A Randomized Trial of Closed-Loop Insulin Delivery Postpartum in Type 1 Diabetes.

OBJECTIVE: This study aimed to evaluate the efficacy of closed-loop insulin delivery postpartum. RESEARCH DESIGN AND METHODS: In this open-label, randomized controlled trial, postpartum individuals with type 1 diabetes were randomized to hybrid closed-loop insulin delivery with the MiniMed 670G/770G system in automode or sensor-augmented pump therapy in the first 12-weeks postpartum followed by a continuation phase with closed-loop insulin delivery for all until 24 weeks postpartum. RESULTS: Eighteen participants (mean ± SD age 32 ± 3.5 years, diabetes duration 22 ± 7.3 years, and early pregnancy HbA1c 52 ± 6.8 mmol/mol [6.9 ± 0.9%]) completed 24 weeks of postpartum follow-up. In the randomized phase, percent time in range 70-180 mg/dL (3.9-10 mmol/L) did not differ between groups (79.2 ± 8.7% vs. 78.2 ± 6.0%; P = 0.41). Participants randomized to closed-loop insulin delivery spent less time <70 mg/dL (3.9 mmol/L) and <54 mg/dL (3.0 mmol/L) (1.7 ± 0.8% vs. 5.5 ± 3.3% [P < 0.001] and 0.3 ± 0.2% vs. 1.1 ± 0.9% [P = 0.008]). Time >180 mg/dL (10 mmol/L) was not different between groups (18.7 ± 8.8% vs. 15.9 ± 7.7%; P = 0.21). In the continuation phase, those initially randomized to sensor-augmented pump therapy had less time <70 mg/dL after initiation of closed-loop insulin delivery (5.5 ± 3.3% vs. 3.3 ± 2.2%; P = 0.039). The closed-loop group maintained similar glycemic metrics in both study phases. There were no episodes of diabetic ketoacidosis or severe hypoglycemia in the randomized or continuation phase in either group. CONCLUSIONS: Women randomized to closed-loop insulin delivery postpartum had less hypoglycemia than those randomized to sensor-augmented pump therapy. There were no safety concerns. These findings are reassuring for use of closed-loop insulin delivery postpartum because of its potential to reduce hypoglycemia.

Management of type 1 diabetes in pregnancy: update on lifestyle, pharmacological treatment, and novel technologies for achieving glycaemic targets.

Glucose concentrations within target, appropriate gestational weight gain, adequate lifestyle, and, if necessary, antihypertensive treatment and low-dose aspirin reduces the risk of pre-eclampsia, preterm delivery, and other adverse pregnancy and neonatal outcomes in pregnancies complicated by type 1 diabetes. Despite the increasing use of diabetes technology (ie, continuous glucose monitoring and insulin pumps), the target of more than 70% time in range in pregnancy (TIRp 3·5-7·8 mmol/L) is often reached only in the final weeks of pregnancy, which is too late for beneficial effects on pregnancy outcomes. Hybrid closed-loop (HCL) insulin delivery systems are emerging as promising treatment options in pregnancy. In this Review, we discuss the latest evidence on pre-pregnancy care, management of diabetes-related complications, lifestyle recommendations, gestational weight gain, antihypertensive treatment, aspirin prophylaxis, and the use of novel technologies for achieving and maintaining glycaemic targets during pregnancy in women with type 1 diabetes. In addition, the importance of effective clinical and psychosocial support for pregnant women with type 1 diabetes is also highlighted. We also discuss the contemporary studies examining HCL systems in type 1 diabetes during pregnancies.

Assessment of maternal knowledge of infant movement and nutrition guidelines in Canada: The PREVENT survey study (Physical activity, Rest, Exercise and nutrition Values for Education of New moms with Type 2 diabetes/gestational diabetes).

