{"id":"https://openalex.org/W2897451900","doi":"https://doi.org/10.1093/humrep/dey294","title":"Prevalence and risk factors of zygotic splitting after 937 848 single embryo transfer cycles","display_name":"Prevalence and risk factors of zygotic splitting after 937 848 single embryo transfer cycles","publication_year":2018,"publication_date":"2018-09-17","ids":{"openalex":"https://openalex.org/W2897451900","doi":"https://doi.org/10.1093/humrep/dey294","mag":"2897451900","pmid":"https://pubmed.ncbi.nlm.nih.gov/30299468"},"language":"en","primary_location":{"id":"doi:10.1093/humrep/dey294","doi":"https://doi.org/10.1093/humrep/dey294","is_oa":true,"landing_page_url":"https://doi.org/10.1093/humrep/dey294","pdf_url":"https://academic.oup.com/humrep/article-pdf/33/11/1984/26124052/dey294.pdf","source":{"id":"https://openalex.org/S127900037","display_name":"Human Reproduction","issn_l":"0268-1161","issn":["0268-1161","1460-2350"],"is_oa":false,"is_in_doaj":false,"is_core":true,"listed_in":["anvur-scientific","cwts-core","dongbi-a","doyens","jufo-3","ki-jl-2","medline","norway-2","poland-140","russia-white-list-1","vabb-shw"],"host_organization":"https://openalex.org/P4310311648","host_organization_name":"Oxford University Press","host_organization_lineage":["https://openalex.org/P4310311648","https://openalex.org/P4310311647"],"host_organization_lineage_names":["Oxford University Press","University of Oxford"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Human Reproduction","raw_type":"journal-article"},"volume":null,"type":"article","is_traditional":true,"indexed_in":["crossref","pubmed"],"open_access":{"is_oa":true,"oa_status":"bronze","oa_url":"https://academic.oup.com/humrep/article-pdf/33/11/1984/26124052/dey294.pdf","any_repository_has_fulltext":false},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5012865579","display_name":"Yuko Ikemoto","orcid":"https://orcid.org/0000-0001-9990-4912","observed_orcids":["https://orcid.org/0000-0001-9990-4912"]},"institutions":[{"id":"https://openalex.org/I34077901","display_name":"Juntendo University","ror":"https://ror.org/01692sz90","country_code":"JP","type":"education","lineage":["https://openalex.org/I34077901"]}],"countries":["JP"],"is_corresponding":false,"raw_author_name":"Y Ikemoto","raw_affiliation_strings":["Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan","institution_ids":["https://openalex.org/I34077901"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5057344007","display_name":"Keiji Kuroda","orcid":"https://orcid.org/0000-0003-2759-9159","observed_orcids":["https://orcid.org/0000-0003-2759-9159"]},"institutions":[{"id":"https://openalex.org/I34077901","display_name":"Juntendo University","ror":"https://ror.org/01692sz90","country_code":"JP","type":"education","lineage":["https://openalex.org/I34077901"]},{"id":"https://openalex.org/I4405254268","display_name":"Center for Reproductive Medicine and Implantation Research, Sugiyama Clinic","ror":"https://ror.org/01m316d02","country_code":"JP","type":"facility","lineage":["https://openalex.org/I4405254268"]}],"countries":["JP"],"is_corresponding":true,"raw_author_name":"K Kuroda","raw_affiliation_strings":["Center for Reproductive Medicine and Implantation Research, Sugiyama Clinic Shinjuku, Nishi-shinjuku 1-19-6, Shinjuku-ku, Tokyo, Japan","Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Center for Reproductive Medicine and Implantation Research, Sugiyama Clinic Shinjuku, Nishi-shinjuku 1-19-6, Shinjuku-ku, Tokyo, Japan","institution_ids":["https://openalex.org/I4405254268"]},{"raw_affiliation_string":"Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan","institution_ids":["https://openalex.org/I34077901"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5065390850","display_name":"Asako Ochiai","orcid":null,"observed_orcids":[]},"institutions":[{"id":"https://openalex.org/I34077901","display_name":"Juntendo