| 1. |
- Magnus, M. C., et al.
(author)
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Maternal Risk of Cardiovascular Disease After Use of Assisted Reproductive Technologies
- 2023
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In: Jama Cardiology. - 2380-6583. ; 8:109, s. 837-845
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Journal article (peer-reviewed)abstract
- IMPORTANCE Studies examining the associations of different combinations of intensity-specific aerobic and muscle strengthening activity (MSA) with all-cause and cause-specific mortality are scarce; the few available estimates are disparate.OBJECTIVE To examine the prospective associations of different combinations of moderate aerobic physical activity (MPA), vigorous aerobic physical activity (VPA), and MSA with all-cause, cardiovascular (CVD), and cancer mortality.DESIGN, SETTING, AND PARTICIPANTS This nationwide prospective cohort study used data from the US National Health Interview Survey. A total of 500705 eligible US adults were included in the study and followed up during a median of 10.0 years (5.6 million person-years) from 1997 to 2018. Data were analyzed from September 1 to September 30, 2022. EXPOSURES Self-reported cumulative bouts (75 weekly minutes) of MPA and VPA with recommended MSA guidelines (yes or no) to obtain 48 mutually exclusive exposure categories.MAIN OUTCOMES AND MEASURES All-cause, CVD, and cancer mortality. Participants were linked to the National Death Index through December 31, 2019.RESULTS Overall, 500 705 participants (mean [SD] age, 46.4 [17.3] years; 210 803 [58%] female; 277 504 [77%] White) were included in the study. Compared with the reference group (doing no MPA or VPA and less than recommended MSA), the category associated with the lowest hazard ratio (HR) for all-cause mortality was more than 0 to 75 minutes of MPA combined with more than 150 minutes of VPA and 2 or more MSA sessions per week (HR, 0.50; 95% CI, 0.42-0.59). The optimal combinations for CVD and cancer mortality risk reduction were more than 150 to 225 minutes of MPA, more than 0 to 75 minutes of VPA, and 2 or more MSA sessions per week (HR, 0.30; 95% CI, 0.15-0.57), and more than 300 minutes of MPA, more than 0 to 75 minutes of VPA, and 2 or more MSA sessions per week (HR, 0.44; 95% CI, 0.23-0.82), respectively. Adjusted mortality rates represented an approximately 50% lower mortality rate for all-cause and cancer mortality and an approximately 3-fold lower mortality rate for CVD mortality. CONCLUSIONS AND RELEVANCE This cohort study demonstrated that balanced levels of MPA, VPA, and MSA combined may be associated with optimal reductions of mortality risk. Higher-than-recommended levels of MPA and VPA may further lower the risk of cancer and all-cause mortality, respectively.
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| 2. |
- Terho, A M, et al.
(author)
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High birth weight and large-for-gestational-age in singletons born after frozen compared to fresh embryo transfer, by gestational week: a Nordic register study from the CoNARTaS group.
- 2021
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In: Human reproduction (Oxford, England). - : Oxford University Press (OUP). - 1460-2350 .- 0268-1161. ; 36:4, s. 1083-1092
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Journal article (peer-reviewed)abstract
- When do the differences in birth weights become apparent between singletons born after frozen embryo transfer (FET) and fresh embryo transfer (fresh ET)?Mean birth weights after FET become significantly higher starting from gestational week (GW) 33 among boys and from GW 34 among girls.In recent years, there has been a steep rise in recorded FET treatments, enabling widespread use of elective single embryo transfer, thus reducing the risks associated with multiple gestations. However, singletons born after FET are heavier and there is a higher risk of large-for-gestational-age (LGA) (birth weight > 90 percentiles) compared to fresh ET. In contrast, risk of small-for-gestational-age (SGA, birth weight < 10 percentiles) is lower in singletons born after FET compared to fresh ET. The reasons, timing and consequences of these differences remain largely unclear. There is limited evidence about whether this difference in growth develops before the last trimester of pregnancy.This retrospective Nordic register-based cohort study compared singletons born after FET (n=17500) to singletons born after fresh ET (n=69510) and natural conception (NC, n=3311588). All live born singletons born between the years 2000 and 2015 in Denmark, Norway and Sweden at gestational age ≥22weeks were included from the population-based Committee of Nordic ART and Safety (CoNARTaS) study population.Children born after FET were compared to those born after fresh ET and NC for mean birth weight