1.
Spangmose, A. L., et al.
(författare)
Obstetric and perinatal risks in 4601 singletons and 884 twins conceived after fresh blastocyst transfers: a Nordic study from the CoNARTaS group
2020
Ingår i: Human Reproduction. - 0268-1161 .- 1460-2350. ; 35:4, s. 805-815
Tidskriftsartikel (refereegranskat) abstract
STUDY QUESTION: Are obstetric and perinatal outcomes in pregnancies after fresh blastocyst transfer (BT) comparable with those born after fresh cleavage stage transfer (CT) and spontaneous conception (SC)? SUMMARY ANSWER: Fresh BT is associated with a higher risk of placental and perinatal complications. WHAT IS KNOWN ALREADY: BT optimizes the selection of top-quality embryos and increases pregnancy and live birth rates per transfer compared to CT. However, concerns have been raised as extended culture duration may increase obstetric complications and impair perinatal outcomes. Previous studies have shown a higher risk of preterm birth (PTB) among infants born after BT compared with CT. Pregnancies after BT are also prone to a higher risk of same-sex twins after single embryo transfer (SET). STUDY DESIGN, SIZE, DURATION: A retrospective register-based cohort study used data from Denmark, Norway and Sweden including three cohorts: 56557 singletons and 16315 twins born after fresh IVF/ICSI cycles and 2808323 SC singletons in Denmark (birth years 1997-2014), Norway (2010-2015) and Sweden (2002-2015). Of the fresh IVF/ICSI singletons, 4601 were born after BT and 51956 after CT. The twin cohort consisted of 884 fresh IVF/ICSI children born after BT and 15431 fresh IVF/ICSI children born after CT. PARTICIPANTS/MATERIALS, SETTING, METHODS: Data were obtained from a large Nordic cohort of children born after ART and SC initiated by the Committee of Nordic ART and Safety (CoNARTaS). The CoNARTaS cohort was established by cross-linking National ART-, Medical Birth-, and National Patients Registers using the unique personal identification number, allocated to every citizen in the Nordic countries. Obstetric and perinatal outcomes after BT, CT and SC were compared using logistic regression analysis. For perinatal outcomes, we calculated gestational age based on the date of oocyte pick-up (OPU) and in sensitivity analyses on data from Denmark and Norway, we also calculated gestational age based on the second-trimester ultrasonography (US) scan. Risk of pregnancies with same-sex twins after SET was used as a proxy for risk of monozygotic twins. Adjustments were made for child's sex, birth year, parity (0 or >1), maternal age, body mass index, smoking, educational level, fertilization method (IVF/ICSI), the number of aspirated oocytes, SET and country. Information on educational level and the number of aspirated oocytes was not available for Norway. Children born after frozen embryo transfer were not included. The birth cohorts were restricted according to the year in which BT was introduced in the different countries. MAIN RESULTS AND THE ROLE OF CHANCE: A higher risk of placenta previa was found in singleton pregnancies after BT compared with CT (adjusted odds ratio [aOR] 2.11 [95% CI 1.76; 2.52]). Singletons born after BT had a higher risk of PTB (aOR 1.14 [95% CI 1.01; 1.29]) compared with CT singletons, when estimated based on OPU. Furthermore, an altered male/female ratio (aOR 1.13 [95% CI 1.06; 1.21]) with more males following BT compared with CT was seen. Risk of same-sex twins after SET was higher after single BT compared with single CT (aOR 1.94 [95% CI 1.42; 2.60]). LIMITATIONS, REASONS FOR CAUTION: Residual confounding cannot be excluded, in particular related to duration and cause of infertility that we could not adjust for due to lack of reliable data. WIDER IMPLICATIONS OF THE FINDINGS: Extended embryo culture to the blastocyst stage has the potential to compromise obstetric and perinatal outcomes in fresh cycles. These results are important since an increasing number of IVF/ICSI treatments are performed as BT. STUDY FUNDING/COMPETING INTEREST(S): NORDFORSK (project no: 71450). The Research Fund of Rigshospitalet, Copenhagen University Hospital. ReproUnion Collaborative study, co-financed by the European Union, Interreg V ÖKS. Grants from Swedish state under the agreement between the Swedish government and the county councils, the ALF-agreement (LUA/ALF 70940), Hjalmar Svensson Research Foundatio . The Research Council of Norway through its Centres of Excellence funding scheme, project number 262700. None of the authors has any conflicts of interests to declare regarding this study. TRIAL REGISTRATION NUMBER: ISRCTN11780826. © The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
2.
de Brun, Maryam, 1991-, et al.
