We developed a coding framework using an inductive-deductive model to avoid ‘rigid operationalisation’ of the TDF (38). Using an inductive approach, two researchers (AL, AW) generated theme labels for similar clusters of data. We developed theme definitions in consultation with co-authors. For the deductive element, we categorised themes into domains using a TDF-based coding manual, which contained clear statements about how the inductively generated themes would be categorised within the TDF ( Supplemental Materials S5 ). We updated the coding framework and manual iteratively during data collection, practising reflexivity throughout (39).

After data familiarisation, two researchers (AL, AW) jointly coded one transcript. Using the manual, we coded all text relevant to the target behavior into its corresponding TDF domain, and again as a barrier or enabler. Following this, both researchers coded two (10%) transcripts independently. Inter-rater reliability was calculated using the NVivo coding comparison function (Kappa coefficient=0.73, 99% agreement). Coding differences were discussed and considered within the broader contextual meaning. Following this, one researcher (AW) coded remaining transcripts with queries addressed in consultation with co-authors. Participant responses about preferences for resource and reminders formats, and home-based alternatives to the postpartum OGTT were excluded from the main analysis but are available in Supplemental Materials (S6).

We used three established criteria to identify TDF domains of ‘high importance’: frequency (total number of codes to a TDF domain), presence of conflicting beliefs/themes, and evidence of themes likely to influence behavior (39). Responses to ‘important’ TDF domains are reported below, responses to remaining TDF domains are reported in Supplemental Materials (S7).

Using the BCW ( Figure 1 ), we developed a conceptual model linking qualitative data (synthesised into the TDF domains of ‘high importance’ and mapped to COM-B elements) to intervention functions (29). We then used established procedure and taxonomies to make recommendations on behavior change techniques to underpin intervention content (29, 31).

All participants were aware of the association between GDM and T2D and understood that the purpose of postpartum screening was “…to make sure it [GDM] disappeared” (ID11). Women who understood that GDM increases the risk of developing T2D generally assigned greater importance to screening: “I’m higher risk … I have gone and done the follow-up testing” (ID10). Some noted that knowledge of the OGTT procedure and requirements acquired at GDM diagnosis was helpful as “…you know what to expect” (ID05).

Women’s knowledge of ongoing screening requirements was low: “It hadn’t registered that it was a yearly thing” (ID04) and “It’s just one blood test you have to take, is it?” (ID12). Relatedly, lack of knowledge of immediate and ongoing T2D risk translated into confusion about the rationale for regular follow-up: “I thought once I had the – the six week one, I’d be in the all-clear” (ID14).

Women described the impact of cognitive overload associated with the demands of managing life with a baby: “I don’t think I actively decided against it [OGTT], it was just … a bit too hard” (ID01). Women also had difficulty maintaining attention to ongoing risk and screening requirements: “I put it out of my mind for a little bit … and then I forgot” (ID11). Relatedly, the asymptomatic nature of T2D meant that it was “easy to … forget when you have no symptoms” (ID01). Conversely, screening reminders were unanimously valued “my trigger to get it done” (ID03) and prompted attention to ongoing risk: “this is something you should still check-up on” (ID13).

Competing demands. Women often described how personal circumstances reduced opportunity to schedule “A time around their [newborn] chaotic routine” (ID08). This was just one of multiple competing demands the women faced: “I don’t feel like I’ve got any time ever to do things that I need to do” (ID13).

Screening requirements and environment. Women expressed that the requirements, timing, and duration of screening were impractical: “…you have to sit around for at least two hours, and it was just not very possible with the newborn” (ID01). For some, seeking alternate care for their newborn was undesirable: “… it’s not very practical … for a mum to leave the baby for that long” (ID03). Lack of child and nursing-friendly facilities and extended waiting times exacerbated these challenges: “…there’s just nowhere nice to sit and breastfeed and it was dusty” (ID08). Unique to the context of the COVID-19 pandemic were concerns about physical safety during the screening visit: “I don’t want to sit in a hospital around sick people for three hours … and especially now with all this Coronavirus, I definitely wouldn’t do it” (ID02).

Education and resources. Antenatal education was a key enabler to understanding T2D risk and importance of postpartum screening: “…in the first education session, they drilled it into us just to make sure you go” (ID04). For some, print-based resources reinforced learnings. Conversely, some noted reduction of “information after having the baby” (ID10), while others perceived that screening information was buried within an excess of “…piles of paperwork” (ID15).

Social support. Availability of practical support for the logistics of screening reduced the strain of competing demands: “I have a very supportive husband … he made sure that he was helpful with the other kids so that I could get to the appointment” (ID10). Family and friends were a powerful influence on women’s screening decisions: “… if they’re concerned about me or are trying to support me in trying to do something for my own health then I certainly respect that and listen to them” (ID16).

Communication with health professionals. Health professionals were regarded as a trusted and valuable source of information: “…they know your health status … if your GP calls you and tells you to do something, you generally do it” (ID14). Continuity of care reinforced the value placed on advice: “I already had that trusting relationship with them, and they knew my history … I was comfortable in her expertise in the condition” (ID14). While most women were informed about their T2D risk, few were advised about ongoing screening requirements: “She [GP] didn’t tell me” (ID02).

Social comparison. Knowing that other women attended screening was an enabler. For example, one participant identified closely with an online blogger who had been diagnosed with T2D after GDM, and whose narrative reinforced the importance of screening: “I had it in the back of my mind that she had developed it … I’m sure that probably had a subconscious role to play” (ID03).

