What is Chadwick sign with anatomy pregnancy and diagnosis

Chadwick ‘s sign refers to the change in color of the cervix, vagina and genital lips in a woman’s gynecological examination when pregnancy is suspected.

Under normal conditions, the cervix and vagina are pink mucous membranes and the labia are the same color as the patient’s skin. The change in color of these organs from pink/reddish to blue or violet is due to increased blood supply to that area.

Chadwick’s sign is one of the first indicators that alert the doctor that a pregnant patient may have it. That is, it is the first indication of a possible pregnancy.

Subsequently, and over time, other changes occur in the female anatomy. All of these changes occur to keep the fetus in a state of maturation until it is expelled through the birth canal.

Chadwick’s sign

It is known as Chadwick’s sign to change the color of the cervix, vagina and vulva of pregnant women. It is evident to the gynecologist when performing the genital examination.

These changes were first described in 1836 by the French physician Étienne Joseph Jacquemin (1796-1872). However, the eponym for the sign comes from Dr. James Read Chadwick, who in 1886 wrote and published a series of cases describing the changes evidenced by Jacquemin.

Although the physiological changes discussed in Chadwick’s publication Jacquemin credited Jacquemin as the first to describe them, Chadwick was popularized by naming this sign.

The internal genitals, cervix and vagina, are pinkish organs similar to the lining of the mouth. The color of the vulva matches the woman’s skin color.

Both the vagina and the vulva are organs that receive an extensive blood supply from various arterial groups, forming a true arteriovenous network.

During pregnancy, blood flow increases to and from the external genitalia, causing venous congestion. Both the increase in vascularity and the venous congestion make the vaginal mucosa and the cervix acquire a violet color from approximately the 6th week of pregnancy.

Darkening of the skin on the outer lips and mount of Venus is a common change that occurs for the same reason.

In some cases, venous vascular congestion can lead to the formation of vulvar varicose veins that can become very uncomfortable during pregnancy.



The vagina is part of the internal genital organs of women. At the top is the cervix; The bottom is the opening to the outside.

The vagina consists of three layers:

– Mucous layer: is a tunic that contains mucous folds. It reacts to hormones by changing its thickness in each phase of the menstrual cycle.

– Muscular layer: it is formed by smooth and musculoskeletal muscle fibers.

– Adventitia layer: is the connective tissue. It contains the neuro-vascular plexus.

As for the blood supply of the vaginal mucosa, it consists of an important arterial network that involves direct branches of the uterine arteries, hypogastric artery and internal pudendal artery.


The set of female external genitalia is known as the vulva. It consists of the labia major and minor, the clitoris and the pubis or mount of Venus.

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Vulvar anatomy differs greatly from one person to another, depending on the texture, size, skin color, thickness of the labia minora, among other characteristics; therefore, it is not possible to describe specific anatomical features that are common to all women.

The vulva is abundantly irrigated by the three pudendal arteries (superficial external pudendal, internal pudendal and deep external pudendal).


The term pregnancy refers to the physiological changes that occur in women so that they can maintain and cope with pregnancy.

In turn, the term gestation is the development of the fetus inside the uterus. Gestation begins when the embryo is implanted in the uterus and ends with birth.

Pregnancy consists of three periods of three months each or trimesters. When the woman begins the third trimester, the fetus is viable to live outside the uterus.

– Physiology

Pregnancy begins when the embryo, which is the egg fertilized by the sperm, is implanted in the deep layer of the uterus. There he receives adequate blood nutrition to continue his development.

When this occurs, they initiate a series of physiological changes in women designed to keep the fetus in the womb until birth. A full pregnancy lasts between 38 and 40 weeks.

Some of the physical changes in pregnant women are recognized with the naked eye, such as an increase in the size of the uterus or breast.

However, in addition to these changes in women’s physiognomy, there are also subtle changes that can be evidenced by the physician during the gynecological physical examination.

These changes can be found in the early stages of pregnancy and are known as signs of likelihood of pregnancy.

– Diagnosis

Signs of certainty and probability

There are signs and symptoms that lead women to suspect pregnancy. Some of them are well known like delay in menstruation date, nausea and pain and breast enlargement among others.

During the gynecological physical examination of a woman who suspects pregnancy, the specialist doctor pays special attention to the so-called probability signs.

Probability signs are changes that can be found in a pregnant woman and that guide the diagnosis, but do not guarantee that the patient is pregnant.

Probability signs give a high degree of suspicion of pregnancy and, if one or more are evidenced during the physical examination, the doctor must indicate a series of tests that confirm the diagnosis.

Although these signs are present in a large percentage of pregnant women, there are conditions such as pseudocyesis or psychological pregnancy, in which a woman can experience these changes without actually being pregnant. That is why the diagnosis must be confirmed.

These signs that guarantee the diagnosis of pregnancy are known as sure signs. Among them are:

– Pelvic ultrasound showing the presence of the fetus in the uterus.

– Fetal cardiac activity through ultrasound with Doppler effect (ultrasound function that shows blood flow in an organ).

The physiological changes that occur in pregnant women, such as increased irrigation, modification of the collagen fibers of the uterine tissue and increased pigmentation of the external genitalia and nipples, are some of the probable signs that lead the specialist to guide the definitive diagnosis of pregnancy.

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