University","ror":"https://ror.org/01692sz90","country_code":"JP","type":"education","lineage":["https://openalex.org/I34077901"]}],"countries":["JP"],"is_corresponding":false,"raw_author_name":"A Ochiai","raw_affiliation_strings":["Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan","institution_ids":["https://openalex.org/I34077901"]}]},{"author_position":"middle","author":{"id":null,"display_name":"S Yamashita","orcid":null,"observed_orcids":[]},"institutions":[{"id":"https://openalex.org/I188815454","display_name":"Oita University","ror":"https://ror.org/01nyv7k26","country_code":"JP","type":"education","lineage":["https://openalex.org/I188815454"]},{"id":"https://openalex.org/I34077901","display_name":"Juntendo University","ror":"https://ror.org/01692sz90","country_code":"JP","type":"education","lineage":["https://openalex.org/I34077901"]}],"countries":["JP"],"is_corresponding":false,"raw_author_name":"S Yamashita","raw_affiliation_strings":["Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan","Department of Obstetrics and Gynecology, Oita University, Faculty of Medicine, Idaigaoka 1-1, Hasama-machi, Yufu-shi, Oita, Japan"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan","institution_ids":["https://openalex.org/I34077901"]},{"raw_affiliation_string":"Department of Obstetrics and Gynecology, Oita University, Faculty of Medicine, Idaigaoka 1-1, Hasama-machi, Yufu-shi, Oita, Japan","institution_ids":["https://openalex.org/I188815454"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5069369074","display_name":"Shinichiro Ikuma","orcid":null,"observed_orcids":[]},"institutions":[{"id":"https://openalex.org/I34077901","display_name":"Juntendo University","ror":"https://ror.org/01692sz90","country_code":"JP","type":"education","lineage":["https://openalex.org/I34077901"]}],"countries":["JP"],"is_corresponding":false,"raw_author_name":"S Ikuma","raw_affiliation_strings":["Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan","institution_ids":["https://openalex.org/I34077901"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5070681101","display_name":"Shuko Nojiri","orcid":"https://orcid.org/0000-0003-0422-8152","observed_orcids":["https://orcid.org/0000-0003-0422-8152"]},"institutions":[{"id":"https://openalex.org/I34077901","display_name":"Juntendo University","ror":"https://ror.org/01692sz90","country_code":"JP","type":"education","lineage":["https://openalex.org/I34077901"]},{"id":"https://openalex.org/I4210145596","display_name":"Juntendo University Hospital","ror":"https://ror.org/04g0m2d49","country_code":"JP","type":"healthcare","lineage":["https://openalex.org/I4210145596"]},{"id":"https://openalex.org/I4405286289","display_name":"Medical Technology Innovation Center, Juntendo University","ror":"https://ror.org/01rar7g66","country_code":"JP","type":"facility","lineage":["https://openalex.org/I34077901","https://openalex.org/I4405286289"]}],"countries":["JP"],"is_corresponding":false,"raw_author_name":"S Nojiri","raw_affiliation_strings":["Clinical Research and Trial Center, Juntendo University Hospital, Hongo 2-1-1, Bunkyoku, Tokyo, Japan","Medical Technology Innovation Center, Juntendo University, Hongo 2-1-1, Bunkyoku, Tokyo, Japan"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Clinical Research and Trial Center, Juntendo University Hospital, Hongo 2-1-1, Bunkyoku, Tokyo, Japan","institution_ids":["https://openalex.org/I4210145596"]},{"raw_affiliation_string":"Medical Technology Innovation Center, Juntendo University, Hongo 2-1-1, Bunkyoku, Tokyo, Japan","institution_ids":["https://openalex.org/I34077901","https://openalex.org/I4405286289"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5022274340","display_name":"Atsuo Itakura","orcid":"https://orcid.org/0000-0002-4554-164X","observed_orcids":["https://orcid.org/0000-0002-4554-164X"]},"institutions":[{"id":"https://openalex.org/I34077901","display_name":"Juntendo University","ror":"https://ror.org/01692sz90","country_code":"JP","type":"education","lineage":["https://openalex.org/I34077901"]}],"countries":["JP"],"is_corresponding":false,"raw_author_name":"A