{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,4]],"date-time":"2025-12-04T03:05:23Z","timestamp":1764817523135,"version":"3.46.0"},"reference-count":20,"publisher":"Wiley","issue":"6","license":[{"start":{"date-parts":[[2025,10,8]],"date-time":"2025-10-08T00:00:00Z","timestamp":1759881600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pregnancy"],"published-print":{"date-parts":[[2025,11]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>In this study we performed a retrospective chart review of alloimmunized pregnancies undergoing monitoring for hemolytic disease of the fetus and newborn (HDFN) in a cohort with known fetal antigen (FA) status. The objective was to compare fetal monitoring with titers and middle cerebral artery peak systolic velocity Doppler (MCA\u2010PSV Doppler) in FA\u2010negative and FA\u2010positive pregnancies and to understand downstream impacts of screening with titers in FA\u2010negative pregnancies.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Retrospective chart review of alloimmunized pregnant patients who underwent FA cell\u2010free DNA (cfDNA) analysis and participated in a registry in which neonatal genotyping was performed to confirm FA cfDNA results. Patients were divided into FA\u2010positive or FA\u2010negative cohorts based on the FA genotypes. Medical records were reviewed to characterize monitoring for anemia, titer results, MCA\u2010PSV Doppler results, and whether interventions were performed. Fischer's exact or chi\u2010square tests were performed as appropriate to ascertain differences between the cohorts.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Sixty\u2010nine alloimmunized pregnant individuals were included. Forty pregnancies (58%) were FA positive. Of 29 FA\u2010positive pregnancies who had titers more than once, 20 (69%) had titers that rose over two or more time points. There were 29 FA\u2010negative pregnancies (42%). Of 20 FA\u2010negative pregnancies that underwent titers more than once, 10 (50%) had titers that rose over two or more time points. The FA\u2010positive and FA\u2010negative cohorts had similar proportions of pregnancies that reached critical titers\u201470% (28\/40) and 69% (20\/29), respectively. In the FA\u2010positive cohort 14 of 34 participants who underwent MCA\u2010PSV Doppler reached greater than 1.5 multiples of the median (MoM), suggestive of fetal anemia. One patient in the FA\u2010negative cohort reached 1.5 MoM.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Titers frequently yield elevations that, while reflective of maternal alloimmunization, are not indicative of positive FA status or risk for HDFN in antigen\u2010negative pregnancies. Such results lead to unnecessary monitoring, including MCA\u2010PSV Doppler as well as invasive interventions. These outcomes can be avoided using methods including FA cfDNA, which has been shown to be highly accurate. These results suggest that monitoring for fetal anemia should be discontinued if FA cfDNA has determined the FA status is negative, as this will reduce downstream burdens and risks to alloimmunized patients who are not at risk for HDFN.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/pmf2.70113","type":"journal-article","created":{"date-parts":[[2025,10,8]],"date-time":"2025-10-08T10:58:49Z","timestamp":1759921129000},"source":"Crossref","is-referenced-by-count":0,"title":["High frequency of critical and rising titers in alloimmunized pregnancies with antigen\u2010negative fetuses"],"prefix":"10.1002","volume":"1","author":[{"given":"Olaide","family":"Ashimi Balogun","sequence":"first","affiliation":[{"name":"Obstetrix Maternal\u2010Fetal Medicine Specialists  Houston Texas USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1910-7441","authenticated-orcid":false,"given":"Shannon","family":"Rego","sequence":"additional","affiliation":[{"name":"BillionToOne, Inc  Menlo Park California USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5220-6022","authenticated-orcid":false,"given":"Julia","family":"Wynn","sequence":"additional","affiliation":[{"name":"BillionToOne, Inc  Menlo Park California USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rachel","family":"Levan","sequence":"additional","affiliation":[{"name":"BillionToOne, Inc  Menlo Park California USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kirsten","family":"Emanuel","sequence":"additional","affiliation":[{"name":"Obstetrix Maternal\u2010Fetal Medicine Specialists  Houston Texas USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rachael","family":"Overcash","sequence":"additional","affiliation":[{"name":"Division of Maternal\u2010Fetal Medicine Department of Women's and Infant's Services MedStar Washington Hospital Center  Washington District of Columbia USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1976-7987","authenticated-orcid":false,"given":"Lylach","family":"Haizler\u2010Cohen","sequence":"additional","affiliation":[{"name":"Division of Maternal\u2010Fetal Medicine Department of Women's and Infant's Services MedStar Washington Hospital Center  Washington District of Columbia USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sara N.","family":"Iqbal","sequence":"additional","affiliation":[{"name":"Division of Maternal\u2010Fetal Medicine Department of Women's and Infant's Services MedStar Washington Hospital Center  Washington District of Columbia USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Juan M.","family":"Gonzalez Velez","sequence":"additional","affiliation":[{"name":"Department of Obstetrics Gynecology and Reproductive Sciences University of California, San Francisco  San Francisco California USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2025,10,8]]},"reference":[{"key":"e_1_2_10_2_1","doi-asserted-by":"publisher","DOI":"10.1182\/bloodadvances.2023012241"},{"key":"e_1_2_10_3_1","doi-asserted-by":"publisher","DOI":"10.1097\/AOG.0000000000002528"},{"key":"e_1_2_10_4_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41598\u2010023\u201039283\u20103"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.1097\/AOG.0000000000005630"},{"key":"e_1_2_10_6_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1471\u20100528.2011.03028.x"},{"key":"e_1_2_10_7_1","doi-asserted-by":"publisher","DOI":"10.1111\/tog.12125"},{"key":"e_1_2_10_8_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1471\u20100528.2010.02518.x"},{"key":"e_1_2_10_9_1","doi-asserted-by":"publisher","DOI":"10.1097\/AOG.0000000000005709"},{"key":"e_1_2_10_10_1","doi-asserted-by":"publisher","DOI":"10.1097\/AOG.0000000000005692"},{"key":"e_1_2_10_11_1","article-title":"D Alloimmunization in Pregnancy: Management","author":"Moise K. 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