Fear/anxiety. Some participants fear of T2D diagnosis impacted screening behavior: “I was worried that I would have it” (ID04). Often, this arose from perceiving T2D management as analogous to the “…regimented living style” (ID06) experienced during GDM. While fear was a clear barrier, a sense of relief and “peace of mind” (ID01) encouraged women “to keep getting the checks done” (ID21). Conversely, for a minority, an appropriate level of concern motivated screening attendance: “I was nervous that I might still have it … I wanted to get it done” (ID16). Some participants feared “needles” (ID12) or had misconceptions about potential harm: “…I felt the sugar flushed in my blood … you always worry about whether your body will react properly” (ID09).

Postpartum abandonment. Participants described disappointment about the rapid reduction of support after birth which greatly contrasted with experiences during pregnancy: “…the support that we received was fantastic … the minute the baby was born it, sort of, stopped” (ID16). Some described postpartum care as highly infant-focused: “I did leave that session thinking, ‘Great. My baby’s happy and healthy.’ But, for me it was, like, two questions and done” (ID04). Participants noted the need for ongoing support to prioritise their health: “reinforcing you are as important as your baby” (ID12).

Perceived necessity. Believing that T2D screening is important for future health was a powerful enabler: “for my own body’s sake, it was the right thing to do” (ID04). Conversely, lack of symptoms and “feeling okay” (ID06) reduced perceived necessity: “I don’t feel any different from before I was pregnant, so it’s not of real urgency for me” (ID02). Perceiving GDM as transient meant screening was “less of a priority” (ID01) for some. Annual screening was sometimes perceived as unnecessary if the women had received a negative OGTT result “…it’ll be fine” (ID08) or were planning another pregnancy: “… they’ll screen me when I get pregnant again” (ID13).

Consequences of screening. Screening benefits typically outweighed costs. Knowing one’s health status was an enabler for some: “It’s important for women to be aware of what’s going on in their bodies, so the screening is really helpful” (ID10), but not all: “I’m not prepared to know” (ID06). For some, the appointment provided opportunity for personal time in the early postpartum period: “being able to just sit and have some time out to read a book was actually pleasant” (ID21). Most described minimal negative consequences: “It wasn’t really anything too onerous, except for a couple of hours to sit around and wait, which didn’t bother me” (ID04).

Anticipated outcome. For some, the possibility of undiagnosed diabetes was a motivator: “…it could be worse if I wasn’t tested regularly” (ID05). For others, anticipating that they may already have T2D was a barrier: “…it could be too late” (ID06). Expectation of a negative OGTT result was an enabler: “I knew it was going to be a normal test, so I wasn’t anxious” (ID01).

Social identity and motherhood role expectations were both barriers and enablers. Some women described that they “prioritise [their child’s] health over [their] own health” (ID12). For others, being a mother motivated them to screen: “…to be a good mum … you need to make sure that you’re also looking after yourself” (ID21).

Perceived competence. For some, compensatory strategies such as continuing to self-monitor blood glucose or engaging in healthy habits reduced the perceived necessity of screening: “…I haven’t had a test yet, but I’ve pricked myself a few times and it’s always been normal” (ID02). A minority believed that they would recognize symptoms of T2D: “I can read my body pretty well … if everything felt fine I probably wouldn’t [screen]” (ID13).

Perceived ability to manage T2D risk. Believing that T2D can be prevented, delayed, or managed influenced willingness to screen. High self-efficacy (i.e., belief in capability to manage risk or T2D) appeared to foster a sense of agency and reduce apprehension related to screening: “I feel like it’s within my control to a certain extent” (ID05). Conversely, one participant reported that low confidence in making diet and lifestyle change led to avoidance of screening: “I haven’t learned a different way of how to deal with stress aside from eating” (ID06).

Prior recommendations to increase screening uptake typically targeted knowledge (12, 13). While an important prerequisite, our findings suggest that ‘Knowledge’ is already broadly addressed by existing educational policies in an Australian context. However, screening prompts and reminders provided by Australia’s National Gestational Diabetes Register could be improved by review to ensure that the messaging both addresses the determinants identified in this study and is underpinned by the recommended behaviour change techniques. Most of the modifiable determinants of T2D screening uptake relate to the Opportunity and Motivation elements of the COM-B model. Therefore, screening uptake is most likely to be improved by timely (44), person-centred messaging that addresses opportunistic barriers (e.g., competing demands and elements of the screening procedure), motivational factors (e.g., emotions, beliefs, self-efficacy, maternal identity).

A further consideration for policymakers is the current reliance on the 6–12-week OGTT, which is a barrier to screening and could be replaced with a simpler fasting glucose, HbA1c or home-based alternatives. This would require further research to establish their feasibility and effectiveness. Finally, the women’s concerns about postpartum abandonment suggest that greater consideration needs to be given to ensuring appropriate handovers from tertiary to primary care, and continued support during this time.

We have identified behavior change techniques to underpin psychoeducational messaging ( Figure 2 ). These techniques can be extrapolated for use in the clinical context. For example, clinicians could promote screening uptake through providing accurate and timely information about T2D risk, the rationale and positive health consequences of screening. It is important that clinicians use a gain-framed approach to emphasize the potential positive outcomes of screening such as reassurance if screening is negative and the ability to access timely and effective treatments if screening is positive. Clinicians are well placed to arrange or address practical or emotional support to overcome the unique barriers that the woman may be experiencing. Further, clinicians can frame screening as an important role modelling behavior which is of direct benefit to the health and wellbeing of the family (44). Specific communication points for clinicians are reported in a recent systematic review published by our research team (14).