Itakura","raw_affiliation_strings":["Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan","institution_ids":["https://openalex.org/I34077901"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5063827400","display_name":"Satoru Takeda","orcid":"https://orcid.org/0000-0001-9547-1435","observed_orcids":["https://orcid.org/0000-0001-9547-1435"]},"institutions":[{"id":"https://openalex.org/I34077901","display_name":"Juntendo University","ror":"https://ror.org/01692sz90","country_code":"JP","type":"education","lineage":["https://openalex.org/I34077901"]}],"countries":["JP"],"is_corresponding":false,"raw_author_name":"S Takeda","raw_affiliation_strings":["Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyoku, Tokyo, Japan","institution_ids":["https://openalex.org/I34077901"]}]}],"institutions":[],"countries_distinct_count":1,"institutions_distinct_count":5,"corresponding_author_ids":["https://openalex.org/A5057344007"],"corresponding_institution_ids":["https://openalex.org/I34077901","https://openalex.org/I4405254268"],"apc_list":{"value":4097,"currency":"EUR","value_usd":4630},"apc_paid":null,"fwci":8.9151,"has_fulltext":true,"cited_by_count":73,"citation_normalized_percentile":{"value":0.98446127,"is_in_top_1_percent":false,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":96,"max":99},"biblio":{"volume":"33","issue":"11","first_page":"1984","last_page":"1991"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T11732","display_name":"Assisted Reproductive Technology and Twin Pregnancy","score":1.0,"subfield":{"id":"https://openalex.org/subfields/2735","display_name":"Pediatrics, Perinatology and Child Health"},"field":{"id":"https://openalex.org/fields/27","display_name":"Medicine"},"domain":{"id":"https://openalex.org/domains/4","display_name":"Health Sciences"}},"topics":[{"id":"https://openalex.org/T11732","display_name":"Assisted Reproductive Technology and Twin Pregnancy","score":1.0,"subfield":{"id":"https://openalex.org/subfields/2735","display_name":"Pediatrics, Perinatology and Child Health"},"field":{"id":"https://openalex.org/fields/27","display_name":"Medicine"},"domain":{"id":"https://openalex.org/domains/4","display_name":"Health Sciences"}},{"id":"https://openalex.org/T11156","display_name":"Reproductive Health and Technologies","score":9.999999747378752e-05,"subfield":{"id":"https://openalex.org/subfields/2743","display_name":"Reproductive Medicine"},"field":{"id":"https://openalex.org/fields/27","display_name":"Medicine"},"domain":{"id":"https://openalex.org/domains/4","display_name":"Health Sciences"}},{"id":"https://openalex.org/T10364","display_name":"Reproductive Biology and Fertility","score":0.0,"subfield":{"id":"https://openalex.org/subfields/2743","display_name":"Reproductive Medicine"},"field":{"id":"https://openalex.org/fields/27","display_name":"Medicine"},"domain":{"id":"https://openalex.org/domains/4","display_name":"Health Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/monozygotic-twinning","display_name":"monozygotic twinning","score":0.9089999794960022},{"id":"https://openalex.org/keywords/single-embryo-transfer","display_name":"single embryo transfer","score":0.8679999709129333},{"id":"https://openalex.org/keywords/multiple-pregnancy","display_name":"multiple pregnancy","score":0.8429999947547913},{"id":"https://openalex.org/keywords/blastocyst-culture","display_name":"blastocyst culture","score":0.9850000143051147},{"id":"https://openalex.org/keywords/artificial-hatching","display_name":"artificial hatching","score":0.6549999713897705},{"id":"https://openalex.org/keywords/in-vitro-fertilization","display_name":"in vitro fertilization","score":0.6010000109672546},{"id":"https://openalex.org/keywords/risk-factors","display_name":"risk factors","score":0.5550000071525574},{"id":"https://openalex.org/keywords/prevalence","display_name":"prevalence","score":0.546999990940094},{"id":"https://openalex.org/keywords/dichorionic-twins","display_name":"dichorionic