition, nipple shields were used to “facilitate” the transfer of milk and to establish breastfeeding at a faster speed. Significantly more mothers of LPT twins indicated that they used a nipple shield during the first week at home and at 1 month compared to mothers of term twins (Table 2).

Transition from hospital to home

During the transition from hospital to home, mothers experienced lack of support and guidance from healthcare professionals. A majority of the mothers of LPT twins (62%) and term twins (55%) had sought help and guidance when the infants were 1 month old, mostly from healthcare staff and friends / family but also on the internet. There were more mothers of LPT twins than mothers of term twins that did not get the help and support when needed, 23% versus 10% respectively, although this was not statistically significant (not presented in a table).

The LPT twins’ mothers’ experiences of support and guidance in the NICU and the maternity unit were noticeably different. The mothers with twins in the NICU viewed the transition to home positively. They felt prepared and experienced the feeding of the twins as less complicated than the mothers with twins in the maternity unit did. A mother from the NICU described her experiences:

“I was so glad for the NICU stay. Tube feeding the twins gave me time to adjust. I was still trying to get the hang of breastfeeding. If the tube feeding had ended earlier, I would not have succeeded in breastfeeding them.” (M5)

In contrast, LPT twins’ mothers with twins in the maternity unit felt insecure and unprepared; they felt that feeding their infants was complicated and did not feel prepared when they went home. They lacked guidance on how to proceed with breastfeeding, both from staff in the maternity unit, and the home midwives. They, as well, lacked information, e.g., on the effects of prematurity on infants’ breastfeeding behaviors, milk production, and the importance of using a breast pump. A mother who stayed in the maternity unit for 2 days, which was the standard practice, thought upon discharge, that everything was going fine, but did not realize that her twins, were not feeding properly:

“Perhaps if I had pumped more and received proper information during the stay in the maternity unit, I would have better understood why and how often I should be pumping because I had not needed to pump while breastfeeding my older child. I needed guidance about why I had to pump so frequently and its implications for milk production and breastfeeding. Because I thought that they [the twins] were doing a good job at the breast, and therefore my milk production would be fine. However, they were, of course, not strong enough.” [The mother stopped breastfeeding during the second month because of perceived too little milk production, although she truly wanted to breastfeed] (M10)

Another mother who breastfed and topped up with finger-feedings, as per recommendations from the maternity unit, was overwhelmed during the second week at home because of the complexity of the feedings: “At that time, I was so overwhelmed. It was so much and so complicated that I almost could not bear to go out of bed.” (M12).

The mothers of LPT twins highly regarded the home midwives and considered them “experts” on health after birth, breastfeeding, and feeding strategies. However, although the home midwives were an important resource for support, several mothers indicated that their guidance was sometimes conflicting and damaging. One mother stated: “I felt like she [the home midwife] considered me to know more than I did about breastfeeding; ‘You have had a baby; this is not your first one.’.. .” (M6). Another mother who struggled with milk production experienced that guidance from the home midwife might have negatively influenced her breastfeeding:

“She [the home midwife] told me not to pump during nights, which I did. But in retrospect, considering things that I have heard [during the last months], I think that this might have been a mistake, as I just never had enough milk.” (M10)

All mothers, regardless of the unit where they stayed after birth and the length of hospital stay, had home visits from a primary healthcare nurse throughout the first month, followed by baby check-ups in the primary healthcare center in the following months. There were mixed feelings about that service. The mothers did not consider the primary care nurses to be knowledgeable in breastfeeding preterm infants: “I thought somehow that their guidance would include feeding strategies after discharge and especially with preterm infants. .. No one talked to me about that, and that was not good.” (M5).

Months two to four and the navigation through feeding: finding your own path

The quantitative and qualitative findings on the LPT twin s’ mothers’ experiences during months two to four are presented in three subcategories.

A constant struggle and tiredness with an uncertain outcome

The LPT twin s’ mothers described the time between two and four months as hectic and crazy, with sleepless nights; the days and nights were filled with tasks and too few hours to do everything that needed to be done. They used phrases like” it is all in a mist,” “it is all blurred,” “I did not sleep,” “I was so tired,” and” it has been the most difficult time in my life.” A lack of sleep and worries affected many mothers physically and mentally and influenced breastfeeding considerably.