(författare)
Changing diagnostic criteria for gestational diabetes (CDC4G) in Sweden : A stepped wedge cluster randomised trial
2024
Ingår i: PLoS Medicine. - : Public Library of Science (PLoS). - 1549-1277 .- 1549-1676. ; 21:7
Tidskriftsartikel (refereegranskat) abstract
BACKGROUND: The World Health Organisation (WHO) 2013 diagnostic criteria for gestational diabetes mellitus (GDM) has been criticised due to the limited evidence of benefits on pregnancy outcomes in different populations when switching from previously higher glycemic thresholds to the lower WHO-2013 diagnostic criteria. The aim of this study was to determine whether the switch from previous Swedish (SWE-GDM) to the WHO-2013 GDM criteria in Sweden following risk factor-based screening improves pregnancy outcomes.METHODS AND FINDINGS: A stepped wedge cluster randomised trial was performed between January 1 and December 31, 2018 in 11 clusters (17 delivery units) across Sweden, including all pregnancies under care and excluding preexisting diabetes, gastric bypass surgery, or multifetal pregnancies from the analysis. After implementation of uniform clinical and laboratory guidelines, a number of clusters were randomised to intervention (switch to WHO-2013 GDM criteria) each month from February to November 2018. The primary outcome was large for gestational age (LGA, defined as birth weight >90th percentile). Other secondary and prespecified outcomes included maternal and neonatal birth complications. Primary analysis was by modified intention to treat (mITT), excluding 3 clusters that were randomised before study start but were unable to implement the intervention. Prespecified subgroup analysis was undertaken among those discordant for the definition of GDM. Multilevel mixed regression models were used to compare outcome LGA between WHO-2013 and SWE-GDM groups adjusted for clusters, time periods, and potential confounders. Multiple imputation was used for missing potential confounding variables. In the mITT analysis, 47 080 pregnancies were included with 6 882 (14.6%) oral glucose tolerance tests (OGTTs) performed. The GDM prevalence increased from 595/22 797 (2.6%) to 1 591/24 283 (6.6%) after the intervention. In the mITT population, the switch was associated with no change in primary outcome LGA (2 790/24 209 (11.5%) versus 2 584/22 707 (11.4%)) producing an adjusted risk ratio (aRR) of 0.97 (95% confidence interval 0.91 to 1.02, p = 0.26). In the subgroup, the prevalence of LGA was 273/956 (28.8%) before and 278/1 239 (22.5%) after the switch, aRR 0.87 (95% CI 0.75 to 1.01, p = 0.076). No serious events were reported. Potential limitations of this trial are mainly due to the trial design, including failure to adhere to guidelines within and between the clusters and influences of unidentified temporal variations.CONCLUSIONS: In this study, implementing the WHO-2013 criteria in Sweden with risk factor-based screening did not significantly reduce LGA prevalence defined as birth weight >90th percentile, in the total population, or in the subgroup discordant for the definition of GDM. Future studies are needed to evaluate the effects of treating different glucose thresholds during pregnancy in different populations, with different screening strategies and clinical management guidelines, to optimise women's and children's health in the short and long term.TRIAL REGISTRATION: The trial is registered with ISRCTN (41918550).
3.
H Petersen, Sindre, et al.
(författare)
Risk of Hypertensive Disorders in Pregnancy After Fresh and Frozen Embryo Transfer in Assisted Reproduction: A Population-Based Cohort Study With Within-Sibship Analysis.
