AAAnders Nyboe Andersen

Anders Nyboe Andersen

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Anders Nyboe Andersen has a total of 85 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    A Novel Approach to Predicting Early Pregnancy Outcomes Dynamically in a Prospective Cohort Using Repeated Ultrasound and Serum Biomarkers

    by Jesper Friis Petersen, Lennart Jan Friis-Hansen, Thue Bryndorf, Andreas Kryger Jensen, Anders Nyboe Andersen, Ellen Løkkegaard

    This study aimed to develop a dynamic model for predicting outcome during the first trimester of pregnancy using baseline demographic data and serially collected blood samples and transvaginal sonographies. A prospective cohort of 203 unselected women with an assumed healthy pregnancy of < 8 weeks’ gestation was followed fortnightly from 4–14 weeks’ gestation until either miscarriage or confirmed first trimester viability. The main outcome was development of a model to predict outcome from gestational age-dependent hazard ratios using both baseline and updated serial data from each visit. Secondary outcomes were descriptions of risk factors for miscarriage. The results showed that 18% of the women experienced miscarriages. A fetal heart rate detected before 8 weeks’ gestation indicated a 90% (95% CI 85–95%) chance of subsequent delivery. Maternal age (≥ 35 years), insufficient crown-rump-length (CRL) and mean gestational sac diameter (MSD) development, and presence of bleeding increased the risk of miscarriage. Serum biomarkers, including hCG, progesterone, and estradiol, were found to impact the risk of miscarriage with estradiol as the most important. The best model to predict miscarriage was a combination of maternal age, vaginal bleeding, CRL, and hCG. The second-best model was the sonography-absent model of maternal age, bleeding, hCG, and estradiol. This study suggests that combining maternal age, and evolving data from hCG, estradiol, CRL, and bleeding could be used to predict fetal outcome during the first trimester of pregnancy.Trial registration ClinicalTrials.gov identifier: NCT02761772.


  • Impact of letrozole co-treatment during ovarian stimulation with gonadotrophins for IVF: a multicentre, randomized, double-blinded placebo-controlled trial

    by Nathalie Søderhamn Bülow, Sven Olaf Skouby, Agnieszka Katarzyna Warzecha, Hanne Udengaard, Claus Yding Andersen, Marianne Dreyer Holt, Marie Louise Grøndahl, Anders Nyboe Andersen, Negjyp Sopa, Anne Lis Englund Mikkelsen, et al.

    Does letrozole co-treatment during ovarian stimulation with gonadotrophins for IVF reduce the proportion of women with premature progesterone levels above 1.5 ng/ml at the time of triggering final oocyte maturation? The proportion of women with premature progesterone above 1.5 ng/ml was not significantly affected by letrozole co-treatment. IVF creates multiple follicles with supraphysiological levels of sex steroids interrupting the endocrine milieu and affects the window of implantation. Letrozole is an effective aromatase inhibitor, normalizing serum oestradiol, thereby ameliorating some of the detrimental effects of IVF treatment. A randomized, double-blinded placebo-controlled trial investigated letrozole intervention during stimulation for IVF with FSH. The trial was conducted at four fertility clinics at University Hospitals in Denmark from August 2016 to November 2018. A cohort of 129 women with expected normal ovarian reserve (anti-Müllerian hormone 8–32 nmol/l) completed an IVF cycle with fresh embryo transfer and received co-treatment with either 5 mg/day letrozole (n = 67) or placebo (n = 62), along with the FSH. Progesterone, oestradiol, FSH, LH and androgens were analysed in repeated serum samples collected from the start of the stimulation to the mid-luteal phase. In addition, the effect of letrozole on reproductive outcomes, total FSH consumption and adverse events were assessed. The proportion of women with premature progesterone >1.5 ng/ml was similar (6% vs 0% (OR 0.0, 95% CI [0.0; 1.6], P = 0.12) in the letrozole versus placebo groups, respectively), whereas the proportion of women with mid-luteal progesterone >30 ng/ml was significantly increased in the letrozole group: (59% vs 31% (OR 3.3, 95% CI [1.4; 7.1], P = 0.005)). Letrozole versus placebo decreased oestradiol levels on the ovulation trigger day by 68% (95% CI [60%; 75%], P < 0.0001). Other hormonal profiles, measured as AUC, showed the following results. The increase in LH in the letrozole group versus placebo group was 38% (95% CI [21%; 58%], P < 0.0001) and 34% (95% CI [11%; 61%], P = 0.006) in the follicular and luteal phases, respectively. In the letrozole group versus placebo group, testosterone increased by 79% (95% CI [55%; 105%], P < 0.0001) and 49% (95% CI [30%; 72%], P < 0.0001) in the follicular and luteal phases, respectively. In the letrozole group versus placebo group, the increase in androstenedione was by 85% (95% CI [59%; 114%], P < 0.0001) and 69% (95% CI [48%; 94%], P < 0.0001) in the follicular and luteal phases, respectively. The ongoing pregnancy rate was similar between the letrozole and placebo groups (31% vs 39% (risk-difference of 8%, 95% CI [−25%; 11%], P = 0.55)). No serious adverse reactions were recorded in either group. The total duration of exogenous FSH stimulation was 1 day shorter in the intervention group, significantly reducing total FSH consumption (mean difference −100 IU, 95% CI [−192; −21], P = 0.03). Late follicular progesterone samples were collected on the day before and day of ovulation triggering for patient logistic considerations, and the recently emerged knowledge about diurnal variation of progesterone was not taken into account. The study was powered to detect hormonal variations but not differences in pregnancy outcomes. Although the use of letrozole has no effect on the primary outcome, the number of women with a premature increase in progesterone on the day of ovulation triggering, the increased progesterone in the mid-luteal phase due to letrozole may contribute to optimizing the luteal phase endocrinology. The effect of letrozole on increasing androgens and reducing FSH consumption may be used in poor responders. However, the effect of letrozole on implantation and ongoing pregnancy rates should be evaluated in a meta-analysis or larger randomized controlled trial (RCT). Funding was received from EU Interreg for ReproUnion and Ferring Pharmaceuticals, and Roche Diagnostics contributed with assays. N.S.M. and A.P. have received grants from Ferring, Merck Serono, Anecova and Gedeon Richter, and/or personal fees from IBSA, Vivoplex, ArtPred and SPD, outside the submitted work. The remaining authors have no competing interests. NCT02939898 and NCT02946684 15 August 2016. 22 August 2016.


