STUDY QUESTION:Are maternal concentrations of pregnancy-associated plasma protein-A (PAPP-A) and insulin-like growth factor-1 (IGF-1) influenced by the frozen embryo transfer (FET) protocol in early pregnancy? SUMMARY ANSWER:Maternal concentrations of PAPP-A and IGF-1 were significantly lower in programmed cycle (PC) FET compared to modified natural cycle (mNC) FET among ovulatory women and compared to gonadotrophin-stimulated cycle (gSC) FET in anovulatory women. WHAT IS KNOWN ALREADY:PC-FET has been associated with increased risks of preeclampsia and other placenta-related complications, pointing to altered placental development. PAPP-A and IGF-1 are biochemical markers of early placental function, and reduced levels have been linked to preeclampsia and other adverse outcomes. These markers may therefore provide insight into the pathways underlying the distinct risk profile of PC-FET. STUDY DESIGN, SIZE, DURATION:This is a secondary analysis from a randomized controlled trial investigating estradiol and progesterone concentrations in FET treatments. The trial was conducted at Copenhagen University Hospital-Herlev, Denmark, from April 2021 to December 2024. Biochemical analyses for PAPP-A and IGF-1 were performed on stored biobank samples from the trial. The main analyses included women with ongoing pregnancies (n = 116), while additional analyses of IGF-1 were conducted in all ovulatory women with available biobank samples (n = 193). PARTICIPANTS/MATERIALS, SETTING, METHODS:Eligible participants were women aged 18-40 years with BMI ≤35 kg/m2 undergoing frozen-thawed autologous blastocyst transfer. Ovulatory women were randomized to mNC or PC, and anovulatory women to gSC or PC. Samples were collected at the following 7 timepoints throughout treatment: on the 2nd or 3rd day of menstrual bleeding, on the day of trigger/endometrial thickness ≥7 mm, on the day of embryo transfer and by gestational ages (GA) 4 + 2, 6 + 0, 8 + 0, and 9 + 6. Data on placental weight were collected at delivery. MAIN RESULTS AND THE ROLE OF CHANCE:The present analyses included women with ongoing pregnancies from the parent trial: 43 in the ovulatory mNC group, 42 in the ovulatory PC group, 16 in the anovulatory gSC group, and 15 in the anovulatory PC group. PC had substantially lower IGF-1 concentrations from treatment initiation through GA 8 + 0 compared to both mNC and gSC. Ovulatory women treated with PC showed significantly lower PAPP-A concentrations during endometrial preparation (7.4 vs 8.7 mU/l; adjusted P = 0.02), at embryo transfer (6.7 vs 8.8 mU/l; adjusted P < 0.001), and GA 4 + 2 (7.2 vs 8.5 mU/l; adjusted P = 0.03) than women treated with mNC. Among anovulatory women, PAPP-A concentrations were also reduced during endometrial preparation (5.8 vs 9.1 mU/l; adjusted P = 0.008) in PC compared to gSC. LIMITATIONS, REASONS FOR CAUTION:As this was a secondary analysis, no formal power calculation was made, and statistical power may therefore be limited. WIDER IMPLICATIONS OF THE FINDINGS:We provide evidence that PC-FET was followed by lower IGF-1 concentrations in early pregnancy and by time-dependent reductions in PAPP-A compared to mNC-FET and gSC-FET. These findings suggest alterations in early placental biology that may contribute to the adverse obstetric risk profile associated with PC-FET. Future studies should clarify whether these changes are related to the use of oral estradiol and whether alternative administration routes could modify this risk. STUDY FUNDING/COMPETING INTEREST(S):The trial was funded by Gedeon Richter Nordics AB, including analysis of biobank samples (grant numbers DK-2019-04, DK-2022-03, DK-2023-08, DK-2023-06, DK-2024-08). The trial also received one grant from the Gangsted-Rasmussen Foundation (grant number A39784) and a grant was obtained from the local research board at Copenhagen University Hospital-Herlev. The study was designed and planned independently, with no involvement from the funders in data analysis or interpretation of the results. N.F.M. has received funding for congress attendance from Gedeon Richter Nordics AB and Merck A/S, unrelated to the present work. B.N. has received grants to the institution from Merck A/S, Gedeon Richter Nordics AB, and Ferring Pharmaceuticals A/S, along with personal fees from Ferring Pharmaceuticals A/S, travel support from Gedeon Richter Nordics AB, and has participated in a data safety monitoring or advisory board for Ferring Pharmaceuticals A/S, outside of this research. M.K. has received funding from Rigshospitalets Research Board outside of this research. L.R. has received a research grant from the Novo Nordisk Foundation outside of this research. P.F.S. has received grants from Merck A/S, Gedeon Richter Nordics AB, and Ferring Pharmaceuticals A/S, travel support from Ferring Pharmaceuticals A/S, and personal fees from Novo Nordisk for webinars, outside of this study. TRIAL REGISTRATION NUMBER:2020-001218-39 in EudraCT.

