What Are the Physiological Changes During Pregnancy?

#Pregnancy occurs when an egg is fertilized by a sperm, grows inside a woman's uterus (womb), and develops into a baby. In humans, this process takes about 264 days from the date of fertilization of the egg, but the obstetrician will date the pregnancy from the first day of the last menstrual period (280 days 40 weeks). A typical pregnancy lasts 40 weeks from the first day of your last menstrual period (LMP) to the birth of the baby. Pregnancy is divided into three stages, called trimesters: first trimester, second trimester, and third trimester. During these stages, the fetus undergoes many changes to mature and the mother’s body changes as well.  
It is a period characterized by many signs and symptoms linked to physiological changes that happen within the mother’s body and I feel it's important to teach people exactly what goes on. Apart from the changes we see on the mother, there are other changes that we don't see because they are hidden but this does not mean they do not exist. Many of these changes happen due to the hormones that help maintain the baby in the womb, and the moment the baby is born, the symptoms start diminishing. These changes include:

Vulva: Vulva becomes oedematous(swollen) and more blood is usually supplied to this region. The labia minora part of the vagina becomes highly pigmented and its muscles increase in size.

Vagina: Vaginal walls become large and swollen, though the mother never feels pain. Increased blood supply surrounding the walls of the vagina makes it acquire blue coloration. Sometimes the women may wonder if this is normal because blue colorations on the normal human body are usually a sign that the organ is not getting adequate blood supply. But during pregnancy, this is healthy and normal, and the color vanishes the moment the baby is born.

Secretion: The vaginal secretion increases and becomes thin, and most of the time is curdy or white (milky-like) due to many exfoliated cells and bacteria from the vaginal canal. The pH changes too and becomes acidic (3.5-6) because more glycogen is converted into lactic acid as a result of elevated levels of estrogenic within the woman’s body during pregnancy.  The acidic pH is very helpful to the woman. Why? It prevents the multiplication of bacteria within the vagina, blocking them from affecting both the mother and the child.

Uterus: This is the first thing that increases in size after a woman gets pregnant. It experiences enormous growth to adjust and accommodate the growing baby. The uterus which is in a nonpregnant state weighs about 60g in weight, with a cavity of 5-10mL, and measures about 7.5cm in length. At term, it weighs 900-1,000g and measures 35cm in length. The capacity increases by 500-1,000 times. I know you may wonder how this happens but one thing about the uterus is that it's made up of muscles that can highly stretch without being torn. That’s why it grows up to such a size and then shrinks back to normal after the pregnancy is over.

Breasts: The increase in the size of the breasts becomes more evident even in the early weeks. Vascularity is increased and as a result, colorations of bluish veins running under the skin become evident. As the baby continues to grow, the breasts become enlarged and painful. There may be evidence of a stretch market due to excessive stretching of the skin around this region. Nipples on the other hand become larger, erectile, and deeply pigmented. An outer zone of the breast becomes irregular and the pigment appears in the second trimester. Secretion of milk (colostrum) can be squeezed out of the breasts at about the 12th week, but at this point, it is usually sticky. Later on, by the 16th week, it becomes thick and yellowish in color.

Skin or Cutaneous Changes: The face is one of the major parts that experience extreme forms of pigmentation especially around the cheeks, forehead, and eyes. The pigmentation may be patchy or diffuse and disappears spontaneously after delivery. Abdomen: There is always a continuous brownish-black pigmented area in the midline that stretches from the sternum (chest bone) to the pubis and it is called Linea Nigra. The majority of the women experience Striae gravidarum, also called stretch marks, which are predominantly found in the abdominal wall below the umbilicus, sometimes over the thighs and breasts. These stretch marks represent the scar tissues in the deeper layer of the skin. Initially, these are pinkish lines but after the delivery, the scar tissues contract, and capillaries change and become glistening white in appearance. To reduce the occurrence of these stretch marks, controlling the weight gain during pregnancy and massaging the abdominal wall using olive oil and other special oils may help reduce their formation.

Weight Gain: In the early weeks of the pregnancy the woman may lose weight especially if he is experiencing extreme nausea or vomiting. During subsequent months, the weight gain is progressive until the last 1or 2 weeks when the weight remains static. The total weight gain during the course of pregnancy for a healthy woman averages 11kg (24lb). This is often distributed to 1kg in the first trimester and 5kg in each of the two remaining trimesters.  

Body Water Metabolism: During pregnancy, the amount of water retained within the body at term is usually about 6. 5litres.This water content comes from the fetus, placenta, and amniotic fluid and adds up to 3.5litres. It is highly recommended to stay hydrated during this period because the chances of getting dehydrated are also high.

Hematological Changes: The blood volume starts to increase from about the 6th week of pregnancy, and expands rapidly thereafter to a maximum of 40-50% above normal. After this, the level of blood remains almost static till delivery. The blood increases to ensure that the woman gets enough oxygen and that her cells and organs are well perfused. Failure to have enough blood, the woman becomes weak, tired, can faint, and even die, which all threatens the life of the growing baby.

Alimentary system: The gums in the mouth become congested and spongy and may bleed when lightly touched. Cardiac sphincter relaxation forces regurgitation of acid stomach content into the esophagus, which causes chemical esophagitis and heartburn. Did you now see where the heartburn in pregnant women originates from? The secretion of the stomach juices and acids reduces, which in return delays the emptying time of the stomach. This is what makes pregnant women suffer from constipation.

Skeletal System: There is increased mobility of the pelvic joints due to softening of the ligaments caused mainly by hormones. This along with increased pressure exerted by the growing baby during the later months of pregnancy causes severe backache and waddling gait often witnessed in many women.

As we can see above, pregnancy is a period associated with many situations that may not favor the health of the woman. Some of these changes happen as a result of changes in hormones while others are simply ways of protecting the growing baby. Understanding what women experience during these tough times may shed light on many people, especially those who stay with these women. Sometimes people may mistake how a woman is feeling simply because they don't even know the risks associated with pregnancy. I believe that this information will help people appreciate women more because of what they go through for the sake of their babies.


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