twins","score":0.7799999713897705},{"id":"https://openalex.org/keywords/clinical-pregnancy-rate","display_name":"clinical pregnancy rate","score":0.5680000185966492},{"id":"https://openalex.org/keywords/assisted-reproductive-technology","display_name":"assisted reproduction","score":0.3889999985694885}],"concepts":[{"id":"https://openalex.org/C2910802627","wikidata":"https://www.wikidata.org/wiki/Q237118","display_name":"Single Embryo Transfer","level":4,"score":0.8433231115341187},{"id":"https://openalex.org/C2779234561","wikidata":"https://www.wikidata.org/wiki/Q11995","display_name":"Pregnancy","level":2,"score":0.6668343544006348},{"id":"https://openalex.org/C117354338","wikidata":"https://www.wikidata.org/wiki/Q1165112","display_name":"Singleton","level":3,"score":0.6374890804290771},{"id":"https://openalex.org/C131872663","wikidata":"https://www.wikidata.org/wiki/Q5284418","display_name":"Obstetrics","level":1,"score":0.6344031095504761},{"id":"https://openalex.org/C160099875","wikidata":"https://www.wikidata.org/wiki/Q237118","display_name":"Embryo transfer","level":3,"score":0.6260685920715332},{"id":"https://openalex.org/C2910541586","wikidata":"https://www.wikidata.org/wiki/Q237118","display_name":"Blastocyst Transfer","level":5,"score":0.6224656105041504},{"id":"https://openalex.org/C2778279030","wikidata":"https://www.wikidata.org/wiki/Q1543380","display_name":"Live birth","level":3,"score":0.548708438873291},{"id":"https://openalex.org/C71924100","wikidata":"https://www.wikidata.org/wiki/Q11190","display_name":"Medicine","level":0,"score":0.547631561756134},{"id":"https://openalex.org/C2909855057","wikidata":"https://www.wikidata.org/wiki/Q159979","display_name":"Twin Pregnancy","level":4,"score":0.5237058401107788},{"id":"https://openalex.org/C2780340734","wikidata":"https://www.wikidata.org/wiki/Q7579057","display_name":"Spontaneous conception","level":4,"score":0.5173422694206238},{"id":"https://openalex.org/C29456083","wikidata":"https://www.wikidata.org/wiki/Q1221899","display_name":"Gynecology","level":1,"score":0.46759408712387085},{"id":"https://openalex.org/C2778376644","wikidata":"https://www.wikidata.org/wiki/Q2253111","display_name":"Gestational age","level":3,"score":0.44466015696525574},{"id":"https://openalex.org/C151956035","wikidata":"https://www.wikidata.org/wiki/Q1132755","display_name":"Logistic regression","level":2,"score":0.42875024676322937},{"id":"https://openalex.org/C2778177303","wikidata":"https://www.wikidata.org/wiki/Q227717","display_name":"Blastocyst","level":4,"score":0.35604292154312134},{"id":"https://openalex.org/C512716672","wikidata":"https://www.wikidata.org/wiki/Q200117","display_name":"In vitro fertilisation","level":3,"score":0.31068867444992065},{"id":"https://openalex.org/C196843134","wikidata":"https://www.wikidata.org/wiki/Q33196","display_name":"Embryo","level":2,"score":0.2813294529914856},{"id":"https://openalex.org/C46973012","wikidata":"https://www.wikidata.org/wiki/Q28627","display_name":"Gestation","level":3,"score":0.27386635541915894},{"id":"https://openalex.org/C86803240","wikidata":"https://www.wikidata.org/wiki/Q420","display_name":"Biology","level":0,"score":0.2584758400917053},{"id":"https://openalex.org/C54355233","wikidata":"https://www.wikidata.org/wiki/Q7162","display_name":"Genetics","level":1,"score":0.1237630546092987},{"id":"https://openalex.org/C126322002","wikidata":"https://www.wikidata.org/wiki/Q11180","display_name":"Internal medicine","level":1,"score":0.09074509143829346},{"id":"https://openalex.org/C87073359","wikidata":"https://www.wikidata.org/wiki/Q33196","display_name":"Embryogenesis","level":3,"score":0.06402587890625}],"mesh":[{"descriptor_ui":"D001723","descriptor_name":"Birth Rate","qualifier_ui":null,"qualifier_name":null,"is_major_topic":false},{"descriptor_ui":"D005260","descriptor_name":"Female","qualifier_ui":null,"qualifier_name":null,"is_major_topic":false},{"descriptor_ui":"D005307","descriptor_name":"Fertilization