and proportion of LGA and SGA for each GW at birth. Chi-square test and tests for relative proportions were used to compare categorical variables and Student's t-test was used to compare continuous variables. Adjusted odds ratios (aORs) for LGA and SGA were calculated using logistic regressions, adjusting for year of birth, maternal age, parity, BMI, chronic hypertension, diabetes, smoking and offspring sex.Mean birth weights were significantly higher after FET compared to fresh ET starting from GW 33 (range from 75g to 228g by week) for boys and starting from GW 34 (range from 90g to 236g by week) for girls. Boys born after FET had a significantly higher proportion of LGA (11.0-15.1%) at birth between GW 36 and 42, compared to those born after fresh ET (7.1-9.4%) (range from P<0.001 to P=0.048 by week). For girls born after FET, the difference was seen between GW 37 and 42 (10.6-13.4%) compared to those born after fresh ET (6.6-8.0%) (range from P<0.001 to P=0.009 by week).The proportion of SGA was significantly lower among boys born after FET (7.6-8.7%) compared to fresh ET (11.9-13.6%) between GW 36 and 42 (range from P<0.001 to P=0.016 by week). For girls born after FET, the difference was seen between GW 38 and 42 (7.0-9.3%) compared to those born after fresh ET (13.0-14.6%) (P<0.001). The proportion of LGA (12.3-15.1%) was significantly higher for boys born after FET between GW 38 and 41 (P<0.001) and for girls born after FET (12.6-13.4%) between GW 37 and 40 (range from P<0.001 to P=0.018 by week), compared to naturally conceived boys (9.7-9.9%) and girls (9.0-10.0%). All singletons born after FET had a higher risk of LGA compared to singletons born after fresh ET (aOR 1.87, 95% CI 1.76-1.98) and singletons born after NC (aOR 1.28, 95% CI 1.22-1.35).There may be residual confounding factors that we were not able to control for, most importantly the causes of preterm birth, which may also influence foetal growth. A further limitation is that we have no knowledge on growth patterns between implantation and GW 22. Finally, the number of children born extremely preterm or post-term was limited even in this large study population.This is, to date, the largest study on birth weights among preterm and term ART singletons with a population-based design and NC control group. The results suggest that the freeze-thaw process is associated with higher birthweights and greater risk of LGA at least in the last trimester of pregnancy. This is an important aspect of the safety profile of ART. More research is needed on the long-term outcome of these children.The CoNARTaS collaboration has received the following funding: the Nordic Trial Alliance: a pilot project jointly funded by the Nordic Council of Ministers and NordForsk [71450], the Central Norway Regional Health Authorities [46045000], the Norwegian Cancer Society [182356-2016], the Nordic Federation of Obstetrics and Gynaecology [NF13041, NF15058, NF16026 and NF17043], the Interreg Öresund-Kattegat-Skagerrak European Regional Development Fund (ReproUnion project) and the Research Council of Norway's Centre of Excellence funding scheme [262700]. None of the authors have any competing interests to declare.ISRCTN11780826.
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| 3. |
- Henningsen, A. A., et al.
(author)
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Imprinting disorders in children born after ART: a Nordic study from the CoNARTaS group
- 2020
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In: Human Reproduction. - : Oxford University Press (OUP). - 0268-1161 .- 1460-2350. ; 35:5, s. 1178-1184
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Journal article (peer-reviewed)abstract
- STUDY QUESTION: Is the risk of imprinting disorders increased in children conceived after ART? SUMMARY ANSWER: We found an adjusted odds ratio (AOR) of 2.84 [95% CI: 1.34-6.01] for Beckwith-Wiedemann syndrome in ART children, while the risk of Prader-Willi syndrome, Silver-Russell syndrome or Angelman syndrome was not increased in children conceived after ART. WHAT IS KNOWN ALREADY: Earlier studies, most of them small, have suggested an association between ART and imprinting disorders. STUDY DESIGN, SIZE, DURATION: This was a binational register-based cohort study. All children conceived by ART in Denmark (n = 45 393, born between 1994 and 2014) and in Finland (n = 29 244, born between 1990 and 2014) were identified. The full background populations born during the same time periods in the two countries were included as controls. Odds ratios of imprinting disorders in ART children compared with naturally conceived (NC) children were calculated. The median follow-up time was 8 years and 9 months for ART children and 11 years and 9 months for NC children. PARTICIPANTS/MATERIALS, SETTING, METHODS: From the national health registries in Denmark and Finland, we identified