Midwives and public health nurses' knowledge and clinical practice in securing sufficient iodine status in relation to pregnancy: A cross‐sectional study

Abstract Aim To investigate midwives' (MWs) and public health nurses' (PHNs) clinical practice and knowledge related to nutrition, with a particular focus on iodine in northern parts of Norway. Maternal iodine status prior to and during pregnancy, and the lactating period, is crucial for brain development and growth of the foetus and infant, from conception up until the first two years of life. In Norway, studies have documented mild to moderate iodine deficiency in this group. Design/Methods MWs (n = 128) and PHNs (n = 154) responded to a survey regarding nutrition and iodine. Descriptive data and non‐parametric tests were used to analyse data. Results Around half of the participants provided dietary guidance to a great extent. Practice of iodine‐specific recommendations was lower, particularly regarding lactating women. Compared to other nutrients, iodine was not a priority. Conclusion The study indicates a lack of knowledge and poor clinical practice about iodine among MWs and PHNs.


| INTRODUC TI ON
Maternal iodine status in pre-pregnancy, pregnancy and the lactating period is crucial to the brain development and growth of the foetus and infant (WHO, 2007;Zimmermann, 2009). The latest estimate is that 1.88 billion people globally have insufficient dietary iodine intake (Andersson et al., 2012). In Norway, recent, studies have documented mild to moderate iodine deficiency in young fertile women, and pregnant and lactating women (Aakre et al., 2020;Berg et al., 2017;Groufh-Jacobsen et al., 2020;Henjum et al., 2018;Henjum et al., 2019;Naess et al., 2021). Concurrently, a low level of knowledge among the fertile female population of the importance of iodine, dietary sources and daily recommended intake of iodine has been documented (Garnweidner-Holme et al., 2017;Groufh-Jacobsen et al., 2020;Henjum et al., 2018). The Norwegian National Council for Nutrition concluded that iodine deficiency is present in these vulnerable groups and that due to their competence and practice, healthcare professionals have a special responsibility to ensure an adequate iodine status (Norwegian National Council for Nutrition, 2016).
In the Norwegian healthcare system, midwives (MWs) and public health nurses (PHNs) play an important role in the lives of women and children (Norwegian Directorate of Health, 2014. In pregnancy guidelines, essential nutrients such as folate, iron, calcium, vitamin B12 and vitamin D have been highlighted for many years, but iodine was only included in 2018 in a revised version of the guidelines after a report from the Norwegian National Council An unbalanced diet or reduced iodine levels in food entail a risk of iodine deficiency (Zimmermann, 2009). Important Norwegian food sources are fish, seafood, eggs, cow's milk, hereafter called milk, and dairy products, with the latter two contributing around 60% of iodine intake. No iodine fortification programme exists in Norway (Norwegian National Council for Nutrition, 2016). Maternal iodine requirements are increased during pregnancy, with the embryonic period as the most critical. Iodine deficiency in the preconception period thus challenges maternal and foetal health (Zimmermann, 2009). Also, exclusively breastfed infants are entirely dependent on iodine supplied via breast milk, to cover their high rates of thyroid hormone production (Andersson et al., 2007). For the child, maternal iodine deficiency may have serious to less serious health effects on brain development and cognition: intellectual disability, decreased IQ, and in the worst case induces cretinism (Zimmermann, 2011). The brain needs iodine for its development up until the first 2 years of life (WHO, 2007).
Iodine deficiency is simple to prevent, with a low-cost intervention (Zimmermann, 2009). Healthcare professionals such as MWs and PHNs are in a unique position to contribute knowledge and ensure adequate iodine intake in relation to preconception, maternal and postnatal needs (Arrish et al., 2016;Bouga et al., 2018;Norwegian National Council for Nutrition, 2016;Othman et al., 2020). Studies highlight the need to improve healthcare providers' clinical practice and education concerning nutrition and diet in general and in particular related to iodine (Arrish et al., 2014;Arrish et al., 2016;Bryant et al., 2019;Charlton et al., 2012;Guess et al., 2017;Lee et al., 2018;Lucas et al., 2014;Malta et al., 2016;Soltani et al., 2017). To the best of our knowledge, no previous research studies of Norwegian healthcare professionals' clinical practice concerning iodine exist.
This study targets midwives and public health nurses in northern parts of Norway. The aim is to investigate clinical practice and knowledge regarding nutrition with a special focus on iodine.