This cohort study evaluates the potential association between prenatal acetaminophen exposure and risk of autism in Danish national registers.

INTRODUCTION:Preeclampsia is known to be associated with a two- to fourfold elevated risk of developing cardiovascular disease in the first 15 years following pregnancy. In this cross-sectional study of 892 women with prior preeclampsia, we aimed to assess differences in circulating angiogenic biomarker concentrations according to CT-assessed coronary atherosclerosis in women up to 28 years after an index pregnancy complicated by preeclampsia. MATERIAL AND METHODS:Women were identified from clinical databases consisting of data from all deliveries within the Capital Region of Denmark from 1995 onwards. Women with prior preeclampsia and a current age between 35 and 55 years were included from the CPH-PRECIOUS cohort. The primary outcome was differences in circulating angiogenic biomarkers according to CT-assessed coronary atherosclerosis. RESULTS:The median time since the pregnancy complicated by preeclampsia was 12.5 years (range: 0-28 years). PlGF concentrations were significantly higher in women with coronary atherosclerosis (9.6 pg/mL [IQR 4.9-12.6] vs. 7.4 pg/mL [IQR 3.9-11.3], p = 0.001), and subsequently a lower calculated sFlt-1/PlGF ratio (4.2 [IQR 3.1-6.3] vs. 5.0 [IQR 3.6-6.9], p = 0.001) was found. No differences in sFlt-1 concentrations were observed. Higher PlGF concentrations were significantly associated with coronary atherosclerosis; however, associations were attenuated in adjusted analysis. CONCLUSIONS:This is the first large study to investigate long-term differences in circulating angiogenic biomarker concentrations after preeclampsia, highlighting the complex relationship between angiogenic biomarkers, preeclampsia, and later atherosclerotic burden.

OBJECTIVE:Mental health status during pregnancy may matter for both maternal and infant outcomes. We aimed to evaluate the association between psychological well-being during early pregnancy and pregnancy outcomes: preeclampsia, preterm birth, and fetal growth deviations. METHODS:The study sample comprised 36,835 women from the Copenhagen Pregnancy Cohort with complete data on psychological well-being during early pregnancy, who gave birth to live-born singletons from October 2012 to December 2022. The exposure of interest was low psychological well-being, defined as a score of ≤ 50 on the World Health Organization-5 Well-Being Index (WHO-5 index). The outcomes were preeclampsia, preterm birth, and fetal growth deviations -defined as small for gestational age (SGA) and large for gestational age (LGA) - identified using Danish national registries. Multivariable logistic regression analyses were conducted to estimate associations, while adjusting for relevant a priori selected covariates. RESULTS:We found that women with low psychological well-being measured on the WHO-5 index had a statistically significantly lower risk of preeclampsia compared to those with higher psychological well-being (adjusted odds ratio 0.81, 95% CI: 0.69-0.95, p = 0.009). No significant associations were found for preterm birth or fetal growth deviations (SGA and LGA). CONCLUSIONS:Low psychological well-being measured by the WHO-5 index was associated with a lower risk of preeclampsia, while no associations were found for preterm birth or fetal growth deviations. This finding highlights the complex interplay between maternal mental health and pregnancy outcomes. Future studies are needed to evaluate whether this finding replicates and clarify their clinical implications.