Infants born to mothers with type 2 diabetes (T2D) and gestational diabetes (GDM) are at an increased risk of being overweight/obese. Modifiable lifestyle factors play a role in prevention of overweight and obesity. In 2017, the Canadian 24 h Movement Guidelines for the Early Years (CMG) were released. Alongside physical activity recommendations, sweetened beverage consumption (SBC) recommendations were also released by the American Academy of Pediatrics in 2017. The objective of this study was to determine the knowledge pregnant women with T2D and GDM have on the CMG and SBC recommendations, and to determine what factors affect this. A survey with questions regarding demographics, socioeconomic variables and the CMG and SBC recommendations was administered to pregnant women at Diabetes in Pregnancy clinics in Calgary, Alberta from July 2019 to January 2020. Surveys were analyzed utilizing the non-parametric Kruskall-Wallis Rank-Sum test, chi-square test and linear regression. A total of 79 respondents with T2D and GDM were collected. Respondents had the highest knowledge of SBC recommendations and the lowest knowledge of CMG recommendations. A bachelor's or higher degree was associated with significantly higher knowledge scores than a high-school education or less. In conclusion, pregnant women with T2D and GDM in this study had overall poor knowledge of the CMG and SBC recommendations, with less knowledge regarding the CMG. Level of education was found to be associated with knowledge regarding these recommendations. Future programs to improve education around infant and toddler physical activity and SBC recommendations may be beneficial for this patient population.

Real-world use of Control-IQ™ technology automated insulin delivery in pregnancy: A case series with qualitative interviews.

BACKGROUND: Most commercially available automated insulin delivery (AID) systems are not approved for pregnancy use. Information regarding use of the Tandem t:slim X2 insulin pump with Control-IQ™ technology in pregnancy is lacking. AIMS: This case series aimed to explore glycaemic and qualitative experiences of four early adopters of Control-IQ technology in pregnancy. METHODS: Participants used Control-IQ technology in pregnancy and postpartum and consented to analysis of glycaemic data and semi-structured interviews. RESULTS: Case 1 began Control-IQ technology at 10 weeks gestation. Her pregnancy glucose time-in-range (3.5-7.8 mmol/L [63-140 mg/dL]) increased from 58.7% to 73.3% by third trimester. Cases 2-4 began using Control-IQ technology 0-2 months preconception. Pregnancy time-in-range glucose increased from 73.4% to 78.7%, 78% to 83.6%, and 46.5% to 71.9% between first and third trimesters, respectively. A mid-pregnancy decline in time-in-range glucose was observed in two of the four participants related to suboptimal pump setting adjustments and delays in sensor and infusion set replacement. No diabetic ketoacidosis or severe hypoglycaemia occurred. All participants reported reduced diabetes management burden and improved sleep with Control-IQ technology use. CONCLUSIONS: Early adopters of Control-IQ technology safely used this system off-label in pregnancy and reported reduced diabetes management burden and improved sleep. The largest glycaemic improvements were observed among those with the lowest pregnancy time-in-range glucose at the beginning of pregnancy. Participants with low pregnancy glucose time-in-range increased their time-in-range with Control-IQ technology use and participants with high pregnancy glucose time-in-range maintained and increased their time-in-range with less diabetes management burden.

Outcomes in children of women with type 2 diabetes exposed to metformin versus placebo during pregnancy (MiTy Kids): a 24-month follow-up of the MiTy randomised controlled trial.

BACKGROUND: Metformin is increasingly being used during pregnancy, with potentially adverse long-term effects on children. We aimed to examine adiposity in children of women with type 2 diabetes from the Metformin in Women with Type 2 Diabetes in Pregnancy (MiTy) trial, with and without in-utero exposure to metformin, up to 24 months of age. METHODS: MiTy Kids is a follow-up study that included infants of women who participated in the MiTy randomised controlled trial, receiving either oral 1000 mg metformin twice daily or placebo. Caregivers and researchers remained masked to the type of medication (metformin or placebo) mothers received during their pregnancy. Anthropometric measurements, including weight, height, and skinfold thicknesses, were taken at 3, 6, 12, 18, and 24 months. At 24 months, linear regression was used to compare the BMI Z score and sum of skinfolds in the metformin versus placebo groups, adjusted for confounders. Fractional polynomials were used to assess growth trajectories. This study is registered with ClinicalTrials.gov, NCT01832181. FINDINGS: Of the 465 eligible children, 283 (61%) were included from 19 centres in Canada and Australia. At 24 months, there was no difference between groups in mean BMI Z score (0·84 [SD 1·52] with metformin vs 0·91 [1·38] with placebo; mean difference 0·07 [95% CI -0·31 to 0·45], p=0·72) or mean sum of skinfolds (23·0 mm [5·2] vs 23·8 mm [5·4]; mean difference 0·8 mm [-0·7 to 2·3], p=0·31). Metformin was not a predictor of BMI Z score at 24 months of age (mean difference -0·01 [95% CI -0·42 to 0·37], p=0·92). There was no overall difference in BMI trajectory but, in males, trajectories were significantly different by treatment (p=0·048); BMI in the metformin group was higher between 6 and 24 months. Children of women with type 2 diabetes were approximately 1 SD heavier than the WHO reference population. INTERPRETATION: Anthropometrics were similar in children exposed and those not exposed to metformin in utero; hence, overall, data are reassuring with regard to the use of metformin during pregnancy in women with type 2 diabetes and the long-term health of their children. FUNDING: Canadian Institute for Health Research.