| MATERIAL S AND ME THODS
This cross-sectional study is part of the MISA study at UiT The Arctic University of Norway focusing on diet, lifestyle factors and persistent toxic elements related to reproductive health in women living in selected areas of northern Norway. Midwives and public health nurses operating in public services in northern Norway were invited to respond to a survey of clinical practice concerning these topics.
The present sub-study investigates practice and knowledge about diet, with a focus on iodine.
Prior to the survey, all the special clinics, hospital maternity wards and midwifery-led units (n = 15) (hereafter named maternity wards) and child health clinics (n = 84) in northern Norway were contacted. With the exception of one child health clinic with a partly reported number of personnel, all institutions reported the total number of target personnel serving young, fertile, pregnant and lactating women. Invitation letters with unique participant numbers and pin codes to a web-based questionnaire were delivered to the service units for internal distribution. For promotion, posters and repeated emails to target personnel were utilised. The study period was nine weeks, from December 2017 until January 2018.

| Population and sample
A total of 669 invitation letters were distributed, of which 35 were reported to be internally undelivered and four participants were registered at two units. Among the 630 eligible for participation, 128 (49%) MWs and 155 (42%) PHNs answered the questionnaire. One of the PHNs was excluded from the survey due to an incomplete questionnaire. Thus, 282 participants were included in the present study ( Figure 1). Of these, six had a position as both a MW and PHN.
For convenience, and based on education, healthcare institution and percentage employment, these participants were classified as either MW (n = 2) or PHN (n = 4).

| Questionnaire
From the entire questionnaire comprising 56 questions, the present study was restricted to 32 questions explaining background variables, and dietary and specifically iodine clinical practice and knowledge.
Demographic characteristics were described: age, years of professional experience, employment status and professional education (MW, PHN, constituted PHN), and user group serviced (pregnant, lactating or non-pregnant young women).
Questions regarding clinical practice such as dietary advice in general, iodine and other nutrients were inspired by previous research (Arrish et al., 2016;Guess et al., 2017;Lucas et al., 2014) and with reference to the National Guidelines for antenatal care  (Combet et al., 2015;Lucas et al., 2014).
Four MWs and PHNs commended on the questionnaire before distributing the survey, after which a few changes were made.
NSD-the Norwegian Centre for Research Data was responsible for the technical performance and collection of the survey.

| Statistical analyses
All statistical analyses were conducted using STATA (version 16.0; StataCorp). Demographic data are presented as frequencies and percentages, and mean, min-max and standard deviation (SD).
Demographic information and clinical practice with related topics were reported for two (MWs and PHNs) or three groups (MWs and PHNs caring for lactating mothers and MWs in antenatal care).
T-test, Mann Withney U Test or Chi-square Test were used to test for differences between MWs and PHNs and, for some questions, further separated into pregnant women or lactating women. In the analyses, the five categories on the Likert scale were recoded into three categories: not at all/to a small extent, to some extent and a great extent/a very great extent. Missing numbers were reported in tables.
Further, we investigated the bivariate relationships between the ability to give specific dietary recommendations to ensure adequate iodine nutrient intake and such factors as a profession, demography, dietary clinical practice and education, and iodine knowledge.
Correlations between to ordinal variables were examined using Spearman's Rank-Order Correlation. We applied Mann Withney U Test for comparing the ordinal data of two groups, and the Kruskal Wallis Test for more than two groups. p ≤ 0.05 was considered statistically significant.

| Ethical considerations
The Norwegian Regional Committee for Medical and Health Research Ethics (REC North) approved the study (#2017/816). Participants received written information about the study. Information given by participants was evaluated as non-personally identifiable and thus, no written consent was required. The present study was conducted in accordance with the Helsinki Declaration.   Table 1 summarises the personal and employment characteristics of the study group. The mean age was ~46 years old for both MWs and PHNs, and the age distribution was similar (p = 0.34). Average years of clinical experience were 15 years among the MWs and 10 years for PHNs (p < 0.01). A majority of the MWs (59%) had a position in a maternity ward, 24% in antenatal care and 16% worked in a combined position in a maternity unit and antenatal care. Almost all MWs cared for both pregnant and lactating women. Among the PHNs, 13% of the positions were filled by constituted PHNs. Most PHNs worked within the public health centres' diverse range of services spanning from infants to adolescents. Of relevance, 80% of the PHNs provided services to lactating mothers and 75% to young adolescent females (Table 1). Table 2 shows clinical practice regarding dietary advice to pregnant and lactating women. The majority of MWs and PHNs (83%-89%) stated that they provided dietary guidance to pregnant or lactating women to a great extent or some extent. The majority of the MWs (~75%) and almost half of the PHNs reported prioritising dietary guidance over other guidance. Furthermore, a majority of both MWs (~70%) and PHNs (~80%) communicated the importance of diet for the foetus or infant to some or to a great extent. These topics of guidance or information were emphasised more towards pregnant women than towards lactating women. Regarding lactating women, MWs prioritised dietary guidance over other guidance to a greater extent than PHNs (p = 0.02), but otherwise, there were no significant differences in practice (Table 2).

