Table 1.

Key themes from interviewee responses (language spoken by patients (SP and HC) is indicated in brackets if not English; practitioner type is indicated in brackets)

Domain	Category	Comments
Patients: what they think and know	Motivation to comply	‘I take care of what I have to when I have to as far as my baby, and her being inside of me and me being sick taking care of me is taking care of her. So during my pregnancy I was at the doctor's when I was supposed to be on time and it was like at least three times a week I had to be in that hospital. I hated it but I did it for her’.
	Knowledge: consequences cause concern Knowledge: not worried reconsequences	‘Where I come from diabetes are not something like you just play with. We hear that people get amputated from diabetes [or a sore that] doesn't heal because you have sugar and it keeps getting bigger and bigger. I thought that maybe I was at risk and the pregnancy was at risk or maybe the baby, too, might get diabetes’. [SP] ‘It's a very treacherous disease’. ‘Just, no, you can't take it lightly'. ‘Cause you can't be selfish and think of yourself, you have to think about that little person that's growing inside you that's you know, relying on you to do what you need to do in order for them to survive’.  ‘I had heard people say that there were people who suffer from that, but at the same time, they told me not to worry about it, that's normal this happens to a lot of women but once the girl is born, it's going to be over. It goes away’. [SP] ‘I have no diabetes anymore that my blood's all right I'm okay’. [SP]
Patient characteristics according to providers	Competing priorities Consequences Risk versus reassurance	‘They're limited, no money, it's not a priority for them. GDM is not painful, so then they go and talk to their friends and family members who have advice that is logical to them but not medically appropriate’. ‘I don't mean to degrade my patients, and I feel like whatever they're doing is the best they can do’. [CNM] ‘[They're] concerned for future pregnancies. I don't know if the motivation is find out if I have diabetes’. [CNM]  ‘You do so well with all the other things, yes it's complex, but you are going to be able to do it really well and we will just take it step by step’. [OB] ‘We want to optimize your health there's something there that's a red flag but it's not too bad’. ‘You know it's good to stay motivational as opposed to just scare people with diagnoses because that can be not helpful at all’.
Intervention: patients	Testing and monitoring make sense Testing is unpleasant, makes no sense Challenges to showing up for testing	Since I wanted to see if I was well because if I had has ended up with that, I would have to continue treatment and to come to terms and I would have to ask for counseling or something to help me cope with that, because I think it would have been very hard for me to know that I ended up with that. At a later time on another appointment they would be monitoring me. My mom died of diabetes, you know, I would have genetic predisposition to that. Every time that I have an appointment they would be checking me. [SP]  ‘I said that they had given me something sweet that made me throw up. Me, I had a problem with them taking blood. I don't like needles. They take a lot of blood and they don't give me anything to replace it back. That's my problem’. [HC] ‘It was funny. They give you the sugar water. How can you give somebody sugar to drink and then you're going to have to test it? They're definitely going to find the sugar’. Oh!, the difficulty right now is because of the winter. He has to work he has to take me. So, it's very difficult to get around’. [SP] ‘They wanted to help me [and]they were worried about my baby but they always gave me a schedule that I couldn't do. I couldn't leave work because they could take it away and I knew the situation I was in, I needed to work’. [SP] ‘I supposed to ask them to test but I didn't ask because I have no time. Yeah, so now I didn't have time to shower, how I get a blood test?’.
Intervention: providers	Timing of the test at 8–12 weeks	‘Most providers know to do it. Whether or not most providers are doing it is a different story’. [Laborist] ‘One of the complications is, my understanding is, that we usually do [the test] at 12 weeks. So, we fall into a gap of the shift to primary care. So I didn't recommend it happening. It‘s not a really easy test to coordinate because we tend to see people up to 6 weeks and then the disengagement happens and it's not ideal. Sometimes I've brought people back for a 12 week visit but it takes that extra step of coordination and for example, about 60% of patients come for the postpartum visit. So it's a visit that's traditionally missed, the mothers’ busy, she has a new baby and if she feels well she does not want to come, so making that link’. [CNM] ‘I think most people who come back for their postpartum visit will come back for the test, but if you don't do it that same day then you're asking for an additional visit which ends up just having all of the barriers you have in usual care[and]often times they end up not being able to wait the 2 hours and they say, ‘I'm going to have to come back another day. But then some percentage of them don't’. [OB]
Inner context	The OB collaborative model of care Links between specialties and sense of expertise EMR capacity	‘I try to remind the residents to put it in the discharge summaries because not everybody comes back to me as a provider’. [102] ‘There are people who fall through the cracks because they don't come to their postpartum visit and it's a question of do we track those patients and follow them and follow and make sure that those things are happening. And honestly right now, that isn't something that has been made a priority’. [CNM] ‘Unless they have some complication, I don't really follow them’. [Laborist] ‘I think as we go ahead, one of the things that we are all going to be looking at is how do we bridge those specialty care to primary care gaps? How do we bridge that long-term heath vision and how to we make sure the hand offs are really safe?’. [CNM] ‘But I don't feel equipped to handle a positive test, so I think that's why I don't have them follow up with me, because I don't know all of the things about the Like, I want, I want them to follow up with their primary care provider, so they can say “Okay, this is how we're going to go forward in the future. And I feel like I'm not equipped to give them that information, so it wheels down to be like ‘Test is normal, you know, Bye”’. [CNM] ‘I'll be in touch with them whatever the results are, just to make sure that they've got a primary care connection, which can be challenging because sometimes they don't have a primary care provider’. [CNM] ‘I feel like we get a lot of things across our desktop and I don't flag normal results to people, you know, generally I don't’. [OB/GYN] ‘So in the ideal world they'll come in and they‘ll get the result and then I could talk to them about that I think that it would be much better to have the results in your hand (sat the last OB visit), already have made the referral, had the doctors name, write it down for them.’. [Laborist] If it's not in the problem list, the resident who is seeing the patient that day may not know about GDM because he would have to look back at her other laboratories. You see the patient and talk about the baby but not beyond’.
Outer context	Primary care linkage Registry	‘How do we bridge that long-term health vision and make sure handoffs are really safe?’. [CNM] ‘Every woman would get testing in the home and have data funneled into a registry and every woman would get contacted with results and what to do about it.’. [Endocrinologist]

CNM, certified nurse midwife; FM, family medicine physician; HC, Haitian Creole; MFM, maternal fetal medicine; OB, obstetrician; SP, Spanish.