Existing standardised questionnaires do not adequately capture quality-of-life outcomes of greatest importance for those living with type 1 diabetes in pregnancy.

BACKGROUND: No standardised questionnaires have been specifically developed to assess the considerable demands of managing type 1 diabetes (T1D) during pregnancy. AIMS: This study aimed to explore what domains of measurement are important to quality of life during pregnancy with TID and to assess if standardised questionnaires, used by previous researchers, adequately capture patients' reported experience of TID in pregnancy. METHODS: A qualitative inquiry was conducted using semi-structured focus groups with Canadian women who have experienced T1D in pregnancy. Participants were asked open-ended questions about experiences managing T1D during pregnancy and whether options on standardised tools captured their pregnancy experiences. Audio from focus groups was transcribed verbatim. Two researchers independently analysed the transcripts using inductive thematic analysis. Salient ideas, experiences and key words were coded iteratively and grouped into broader themes and subsequently reviewed by five participants. RESULTS: The sample included nine participants. Emergent themes included changes in day-to-day routines to manage T1D in pregnancy, fear of hyperglycaemia during pregnancy and of hypoglycaemia postpartum. Participants felt that existing options on standardised questionnaires did not adequately quantify diabetes interference in work, family time, planned activities and sleep, and did not address hyperglycaemia fear. CONCLUSIONS: Existing standardised questionnaires do not adequately capture patient-reported outcomes of greatest importance for those living with T1D in pregnancy. Future research assessing the impact of therapies on quality-of-life measures in TID pregnancies should quantify their influence on day-to-day activities, adjust measures of sleep quality and capture fear of hyperglycaemia in pregnancy and hypoglycaemia postpartum.

The Resistance Exercise in Already Active Diabetic Individuals (READI) Randomized Clinical Trial.

CONTEXT: Resistance exercise training (strength training) and aerobic exercise training are both recommended for people with type 1 diabetes, but it is unknown whether adding resistance exercise provides incremental benefits in people with this condition who already perform aerobic exercise regularly. OBJECTIVE: This work aimed to evaluate the incremental effect of resistance training on glycated hemoglobin A1c (HbA1c), fitness, body composition, and cardiometabolic risk factors in aerobically active people with type 1 diabetes. METHODS: The Resistance Exercise in Already-active Diabetic Individuals (READI) trial (NCT00410436) was a 4-center, randomized, parallel-group trial. After a 5-week run-in period with diabetes management optimization, 131 aerobically active individuals with type 1 diabetes were randomly assigned to resistance exercise (n = 71, intervention-INT) or control (n = 60, CON) for 22 additional weeks. Both groups maintained their aerobic activities and were provided dietary counseling throughout. Exercise training was 3 times per week at community-based facilities. The primary outcome was HbA1c, and secondary outcomes included fitness (peak oxygen consumption, muscle strength), body composition (anthropometrics, dual-energy x-ray absorptiometry, computed tomography), and cardiometabolic risk markers (lipids, apolipoproteins). Assessors were blinded to group allocation. RESULTS: There were no significant differences in HbA1c change between INT and CON. Declines in HbA1c (INT: 7.75 ± 0.10% [61.2 ± 1.1 mmol/mol] to 7.55 ± 0.10% [59 ± 1.1 mmol/mol]; CON: 7.70 ± 0.11% [60.7 ± 1.2 mmol/mol] to 7.57 ± 0.11% [59.6 ± 1.3 mmol/mol]; intergroup difference in change -0.07 [95% CI, -0.31 to 0.18]). Waist circumference decreased more in INT than CON after 6 months (P = .02). Muscular strength increased more in INT than in CON (P < .001). There were no intergroup differences in hypoglycemia or any other variables. CONCLUSION: Adding resistance training did not affect glycemia, but it increased strength and reduced waist circumference, in aerobically active individuals with type 1 diabetes.