all children diagnosed with Prader-Willi syndrome (n = 143), Silver-Russell syndrome (n = 69), Beckwith-Wiedemann syndrome (n = 105) and Angelman syndrome (n = 72) born between 1994/1990 and 2014, respectively. MAIN RESULTS AND THE ROLE OF CHANCE: We identified a total of 388 children diagnosed with imprinting disorders; 16 of these were conceived after ART. The overall AOR for the four imprinting disorders in ART children compared with NC children was 1.35 [95% CI: 0.80-2.29], but since eight ART children were diagnosed with Beckwith-Wiedemann syndrome, the AOR for this specific imprinting disorder was 2.84 [95% CI: 1.34-6.01]. The absolute risk of Beckwith-Wiedemann syndrome in children conceived after ART was still low: 10.7 out of 100 000 newborns. The risks of Prader-Willi syndrome, Silver-Russell syndrome and Angelman syndrome were not increased in children conceived after ART. LIMITATIONS, REASONS FOR CAUTION: Imprinting disorders are rare events and our results are based on few ART children with imprinting disorders. The aetiology is complex and only partly clarified, and the clinical diagnoses are challenged by a broad phenotypic spectrum. WIDER IMPLICATIONS OF THE FINDINGS: In the existing studies, results on the risk of imprinting disorders in children conceived after ART are ambiguous. This study adds that the risk of imprinting disorders in ART children is very small and perhaps restricted to Beckwith-Wiedemann syndrome.
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| 4. |
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| 5. |
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| 6. |
- Henningsen, A. K. A., et al.
(author)
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Risk of congenital malformations in live-born singletons conceived after intracytoplasmic sperm injection: a Nordic study from the CoNARTaS group
- 2023
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In: Fertility and Sterility. - 0015-0282 .- 1556-5653. ; 120:5, s. 1033-1041
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Journal article (peer-reviewed)abstract
- Objective: To investigate whether the risk of major congenital malformations is higher in live-born singletons conceived with intracytoplasmic sperm injection (ICSI) compared with in vitro fertilization (IVF)?Design: Nordic register-based cohort study.Setting: Cross-linked data from Medical Birth Registers and National ART and Patient Registers in Denmark, Norway and Sweden. Data were included from the year the first child conceived using ICSI was born: Sweden, 1992; Denmark, 1994; and Norway, 1996. Data were included until 2014 for Denmark and 2015 for Norway and Sweden. Patient(s): All live-born singletons conceived using fresh ICSI (n = 32,484); fresh IVF (n = 47,178); without medical assistance (n = 4,804,844); and cryo-ICSI (n = 7,200) during the study period. Intervention(s): Different in vitro conception methods, and cryopreservation of embryos.Main Outcome Measure(s): Risk of major congenital malformations on the basis of International Classification of Diseases codes. The European Concerted Action on Congenital Anomalies and Twins was used to differentiate between major and minor malformations. Result(s): Among singletons conceived using fresh ICSI, 6.0% had a major malformation, compared with 5.3% of children conceived using fresh IVF; 4.2% of children conceived without medical assistance; and 4.9% of children conceived using cryoICSI; adjusted odds ratio (AOR) 1.07 (95% confidence interval [CI] 1.01-1.14) in ICSI vs. IVF; and AOR 1.28 (95% CI, 1.23- 1.35) in ICSI vs. no medical assistance; and AOR 1.11 (95% CI, 0.99-1.26) in ICSI fresh vs. cryo-ICSI. When malformations were grouped by different organ systems, children conceived using ICSI had a higher risk of respiratory and chromosomal malformations compared with children conceived using IVF, but there were very few cases in each group. When categorizing children conceived using ICSI according to treatment indication (male factor infertility only vs. other indications), we found a higher risk of hypospadias when ICSI was performed because of male factor infertility only (AOR 1.85 [95% CI 1.03-332]). The indications for ICSI changed over time, as male factor infertility did not remain the primary indication for ICSI throughout the study period.Conclusion(s): In this large cohort study, we found the risk of major malformations in live-born singletons to be slightly higher after fresh ICSI compared with fresh IVF. These findings should be considered when choosing the assisted reproductive technology method for couples without male factor infertility. (Fertil Sterile 2023;120:1033-41. (c) 2023 by American Society for Reproductive Medicine.) El resumen esta disponible en Espanol al final del articulo.
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| 7. |
- Henningsen, A. K. A., et al.