  • Open Access

    Use of cryopreserved ovarian tissue in the Danish fertility preservation cohort

    by Stine Gry Kristensen, Yu Wakimoto, Lotte Berdiin Colmorn, Margit Dueholm, Susanne Elisabeth Pors, Kirsten Tryde Macklon, Linn Salto Mamsen, Dmitry Nikiforov, Jesús Cadenas, Vinnie Hornshøj Greve, et al.


  • The importance of the ‘family clock’: women’s lived experience of fertility decision-making 6 years after attending the Fertility Assessment and Counselling Clinic

    by Emily Koert, Randi Sylvest, Ida Vittrup, Helene Westring Hvidman, Kathrine Birch Petersen, Jacky Boivin, Anders Nyboe Andersen, Lone Schmidt

    This study explored women’s lived experience of making fertility decisions six years after attending the Fertility Assessment and Counselling (FAC) clinic in Copenhagen, Denmark, which is a personalised fertility awareness intervention. We conducted a qualitative interview study with 24 women who attended the FAC clinic 6 years earlier. Interviews were semi-structured and broadly examined the women’s perceptions and experience of the intervention during follow-up. Data was analysed using a phenomenological framework and themes were identified related to women’s experience of making fertility decisions after attending the FAC clinic. The overarching theme regarding the women’s lived experience of making fertility decisions after attending the FAC clinic was: Fertility decisions were guided by the ‘family clock’. There were four themes: (i) Deciding to ‘get started’ by attending the FAC clinic; (ii) Sense of making informed and empowered decisions; (iii) Influence of partner status on fertility decisions; and (iv) Decisions dictated by circumstance over preference and knowledge. At follow-up, the majority (21 women, 88%) had become parents. More than half of the women said that they had not achieved their desired family size. Consideration of women’s ‘family clock’ is necessary in personalised fertility awareness interventions to enable women to achieve their family goals.


  • Open Access

    Immediate versus postponed frozen embryo transfer after IVF/ICSI: a systematic review and meta-analysis

    by Sara J Bergenheim, Marte Saupstad, Nina Pistoljevic, Anders Nyboe Andersen, Julie Lyng Forman, Kristine Løssl, Anja Pinborg