The menstrual cycle is one of the most fundamental biological rhythms in human physiology, yet its systemic molecular changes remain poorly understood. Here we show that the menstrual cycle is accompanied by widespread changes in the circulating proteome. By profiling nearly 3,000 plasma proteins in 2,760 women from the UK Biobank, we identified 198 proteins that vary across the cycle, forming distinct temporal patterns aligned with menstrual phases. These proteins include reproductive hormones, cytokines and growth factors, many of which are enriched in endometrial tissue and expressed in epithelial and stromal cell types, highlighting their biological specificity. Several proteins were linked to common reproductive disorders, including endometriosis, leiomyoma and abnormal bleeding. Finally, we developed a proteomic score on the basis of 75 proteins that accurately predicts menstrual cycle phase. Together, these findings provide a systems-level atlas of menstrual cycle biology and inform biomarker discovery in women's health.

ObjectivesTo investigate neurodevelopmental outcome in preschool children with a CHD (congenital heart defect) requiring surgery compared to healthy controls.Materials and methodsThis study includes all Danish children born between 2016-2018 who underwent surgery within the first year for Ventricular Septal Defect (VSD), atrioventricular septal defect, coarctation of the aorta, double outlet right ventricle, tetralogy of fallot, and Transposition of the Great Arteries (TGA). Exclusion criteria: preterm birth (<37 weeks), twins, and genetic aberrations. Cases were matched with two to four healthy controls on age, sex, gestational age at delivery, and region of birth. Neurodevelopmental outcome at 33-60-months was assessed by the Ages & Stages Questionnaire (ASQ). Comparisons were performed by the Mann-Whitney U test and logistic regression analysis and presented as p-values and odds ratios (OR) with 95% confidence intervals (CI).ResultsThere were no differences in ASQ score between 105 cases with any CHD (230 (IQR 195-260)) and 179 controls (235 (IQR 205-265)), p = 0.12. Cases had five-fold increased odds of a low score compared to controls after adjusting for maternal educational level and children's age at ASQ completion (OR 5.02, 95% CI 1.49;16.90). This was primarily driven by cases with prenatally undetected VSD, where 20% scored below -2 standard deviations. No differences were found across individual CHD subgroups. In cases with prenatally undetected TGA, the total ASQ score was 185 (IQR 145-190) compared to 220 (IQR 190-270) in prenatally detected TGA, p = 0.08.ConclusionsThe overall ASQ score in children with surgically corrected CHD was comparable to controls. However, cases had five-fold increased odds of a low score, primarily driven by children with prenatally undetected VSD. Additionally, ASQ scores were lower in TGA cases, especially when undetected prenatally, though not significant. These findings suggest follow-up of all children with a CHD requiring surgery including awareness of potential developmental delays.

OBJECTIVES:This study investigate the angiogenic imbalance of soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PlGF) among women with any diabetes in pregnancy and suspected preeclampsia. STUDY DESIGN:A retrospective study of two cohorts of women with suspected preeclampsia who had sFlt-1/PlGF ratio measured as part of routine clinical care. One cohort was based on a clinician-validated dataset (CV cohort) and the other was based on an ICD-coded dataset (ICD cohort). In each cohort, women were categorised into four groups based on the presence or absence of any diabetes in pregnancy and/or preeclampsia. MAIN OUTCOME MEASURES:sFlt-1, PlGF, and the sFlt-1/PlGF ratio were presented as median and interquartile range. Receiver operating characteristic analyses were performed to evaluate the discriminative ability of the sFlt-1/PlGF ratio for the Four-Week Prediction of preeclampsia, and the area under the curve (AUC) was estimated. RESULTS:A total of 455 and 965 women were included in the two cohorts. In both cohorts, the sFlt-1/PlGF ratio was lower in women with preeclampsia and diabetes compared to women with preeclampsia but without diabetes, however the differences were only statistically significant in the CV cohort. The predictive performance of the sFlt-1/PlGF ratio for preeclampsia among women with diabetes differed with AUC values of 0.88 in the CV cohort and 0.73 in the ICD cohort. CONCLUSIONS:This study demonstrated lower sFlt-1/PlGF ratio in women with diabetes in pregnancy who develop preeclampsia, suggesting a lower diagnostic threshold may be more appropriate in this subgroup of pregnant women.

