Chadwick's Sign in Pregnancy

Chadwick's sign—a dark bluish or purplish discoloration of the vulva, vaginal tissue, or cervix—is a common pregnancy symptom. Once considered an early indication of pregnancy, it can develop as early as six weeks after conception and typically lasts until after delivery.

While a purple or blue labia may look concerning, Chadwick's sign is a normal part of pregnancy. Caused by an increase in blood flow to the pelvis in early pregnancy, it is not typically painful and should not cause any problems.

This article discusses Chadwick’s sign. It explains what it is, how it occurs, and what other conditions mimic Chadwick's sign. 

What Is Chadwick’s Sign?

Chadwick's sign is a bluish or purplish discoloration of the vulva, vagina, and cervix. It occurs when there is an increase in venous (from the veins) blood flow to the pelvic area. This excess blood flow is triggered by an increase in estrogen levels during pregnancy.

The bluish-purple discoloration is caused by blood congestion in the veins of the labia, vulva, vagina, or cervix. It usually first appears about six to eight weeks after conception. It typically subsides during the pregnancy or soon after delivery.

First identified during the 1800s, it is named after Dr. James Read Chadwick. In the days before home pregnancy tests, Chadwick's sign was used alongside other signs to diagnose pregnancy, such as:

• Goodell’s sign: A softening of the cervix at around six to eight weeks of gestation
• Hegar’s sign: Softening of the lower segment of the uterus, which occurs around six to 12 weeks of gestation
• Jacquemier’s sign: Similar to Chadwick's sign, but the tissue appears more blue than purple

Today, these changes are considered probable signs of pregnancy, and while they occur in early pregnancy, most people will have a positive pregnancy test prior to these signs.

Does Chadwick’s Sign Mean You’re Pregnant?

Chadwick's sign is not a definitive indicator that a person is pregnant. Tests will need to be done to confirm a pregnancy, often starting with an at-home pregnancy test.

A healthcare provider can then use several methods to confirm a pregnancy. Common ways to diagnose pregnancy include:

• A thorough history (such as gathering information about a person’s menstrual periods)
• A physical examination (to check for any presumptive signs of pregnancy, including Chadwick’s sign)
• Laboratory tests (such as a test that detects levels of human chorionic gonadotropin [hCG], a hormone produced by the placenta during pregnancy)
• Sonography (which uses ultrasound waves to bounce off structures and create images of the uterus)

What Are the Different Symptoms of Pregnancy?

There are several categories to describe signs of pregnancy, including presumptive, probable, and positive signs.

Presumptive (Possible) Signs of Pregnancy

Presumptive signs are those that raise some suspicion that a person might be pregnant. These signs are subjective, meaning they are reported by the patient.

• Nausea and vomiting (morning sickness)
• Missed menstrual periods (amenorrhea)
• Severe fatigue
• Breast enlargement
• Painful breasts
• An increase in urination
• Quickening (a feeling of movement in the lower abdomen, usually felt for the first time at around 16 to 22 weeks of gestation)

Probable Signs of Pregnancy

Probable signs of pregnancy are those that are strongly linked with pregnancy but can also be symptoms of other underlying conditions. Probable signs of pregnancy include:

• Chadwick’s sign
• Goodell’s sign
• Hegar’s sign
• Jacquemier's sign

Other Signs

There are also other signs that indicate pregnancy is likely but not certain. These signs may seem like positive signs of pregnancy but can also be brought on by other causes.

These signs include:

• A positive hCG test (which measures the amount of human chorionic gonadotropin hormone in the urine or blood)
• External ballottement (palpation performed by a doctor that causes the fetus to bounce back against their fingers when the uterus is pushed)
• Braxton Hicks contractions (labor pains that are considered false labor because they do not cause cervical changes, such as dilatation)
• An enlarged uterus

Positive Signs of Pregnancy

Positive signs of pregnancy are those that have no other underlying cause. Definitive of signs of pregnancy can be determined by:

• Doppler (an electronic device that detects fetal heart sounds)
• Fetal movements (felt or seen by the diagnostician)
• Ultrasound (sonography; detects the fetus)
• Birth of the baby

Conditions That Mimic Chadwick’s Sign

If a pregnancy is not confirmed, other causes will need to be evaluated. Some medical conditions can mimic the symptoms of pregnancy, including Chadwick’s sign.

There are other conditions that can cause bluish discoloration of the cervix:

• Cervical endometriosis: This condition can cause blue cervical lesions and other symptoms, such as red, black, or blue cervical lesions; discharge; dysmenorrhea (painful menstruation); and pelvic pain.
• Adenomyosis: When endometrial tissue is present in the uterine muscle, it may also affect the cervix if a mass protrudes into the endocervical canal.
• Peudocyesis (false pregnancy): False pregnancy occurs when a person believes they are pregnant when they are not. The belief can trigger the brain to release pregnancy hormones such as estrogen and progesterone. An increase in hormone levels causes a person to have the physical signs and symptoms of pregnancy, including Chadwick's sign.
  

When to Call Your Healthcare Provider

Chadwick's sign is not usually the first indicator of pregnancy, but it can appear early on and might prompt you to confirm that you are pregnant.

If you experience a bluish or purplish discoloration of the vulva or vaginal area or have other signs of pregnancy, like a missed period, take a home pregnancy test and follow up with your healthcare provider.

Summary

Chadwick's sign is an expected physical change related to pregnancy. It occurs when blood flow to the pelvic area increases due to pregnancy hormones. This causes the labia, vulva, vagina, or cervix to turn a bluish-purple color.

Chadwick's sign was once considered an early indication of pregnancy and can appear about six weeks after conception. Today, most people will have a positive pregnancy test before Chadwick's sign or other pregnancy symptoms.

While common in pregnancy, Chadwick's sign does not definitively mean that someone is pregnant. Other conditions that can cause similar changes include cervical endometriosis, adenomyosis, and false pregnancy.

If you experience any genital discoloration, talk to your healthcare provider, who can use other diagnostic methods to confirm that you are pregnant or identify the underlying cause.