Missed antenatal diabetes care appointments and neonatal outcomes for pregnancies with Type 1 and Type 2 diabetes.

BACKGROUND: There is limited information regarding the association between missed appointments and neonatal outcomes for diabetes in pregnancy. STUDY METHODS: This retrospective live birth cohort included pregnant women with Type 1 or 2 diabetes who attended specialized clinics from 2008 to 2020. The association between at least one missed antenatal diabetes appointments and outcomes were assessed using logistic regression and reported as adjusted odds ratios (aOR) (95% confidence interval). Mediation analyses were conducted to examine if above target HbA1c mediated these relationships. RESULTS: The cohort included 407 and 902 women with Type 1 and 2 diabetes, respectively, of whom 25.1% and 34.5% missed at least one appointment. Women with Type 1 diabetes who missed an appointment were more likely to have a caesarean section (aOR 1.95 [1.15, 3.31]) and their babies more likely to be admitted to the neonatal intensive care unit (aOR 2.25 [1.35, 3.75]). Women with Type 2 diabetes who missed an appointment were more likely to have a large-for-gestational-age infant (aOR 1.61 [1.13, 2.28]), and an extreme large-for-gestational-age infant (aOR 1.69 [1.02, 2.81]) compared with women who did not miss appointments. Above target HbA1c mediated the relationship between missed appointments and caesarean delivery in Type 1 diabetes and large-for-gestational age and extreme large-for-gestational age in Type 2 diabetes. CONCLUSION: In individuals with Type 1 and 2 diabetes, there are differences in neonatal outcomes between those who missed an appointment compared to those who did not. It remains unclear if missed diabetes appointments are causative or a marker of other health behaviours or risk factors leading to neonatal morbidity.

Determinants of Small for Gestational Age in Women With Type 2 Diabetes in Pregnancy: Who Should Receive Metformin?

OBJECTIVE: In the MiTy (Metformin in Women With Type 2 Diabetes in Pregnancy) randomized trial of metformin versus placebo added to insulin, we found numerous benefits with metformin but identified an increased proportion of infants who were small for gestational age (SGA). We aimed to determine the predictors of SGA in order to individualize care. RESEARCH DESIGN AND METHODS: Using logistic regression, we assessed baseline maternal characteristics as predictors of SGA. We compared maternal/neonatal outcomes in SGA metformin and placebo groups using the t, χ2, or Fisher exact test, as appropriate. RESULTS: Among the 502 mothers, 460 infants were eligible for this study. There were 30 infants with SGA in the metformin group (12.9%) and 15 in the placebo group (6.6%) (P = 0.026). Among SGA infants, those in the metformin group were delivered significantly later than those in the placebo group (37.2 vs. 35.3 weeks; P = 0.038). In adjusted analyses, presence of a comorbidity (chronic hypertension and/or nephropathy) (odds ratio [OR] 3.05; 95% CI 1.58-5.81) and metformin use (OR 2.26; 95% CI 1.19-4.74) were predictive of SGA. The absolute risk of SGA was much higher in women receiving metformin with comorbidity compared with women receiving metformin without comorbidity (25.0% vs. 9.8%). CONCLUSIONS: In this study, we observed a high percentage of SGA births among women with type 2 diabetes and chronic hypertension and/or nephropathy who were treated with metformin. Therefore, with the aim of reducing SGA, it is reasonable to be cautious in our use of metformin in those with type 2 diabetes and chronic hypertension or nephropathy in pregnancy.

The association between gestational diabetes and stillbirth: a systematic review and meta-analysis.