Background: Preterm prelabor rupture of the fetal membranes (PPROM) increases the risk of neonatal mortality and morbidity. The etiology behind the condition is multifactorial but believed to result from an overactivation of inflammatory pathways. This systematic review aimed to synthesize the literature behind first-trimester biomarkers associated with PPROM and compare it to literature within the same area for preterm birth. Methods: A search strategy was performed in PubMed, Embase, and CINAHL from 1993 to 2024 resulting in 14,889 articles screened by two independent authors and presented according to PRISMA guidelines. The biomarkers from the included articles were categorized into four medical headings: The immune system, metabolism and endocrinology, hematology, and reproduction. Results: Biomarkers associated with PPROM were primarily related to the immune system. C-reactive protein (CRP) and white blood cells (WBC) were often investigated for an association with PPROM but displayed divergent results of varying quality. Decreased concentrations of placental growth factor (PlGF) were associated with PPROM and spontaneous preterm birth, potentially highlighting a shared etiology, making soluble fms-like tyrosine kinase-1 (sFlt-1) interesting to investigate as well. Conclusion: Most biomarkers were examined in single studies, providing limited data to make significant conclusions about each biomarker. This review encourages further investigation of CRP, WBC, PlGF, and sFlt-1.

Background High-sensitivity cardiac troponin (hs-cTn) assays are prone to negative and positive interferences caused by endogenous cardiac troponin-specific autoantibodies (cTnAAbs). Large macrotroponin complexes formed of cardiac troponin (cTn) and cTnAAbs may result in falsely elevated hs-cTn results. This is potentially due to reduced clearance of macrotroponin, but direct evidence is still lacking. In this study, we investigated the possible effects of cTnAAbs on the elimination of cTn. Methods Twenty patients with ST-elevation myocardial infarction (MI) underwent plasmapheresis within 24 h after revascularization to harvest plasma with a high cTn concentration. After clinical recovery, patients returned to the hospital for autologous plasma re-transfusion. Following re-transfusion, blood samples were collected at fixed time points and analyzed with 5 commercial hs-cTn assays. The presence of cTnAAbs in the samples and the epitope specificity of cTnAAbs were investigated with in-house immunoassays. Results Altogether, 2 out of 20 patients (10%) were cTnAAb-positive. With 4 commercial hs-cTn assays, cTnAAb-positive patients mainly showed longer elimination half-lives and slower cTn clearances than most cTnAAb-negative patients. One hs-cTn assay was prone to negative cTnAAb interference but correspondingly less prone to positive macrotroponin interference. The central part of cardiac troponin I (cTnI) was predominantly affected by cTnAAbs. Conclusions Endogenous cTnAAbs were for the first time shown to prolong the elimination half-life and reduce the clearance of cTn in the circulation. Additionally, the extent of analytical interference from cTnAAbs and their reactivity to macrotroponin varies among commercial hs-cTn assays, an important consideration for laboratories to ensure accurate diagnosis of MI.

Numerous circulating microRNAs (miRNAs) have been detected in maternal blood. Initial studies in third trimester demonstrated differential miRNA expression profiles between uncomplicated pregnancies and pregnancies complicated by pre-eclampsia (PE). Recently, studies in first trimester have shown similar differential profiles, however, these studies were often under-powered. We conducted a nested case-control study, in which serum samples, taken between 10 and 14 weeks gestation, were obtained from 413 singleton pregnant women, 126 of which later developed PE. Total RNAs were purified and a selection of 46 miRNAs plus two miRNA controls were quantitated by real time quantitative PCR. Seven of the miRNAs, hsa-miR-181b-5p, -323a-3p, -518b, -363-3p, -20a-5p, -29a-3p, and − 142-3p, could differentiate between uncomplicated pregnancies and pregnancies which develop PE, but only a single miRNA, hsa-miR-363-3p, could differentiate between mild and severe PE. A combination of all seven differentiating miRNAs was the best at discriminating between PE and uncomplicated pregnancies (AUC = 0.879). First trimester maternal serum miRNA expression profile could differentiate between uncomplicated pregnancies and pregnancies complicated by PE. These circulating miRNA markers have the potential to improve risk assessment of PE in the first trimester, weeks before the onset of symptoms.