2022
Ingår i: Hypertension (Dallas, Tex. : 1979). - 1524-4563. ; 80:2
Tidskriftsartikel (refereegranskat) abstract
Frozen embryo transfer (frozen-ET) is increasingly common because of improved cryopreservation methods and elective freezing of all embryos. Frozen-ET is associated with higher risk of hypertensive disorders in pregnancy than both natural conception and fresh embryo transfer (fresh-ET), but whether this is attributable to parental factors or treatment is unknown.Using the Medical Birth Registries of Denmark (1994-2014), Norway, and Sweden (1988-2015), linked to data from national quality registries and databases on assisted reproduction, we designed a population-based cohort study with within-sibship comparison. We included 4426691 naturally conceived, 78300 fresh embryo transfer, and 18037 frozen-ET singleton pregnancies, of which 33209 sibships were conceived using different conception methods. Adjusted odds ratios (aOR) of hypertensive disorders in pregnancy for fresh embryo transfer and frozen-ET versus natural conception with 95% CI were estimated using multilevel logistic regression, where random effects provided conventional population-level estimates and fixed effects gave within-sibship estimates. Main models included adjustment for birth year, maternal age, parity, and country.Risk of hypertensive disorders in pregnancy was higher after frozen-ET compared to natural conception, both at population level (7.4% versus 4.3%, aOR, 1.74 [95% CI, 1.61-1.89]) and within sibships (aOR, 2.02 [95% CI, 1.72-2.39]). For fresh embryo transfer, risk was similar to natural conception, both at population level (aOR, 1.02 [95% CI, 0.98-1.07]) and within sibships (aOR, 0.99 [95% CI, 0.89-1.09]).Frozen-ET was associated with substantially higher risk of hypertensive disorders in pregnancy, even after accounting for shared parental factors within sibships.
4.
Kluge, Linda, 1968, et al.
(författare)
The association between body mass index and live birth and maternal and perinatal outcomes after in-vitro fertilization: a national cohort study
2023
Ingår i: Frontiers in Endocrinology. - 1664-2392. ; 14
Tidskriftsartikel (refereegranskat) abstract
Objective: To investigate the association between female body mass index (BMI) and live birth rates and maternal and perinatal outcomes after in-vitro fertilization (IVF). Methods: We performed a national, population-based cohort study including women undergoing IVF between 2002 and 2020. The cohort included 126,620 fresh cycles and subsequent frozen embryo transfers between 2007 and 2019 (subpopulation 1) and 58,187 singleton deliveries between 2002 and 2020 (subpopulation 2). Exposure was female BMI (kg/m2) categorized according to the World Health Organization as underweight (<18.5), normal weight (18.5–24.9, reference), overweight (25.0–29.9), class I obesity (30.0–34.9), class II obesity (35.0–39.9), and class III obesity (≥40.0). The primary outcome in subpopulation 1 was cumulative live birth per started fresh IVF cycle, including fresh and subsequent frozen embryo transfers. Primary outcomes in subpopulation 2 were hypertensive disorders of pregnancy and preterm birth at less than 37 weeks. Risk ratios (RRs) with 95% confidence intervals (CIs) for the association between BMI class and outcomes were calculated using generalized linear models after adjustment for relevant confounders. Results: The cumulative live birth rate decreased significantly with increasing BMI from 32.6% in normal-weight women to 29.4% in overweight women, 27.0% in women in obesity class I, 21.8% in women in obesity class II, and 7.6% in women in obesity class III. The risk of hypertensive disorders of pregnancy increased significantly and progressively with increasing BMI, from 4.6% in normal-weight women to 7.8% in overweight women and 12.5%, 17.9%, and 20.3% in women in obesity classes I, II, and III. The risk of preterm birth followed a similar pattern, from 6.3% in normal-weight women to 7.5% in overweight women and 8.9%, 9.9%, and 15.3% in women in obesity classes I, II, and III. The risks of other perinatal complications, such as perinatal death, showed an even more pronounced increase. Conclusion: Using a large and complete national cohort of women undergoing IVF, we demonstrate a dose-dependent decrease in live birth rate and a substantial increase in maternal and perinatal complications with increasing BMI. Strategies to improve this situation are warranted.
5.
6.
Alkmark, Mårten, 1973, et al.
(författare)
Induction of labour at 41 weeks or expectant management until 42 weeks: A systematic review and an individual participant data meta-analysis of randomised trials.