AIMS/HYPOTHESIS: Controversy exists over whether gestational diabetes increases the risk of stillbirth. The aim of this review was to examine the association between gestational diabetes and stillbirth. METHODS: We performed searches of the published literature to May 2021. Study selection and data extraction were performed in duplicate by independent reviewers. Meta-analyses of summary measures were conducted using random-effect models for cohort and case-control studies separately. The study protocol was registered in PROSPERO (registration ID CRD42020166939). RESULTS: From 9981 citations, 419 were identified for full-text review and 73 met inclusion criteria (n = 70,292,090). There was no significant association between gestational diabetes and stillbirth in cohort studies (pooled OR 1.04 [95% CI 0.90, 1.21]; I2 86.1%) or in case-control studies (pooled OR 1.57 [95% CI 0.83, 2.98]; I2 94.8%). Gestational diabetes was associated with lower odds of stillbirth among cohort studies presenting with an adjusted OR (pooled OR 0.78 [95% CI 0.68, 0.88]; I2 42.7%). Stratified analyses by stillbirth ≥28 weeks' gestation, studies published prior to 2013 and studies identified as low quality demonstrated a significantly higher odds of stillbirth in meta-regression (p = 0.016, 0.023 and 0.005, respectively). Egger's test for all included cohort studies (p = 0.018) suggests publication bias for the main meta-analysis. CONCLUSIONS/INTERPRETATION: Given the substantial heterogeneity across studies, there are insufficient data to define the relationship between stillbirth and gestational diabetes adequately. In the main analyes, gestational diabetes was not associated with an increased risk of stillbirth. However, heterogeneity across studies means this finding should be interpreted cautiously.

Prevalence of and risk factors for excess weight gain in pregnancy: a cross-sectional study using survey data.

BACKGROUND: Maternal weight gain during pregnancy is required for fetal development; however, excess gestational weight gain is associated with increased maternal and neonatal morbidity. We aimed to determine the proportion of Canadian women who gained excess weight during pregnancy and to identify risk factors for excess gestational weight gain. METHODS: Self-reported data on maternal weight gain were collected from the 2015/16 and 2017/18 cycles of the Canadian Community Health Survey (CCHS), a cross-sectional population-based survey. We included females aged 15 to 54 years with data on height, prepregnancy weight and gestational weight gain. We defined excess gestational weight gain in terms of preconception body mass index (BMI) according to the 2009 guideline of the US Institute of Medicine. We used logistic regression to evaluate potential risk factors for excess gestational weight gain. RESULTS: Of 1 335 615 Canadian women (weighted from approximately 9300 survey respondents), 422 043 (32%) gained excess weight during pregnancy. Women with obesity had 33% lower odds of gaining excess weight relative to women with overweight (odds ratio 0.67, 95% confidence interval 0.48-0.94). Risk factors for excess gestational weight gain were lower education level, white or Indigenous identity, smoking, mood disorder, anxiety disorder and Canadian citizenship. INTERPRETATION: One-third of Canadian women in this survey had excess gestational weight gain during pregnancy, and women with obesity had lower odds of gaining excess weight during pregnancy relative to women with overweight. Strategies are needed to reduce the proportion of Canadian women who gain excess weight during pregnancy, regardless of preconception BMI.

Metformin in Pregnancy for Women with Type 2 Diabetes: a Review.

PURPOSE OF REVIEW: To review the current evidence for the use of metformin in pregnancy for women with type 2 diabetes. RECENT FINDINGS: A large, multicenter, double-blind randomized controlled trial found that women with type 2 diabetes in pregnancy treated with metformin as an adjunct to insulin therapy had less gestational weight gain, insulin requirements, caesarian sections, macrosomia, and neonatal adiposity, but more neonates were small for gestational age (SGA) compared with insulin alone. It is unclear if the higher number of SGA infants are a direct result of metformin exposure or mediated through other effects such as less gestational weight gain and improved glycemic control. Additional follow-up studies of offspring exposed to metformin in utero are required. Metformin may be a useful adjunctive treatment for women with type 2 diabetes in pregnancy to help meet glycemic targets if there are no concerns for or indications of SGA.

Screening for Gestational Diabetes: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force.