| Providing dietary guidance
A majority of MWs (~75%) reported a lack of systematic tools to assess dietary intake among both pregnant and lactating women.
Addressing lactating women, the lack of such tools was even more prominent among PHNs (91%) compared to MWs (p < 0.01). Also, a lack of time to provide guidance on living habits was challenging for half of the MWs providing both pregnancy and lactation advisory services and was most prominent for the PHNs (73%) who addressed lactating women (p < 0.01, Table 2).

| Addressing iodine in dietary guidance
Several questions addressed iodine-related issues in dietary guidance (Table 3, Figures 2 and 3). When giving dietary guidance to pregnant or lactating women, the majority of both MWs (61%) and PHNs (70%) did not recommend or to a small extent recommended women specifically to ensure adequate iodine intake (p > 0.05, Figure 2). Compared to iodine, both MWs and PHNs put greater emphasis on dietary recommendations to specifically ensure an adequate intake of other nutrients such as calcium, folate, iron and omega-3 fatty acids and vitamin D ( Figure 2). MWs significantly emphasised folate, iron and Omega-3 more than PHN (p < 0.05, Figure 2).
According to the advice about ensuring a nutritious diet, the level of simultaneous advice on what specifically to eat was high (80% ,   Table 3). Assessing dietary items to gain an impression of whether nutrient intakes were satisfactory was practised more frequently for other items than typical iodine sources such as milk/dairy and lean fish ( Figure 3). For these iodine sources, no differences across MWs and PHNs were observed (p > 0.05). Furthermore, approximately half of the MWs (~50%) and slightly more PHNs (~60%) provided specific advice to those who rarely or never ate lean fish, or drank milk (Table 3). Additionally, fewer MWs and PHNs recommended iodine supplements by indication. However, approximately 65% of both professions stated that they rarely or never gave recommendations for iodine as a supplement (Table 3).

| Iodine knowledge and dietary education among the participants
The descriptive data about iodine knowledge and dietary education is presented in Table 4. Concerning national iodine recommendations for pregnant women, 29% of the MWs and 22% of the PHNs were aware of the recommendation. Overall, 46% recognised iodine deficiency among pregnant and lactating women as a current problem. Around half of the participants correctly identified the most important dietary iodine sources, a lack of fish and seafood (70%) and milk and dairy products (49%) in the diet were identified with iodine deficiency. Around 33% of the participants knew that iodine is important for foetal development, 50% that iodine is of importance for normal growth and development in children and 67% acknowledged the importance for normal metabolism (Table 4).
About 40% of the participants to a small or no extent received adequate knowledge about diet and nutrition through their professional training. The majority of MWs (~80%) and half of the PHNs reported that they to a small or no extent were offered sufficient professional courses or updated information about the topic diet and nutrition during their current practice. However, the results show that a larger proportion of PHNs received training in this particular topic compared to the MWs (p < 0.01, Table 4).

| Variables associated with iodine recommendations
Univariate relationships with MWs' and PHNs' degree of providing specific recommendations to ensure adequate iodine nutrient intake and selected variables are shown in Table 5.
A significant association between pregnant and lactating women and the degree of dietary recommendations of iodine intake was seen across services (p < 0.01). The ability to give dietary iodine recommendations was significantly higher for MWs working in antenatal

| Results for PHNs advising young fertile women
A majority of PHNs who served young fertile women stated that, when in contact, they offered dietary guidance to a great extent (71%) or to some extent (26%). Around half of them provided special advice to those who rarely or never ate fish (52%) or drank milk (50%). The majority of the PHNs to a small or no extent emphasised the importance of establishing optimal lifestyle habits for future pregnancy (61%) ( Table 6).

