Chadwick Sign · What Is It, Causes, and More

The Chadwick sign is a non-specific, early sign of pregnancy that’s typically characterized by a bluish discoloration of the cervix, vagina, and vulva. The Chadwick sign can typically be observed as early as 6 to 8 weeks after conception, and commonly disappears shortly after birth. It does not commonly present with any other specific signs and symptoms such as pain but may coexist with signs and symptoms of the underlying condition.  

While the Chadwick sign is commonly associated with pregnancy, some conditions that may mimic signs of pregnancy and have a positive Chadwick sign include cervical endometriosis, a condition characterized by endometrial tissue outside the uterine cavity; the presence of endometrial tissue in the uterine muscle (i.e., adenomyosis); false pregnancy (i.e., pseudocyesis); and any other causes of chronic pelvic venous congestion such as varicose veins in the pelvic region or pelvic organ prolapse.  

The Chadwick sign is not a definitive indication of pregnancy, and the absence of it on physical exam does not exclude a potential pregnancy. Other non-specific early signs of pregnancy include the Goodell and Hegar signs. The Goodell sign is characterized by the softening of the cervical area, whereas the Hegar sign is characterized by the compressibility and softening of the cervical isthmus, which is the portion of the cervix between the uterus and the vaginal portion of the cervix. Serum hCG testing and transvaginal ultrasound are the gold standard for confirming pregnancy due to their superior accuracy and reliability compared to traditional clinical signs.  

The Chadwick sign is typically caused by various physiological changes that occur during the early stages of pregnancy. Early in pregnancy, increased venous blood flow to the cervix, vagina, and vulva, as well as pelvic vasodilation triggered by an increase in various hormones like estrogen and progesterone and prostaglandin synthesis, may alter cervical tissue composition and lead to a bluish discoloration in the area. 

Individuals may seek medical advice to have the Chadwick sign assessed. A thorough medical history, physical examination, laboratory tests, and ultrasound imaging may be completed. If pregnancy is not the underlying cause, other conditions that can mimic pregnancy and cause a positive Chadwick sign may be investigated and treated accordingly. For example, cervical endometriosis may be characterized by red, black, and/or blue cervical lesions; adenomyosis may affect the cervix resulting in discoloration; and pseudocyesis may trigger a release of pregnancy hormones which can result in the Chadwick sign. Similarly, varicose veins near the cervix or uterine prolapse may cause stasis of the venous blood flow giving the pelvic region this characteristic bluish color.