2020
Ingår i: PLoS medicine. - : Public Library of Science (PLoS). - 1549-1676 .- 1549-1277. ; 17:12
Tidskriftsartikel (refereegranskat) abstract
The risk of perinatal death and severe neonatal morbidity increases gradually after 41 weeks of pregnancy. Several randomised controlled trials (RCTs) have assessed if induction of labour (IOL) in uncomplicated pregnancies at 41 weeks will improve perinatal outcomes. We performed an individual participant data meta-analysis (IPD-MA) on this subject.We searched PubMed, Excerpta Medica dataBASE (Embase), The Cochrane Library, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and PsycINFO on February 21, 2020 for RCTs comparing IOL at 41 weeks with expectant management until 42 weeks in women with uncomplicated pregnancies. Individual participant data (IPD) were sought from eligible RCTs. Primary outcome was a composite of severe adverse perinatal outcomes: mortality and severe neonatal morbidity. Additional outcomes included neonatal admission, mode of delivery, perineal lacerations, and postpartum haemorrhage. Prespecified subgroup analyses were conducted for parity (nulliparous/multiparous), maternal age (<35/≥35 years), and body mass index (BMI) (<30/≥30). Aggregate data meta-analysis (MA) was performed to include data from RCTs for which IPD was not available. From 89 full-text articles, we identified three eligible RCTs (n = 5,161), and two contributed with IPD (n = 4,561). Baseline characteristics were similar between the groups regarding age, parity, BMI, and higher level of education. IOL resulted overall in a decrease of severe adverse perinatal outcome (0.4% [10/2,281] versus 1.0% [23/2,280]; relative risk [RR] 0.43 [95% confidence interval [CI] 0.21 to 0.91], p-value 0.027, risk difference [RD] -57/10,000 [95% CI -106/10,000 to -8/10,000], I2 0%). The number needed to treat (NNT) was 175 (95% CI 94 to 1,267). Perinatal deaths occurred in one (<0.1%) versus eight (0.4%) pregnancies (Peto odds ratio [OR] 0.21 [95% CI 0.06 to 0.78], p-value 0.019, RD -31/10,000, [95% CI -56/10,000 to -5/10,000], I2 0%, NNT 326, [95% CI 177 to 2,014]) and admission to a neonatal care unit ≥4 days occurred in 1.1% (24/2,280) versus 1.9% (46/2,273), (RR 0.52 [95% CI 0.32 to 0.85], p-value 0.009, RD -97/10,000 [95% CI -169/10,000 to -26/10,000], I2 0%, NNT 103 [95% CI 59 to 385]). There was no difference in the rate of cesarean delivery (10.5% versus 10.7%; RR 0.98, [95% CI 0.83 to 1.16], p-value 0.81) nor in other important perinatal, delivery, and maternal outcomes. MA on aggregate data showed similar results. Prespecified subgroup analyses for the primary outcome showed a significant difference in the treatment effect (p = 0.01 for interaction) for parity, but not for maternal age or BMI. The risk of severe adverse perinatal outcome was decreased for nulliparous women in the IOL group (0.3% [4/1,219] versus 1.6% [20/1,264]; RR 0.20 [95% CI 0.07 to 0.60], p-value 0.004, RD -127/10,000, [95% CI -204/10,000 to -50/10,000], I2 0%, NNT 79 [95% CI 49 to 201]) but not for multiparous women (0.6% [6/1,219] versus 0.3% [3/1,264]; RR 1.59 [95% CI 0.15 to 17.30], p-value 0.35, RD 27/10,000, [95% CI -29/10,000 to 84/10,000], I2 55%). A limitation of this IPD-MA was the risk of overestimation of the effect on perinatal mortality due to early stopping of the largest included trial for safety reasons after the advice of the Data and Safety Monitoring Board. Furthermore, only two RCTs were eligible for the IPD-MA; thus, the possibility to assess severe adverse neonatal outcomes with few events was limited.In this study, we found that, overall, IOL at 41 weeks improved perinatal outcome compared with expectant management until 42 weeks without increasing the cesarean delivery rate. This benefit is shown only in nulliparous women, whereas for multiparous women, the incidence of mortality and morbidity was too low to demonstrate any effect. The magnitude of risk reduction of perinatal mortality remains uncertain. Women with pregnancies approaching 41 weeks should be informed on the risk differences according to parity so that they are able to make an informed choice for IOL at 41 weeks or expectant management until 42 weeks. Study Registration: PROSPERO CRD42020163174.
7.
Furenäs, Eva, et al.