Importance: Gestational diabetes is associated with several poor health outcomes. Objective: To update the 2012 review on screening for gestational diabetes to inform the US Preventive Services Task Force. Data Sources: MEDLINE, EMBASE, and CINAHL (2010 to May 2020), ClinicalTrials.gov, reference lists; surveillance through June 2021. Study Selection: English-language intervention studies for screening and treatment; observational studies on screening; prospective studies on screening test accuracy. Data Extraction and Synthesis: Dual review of titles/abstracts, full-text articles, and study quality. Single-reviewer data abstraction with verification. Random-effects meta-analysis or bivariate analysis (accuracy). Main Outcomes and Measures: Pregnancy, fetal/neonatal, and long-term health outcomes; harms of screening; accuracy. Results: A total of 76 studies were included (18 randomized clinical trials [RCTs] [n = 31 241], 2 nonrandomized intervention studies [n = 190], 56 observational studies [n = 261 678]). Direct evidence on benefits of screening vs no screening was limited to 4 observational studies with inconsistent findings and methodological limitations. Screening was not significantly associated with serious or long-term harm. In 5 RCTs (n = 25 772), 1-step (International Association of Diabetes and Pregnancy Study Group) vs 2-step (Carpenter and Coustan) screening was significantly associated with increased likelihood of gestational diabetes (11.5% vs 4.9%) but no improved health outcomes. At or after 24 weeks of gestation, oral glucose challenge tests with 140- and 135-mg/dL cutoffs had sensitivities of 82% and 93%, respectively, and specificities of 82% and 79%, respectively, against Carpenter and Coustan criteria, and a test with a 140-mg/dL cutoff had sensitivity of 85% and specificity of 81% against the National Diabetes Group Data criteria. Fasting plasma glucose tests with cutoffs of 85 and 90 mg/dL had sensitivities of 88% and 81% and specificities of 73% and 82%, respectively, against Carpenter and Coustan criteria. Based on 8 RCTs and 1 nonrandomized study (n = 3982), treatment was significantly associated with decreased risk of primary cesarean deliveries (relative risk [RR], 0.70 [95% CI, 0.54-0.91]; absolute risk difference [ARD], 5.3%), shoulder dystocia (RR, 0.42 [95% CI, 0.23-0.77]; ARD, 1.3%), macrosomia (RR, 0.53 [95% CI, 0.41-0.68]; ARD, 8.9%), large for gestational age (RR, 0.56 [95% CI, 0.47-0.66]; ARD, 8.4%), birth injuries (odds ratio, 0.33 [95% CI, 0.11-0.99]; ARD, 0.2%), and neonatal intensive care unit admissions (RR, 0.73 [95% CI, 0.53-0.99]; ARD, 2.0%). The association with reduction in preterm deliveries was not significant (RR, 0.75 [95% CI, 0.56-1.01]). Conclusions and Relevance: Direct evidence on screening vs no screening remains limited. One- vs 2-step screening was not significantly associated with improved health outcomes. At or after 24 weeks of gestation, treatment of gestational diabetes was significantly associated with improved health outcomes.

An exploration of differences in infant feeding practices among women with and without diabetes in pregnancy: A mixed-methods study.

AIMS: (1) To determine the likelihood of full breastfeeding at 3 months postpartum in women with and without diabetes in pregnancy (DiP); (2) to explore the associations between diabetes management practices and infant feeding practices in those who had DiP and (3) to examine women's experiences of feeding their infants after having DiP. METHODS: The quantitative study used data from Alberta Pregnancy Outcomes and Nutrition (APrON) cohort study. Participants who had DiP (n = 62) were matched 1:3 to participants without DiP for pre-pregnancy BMI, parity, mode of delivery and pre-term birth. Infant feeding questionnaires, prospective breastfeeding diaries and medical chart data were analysed to determine likelihood of fully breastfeeding at 3 months postpartum. For the qualitative study, interviews were conducted with postpartum women who had DiP to explore the experiences of infant feeding. Interviews were thematically analysed, and the results were compared between women who were categorized as 'full breast feeders' or 'mixed feeders'. RESULTS: The odds of fully breastfeeding were 50% lower in women with DiP than women without DiP (OR: 0.50, 95% CI 0.25-0.99, p = 0.04). Qualitative interviews identified that although all women showed resilience in the face of infant feeding challenges, those who were fully breastfeeding reported seeking out external infant feeding supports, for example, classes or Doula's. Mixed Feeders perceived there was a lack of infant feeding information and support given to them prior to giving birth. CONCLUSION: Women with DiP may require additional prenatal and postnatal infant feeding support to be better prepared to overcome feeding challenges they may face.

Impact of levothyroxine in women with positive thyroid antibodies on pregnancy outcomes: a systematic review and meta-analysis of randomised controlled trials.