in Vitro","qualifier_ui":"Q000379","qualifier_name":"methods","is_major_topic":false},{"descriptor_ui":"D005307","descriptor_name":"Fertilization in Vitro","qualifier_ui":"Q000706","qualifier_name":"statistics & numerical data","is_major_topic":false},{"descriptor_ui":"D006801","descriptor_name":"Humans","qualifier_ui":null,"qualifier_name":null,"is_major_topic":false},{"descriptor_ui":"D007564","descriptor_name":"Japan","qualifier_ui":null,"qualifier_name":null,"is_major_topic":false},{"descriptor_ui":"D011247","descriptor_name":"Pregnancy","qualifier_ui":null,"qualifier_name":null,"is_major_topic":false},{"descriptor_ui":"D011272","descriptor_name":"Pregnancy, Multiple","qualifier_ui":"Q000706","qualifier_name":"statistics & numerical data","is_major_topic":true},{"descriptor_ui":"D012189","descriptor_name":"Retrospective Studies","qualifier_ui":null,"qualifier_name":null,"is_major_topic":false},{"descriptor_ui":"D012307","descriptor_name":"Risk Factors","qualifier_ui":null,"qualifier_name":null,"is_major_topic":false},{"descriptor_ui":"D014310","descriptor_name":"Triplets","qualifier_ui":"Q000706","qualifier_name":"statistics & numerical data","is_major_topic":false},{"descriptor_ui":"D014427","descriptor_name":"Twins","qualifier_ui":"Q000706","qualifier_name":"statistics & numerical data","is_major_topic":false},{"descriptor_ui":"D038522","descriptor_name":"Twinning, Monozygotic","qualifier_ui":"Q000502","qualifier_name":"physiology","is_major_topic":true},{"descriptor_ui":"D046149","descriptor_name":"Embryo Culture Techniques","qualifier_ui":"Q000379","qualifier_name":"methods","is_major_topic":false},{"descriptor_ui":"D056826","descriptor_name":"Single Embryo Transfer","qualifier_ui":"Q000379","qualifier_name":"methods","is_major_topic":true}],"locations_count":2,"locations":[{"id":"doi:10.1093/humrep/dey294","doi":"https://doi.org/10.1093/humrep/dey294","is_oa":true,"landing_page_url":"https://doi.org/10.1093/humrep/dey294","pdf_url":"https://academic.oup.com/humrep/article-pdf/33/11/1984/26124052/dey294.pdf","source":{"id":"https://openalex.org/S127900037","display_name":"Human Reproduction","issn_l":"0268-1161","issn":["0268-1161","1460-2350"],"is_oa":false,"is_in_doaj":false,"is_core":true,"listed_in":["anvur-scientific","cwts-core","dongbi-a","doyens","jufo-3","ki-jl-2","medline","norway-2","poland-140","russia-white-list-1","vabb-shw"],"host_organization":"https://openalex.org/P4310311648","host_organization_name":"Oxford University Press","host_organization_lineage":["https://openalex.org/P4310311648","https://openalex.org/P4310311647"],"host_organization_lineage_names":["Oxford University Press","University of Oxford"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Human Reproduction","raw_type":"journal-article"},{"id":"pmid:30299468","doi":null,"is_oa":false,"landing_page_url":"https://pubmed.ncbi.nlm.nih.gov/30299468","pdf_url":null,"source":{"id":"https://openalex.org/S4306525036","display_name":"PubMed","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"listed_in":[],"host_organization":"https://openalex.org/I1299303238","host_organization_name":"National Institutes of Health","host_organization_lineage":["https://openalex.org/I1299303238"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Human reproduction (Oxford, England)","raw_type":"Journal Article"}],"best_oa_location":{"id":"doi:10.1093/humrep/dey294","doi":"https://doi.org/10.1093/humrep/dey294","is_oa":true,"landing_page_url":"https://doi.org/10.1093/humrep/dey294","pdf_url":"https://academic.oup.com/humrep/article-pdf/33/11/1984/26124052/dey294.pdf","source":{"id":"https://openalex.org/S127900037","display_name":"Human