(författare)
Cardiac Complications during Pregnancy Related to Parity in Women with Congenital Heart Disease
2020
Ingår i: Cardiology. - : S. Karger AG. - 0008-6312 .- 1421-9751. ; 145:8, s. 533-541
Tidskriftsartikel (refereegranskat) abstract
Objective:To describe the frequency of cardiac complications during pregnancy related to parity in women with congenital heart defects.Methods:A retrospective tertiary single-center study at the Adult Congenital Heart Disease Centre that followed 307 women with congenital heart disease during the years 1997-2015 in Gothenburg, Sweden. Ma-ternal cardiac complications were noted for each pregnancy using medical and obstetric records. The CARPREG I and modified WHO (mWHO) risk classifications were used. Twin pregnancies, miscarriages before gestational week 13, and pregnancy terminations were excluded.Results:Five hundred seventy-one deliveries and 9 late miscarriages were analyzed. The mean parity was 1.74 per woman (range 1-8). Eighty-four (14.6%) maternal cardiac complications were experienced; arrhythmia (5.7%) and heart failure (4.4%) being the most prevalent, and there was 1 maternal death. Heart failure occurred during the first pregnancy in 12 women (3.9%), in the second pregnancy in 8 women (4.3%), and in the third pregnancy in 4 women (7.7%). CARPREG I and mWHO scores were associated with an increased risk of having a cardiac complication, while parity per se was not associated. The OR for having a maternally uneventful second pregnancy if the first pregnancy was without cardiac complications was 5.47 (95% CI 1.76-16.94) after controlling for CARPREG I and mWHO scores.Conclusion:The risk of severe maternal cardiac complications during pregnancy in women with congenital heart disease is low. In this largest analysis to date with a focus on parity in 307 women, the risk classification predicts the maternal outcome more than parity per se. If the first pregnancy is uneventful, the OR is 5.5 for an uneventful second pregnancy if CARPREG I and mWHO scores remain unchanged.
8.
Hagman, Anna, et al.
(författare)
Morbidity and mortality after childbirth in women with Turner karyotype.
2013
Ingår i: Human reproduction (Oxford, England). - : Oxford University Press (OUP). - 1460-2350 .- 0268-1161. ; 28:7, s. 1961-1973
Tidskriftsartikel (refereegranskat) abstract
STUDY QUESTION: Do women with Turner karyotype have increased mortality and morbidity in the years after childbirth? SUMMARY ANSWER: No mortality occurred during pregnancy and follow-up in women with Turner karyotype, but a higher rate of circulatory and endocrine diseases and a high risk of aortic aneurysm were confirmed. WHAT IS KNOWN ALREADY: Pregnancies in women with Turner karyotype are high-risk pregnancies with an increased risk of maternal mortality from aortic dissection and morbidity from hypertensive disorders. STUDY DESIGN, SIZE, DURATION: A retrospective Swedish population-based registry study of 124 women with Turner karyotype born between 1957 and 1987 and who gave birth between 1973 and 2010. Women with Turner karyotype without childbirth (n = 378) were selected as controls. A second control group consisted of women from the Swedish Medical Birth Register (MBR) (n = 1230) matched for maternal age, number of children and year of birth of the first child. PARTICIPANTS/MATERIALS, SETTING AND METHODS: Women with Turner karyotype were identified in the Swedish Genetic Turner Register. Data were obtained by using the unique personal identification number with cross linkage to the Swedish MBR, the Cause of Death Register, the National Patient Register and the Swedish Cancer Register. Hazard ratio (HR) with 95% confidence interval (CI) was used in the analysis of morbidity. MAIN RESULTS AND THE ROLE OF CHANCE: No mortality occurred in women with Turner karyotype and childbirth. Diseases of the circulatory system occurred more often in women with Turner syndrome under the age of 40 years compared with the MBR control group (HR 4.59; 95% CI 2.75-7.66) but was similar at or above the age of 40 years. Morbidity from circulatory diseases was increased before pregnancy (HR 3.83; 95% CI 1.02-14.43) and during pregnancy or within 1 year after (HR 5.78; 95% CI 1.94-17.24), but was similar after 1 or more years after delivery (HR 1.91; 95% CI 0.74-4.96). Aortic aneurysm occurred in 11/502 (2.2%) women with Turner karyotype and in three women (2.4%) during pregnancy. The long-term follow-up showed that aortic dissection was a common cause of death in young women with Turner karyotype without childbirth. A thorough cardiac evaluation before pregnancy in women with Turner karyotype is of utmost importance. LIMITATIONS, REASONS FOR CAUTION: Although this was a population-based registry study performed over a period of more than 20 years, a much longer follow-up and larger series are needed to assess rare events. The study also lacks information on phenotype and mode of conception in women with Turner karyotype. Women who gave birth probably represent a selection of healthier women with Turner karyotype. WIDER IMPLICATIONS OF THE FINDINGS: The high risk of aortic aneurysm in young women with Turner karyotype is in agreement with the literature. STUDY FUNDING/COMPETING INTEREST(S): No conflicts of interest exist. The study has been supported by grants from the Gothenburg Medical Society, the Medical Care executive Board of the Region Västra Götaland, grants from the ALF agreement at the Sahlgrenska University Hospital, the Hjalmar Svensson foundation, the Swedish Board of Health and Welfare, the Swedish Heart Lung Foundation and the Swedish Council for Working Life and Social Research. TRIAL REGISTRATION NUMBER: None.