| Providing dietary guidance
Our study sample reported a clinical practice where they gave dietary guidance, they prioritised dietary guidance over other guidance and stated that they communicated the importance of diet for the foetus and infant. These results corroborate previous work from Australia in which a majority of healthcare professionals felt they were providing sufficient nutritional support to women during pregnancy (Soltani et al., 2017). In other studies, MWs agreed on the importance of nutritional guidance during pregnancy and highly rated their significant role in providing education and advice on nutrition during pregnancy (Arrish et al., 2016;Lee et al., 2018;Othman et al., 2020). These studies also revealed poor specific practice regarding dietary assessment and advice to ensure specific nutritional intake (Arrish et al., 2016;Lee et al., 2018 others (Arrish et al., 2016;Othman et al., 2020), may limit the extent of advice and partly explain poor personalisation related to dietary guidance.

| Addressing iodine in dietary guidance
In our present study, the majority of the participants answered that they provided information on what type of food to eat, to get enough of each specific nutrient. However, both this and giving specific advice to groups with a low intake of fish and milk were more common than paying attention to ensuring both iodine dietary intake and iodine assessment. This supports our findings of poor iodine focus and might indicate that providing special advice to those with a low intake of fish and milk might well be related to other nutrients such as Omega 3, vitamin D or calcium. Similarly, Guess et al. (2017) demonstrate that less than half of healthcare professionals discussed dietary sources of iodine with the women, and less than 10% reported dietary screening of women for iodine deficiency when planning pregnancy, during pregnancy or in the lactating period (Guess et al., 2017). Another study from Australia also indicates that healthcare professionals had low engagement, particularly concerning the provision of advice on fish consumption and iodine (Charlton et al., 2012).
One unanticipated finding was that around half of the participants in our study answered that a lack of fish, milk and dairy products can cause iodine deficiency, yet the majority do not have a clinical practice concerning iodine. This means that they have Communicate the importance of establishing optimal living habits for future pregnancy b No extent/to a small extent 61.4 To some extent 28.1 To a great extent 10.5 a Missing number: two participants did not answer any of the questions.
b Five categories originally were merged to three from: not at all, small extent, some extent, great extent and very great extent.

TA B L E 6
Clinical practice related to advising adolescents and young fertile women (n = 116).
knowledge about iodine sources, which makes it somewhat surprising that they do not inform the women about it. A possible interpretation is that the participants are not aware that iodine deficiency is a problem in Norway.
Nevertheless, our results concerning low iodine awareness are supported by previous findings that indicate poor clinical practice and knowledge among healthcare professionals in other countries such as Australia (Arrish et al., 2016;Guess et al., 2017;Lee et al., 2018). Lack of iodine knowledge, as revealed in our study, might negatively influence clinical practice. It is known from earlier research that professional nutritional knowledge influences pregnant women's nutritional knowledge, and as a consequence, this can lead to low adherence to nutrition recommendations and healthy living habits (Bouga et al., 2018;Lee et al., 2018). folate deficiency and neural tube defects that was not discovered until the 1990s, as a problem that did not previously receive much attention (Milunsky et al., 1989). This shows us that it takes time to adapt to new knowledge within the nutrition field and reproductive health, yet it is important to reduce the time from establishing firm scientific evidence to its implementation into clinical practice.

| Variables associated with dietary iodine recommendations
Interestingly, the ability to give specific dietary iodine recommendations was associated with a practice emphasising dietary priority, dietary assessment, giving special advice about iodine-rich items, recommending iodine supplements, protecting those with little or no intake of lean fish and milk, and communicating dietary foetal or infant impact. Together with iodine knowledge, this proactive clinical practice might reflect an approach built on evidence-based practice (NIPH, 2021).
We find it worrying that giving dietary recommendations, particularly specific dietary iodine recommendations, to pregnant women seems to be given higher priority than giving recommendations to lactating women. This finding is consistent with De Waards' (2017) systematic review which points out that recommendations concerning the nutrition status of lactating women and its effect on their infants appears to be scarce. Moreover, uncertainty among the professions, MWs and PHNs, about the responsibility to ensure good nutrition among lactating women seems to be prominent. They are caught between two fields, prenatal and postnatal care, together with a shift of focus from the mother to the infant.
Norwegian national postpartum guidelines do not mention maternal dietary recommendations and the impact these can potentially have on women and infants (Norwegian Directorate of Health, 2014). In light of Norway's high rate of exclusive breastfeeding, the lack of focus on maternal dietary issues raises concern for the breastfed infant (Myhre et al., 2020).