Pre-eclampsia is a common and serious pregnancy complication. This review describes that low-dose acetylsalicylic acid can reduce the risk of preterm pre-eclampsia in high-risk pregnant women if treatment is started before the 16th week of pregnancy. A new screening algorithm can already, in the first trimester of pregnancy, predict an individual woman's risk of developing pre-eclampsia by combining a series of biophysical and biochemical markers with maternal risk factors. The screening has been validated internationally and in Denmark. In 2025, a national implementation project will be initiated to evaluate the effectiveness of a change in screening strategy in Denmark.

Introduction The Cardiometabolic function in Offspring, Mother and Placenta after Assisted Reproductive Technology (COMPART) study is a prospective cohort study aiming to explore health outcomes in mothers and children following assisted reproductive technology (ART), with a particular focus on frozen embryo transfer (FET) versus fresh embryo transfer (fresh-ET). The increasing prevalence of ART and FET emphasises the need to assess potential health risks associated with the procedures, both in pregnancy, such as pre-eclampsia and large for gestational age offspring, and in the children, such as obesity and cardiometabolic dysfunction.Methods and analysis The cohort will include 600 pregnant women, their potential partner and their offspring in a 1:1:1 ratio of pregnancies achieved after ART with FET, ART with fresh-ET and women who conceived naturally. The study will involve extensive data collection from electronic medical records; parental questionnaires; biochemical, genetic and epigenetic analyses in blood, urine and placental tissue; and medical imaging (fetal ultrasound and PEA POD scan) and clinical examinations. Outcomes are grouped into six work packages (WPs) related to fetal growth (WP1), pregnancy (WP2), placenta (WP3), offspring (WP4), genetics (WP5) and epigenetics (WP6).Ethics and dissemination The COMPART study aims to provide valuable insights into the impact of ART and FET on maternal and offspring health and the underlying mechanisms responsible. The study seeks to advance reproductive medicine, shape clinical practice and guidelines and ultimately ensure maternal-fetal health following ART. The study has been approved by the Danish Ethics Committee (H-23071266; February 2024).Trial registration number NCT06334003

INTRODUCTION:Migraine is one of the most prevalent conditions worldwide. This systematic review aimed to evaluate the association between migraine, its subtypes, and adverse pregnancy outcomes. MATERIAL AND METHODS:Eligible cohort and retrospective case-control studies were included from PubMed and Embase databases from their inception to May 2024. Adverse pregnancy outcomes of interest were preeclampsia, preterm birth, low birthweight, small for gestational age, and placental abruption. Study quality was assessed using the Newcastle-Ottawa Scale. Meta-analyses of the outcomes with their odds ratios (ORs) and adjusted ORs (aOR), including a 95% confidence interval (CI), were performed using RevMan. Outcomes were pooled using random effects models, with separate analyses for cohort and retrospective case-control studies. The protocol was registered with PROSPERO (no. CRD42023404759). RESULTS:This meta-analysis included 19 studies (11 cohort and 8 retrospective case-control) encompassing 1 420 690 deliveries. Significant associations were observed between migraine and increased risk of preeclampsia (cohort: aOR 1.28 [95% CI: 1.11-1.47], I2 = 0%), (retrospective case-control: aOR 3.4 [95% CI: 1.81-6.4], I2 = 83%) and preterm birth (cohort: aOR 1.30 [95% CI: 1.17-1.44], I2 = 11%). The meta-analyses of adjusted data on low birthweight and small for gestational age were inconsistent with respect to statistical significance (cohort: aOR 1.27 [95% CI: 0.89-1.82], I2 = 36% and cohort: aOR 1.07 [95% CI: 1.03-1.12], I2 = 0%, respectively). In addition, migraine without aura (MO) (cohort: OR 1.62 [95% CI: 1.30-2.01], I2 = 0%; retrospective case-control: aOR 4.91 [95% CI: 2.78-8.67], I2 = 0%) and migraine with aura (MA) (cohort: OR 2.06 [95% CI: 1-4.27], I2 = 29%) were significantly associated with the risk of preeclampsia. Similarly, MO (cohort: OR 1.28 [95% CI: 1.11-1.49], I2 = 0%) and MA (cohort: OR 1.25 [95% CI: 1.07-1.47], I2 = 0%) were associated with preterm birth risk. CONCLUSIONS:Pregnant women with migraines have a higher risk of preeclampsia and preterm birth compared with those without migraines. Migraine could be associated with an increased risk of low birth weight and small for gestational age. Sub-analyses indicate an elevated risk of preeclampsia and preterm birth across migraine subtypes. Notably, no previous meta-analyses have differentiated between migraine subtypes. Additional studies are needed to strengthen these findings.