    BACKGROUND: In Europe, the number of frozen embryo transfer (FET) cycles is steadily increasing, now accounting for more than 190 000 cycles per year. It is standard clinical practice to postpone FET for at least one menstrual cycle following a failed fresh transfer or after a freeze-all cycle. The purpose of this practice is to minimise the possible residual negative effect of ovarian stimulation on the resumption of a normal ovulatory cycle and receptivity of the endometrium. Although elective deferral of FET may unnecessarily delay time to pregnancy, immediate FET may be inefficient in a clinical setting, following an increased risk of irregular ovulatory cycles and the presence of functional cysts, increasing the risk of cycle cancellation. OBJECTIVE AND RATIONALE: This review explores the impact of timing of FET in the first cycle (immediate FET) versus the second or subsequent cycle (postponed FET) following a failed fresh transfer or a freeze-all cycle on live birth rate (LBR). Secondary endpoints were implantation, pregnancy and clinical pregnancy rates (CPR) as well as miscarriage rate (MR). SEARCH METHODS: We searched PubMed (MEDLINE) and EMBASE databases for MeSH and Emtree terms, as well as text words related to timing of FET, up to March 2020, in English language. There were no limitations regarding year of publication or duration of follow-up. Inclusion criteria were subfertile women aged 18-46 years with any indication for treatment with IVF/ICSI. Studies on oocyte donation were excluded. All original studies were included, except for case reports, study protocols and abstracts only. Covidence, a Cochrane-tool, was used for sorting and screening of literature. Risk of bias was assessed using the Robins-I tool and the quality of evidence using the Grading of Recommendations, Assessment, Development and Evaluation framework. OUTCOMES: Out of 4124 search results, 15 studies were included in the review. Studies reporting adjusted odds ratios (aOR) for LBR, CPR and MR were included in meta-analyses. All studies (n = 15) were retrospective cohort studies involving a total of 6,304 immediate FET cycles and 13,851 postponed FET cycles including 8,019 matched controls. Twelve studies of very low to moderate quality reported no difference in LBR with immediate versus postponed FET. Two studies of moderate quality reported a statistically significant increase in LBR with immediate FET and one small study of very low quality reported better LBR with postponed FET. Trends in rates of secondary outcomes followed trends in LBR regarding timing of FET. The meta-analyses showed a significant advantage of immediate FET (n =2,076) compared to postponed FET (n =3,833), with a pooled aOR of 1.20 (95% CI 1.01–1.44) for LBR and a pooled aOR of 1.22 (95% CI 1.07–1.39) for CPR. WIDER IMPLICATIONS: The results of this review indicate a slightly higher LBR and CPR in immediate versus postponed FET. Thus, the standard clinical practice of postponing FET for at least one menstrual cycle following a failed fresh transfer or a freeze-all cycle may not be best clinical practice. However, as only retrospective cohort studies were assessed, the presence of selection bias is apparent, and the quality of evidence thus seems low. Randomised controlled trials including data on cancellation rates and reasons for cancellation are highly needed to provide high-grade evidence regarding clinical practice and patient counselling.


  • Serum ferritin level is inversely related to number of previous pregnancy losses in women with recurrent pregnancy loss

    by Maja Georgsen, Maria Christine Krog, Anne-Sofie Korsholm, Helene Westring Hvidman, Astrid Marie Kolte, Andreas Stribolt Rigas, Henrik Ullum, Søren Ziebe, Anders Nyboe Andersen, Henriette Svarre Nielsen, et al.


  • Hippo signaling, actin polymerization, and follicle activation in fragmented human ovarian cortex

    by Stine A. Lunding, Anders N. Andersen, Lilja Hardardottir, Hanna Ø. Olesen, Stine G. Kristensen, Claus Y. Andersen, Susanne E. Pors

    The Hippo pathway has been associated with regulation of early follicle growth. Studies of murine ovaries suggest that changes in the actin cytoskeleton, caused by fragmentation, result in inhibition of the Hippo pathway, and in turn, may activate follicle growth. In humans, the connections between fragmentation, the actin cytoskeleton, and follicle activation are yet to be confirmed. In this study, we investigated the impact in vitro fragmentation of a human ovarian cortex on (a) actin polymerization, (b) components of the Hippo pathway, and (c) follicle growth in vivo. The results showed that the ratio between globular and filamentous actin remained unchanged at all timepoints (0, 10, 30, 60, 120, and 240 min) following tissue fragmentation. Neither was the Hippo pathway effector protein YES‐associated protein upregulated nor was gene expression of the downstream growth factors CCN2, CCN3, or CCN5 increased at any timepoint in the fragmented cortex. Furthermore, the number of growing follicles was similar in fragmented and intact cortex pieces after 6 weeks' xenotransplantation. However, the total number of surviving follicles was considerably lower in the fragmented cortex compared with intact tissue, suggesting detrimental effects of fragmentation on tissue grafting. These results indicate that fragmentation is likely to be ineffective to activate follicle growth in the human ovarian cortex.


