title: Abortion, changed paternity, and risk of preeclampsia in nulliparous women.
abstract: A prior birth confers a strong protective effect against preeclampsia, whereas a prior abortion confers a weaker protective effect. Parous women who change partners in a subsequent pregnancy appear to lose the protective effect of a prior birth. This study (Calcium for Preeclampsia Prevention Trial, 1992-1995) examines whether nulliparous women with a prior abortion who change partners also lose the protective effect of the prior pregnancy. A cohort analysis was conducted among participants in this large clinical trial of calcium supplementation to prevent preeclampsia. Subjects were nulliparous, had one prior pregnancy or less, delivered after 20 weeks' gestation, and were interviewed at 5-21 weeks about prior pregnancies and paternity. Women without a history of abortion served as the reference group in logistic regression analyses. Women with a history of abortion who conceived again with the same partner had nearly half the risk of preeclampsia (adjusted odds ratio = 0.54, 95 percent confidence interval: 0.31, 0.97). In contrast, women with an abortion history who conceived with a new partner had the same risk of preeclampsia as women without a history of abortion (adjusted odds ratio = 1.03, 95 percent confidence interval: 0.72, 1.47). Thus, the protective effect of a prior abortion operated only among women who conceived again with the same partner. An immune-based etiologic mechanism is proposed, whereby prolonged exposure to fetal antigens from a previous pregnancy protects against preeclampsia in a subsequent pregnancy with the same father.
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, Iowa City, IA 52242, USA. Audrey-Saftlas@Uiowa.edu
authors.forename: Audrey F
authors.initials: AF
authors.lastname: Saftlas
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Levine
authors.forename: Mark A
authors.initials: MA
authors.lastname: Klebanoff
authors.forename: Karen L
authors.initials: KL
authors.lastname: Martz
authors.forename: Marian G
authors.initials: MG
authors.lastname: Ewell
authors.forename: Cynthia D
authors.initials: CD
authors.lastname: Morris
authors.forename: Baha M
authors.initials: BM
authors.lastname: Sibai
mesh_terms: D000028:Abortion, Induced; D000022:Abortion, Spontaneous; D000293:Adolescent; D000328:Adult; D017610:Calcium Compounds / Q000008:administration & dosage; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D008297:Male; D010298:Parity; D010334:Paternity; D011225:Pre-Eclampsia / Q000175:diagnosis / Q000453:epidemiology* / Q000208:ethnology / Q000517:prevention & control; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000453:epidemiology; D016032:Randomized Controlled Trials as Topic; D018570:Risk Assessment; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology
chemical_list: D017610:Calcium Compounds