OBJECTIVE:To investigate the dynamic changes of soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF) and their ratio in maternal plasma, from preeclampsia diagnosis to postpartum, evaluating its clinical utility. METHODS:Single-center prospective longitudinal cohort study with repeated sample collection in women with established preeclampsia (PE). Seventy-five (n = 75) women with PE were included, from which 19, 21 and 35 developed early-onset (EPE), late-onset (LPE) and severe-LPE (SLPE) preeclampsia, respectively. Thirty-five (n = 35) women with normotensive pregnancy (NP) served as the reference group. RESULTS:In all subgroups of PE, PlGF decreased from diagnosis to peripartum. In contrast, sFlt-1 and the ratio rose in LPE and SLPE subgroups, whereas they remained continuously higher and stable in the EPE subgroup. In all subgroups, postpartum concentrations decreased compared to pregnancy levels. Post-term NP had higher sFlt-1 and ratio, and lower PlGF in comparison to term and late-term NP. Preeclamptic pregnancies complicated with fetal growth restriction (FGR) had continuously higher and stable sFlt-1 concentrations and ratio, and lower PlGF concentrations compared to PE without FGR. Different patterns of the three biomarker trajectories were observed in a case-by-case analysis. CONCLUSION:Further research is warranted to refine pattern analysis and to integrate trajectories of these biomarkers into clinical practice towards personalized care in preeclampsia management.

To investigate the impact of different frozen embryo transfer regimens on maternal thyroid function during early pregnancy and subsequent thyroid function in the newborns. A secondary analysis of a randomized controlled trial including women aged 18–40 years with a body mass index ≤ 35 kg/m2 undergoing frozen embryo transfer at Copenhagen University Hospital – Herlev (April 2021–May 2024). Ovulatory participants were randomized to modified natural or programmed cycle, and anovulatory participants to gonadotrophin-stimulated or programmed cycle. Maternal thyroid-stimulating hormone, free thyroxine, total thyroxine, and total triiodothyronine were measured. Neonatal thyroid-stimulating hormone was evaluated through the neonatal screening program. In total, 251 cycles were analyzed: 94 modified natural and 99 programmed in the ovulatory group, and 29 gonadotrophin-stimulated and 29 programmed in the anovulatory group. Total triiodothyronine and thyroxine levels were significantly higher in programmed cycles during endometrial preparation and early pregnancy. Free thyroxine was elevated at gestational age 4 + 2 in programmed vs. modified natural cycles, but not compared to gonadotrophin-stimulated cycles. Thyroid-stimulating hormone levels were comparable at all time points. Neonatal thyroid-stimulating hormone did not differ between groups. Although significantly higher maternal levels of total triiodothyronine, thyroxine, and free thyroxine were observed in programmed cycle, both maternal and neonatal thyroid-stimulating hormone levels were unaffected. These findings provide reassuring evidence for the endocrine health of women conceiving through programmed cycle and their newborns. The trial was prospectively registered in EudraCT with identification no. 2020–001218-39, registration date: 17 November 2020. Date of first patient’s enrollment: 20 April 2021.