(author)
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Trends over time in congenital malformations in live-born children conceived after assisted reproductive technology
- 2018
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In: Acta Obstetricia Et Gynecologica Scandinavica. - : Wiley. - 0001-6349 .- 1600-0412. ; 97:7, s. 816-823
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Journal article (peer-reviewed)abstract
- Children born after assisted reproductive technology, particularly singletons, have been shown to have an increased risk of congenital malformations compared with children born after spontaneous conception. We wished to study whether there has been a change in the past 20 years in the risk of major congenital malformations in children conceived after assisted reproductive technology compared with children spontaneously conceived. Material and methodsPopulation-based cohort study including 90 201 assisted reproductive technology children and 482 552 children spontaneously conceived, born in Denmark, Finland, Norway and Sweden. Both singletons and twins born after in vitro fertilization, intracytoplasmatic sperm injection and frozen embryo transfer were included. Data on children were taken from when the national Nordic assisted reproductive technology registries were established until 2007. Multiple logistic regression analyses were used to estimate the risks and adjusted odds ratios for congenital malformations in four time periods: 1988-1992, 1993-1997, 1998-2002 and 2003-2007. Only major malformations were included. ResultsThe absolute risk for singletons of being born with a major malformation was 3.4% among assisted reproductive technology children vs. 2.9% among children spontaneously conceived during the study period. The relative risk of being born with a major congenital malformation between all assisted reproductive technology children and children spontaneously conceived remained similar through all four time periods (p = 0.39). However, we found that over time the number of children diagnosed with a major malformation increased in both groups across all four time periods. ConclusionWhen comparing children conceived after assisted reproductive technology and spontaneously conceived, the relative risk of being born with a major congenital malformation did not change during the study period.
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| 8. |
- Klemetti, R., et al.
(author)
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Puberty disorders among ART-conceived singletons: a Nordic register study from the CoNARTaS group
- 2022
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In: Human Reproduction. - : Oxford University Press (OUP). - 0268-1161 .- 1460-2350. ; 37:10, s. 2402-2411
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Journal article (peer-reviewed)abstract
- STUDY QUESTION Do ART-conceived children have an increased risk for puberty disorders? SUMMARY ANSWER Both ART-conceived boys and girls had a higher risk of puberty disorders; early puberty was more common among girls and late puberty among boys. WHAT IS KNOWN ALREADY Some physiological differences in growth and metabolism have been reported for ART-conceived children compared to non-ART-conceived children. Knowledge on pubertal development and disorders in ART-conceived children is limited. STUDY DESIGN, SIZE, DURATION A register-based cohort study was carried out including data from 1985 to 2015. The Committee of Nordic Assisted Reproductive Technology and Safety (CoNARTaS) study population consists of all live and stillborn children, as well as their mothers, registered in the Medical Birth Registers during the study period in Denmark, Sweden, Finland and Norway. PARTICIPANTS/MATERIALS, SETTING, METHODS A total of 122 321 ART-conceived singletons and 6 576 410 non-ART singletons born in Denmark (1994-2014), Finland (1990-2014), Norway (2002-2015) and Sweden (1985-2015) were included. Puberty disorders were defined using International Classification of Diseases and Related Health Problems (ICD)-9/ICD-10 codes and classified in the following groups: late puberty (6268/E30.0), early puberty (2591 and 2958/E30.1 and E30.8) and unspecified disorders (V212 and V579/E30.9 and Z00.3 as well as Z51.80 for Finland). The results in Cox regression were adjusted for maternal age, parity, smoking, gestational diabetes, chronic hypertension, hypertensive disorders during pregnancy and country, and further for either gestational age, birthweight, small for gestational age or large for gestational age. MAIN RESULTS AND THE ROLE OF CHANCE There were 37 869 children with diagnoses related to puberty disorders, and 603 of them were born after ART. ART-conceived children had higher risks for early (adjusted hazard ratio (aHR) 1.45, 95% CI: 1.29-1.64) and late puberty (aHR 1.47, 95% CI: 1.21-1.77). Girls had more diagnoses related to early puberty (aHR 1.46, 95% CI: 1.29-1.66) and boys with late puberty (aHR 1.55, 95% CI: 1.24-1.95). LIMITATIONS, REASONS FOR CAUTION Using reported puberty disorders with ICD codes in health care registers might vary, which may affect the numbers of cases found in the registers. Register data may give an underestimation both among ART and non-ART-conceived children, especially among non-ART children, who may not be as carefully followed as ART-conceived children. Adjustment for causes and duration of infertility, mothers' own puberty characteristics and BMI, as well as children's BMI, was not possible because data were not available or data were missing for the early years. It was also not possible to compare ART to non-ART siblings or to study the pubertal disorders by cause of subfertility owing to a small number of discordant sibling pairs and a large proportion of missing data on cause of subfertility. WIDER IMPLICATIONS OF THE FINDINGS This large, register-based study suggests that ART-conceived children have a higher risk for puberty disorders. However, the mechanisms of infertility and pubertal onset are complex, and ART is a rapidly advancing field with various treatment options. Studying the pubertal disorders of ART-conceived offspring is a continuing challenge. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the Nordic Trial Alliance: a pilot project jointly funded by the Nordic Council of Ministers and NordForsk (71450), the Central Norway Regional Health Authorities (46045000), the Nordic Federation of Obstetrics and Gynaecology (NF13041, NF15058, NF16026 and NF17043), the Interreg oresund-Kattegat-Skagerrak European Regional Development Fund (ReproUnion project), the Research Council of Norway's Centre of Excellence funding scheme (262700), the Swedish state under the agreement between the Swedish government and the county councils, the ALF-agreement (ALFGBG-70940) and FLUX Consortium 'Family Formation in Flux-Causes, Consequences and Possible Futures', funded by the Strategic Research Council, Academy of Finland (DEMOGRAPHY 345130). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. The authors have no conflicts of interest to disclose.
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| 9. |
- Opdahl, S., et al.
(author)
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Risk of hypertensive disorders in pregnancies following assisted reproductive technology: a cohort study from the CoNARTaS group
- 2015
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In: Human Reproduction. - : Oxford University Press (OUP). - 0268-1161 .- 1460-2350. ; 30:7, s. 1724-1731
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Journal article (peer-reviewed)abstract
- STUDY QUESTION: Is the risk of hypertensive disorders in pregnancies conceived following specific assisted reproductive technology (ART) procedures different from the risk in spontaneously conceived (SC) pregnancies? SUMMARY ANSWER: ART pregnancies had a higher risk of hypertensive disorders, in particular following cryopreservation, with the highest risk seen in twin pregnancies following frozen-thawed cycles. WHAT IS KNOWN ALREADY: The risk of hypertensive disorders is higher in ART pregnancies than in SC pregnancies. The increased risk maybe partly explained by multiple pregnancies and underlying infertility, but a contribution from specific ART procedures has not been excluded. STUDY DESIGN, SIZE, DURATION: Population-based cohort study, including sibling design with nationwide data from health registers in Sweden, Denmark and Norway. PARTICIPANTS/MATERIALS, SETTING, METHODS: All registered ART pregnancies and a sample of SC pregnancies with gestational age >= 22 weeks from 1988 to 2007 were included. ART singleton pregnancies (n = 47 088) were compared with SC singleton pregnancies (n = 268 599), matched on parity and birth year. ART twin pregnancies (n = 10 918) were compared with SC twin pregnancies (46 674). We used logistic regression to estimate adjusted odds ratios and risk differences for hypertensive disorders in pregnancies following IVF, ICSI and fresh or frozen-thawed cycles. We also compared freshand frozen-thawed cycles within mothers who had conceived following both procedures using conditional logistic regression (sibling analysis). MAIN RESULTS AND THE ROLE OF CHANCE: Hypertensive disorders were reported in 5.9% of ART singleton and 12.6% of ART twin pregnancies. Comparing singleton pregnancies, the risk of hypertensive disorders was higher after all ART procedures. The highest risk in singleton pregnancies was seen after frozen-thawed cycles [risk 7.0%, risk difference 1.8%, 95% confidence interval (CI) 1.2-2.8]. Comparing twin pregnancies, the risk was higher after frozen-thawed cycles (risk 19.6%, risk difference 5.1%, 95% CI 3.0-7.1), but not after fresh cycles. In siblings, the risk was higher after frozen-thawed cycles compared with fresh cycles within the same mother (odds ratio 2.63, 95% CI 1.73-3.99). There were no clear differences in risk for IVF and ICSI. LIMITATIONS, REASONS FOR CAUTION: The number of ART siblings in the study was limited. Residual confounding cannot be excluded. In addition, we did not have information on all SC pregnancies in each woman's history, and could therefore not compare risk in ART versus SC pregnancies in the same mother. WIDER IMPLICATIONS OF THE FINDINGS: Pregnancies following frozen-thawed cycles have a higher risk of hypertensive disorders, also when compared with fresh cycle pregnancies by the same mother. The safety aspects in frozen-thawed cycles merit further attention. STUDY FUNDING/COMPETING INTEREST(S): Funding was received from the European Society for Human Reproduction and Embryology, the University of Copenhagen, the Danish Agency for Science, Technology and Innovation, the Nordic Federation of Societies of Obstetrics and Gynecology and the Liaison Committee between the Central Norway Regional Health Authority and the Norwegian University of Science and Technology. None of the authors has any competing interests to declare.
