Hegar Sign · What Is It, Causes, and More

Published: Oct 17, 2025
Author: Ali Syed, PharmD•
Editor: Alyssa Haag, MD•
Editor: Emily Miao, PharmD, MD
Illustrator: Jessica Reynolds, MS•
Copyeditor: David G. Walker
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What is the Hegar sign?

The Hegar sign is a non-specific indication of pregnancy that is characterized by the compressibility and softening of the uterine isthmus (i.e., the transitional area between the body of the uterus and cervix). It typically presents between the fourth and sixth week of pregnancy and may persist until the twelfth week. The Hegar sign is not a definitive indicator of pregnancy, and its absence does not exclude a potential pregnancy.  

Other non-specific indicators that can present between the fourth and eighth weeks of pregnancy are the Goodell and Chadwick signs. The Goodell sign is characterized by the softening of the cervix. On the other hand, the Chadwick sign is typically characterized by a bluish discoloration of the cervix, vagina, and vulva due to an increase in venous blood flow to the area. 

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What causes the Hegar sign?

The Hegar sign is typically caused by various physiological changes that occur during the first six weeks of pregnancy. In early pregnancy, increased blood flow, estrogen, progesterone, and prostaglandin synthesis as well as other biochemical changes may alter cervical tissue composition. More specifically, these changes often include a reduction in collagen concentration and an increase in dermatan sulfate proteoglycans (DS-PGs), a type of extracellular matrix glycoprotein, in the cervical tissue, resulting in softening of the cervical isthmus, or Hegar sign. 

How do you check for the Hegar sign?

The Hegar sign can be physically assessed by a medical professional through a bimanual examination. During a bimanual examination, the healthcare provider inserts two fingers of the dominant hand into the vagina applying upward pressure, while the other hand palpates the lower abdomen. This technique allows assessment of the lower uterine segment. A positive Hegar sign is identified when the lower uterine segment feels softer than the uterine body above and the cervix below. 

What are the most important facts to know about the Hegar sign?

Hegar sign is a non-specific indication of pregnancy characterized by the compressibility and softening of the cervical isthmus. The Hegar sign usually presents during the fourth to sixth week of pregnancy and may be present until the 12th week of pregnancy. It typically results from various changes in consistency of the cervical isthmus during the first six weeks of pregnancy. It can be physically assessed by a medical professional by bimanual examination, in which the consistency of the lower uterine segment may feel soft when compared to the body of the uterus and cervix.  

Key Takeaways

Definition 

The Hegar sign is a non-specific indication of pregnancy characterized by the compressibility and softening of the uterine isthmus; it typically appears between the fourth and sixth week of pregnancy and may persist until the twelfth week.  

Cause

- Reduction in collagen concentration and increase in dermatan sulfate proteoglycans (DS-PGs) → softening of the isthmus  

Assessment

- Bimanual examination:  

     - Two fingers inserted into the vagina while applying upward pressure, while the other hand palpates the lower abdomen → assessment of lower uterine segment  

     - Positive sign: lower uterine segment feels softer than the uterine body above and the cervix below 

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References

Hacker NF, Gambone JC, Hobel CJ, eds. Hacker & Moore’s Essentials of Obstetrics & Gynecology. 6th ed. Elsevier; 2016.


Ladinski LJ. Diagnosis of early pregnancy with reference to a particular sign. Med Rec (1866-1922). 1907;71(15):597.


McCann FC. The diagnosis of pregnancy. Hosp. 1906;41(1050):88-89.


Uldbjerg N, Ulmsten U. The physiology of cervical ripening and cervical dilatation and the effect of abortifacient drugs. Bailliere Clin Obstet Gynaecol. 1990;4(2):263-282. doi:10.1016/S0950-3552(05)80226-3