9.
Nejdet, Sarah, et al.
(författare)
High risks of maternal and perinatal complications in singletons born after oocyte donation
2016
Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 0001-6349 .- 1600-0412. ; 95:8, s. 879-886
Tidskriftsartikel (refereegranskat) abstract
Introduction: Previous studies have shown an increased risk of obstetric complications in pregnancies after oocyte donation (OD). The present study includes all singletons born after OD over 10 years in Sweden. Material and methods: This was a retrospective population-based cohort study. Data from all Swedish in vitro fertilization (IVF) clinics between 2003 and 2012 were collected. Data were cross-linked with the Swedish Medical Birth Registry. The study included 388 OD singletons, 26 696 IVF/ICSI singletons and 999 804 spontaneously conceived (SC) singletons. An adjusted odds ratio (aOR) was calculated with adjustment for relevant confounders. Results: Singleton OD pregnancies had a significantly increased risk of preeclampsia compared with IVF (aOR 3.05; 95% CI 2.23–4.16) and SC (aOR 2.84; 95% CI 2.10–3.84), and increased risk of postpartum hemorrhage (>1000 mL) compared with IVF (aOR 2.66; 95% CI 2.04–3.49) and SC (aOR 2.87; 95% CI 2.20–3.71), a higher risk of preterm birth (<37 weeks) compared with IVF (aOR 1.79; 95% CI 1.30–2.46) and SC (aOR 1.58; 95% CI 1.15–2.16) and a higher risk of low birthweight (<2500 g) compared with IVF (aOR 1.67; 95% CI 1.15–2.42) and SC (aOR 1.46; 95% CI 1.01–2.11). The rate of large-for-gestational age was significantly increased in singletons born after OD with frozen cycles than with fresh cycles (odds ratio 5.29, 95% CI 1.30–21.54). Conclusions: Singleton pregnancies conceived after OD are associated with increased maternal and perinatal risks compared with IVF/ICSI pregnancies using the woman's own oocytes and with SC. © 2016 Nordic Federation of Societies of Obstetrics and Gynecology
10.
Fadl, Helena, 1965-, et al.
(författare)
Changing diagnostic criteria for gestational diabetes in Sweden-a stepped wedge national cluster randomised controlled trial-the CDC4G study protocol
2019
Ingår i: Bmc Pregnancy and Childbirth. - : Springer Science and Business Media LLC. - 1471-2393. ; 19:1
Tidskriftsartikel (refereegranskat) abstract
Background The optimal criteria to diagnose gestational diabetes mellitus (GDM) remain contested. The Swedish National Board of Health introduced the 2013 WHO criteria in 2015 as a recommendation for initiation of treatment for hyperglycaemia during pregnancy. With variation in GDM screening and diagnostic practice across the country, it was agreed that the shift to new guidelines should be in a scientific and structured way. The aim of the Changing Diagnostic Criteria for Gestational Diabetes (CDC4G) in Sweden () is to evaluate the clinical and health economic impacts of changing diagnostic criteria for GDM in Sweden and to create a prospective cohort to compare the many long-term outcomes in mother and baby under the old and new diagnostic approaches. Methods This is a stepped wedge cluster randomised controlled trial, comparing pregnancy outcomes before and after the switch in GDM criteria across 11 centres in a randomised manner. The trial includes all pregnant women screened for GDM across the participating centres during January-December 2018, approximately two thirds of all pregnancies in Sweden in a year. Women with pre-existing diabetes will be excluded. Data will be collected through the national Swedish Pregnancy register and for follow up studies other health registers will be included. Discussion The stepped wedge RCT was chosen to be the best study design for evaluating the shift from old to new diagnostic criteria of GDM in Sweden. The national quality registers provide data on the whole pregnant population and gives a possibility for follow up studies of both mother and child. The health economic analysis from the study will give a solid evidence base for future changes in order to improve immediate pregnancy, as well as long term, outcomes for mother and child.