Reproduction","issn_l":"0268-1161","issn":["0268-1161","1460-2350"],"is_oa":false,"is_in_doaj":false,"is_core":true,"listed_in":["anvur-scientific","cwts-core","dongbi-a","doyens","jufo-3","ki-jl-2","medline","norway-2","poland-140","russia-white-list-1","vabb-shw"],"host_organization":"https://openalex.org/P4310311648","host_organization_name":"Oxford University Press","host_organization_lineage":["https://openalex.org/P4310311648","https://openalex.org/P4310311647"],"host_organization_lineage_names":["Oxford University Press","University of Oxford"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Human Reproduction","raw_type":"journal-article"},"sustainable_development_goals":[{"display_name":"Good health and well-being","id":"https://metadata.un.org/sdg/3","score":0.9074000120162964}],"study_designs":[{"display_name":"Observational Study","id":"https://openalex.org/study-designs/observational-study"}],"awards":[],"funders":[],"has_content":{"pdf":true,"grobid_xml":true},"content_urls":{"pdf":"https://content.openalex.org/works/W2897451900.pdf","grobid_xml":"https://content.openalex.org/works/W2897451900.grobid-xml"},"referenced_works_count":39,"referenced_works":["https://openalex.org/W82707134","https://openalex.org/W1973515926","https://openalex.org/W1978403497","https://openalex.org/W2002365613","https://openalex.org/W2006010730","https://openalex.org/W2007590519","https://openalex.org/W2024790307","https://openalex.org/W2036890789","https://openalex.org/W2039875109","https://openalex.org/W2046377650","https://openalex.org/W2050119729","https://openalex.org/W2057682723","https://openalex.org/W2061172194","https://openalex.org/W2074423169","https://openalex.org/W2087480238","https://openalex.org/W2088267656","https://openalex.org/W2095179331","https://openalex.org/W2117338972","https://openalex.org/W2118739591","https://openalex.org/W2129365860","https://openalex.org/W2135195512","https://openalex.org/W2137250627","https://openalex.org/W2138293307","https://openalex.org/W2139241449","https://openalex.org/W2151460311","https://openalex.org/W2165788605","https://openalex.org/W2169301639","https://openalex.org/W2187026089","https://openalex.org/W2246445986","https://openalex.org/W2305623357","https://openalex.org/W2339863821","https://openalex.org/W2406896982","https://openalex.org/W2410021341","https://openalex.org/W2418229802","https://openalex.org/W2606313022","https://openalex.org/W2781653264","https://openalex.org/W2791695566","https://openalex.org/W4230249059","https://openalex.org/W4244691543"],"related_works":["https://openalex.org/W2969504299","https://openalex.org/W4319334152","https://openalex.org/W3093467793","https://openalex.org/W2943997557","https://openalex.org/W1979445259","https://openalex.org/W4390909400","https://openalex.org/W2996609703","https://openalex.org/W7167698283","https://openalex.org/W2891520755","https://openalex.org/W4307396991"],"abstract_inverted_index":{"STUDY":[0,112,419],"QUESTION:":[1],"What":[2],"is":[3,380,390],"the":[4,37,46,58,133,144,150,165,175,180,252,307,352,405,409,428],"prevalence":[5,20,166,253,308],"of":[6,21,40,48,149,167,177,182,235,241,247,254,310,383,411],"multiple":[7,22,52,255],"pregnancy":[8,23,60,202,256,313],"with":[9,24,100,257,275,326,415],"zygotic":[10,25,168,192,258,270,311,412],"splitting":[11,26,259,271,312,413],"after":[12,27,203,250,314,323],"single":[13,315],"embryo":[14,107,417],"transfer":[15,66,317],"(SET)?":[16],"SUMMARY":[17],"ANSWER:":[18],"The":[19,139,430],"SET":[28,49,63,126,224,324],"was":[29,120,141,198,210,260,318,345],"1.36%.":[30,261],"WHAT":[31],"IS":[32],"KNOWN":[33],"ALREADY:":[34],"In":[35,303,351],"2008,":[36],"Japan":[38],"Society":[39],"Obstetrics":[41],"and":[42,67,74,80,108,137,146,152,222,237,342,369],"Gynaecology":[43],"(JSOG)":[44],"recommended":[45],"adoption":[47],"to":[50,56,186,190,267,401,436],"reduce":[51],"births.":[53],"Since":[54],"then,":[55],"improve":[57],"clinical":[59,228],"rate,":[61],"elective":[62],"using":[64,200],"blastocyst":[65,287,316],"frozen-warmed":[68,223,276,360],"ET":[69,277,305,361],"has":[70],"increased.":[71],"Blastocyst":[72],"culture":[73