Page last updated January 2018

This is a FREE resource designed to support the medical profession in their care of women made possible by over 750 expert clinicians who are generously providing their contributions without any remuneration and by the publishers who have paid personally for the creation of this site in the memory of their daughter, Abigail.

Current Authors

Pregnancy Test

HCG is a hormone, produced by placental tissue. 
  • Shortly after implantation of a fertilized ovum in the uterine lining, HCG begins to be produced.
  • Levels of HCG approximately double every 2-3 days in a normal pregnancy.
  • By the time of the first missed menstrual period, pregnancy tests are usually positive (with a sensitivity of 30-35 mIU/ml).
  • Following a miscarriage, HCG levels initially fall quickly, then more gradually, until levels return to normal. This process takes, on average, about a month.

Urine is normally used for the test. A morning urine is more sensitive (in borderline situations) because it is more concentrated.

Serum can be used, and is equally reliable.

Elevations caused by:

  • Pregnancy
  • Gestational Trophoblastic Disease

Decreases caused by:

  • Miscarriage (spontaneous or induced)
  • Following obstetrical delivery
  • With resolution of an ectopic pregnancy

Normal Values:

  mIU/ml IU/L
Non-pregnant Negative <24

Pregnant

Positive >25

 


Positive Pregnancy Test

Source: Operational Medicine 2001,  Health Care in Military Settings, NAVMED P-5139, May 1, 2001, Bureau of Medicine and Surgery, Department of the Navy, 2300 E Street NW, Washington, D.C., 20372-5300