“I calculated that I was breastfeeding for 8 out of 24 hours. It is, of course, a full-time job. People have difficulties sitting for 8 hours. When you have done so for one, two, or three months, then your body is like. .. you feel it. .. That is what I experienced somehow; you are struggling with breastfeeding but somehow not doing enough.” (M1)

Struggles with milk production were still common during this time; some also struggled with breastfeeding at the breast, while for others, breastfeeding was improving despite perceived too little milk production. Hence, feeding was complicated, milk production was uncertain, the result of their breastfeeding struggles was uncertain, and they were tired, which influenced the decisions on breastfeeding, as described by a mother:“I used the breast pump every time I breastfed for six weeks so that I would have breastmilk to give them [the twins] in the bottle when they did not finish their feedings at the breast. Sometimes, although I had to use formula, and at that time, I simply had had enough, and they [the twins] were starting to take the breast fine. So, I decided that I would only use formula in the bottle, quit pumping, and what happened would happen.” (M3) Another mother of LPT twins described that she chose to focus less on milk production, even though she knew the outcome for breastfeeding might be negative:

“I had been doing this [pumping after every breastfeeding] for several days, just not doing anything other than breastfeeding and pumping, having even less sleep at night than before. Then, I thought, ‘This is starting to be a burden,’ it cannot overshadow the time spent with the family and other things I want to do. So, I quit pumping and started to use formula.” (M12)

Managing life and feeding: questioning the worth of breastfeeding efforts

Most of the mothers experienced that the LPT twins’ breastfeeding behaviors were getting better around the time they reached full term. However, as very few mothers exclusively breastfed at the breast at this time, breastfeeding did not become more manageable during the following months. The burden of the complex management of the twins’ feedings (e.g., breastfeeding, pumping, bottle feeding), in addition to perceived insufficient milk production, peaked when the infants were one to three months old and were the key factor in mothers’ breastfeeding decisions during this time. The search for appropriate breastfeeding management, or a feasible routine that allowed breastfeeding exclusively or in combination with bottle feeding, preferably without expressing, was also evident. Some mothers succeeded in finding a breastfeeding routine that was not burdensome and suited their life, and enabled them to do things other than just breastfeed and pump. Others did not; they experienced breastfeeding as too burdensome, felt that their breastmilk production was too little, and that their efforts were therefore not worth it, and consequently ceased breastfeeding: “I just got sick of this always being on the clock. .. And just somehow always experienced like it was not enough. .. I wanted to live life and enjoy it.” (M1). In the mothers’ search for a manageable breastfeeding routine, some simplified feeding by stopping expressing breast milk. One mother that ceased breastfeeding when her twins were 3 months of age stated:

“During the second month, I quit pumping. I just had enough and found it easier to just breast- and bottle feed. Pumping interrupted my sleep at night and just everything. We had three weeks where it was going fine, but suddenly, there was no milk.” (M1)

Other mothers started to bottle feed so that other people could help: “We started to use the bottle so that he [the father] could participate in the feedings and perhaps so that I could have some breaks.” (M14). By quitting expressing and / or breastfeeding less often, milk production often decreased, and / or the benefits of the bottle feeding gradually outweighed the benefits of breastfeeding, and subsequently, many mothers ceased breastfeeding. An evident time saver was a bottle machine that made the formula ready to drink. The mothers praised the machine for saving time and simplifying their lives: “We were lucky to get the bottle machine as a birth gift. It is like a coffee machine for infants. It saved our lives; the nights became much more bearable.” (M10).

Support from husbands was essential in getting through the day and very important to maintain breastfeeding, as it enabled the mothers to dedicate time to breastfeeding and to express milk:” We were totally in it together. He [husband] always woke up with me and heated the bottles and arranged things. We were totally in it together; otherwise, the breastfeeding would never have worked.” (M4) Most fathers were at home for the first two to three months. The situation could change drastically when the fathers returned to work:

“It was around the time he [father] started to work. They were almost three months old. Then, it became difficult to be alone and pump and feed both. I fed them every three hours, and they did not sleep much or at least for very short periods during the days and nights. It became impossible to pump five or seven times a day and feed them [breast and bottle]. I lasted for about two or three weeks after he started to work. Then, I just quit [breast- and bottle feeding]”. (M11)

Need for external support

The mothers felt that receiving help from grandparents was essential to making life manageable: “We could not have done this without my parents. .. My mother sat by their [the twins] side while they slept so we could take a nap.” (M10) Friends were also an invaluable resource for support. They and the grandparents helped with feedings, householding tasks, and taking care of siblings:

“My friend who lives close by sometimes dropped by during lunchtime. .. She, of course, got coffee, but she also fed them [solids] and gave them a bottle [laughs]. .. It somehow turned into this: If someone comes, then he or she is handed the bottle.” (M3)

A lack of relevant support and guidance from healthcare personnel was still present during months two to four; the LPT twins’ mothers repeatedly found that the primary healthcare nurses did not have sufficient knowledge and skills to guide them in sustaining breastfeeding. The mothers sought support on the internet and in twins’ mother’s groups on Facebook: “I just Googled endlessly [for breastfeeding advice]. Google has sort of been my friend through this whole process.” (M5).