OBJECTIVE: To evaluate the effect of levothyroxine therapy on pregnancy outcomes compared with placebo or no treatment in women without overt hypothyroidism with presence of thyroid peroxidase antibodies (TPOAb) and/or thyroglobulin antibodies (TgAb). DESIGN: Systematic review and meta-analysis of randomised controlled trials STUDY ELIGIBILITY CRITERIA: Prespecified criteria for inclusion were: randomised trials of levothyroxine versus control (placebo or no treatment) among women with positive TPOAb or TgAb who were pregnant or considering conception. DATA SOURCES: Ovid MEDLINE, EMBASE, CINAHL, Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials were searched from 1980 to 5 November 2020. OUTCOME MEASURES: Prespecified data elements were extracted and where appropriate, meta-analyses were conducted. Main outcomes include pregnancy achieved, miscarriage, preterm delivery and live birth. RISK OF BIAS ASSESSMENT: Cochrane Risk of Bias Tool for Quality Assessment of Randomised Controlled Trials. RESULTS: From 3023 citations, 79 citations were identified for full-text review. Of these, six trials (total of 2263 women) were included for qualitative and quantitative analyses. Risk of bias was deemed low for only one trial. There was no significant difference in the relative risk (RR) of pregnancy achieved (RR 1.03; 95% CI 0.93 to 1.13), miscarriage (RR 0.93; 95% CI 0.76 to 1.14), preterm delivery (RR 0.66; 95% CI 0.39 to 1.10) or live births (RR 1.01; 95% CI 0.89 to 1.16) in thyroid autoimmune women treated with levothyroxine compared with controls. Sensitivity analyses of preterm birth identified study quality and timing of levothyroxine initiation as sources of heterogeneity. CONCLUSIONS: Among pregnant women or women planning conception, with thyroid autoimmunity, there is a lack of evidence of benefit for levothyroxine use (moderate to high Grading of Recommendations, Assessment, Development and Evaluations). Recommendations to use levothyroxine in this setting need to be reconsidered. PROSPERO REGISTRATION NUMBER: CRD42019130459.

Thyroid Laboratory Testing and Management in Women on Thyroid Replacement Before Pregnancy and Associated Pregnancy Outcomes.

Background: Women with hypothyroidism before pregnancy often require an increase in their levothyroxine dosage to maintain a euthyroid state during pregnancy. The objectives of this study were to investigate: (i) the frequency and distribution of thyrotropin (TSH) testing and levothyroxine dosage adjustment by gestational age, (ii) the magnitude of levothyroxine increase by the underlying etiology of hypothyroidism, and (iii) the relationship of overtreatment or undertreatment during pregnancy with adverse pregnancy outcomes among women using thyroid replacement before pregnancy. Methods: A retrospective cohort study of pregnancies in women on thyroid replacement before pregnancy in Alberta, Canada, was performed. Women using thyroid replacement anytime during the two years before pregnancy who delivered between October 2014 and September 2017 were included. Delivery records, physician billing, and laboratory and pharmacy administrative data were linked. Outcomes included characteristics of TSH testing, levothyroxine dosing, and pregnancy outcomes. The frequency and gestational timing of TSH testing and levothyroxine adjustments were calculated. Multiple logistic regression was used to test whether pregnancies with TSH <0.10 mIU/L (overtreatment) or TSH ≥10.00 mIU/L (undertreatment) compared with control pregnancies (TSH 0.10-4.00 mIU/L) were associated with adverse pregnancy and neonatal outcomes. Results: Of the 10,680 deliveries, 8774 (82.2%) underwent TSH testing at least once during pregnancy, at a median gestational age of six weeks. An adjustment of levothyroxine dosage was made for 4321 (43.7%) during pregnancy. TSH in pregnancy below 0.10 mIU/L increased the odds of preterm delivery when compared with control pregnancies (adjusted odds ratio, 2.14 [95% confidence interval 1.51-2.78]). TSH ≥10.00 mIU/L during pregnancy was not associated with any adverse pregnancy or neonatal outcomes in the multivariable analysis. Conclusions: Although most women on thyroid replacement before conception had TSH measured at some point during pregnancy, it is concerning that 17.8% did not. Levothyroxine overtreatment in pregnancy was associated with preterm delivery. These findings suggest that clinicians should be careful to avoid overtreatment with levothyroxine in pregnancy.