Kate Clancy's 'Pregnancy Interrupted' Examines the False Certainty of Early Pregnancy Tests
In her upcoming book "Pregnancy Interrupted," set to release in August from Princeton University Press, biological anthropologist Kate Clancy examines the historical progression of pregnancy testing, starting with the Aschheim-Zondek (A-Z) test from the 1930s and leading to the at-home tests of the 1980s. The A-Z method required injecting urine into mice, rabbits, and frogs to observe signs of sexual maturity. While contemporary tests identify human chorionic gonadotropin (hCG), Clancy contends that positive hCG results may not accurately reflect pregnancy viability, as hCG can be present in chemical and ectopic pregnancies. She highlights the high rate of nonviable implanted embryos and addresses the differences in miscarriage definitions between the U.S. and U.K., urging for improved early pregnancy diagnostics.
Key facts
- The Aschheim-Zondek (A-Z) test was refined in Scotland in the 1930s and involved injecting mice, rabbits, or frogs with a woman's urine to detect placental matter.
- The first rapid at-home pregnancy tests were introduced in the 1980s, all based on detecting the hormone human chorionic gonadotropin (hCG).
- Kate Clancy's book "Pregnancy Interrupted" will be published in August by Princeton University Press.
- Most pregnancies (implanted embryos) are not viable, and hCG levels can rise in chemical pregnancies, ectopic pregnancies, and miscarriages.
- The term intrauterine pregnancy of unknown viability (I.P.U.V.) describes cases without a yolk sac, with a yolk sac but no embryo, or with an embryo but no detectable heartbeat.
- A U.K. study of about 1,000 I.P.U.V. cases found that approximately one-fifth were viable pregnancies.
- U.S. guidelines define miscarriage as an empty gestational sac of 16 millimeters, while U.K. guidelines use 20 millimeters, creating a 4-millimeter diagnostic discrepancy.
- Gestational age is typically calculated from the last menstrual period, assuming a 28-day cycle, which is inaccurate for women with longer or shorter cycles.
Entities
Artists
- Kate Clancy
Institutions
- Princeton University Press
- The New Yorker
Locations
- Scotland
- United States
- United Kingdom