Abortion, Changed Paternity, and Risk of Preeclampsia in Nulliparous Women

• Published in: American journal of epidemiology Vol. 157; no. 12; pp. 1108 - 1114
• Main Authors: Saftlas, Audrey F., Levine, Richard J., Klebanoff, Mark A., Martz, Karen L., Ewell, Marian G., Morris, Cynthia D., Sibai, Baha M.
• Format: Journal Article
• Language: English
• Published: Cary, NC Oxford University Press 15-06-2003; Oxford Publishing Limited (England)
• Subjects: abortion; Abortion, Induced; Abortion, Spontaneous; adjusted odds ratio; Adolescent; Adult; aOR; Biological and medical sciences; Calcium Compounds - administration & dosage; Calcium for Preeclampsia Prevention; confidence interval; CPEP; Diseases of mother, fetus and pregnancy; Female; Gynecology. Andrology. Obstetrics; Humans; Hypertension - epidemiology; induced; Male; Medical sciences; Parity; Paternity; pre-eclampsia; Pre-Eclampsia - diagnosis; Pre-Eclampsia - epidemiology; Pre-Eclampsia - ethnology; Pre-Eclampsia - prevention & control; Pregnancy; Pregnancy Complications, Cardiovascular - epidemiology; Pregnancy. Fetus. Placenta; Randomized Controlled Trials as Topic; Risk Assessment; Risk Factors; spontaneous; Surveys and Questionnaires; United States - epidemiology; United States; Human; Pregnancy disorders; Paternity; Abortion; Epidemiology; Pregnancy toxemia; spontaneous; paternity; pre-eclampsia; pregnancy; induced; abortion; Preeclampsia; Risk factor; Female; Nulliparity; Public health
• ISSN: 0002-9262; 1476-6256; 0002-9262
• DOI: 10.1093/aje/kwg101

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.