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| 10. |
- Petersen, S. H., et al.
(author)
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Time trends in placenta-mediated pregnancy complications after assisted reproductive technology in the Nordic countries
- 2020
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In: American Journal of Obstetrics and Gynecology. - : Elsevier BV. - 0002-9378 .- 1097-6868. ; 223:2
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Journal article (peer-reviewed)abstract
- Background: The use of assisted reproductive technology is increasing worldwide and conception after assisted reproduction currently comprises 3%–6% of birth cohorts in the Nordic countries. The risk of placenta-mediated pregnancy complications is greater after assisted reproductive technology compared with spontaneously conceived pregnancies. Whether the excess risk of placenta-mediated pregnancy complications in pregnancies following assisted reproduction has changed over time, is unknown. Objectives: To investigate whether time trends in risk of pregnancy complications (hypertensive disorders in pregnancy, placental abruption and placenta previa) differ for pregnancies after assisted reproductive technology compared with spontaneously conceived pregnancies during 3 decades of assisted reproduction treatment in the Nordic countries. Study Design: In a population-based cohort study, with data from national health registries in Denmark (1994–2014), Finland (1990–2014), Norway (1988–2015) and Sweden (1988–2015), we included 6,830,578 pregnancies resulting in delivery. Among these, 146,998 (2.2%) were pregnancies after assisted reproduction (125,708 singleton pregnancies, 20,668 twin pregnancies and 622 of higher order plurality) and 6,683,132 (97.8%) pregnancies were conceived spontaneously (6,595,185 singleton pregnancies, 87,106 twin pregnancies and 1,289 of higher order plurality). We used logistic regression with post-estimation to estimate absolute risks and risk differences for each complication. We repeated analyses for singleton and twin pregnancies, separately. In subsamples with available information, we also adjusted for maternal body mass index, smoking during pregnancy, previous cesarean delivery, culture duration, and cryopreservation. Results: The risk of each placental complication was consistently greater in pregnancies following assisted reproductive technology compared with spontaneously conceived pregnancies across the study period, except for hypertensive disorders in twin pregnancies, where risks were similar. Risk of hypertensive disorders increased over time in twin pregnancies for both conception methods, but more strongly for pregnancies following assisted reproductive technology (risk difference, 1.73 percentage points per 5 years; 95% confidence interval, 1.35–2.11) than for spontaneously conceived twins (risk difference, 0.75 percentage points; 95% confidence interval, 0.61–0.89). No clear time trends were found for hypertensive disorders in singleton pregnancies. Risk of placental abruption decreased over time in all groups. Risk differences were –0.16 percentage points (95% confidence interval, –0.19 to –0.12) and –0.06 percentage points (95% confidence interval, –0.06 to –0.05) for pregnancies after assisted reproduction and spontaneously conceived pregnancies, respectively, for singletons and multiple pregnancies combined. Over time, the risk of placenta previa increased in pregnancies after assisted reproduction among both singletons (risk difference, 0.21 percentage points; 95% confidence interval, 0.14–0.27) and twins (risk difference, 0.30 percentage points; 95% confidence interval, 0.16–0.43), but remained stable in spontaneously conceived pregnancies. When adjusting for culture duration, the temporal increase in placenta previa became weaker in all groups of assisted reproductive technology pregnancies, whereas adjustment for cryopreservation moderately attenuated trends in assisted reproductive technology twin pregnancies. Conclusions: The risk of placenta-mediated pregnancy complications following assisted reproductive technology remains higher compared to spontaneously conceived pregnancies, despite declining rates of multiple pregnancies. For hypertensive disorders in pregnancy and placental abruption, pregnancies after assisted reproduction follow the same time trends as the background population, whereas for placenta previa, risk has increased over time in pregnancies after assisted reproductive technology. © 2020 Elsevier Inc.
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