  • Open Access

    Early pregnancy reference intervals; 29 serum analytes from 4 to 12 weeks’ gestation in naturally conceived and uncomplicated pregnancies resulting in live births

    by Jesper Friis Petersen, Lennart J. Friis-Hansen, Andreas Kryger Jensen, Anders Nyboe Andersen, Ellen C.L. Løkkegaard

    Background: Pregnancy introduces major physiological changes that also alter biochemical analytes. Maternal and perinatal health can be optimized by early intervention and therefore, pregnancy-specific reference intervals (RIs) for the local population are warranted. While the second and third trimester-specific changes are well described, the first trimester is less well characterized. We therefore wanted to facilitate early detection of abnormalities by generating first trimester reference values for 29 common analytes. Methods: In a prospective early pregnancy (PEP) cohort (2016–2017), 203 pregnant women were recruited from 4 to 8 weeks’ gestation. Consecutive blood samples were drawn every 2 weeks until an ongoing second trimester pregnancy (n = 164) or a miscarriage (n = 39) occurred. After exclusion of women with complicated pregnancies or deliveries (n = 42), 122 women were included. The serum samples collected at 12 weeks’ gestation were analyzed for 29 common analytes. Subsequently the RIs were calculated according to the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) recommendations (2.5–97.5th percentiles) and compared with the conventional RIs for non-pregnant women. Results: Human chorionic gonadotropin (hCG), progesterone (P4), estradiol (E2), pregnancy-associated plasma protein A (PAPP-A), cancer antigen 125 (CA125), thyroid stimulating hormone (TSH), creatinine (CREA) and albumin (ALB) showed an early pregnancy-dependent change compared with conventional limits. For ALB the change was seen at 5.5 weeks’ gestation. Conclusions: We report gestational age-specific RIs available from the early part of the first trimester applicable to everyday clinical care of pregnant women. Well-known alterations of RIs seen in later trimesters are also observed in the first.


  • Investigation of anti-Müllerian hormone concentrations in relation to natural conception rate and time to pregnancy

    by Anne-Sofie Korsholm, Kathrine Birch Petersen, Janne Gasseholm Bentzen, Linda Maria Hilsted, Anders Nyboe Andersen, Helene Westring Hvidman


  • Open Access

    Selection of high quality spermatozoa may be promoted by activated vitamin D in the woman

    by Lasse Bøllehuus Hansen, Anders Rehfeld, Rosanna de Neergaard, John Erik Nielsen, Lea Hedegaard Iversen, Ida Marie Boisen, Li Juel Mortensen, Beate Lanske, Kristian Almstrup, Elisabeth Carlsen, et al.

    The vitamin D receptor (VDR) and enzymes involved in activation (CYP2R1, CYP27B1) and inactivation (CYP24A1) of vitamin D are expressed in ovary, testes, and spermatozoa. Determine responsiveness to 1,25-dihydroxyvitamin D (1,25(OH)2D3) in spermatozoa from normal and infertile men, identify site of exposure and how 1,25(OH)2D3 influences sperm function. Spermatozoa expressing VDR, CYP2R1, CYP27B1, and CYP24A1 were analyzed in normal and infertile men. 25-hydroxyvitamin D (25-OHD), 24,25-dihydroxyvitamin D (24,25(OH)2D3), and 1,25(OH)2D3 were measured in serum, seminal fluid, cervical secretions and ovarian follicular fluid. 1,25(OH)2D3 was tested on human spermatozoa. Tertiary centre for fertility. Protein expression in spermatozoa and semen quality were assessed in 230 infertile and 114 healthy men. Vitamin D metabolites were measured in fluids from 245 men and 13 women, while 74 oocytes and 17 semen donors were used for sperm-function tests. VDR and CYP24A1 expressions in spermatozoa, fluid concentrations of 25-OHD, 24,25(OH)2D3 and 1,25(OH)2D3, and 1,25(OH)2D3–induced effects on intracellular calcium concentration ([Ca2+]i) and sperm-oocyte binding in vitro. VDR and CYP24A1 were expressed in >2 fold higher fraction of spermatozoa from normal than infertile men (p2D, and 1,25(OH)2D3 were undetectable in seminal fluid but high in ovarian follicular fluid. Follicular concentrations of 1,25(OH)2D3 induced a modest increase in [Ca2+]i and sperm-oocyte binding in vitro (p2D3 available in the female reproductive tract may promote selection of the best gametes for fertilization.