| Young women
Public health nurses in general give dietary guidance and special advice to young women who never or rarely eat fish or drink milk, but clearly fail to emphasise the importance of establishing optimal living habits for future pregnancy. Based on well-known knowledge about the significant relationship between lifestyle and future pregnancy, we question whether healthcare professionals' responsibility and awareness of dietary guidance for young women are sufficient or clarified. Despite the optimal focus on the present nutrition situation, our study indicates that PHNs to a minor extent convey the importance of current nutrition status in relation to future outcomes.
The responsibility to protect pre-pregnancy health lies with the general practitioners, together with PHNs. 'Too little too late' could be a possible explanation for the iodine deficiency among pregnant women. Increased attention on young women might prevent iodine deficiency when they become pregnant later in life, as suggested by Lee et al. (2018).

| Education and knowledge about iodine
The insufficient basic education and lifelong training about dietary and nutrition issues provided through clinical practice and the pro- This is also in accordance with the Norwegian 'Health Personnel Act' whereby every individual working within healthcare has an independent professional responsibility to maintain disciplinary practice (Helsesersonelloven, 1999).

| Strengths and limitations
This study has several strengths; it is the first study of healthcare personnel's clinical practice concerning iodine in a Norwegian context. All public clinics in northern Norway were invited to participate.
However, due to the indirect recruitment method, with an internal distribution of pre-information, invitation and reminders relying on the clinic's benevolence, the number of invitations that were received is uncertain. At best, the response rate might be higher than reported. Nonetheless, our low participation rate may have introduced non-response bias and limited generalisation, especially for MWs in maternity wards and PHNs. A lack of response might reflect their perception that the survey topics are of less relevance, interest, and priority. Our participation rate is nonetheless in line with declining trends in studies elsewhere (Wu et al., 2022). We used a questionnaire adapted from a pilot version by Henjum et al. (2018), and unfortunately, knowledge about non-animal sources of iodine was, therefore, not listed. Another weakness is the lack of multivariable analyses and the lack of a validated questionnaire addressing clinical practice, yet strengthened by derivations from national guidelines, previous research or reused from other studies. Also, an information bias linked to a self-reported survey cannot be excluded as it presents oneself in a better light and with a better understanding of questions. This survey was conducted in 2017-2018, yet a follow-up is relevant and can serve as a baseline study for evaluating the effect of campaign awareness and the aftermath of implementing iodine guidelines, and whether the increased focus at a national level has been effective. Despite these weaknesses, the results indicate weak practice regarding the iodine issue in relation to reproductive health.

| CON CLUS ION
In their clinical practice, MWs and PHNs are in a unique position to enhance public awareness of iodine, dietary sources and how to safeguard daily intake. However, the results of our study indicate that MWs and PHNs had a lack of clinical practice and knowledge of iodine concerning fertile women and infants, especially among lactating women. Increased focus on iodine and specific dietary guidelines during MWs' and PHNs' professional training and through clinical practice is necessary.

| RELE VAN CE TO CLINI C AL PR AC TI CE
In light of the current iodine deficiency and lack of iodine knowledge among reproductive target groups, especially among lactating mothers, it is important that healthcare providers such as midwives and public health nurses enhance their clinical practice and knowledge in relation to iodine intake and dietary sources, to convey and prevent possible negative outcomes for women, foetus and infant.

ACK N O WLE D G E M ENTS
We would like to thank all the midwives and public health nurses participating in this study. The preparatory work provided by Marie Nygård in relation to her master's thesis was greatly appreciated.
Thanks to Bente A. Augdal for administrative support. We are also grateful to those who participated in the pilot study and to the healthcare services that contributed to distributing the survey.

FU N D I N G I N FO R M ATI O N
The Northern Norway Regional Health Authority has financed parts of the research.

CO N FLI C T O F I NTE R E S T S TATE M E NT
No conflict of interest.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data that support the findings of this study are available on request from the corresponding author, Solrunn Hansen.

PATI E NT O R PU B LI C CO NTR I B UTI O N
Four MWs' and PHNs' commended the questionnaire during the design of the survey, otherwise no patient or public contribution.