,288],"zona":[75],"pellucida":[76],"manipulation,":[77],"including":[78,231],"ICSI":[79],"AH,":[81],"have":[82,97,432],"been":[83],"widely":[84],"reported":[85],"as":[86,205],"risk":[87,410],"factors":[88,163],"for":[89,373,427],"monozygotic":[90],"twinning.":[91],"However,":[92,335],"all":[93],"these":[94],"studies":[95],"may":[96],"included":[98],"cases":[99],"dizygotic":[101],"pregnancies":[102,229,269,272],"produced":[103,225],"by":[104,143,388],"a":[105,109],"transferred":[106],"spontaneous":[110],"conception.":[111],"DESIGN,":[113],"SIZE,":[114],"DURATION:":[115],"A":[116],"retrospective":[117],"observational":[118],"study":[119,140],"performed,":[121],"based":[122],"on":[123,244],"937":[124],"848":[125],"cycles":[127,278,325],"in":[128,173,339,377,408],"registered":[129],"ART":[130,355],"data":[131,358,386],"from":[132],"JSOG":[134,151],"between":[135],"2007":[136],"2014.":[138],"approved":[142],"Registration":[145,372],"Research":[147],"Subcommittee":[148],"Juntendo":[153],"University":[154],"Ethics":[155],"Committee.":[156],"PARTICIPANTS/MATERIALS,":[157],"SETTING,":[158],"METHODS:":[159],"To":[160],"identify":[161],"possible":[162],"affecting":[164],"splitting,":[169],"we":[170],"identified":[171],"pregnancies,":[172],"which":[174],"number":[176,181],"foetuses":[178],"exceeded":[179],"gestational":[183],"sacs":[184],"(GSs),":[185],"restrict":[187],"our":[188],"analysis":[189,197,246,263],"'true'":[191],"splitting.":[193],"Multiple":[194],"logistic":[195],"regression":[196],"performed":[199],"singleton":[201,268],"SET,":[204,251],"control.":[206],"P":[207],"<":[208],"0.05":[209],"considered":[211],"statistically":[212],"significant.":[213],"MAIN":[214],"RESULTS":[215],"AND":[216],"THE":[217,395],"ROLE":[218],"OF":[219,394],"CHANCE:":[220],"Fresh":[221],"276":[226],"934":[227],"(29.5%/SET),":[230],"4310":[232],"twins":[233,249],"(1.56%":[234],"pregnancies)":[236],"109":[238],"triplets":[239],"(0.04%":[240],"pregnancies).":[242],"Based":[243],"sex":[245],"dichorionic":[248],"Statistical":[262],"revealed":[264],"that":[265,322],"compared":[266],"were":[273,425],"associated":[274,414],"(odds":[279],"ratio":[280],"[OR]":[281],"=":[282,290,298,330],"1.34;":[283],"95%":[284,292,300,332],"CI:":[285,293,301,333],"1.16-1.55),":[286],"(OR":[289,297,329],"1.79;":[291],"1.54-2.09)":[294],"or":[295],"AH":[296,374],"1.21;":[299],"1.08-1.35).":[302],"fresh":[304],"cycles,":[306],"rate":[309],"significantly":[319],"higher":[320],"than":[321],"cleavage":[327],"embryos":[328],"2.20;":[331],"1.83-2.66).":[334],"no":[336,381,433],"significant":[337],"difference":[338],"ovarian":[340,367],"stimulation":[341,368],"fertilization":[343,370],"methods":[344],"recognized.":[346],"LIMITATIONS,":[347],"REASONS":[348],"FOR":[349],"CAUTION:":[350],"current":[353],"Japanese":[354],"registry":[356],"system,":[357],"regarding":[359],"do":[362],"not":[363],"include":[364],"information":[365],"about":[366,404],"methods.":[371],"only":[375],"began":[376],"2010.":[378],"There":[379],"way":[382],"validating":[384],"if":[385],"submitted":[387],"clinics":[389],"correct.":[391],"WIDER":[392],"IMPLICATIONS":[393],"FINDINGS:":[396],"Clinicians":[397],"should":[398],"consider":[399],"whether":[400],"counsel":[402],"couples":[403],"small":[406],"increase":[407],"some":[416],"manipulations.":[418],"FUNDING/COMPETING":[420],"INTEREST(S):":[421],"No":[422],"external":[423],"funds":[424],"used":[426],"study.":[429],"authors":[431],"competing":[434],"interests":[435],"declare.":[437],"TRIAL":[438],"REGISTRATION":[439],"NUMBER:":[440],"None.":[441]},"counts_by_year":[{"year":2026,"cited_by_count":8},{"year":2025,"cited_by_count":8},{"year":2024,"cited_by_count":8},{"year":2023,"cited_by_count":11},{"year":2022,"cited_by_count":5},{"year":2021,"cited_by_count":13},{"year":2020,"cited_by_count":12},{"year":2019,"cited_by_count":5},{"year":2018,"cited_by_count":3}],"updated_date":"2026-11-12T12:28:57.059296","created_date":"2018-10-26T00:00:00"}