Missed Period

Historically, the first sign of pregnancy has been considered a missed period.  A delayed or missed period is often the trigger that leads someone to suspect or to test for pregnancy.

What causes a missed period during pregnancy?

A missed period or menstrual cycle is triggered by the pregnancy related hormones released by the placenta informing your body that it is pregnant.

When does a missed period occur?

A missed period is expected during the first month of pregnancy.  However, it is possible to be pregnant and to have a period, but this period is usually lighter, shorter or spottier.  The belief is that this is not actually a period but rather heavier implantation bleeding. 

Some women have actually experienced cyclical bleeding during their pregnancy, but this is rare and not expected.  Most women that do experience a period although pregnant, cease to have a period by the second or third month.

Bleeding is always a symptom that needs to be examined by your health care provider.  Although early bleeding is common

How frequently does a missed period occur?

Although a missed period is expected with each pregnancy; approximately 40% of women experience bleeding during their first month.  Less than half of these result in a miscarriage, but you are still advised to contact your health care provider.

Sources:

Cunningham, F., MD; Leveno, K., MD; Bloom, S., MD; Hauth, J., MD; Gilstrap, L., MD; and Wenstrom, K., MD, Williams Obstetrics 22nd ed., McGraw-Hill, New York, 2005.

Duff, P., MD, Edwards, R., MD, Davis, J., MD, Rhoton-Vlasak, A., MD, Obstetrics and Gynecology: Just the Facts, McGraw-Hill, New York, 2004.

Scott, J., MD; Gibbs, R., MD; Karlan, B., MD; and Haney, A., MD, Danforth’s Obstetrics and Gynecology, 9th ed., Lippincott Williams & Wilkins, Philadelphia, 2003.

Crombleholme, W., MD, “Obstetrics,” Current Medical Diagnosis & Treatment 2003, 42nd ed., McGraw-Hill, New York, 2003.

DeCherney, A., MD, and Nathan, L., MD, Current Obstetric & Gynecologic Diagnosis & Treatment, 9th; McGraw-Hill, New York, 2003.

Harms, R., MD, Mayo Clinic Guide to a Healthy Pregnancy, HarperResource, New York, 2004.

Bankowski, B. MD., Hearne, A. MD, Lambrou, N. MD, Fox, H. MD, and Wallach, E. MD, The Johns Hopkins Manual of Gynecology and Obstetrics, 2nd ed., Lippincott Williams & Wilkins, Philadelphia, 2002.

American College of Obstetricians and Gynecologists, Planning Your Pregnancy and Birth, 3rd ed., ACOG, Washington DC, 2000.

Beck, W., MD, Obstetrics and Gynecology, B.I. Waverly Pvt., Ltd., New Delhi, 1997.

Johnson, R., MD, Mayo Clinic Book of Pregnancy & Baby’s First Year, William Morrow and Company, Inc., New York, 1994.