HEGAR SIGN: WHAT IS IT, PREGNANCY PHYSIOLOGY, ANATOMY - ECONOMÍA - 2024

The sign Hegar is one of the first signs of pregnancy probability evident on physical examination Gynecological a woman. It consists of the change of consistency of the uterus specifically in the isthmus, which is the area where the bottom or upper part of the uterus joins the cervix.

This sign is evident on bimanual palpation. That is, the uterus must be palpated intravaginally and abdominally so that the specialist can feel the change in consistency.

By Internet Archive Book Images - https://www.flickr.com/photos/internetarchivebookimages/14597674650/Source book page: https://archive.org/stream/diagnosistreatmecros/diagnosistreatmecros#page/n78/mode/1up, No restrictions, Under normal conditions, both the uterus and the cervix are felt for firm consistency. However, in pregnant women, from the first 4 weeks, it may feel softer.

Although it is one of the first signs to appear, it is not present in all pregnant women and in multiparous women it is more difficult to show. It should be noted that the fact that the Hegar sign is not present does not exclude the possibility that the patient is pregnant.

What is the sign of Hegar?

The change in consistency of the fundus and isthmus of the uterus is known as Hegar's sign. It can be felt by the specialist doctor through bimanual palpation (intravaginal and abdominal).

It was described in 1895 by the German gynecologist Ernst Ludwig Alfred Hegar (1830-1914), who was a professor at the University of Freiburg. This doctor is recognized worldwide for his innovative aseptic and antiseptic techniques and for the development of instruments and surgical techniques in the field of gynecology, including the description of the sign that bears his name.

The maneuver to show the Hegar sign consists of performing a touch by introducing two fingers of the dominant hand through the vagina. Upon finding the cervix, the fingers are placed in the space in front of the cervix (anterior fornix).

At the same time, abdominal palpation is performed with the other hand, trying to identify the fundus of the uterus. If the fingers of both hands meet through this maneuver, the sign is positive and means that the uterine isthmus is soft and flexible.

The change in consistency occurs because the increased availability of female hormones during pregnancy, especially progesterone and estradiol, have an effect on the collagen fibers found in the uterus.

The hormonal influence causes the collagen to elongate and disperse, forming a much more elastic tissue.

Hegar's sign is one of the first that the doctor shows on physical examination. It occurs from the 4th week of gestation.

Female internal genitalia

The genital organs are those that are intended for sexuality and reproduction. There are external genitalia and internal genitalia. In the case of women, the external ones are the vulva and the mons pubis, while the internal genitalia are made up of the uterus, ovaries, fallopian tubes and vagina.

The uterus, ovaries, and fallopian tubes are located in the pelvis. They are organs totally dependent on hormones and change continuously according to the menstrual cycle. Its main purpose is reproduction.

The ovaries are the containers for the ovules or eggs that mature monthly and pass through the fallopian tubes to the uterus.

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The uterus

The uterus is the organ that receives the fertilized ovum for the gestation of the fetus, during pregnancy. It consists of a broad fundus, an isthmus, and a neck that protrudes into the vagina.

Although the uterus contains a significant amount of muscle fibers, especially in its middle layer, collagen is also an important element of its structure. The firm-elastic consistency of the uterus is due to its high collagen content.

By http://training.seer.cancer.gov/cervical-uterine/cervix/intro/, Public Domain, The woman's uterus is made up of three layers, the serosa being the outermost layer; the myometrium or muscular layer; and the endometrium, which prepares the bed for the implantation of the fertilized ovum.

The uterine arteries and veins are responsible for the blood nutrition of the uterus. One of the most important physiological changes in pregnancy is the increase in blood flow and vascularity of the uterus.

Physiology of pregnancy

When an egg is fertilized by a sperm, a process of cell division begins and an embryo is formed. It attaches itself to the endometrium, the deep layer of the uterus, through a complex hormonal and molecular process.

This is the first stage of pregnancy and, although there are no visible physical changes to the naked eye, they do begin a series of physiological changes that are detected both by blood tests and by the examination of a specialist.

All the changes that occur in the woman are intended to keep the fetus in the womb until the moment of birth. During the 38-42 weeks of pregnancy, the fetus must grow and develop fully within the uterus, receiving nutrition from the mother.

For this to happen, important physiological changes occur such as the increase in blood circulation to the uterus that triggers a collagen splitting process that causes the uterus to become more elastic.

From that moment on, the uterus grows as the fetus grows, without causing trauma to the organ. That is, the uterus becomes more elastic and can increase in size for the fetus to develop, without breaking or tearing.

All the changes that occur in the uterus for the fetus to complete its intrauterine stage of life are called: maturation stage.

Diagnosis

The diagnosis of pregnancy is established in several stages. In the first place, the patient presents the typical symptoms that make her go to the specialist.

Some of the symptoms that raise suspicion of pregnancy are morning sickness, missed periods, and sore breasts.

Already in the gynecologist's examination, this may show physical signs that have a higher degree of suspicion. Some of these signs involve the discoloration of the vaginal mucosa and the change in the consistency of the uterus.

However, these are all signs of probability. That is, from the presence of one or more of these signs, a pregnancy can be suspected but a definitive diagnosis cannot be given since none ensures that there is an embryo developing within the uterus.

To give an accurate diagnosis, more specialized tests are used such as pelvic ultrasound or the demonstration of fetal heart activity through an ultrasound that reveals the heartbeat of the fetus.

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References:

1. Gossman, W; Fagan, SE; Sosa-Stanley, JN; et al. (2019). Anatomy, Abdomen and Pelvis, Uterus. StatPearls (FL). Taken from: ncbi.nlm.nih.gov
2. Fowler, JR; Jack BW. (2019). Pregnancy. StatPearls (FL). Taken from: ncbi.nlm.nih.gov
3. Rådestad, A. (1992) Cervical Softening in Early Pregnancy. Drife JO, Calder AA Prostaglandins and the Uterus. Springer, London
4. Akins, M. L; Luby-Phelps, K; Bank, R. A; Mahendroo, M. (2011). Cervical softening during pregnancy: regulated changes in collagen cross-linking and composition of matricellular proteins in the mouse. Biology of reproduction. Taken from: ncbi.nlm.nih.gov
5. Uldbjeger, N; Ulmsten, U. (1990). The physiology of cervical ripening and cervical dilatation and the effect of abortifacient drugs. Baillieres Clin Obstet Gynaecol. Taken from: ncbi.nlm.nih.gov