Physiologic postpartum period: changes in the maternity woman's body

The puerperal or postpartum period is the period that begins after the birth of the placenta and lasts 8 weeks. During this time, the reverse development (involution) of organs and systems that have undergone changes due to pregnancy and childbirth occurs. The exceptions are the mammary glands and the hormonal system, the function of which reaches its maximum development during the first few days of the postpartum period and continues throughout the entire lactation period.

Early and late postpartum period

The early postpartum period begins from the moment of birth of the placenta and lasts 24 hours. This is an extremely important period of time, during which important physiological adaptations of the mother's body to new living conditions occur, especially the first 2 hours after birth.

In the early postpartum period, there is a risk of bleeding due to impaired hemostasis in the vessels of the placental site, impaired contractile activity of the uterus, and trauma to the soft birth canal.

The first 2 hours after delivery, the mother remains in the delivery room. The obstetrician carefully monitors the general condition of the mother, her pulse, measures blood pressure, body temperature, constantly monitors the condition of the uterus: determines its consistency, the height of the fundus of the uterus in relation to the pubis and navel, monitors the degree of blood loss,

Late postpartum period - begins 24 hours after birth and lasts 6 weeks.

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Uterus

The most pronounced process of reverse development is observed in the uterus. Immediately after childbirth, the uterus contracts, acquires a spherical shape7, a dense consistency. Its fundus is 15-16 cm above the pubis. The thickness of the uterine walls, greatest in the fundus (4-5 cm), gradually decreases towards the cervix, where the thickness of the muscles is only 0.5 cm. The uterine cavity contains a small number of blood clots. The transverse size of the uterus is 12-13 cm, the length of the cavity from the external os to the fundus is 15-18 cm, the weight is about 1000 g. The cervix is freely passable for the hand. Due to the rapid decrease in the volume of the uterus, the walls of the cavity have a folded character, and then gradually smooth out. The most pronounced changes in the uterine wall are noted at the location of the placenta - in the placental site, which is a rough wound surface with blood clots in the area of u200bu200bthe vessels. In other areas, parts of the decidual membrane, the remains of glands from which the endometrium is subsequently restored, are determined. Periodic contractile movements of the uterine muscles are preserved, mainly in the fundus area.

During the following week, due to the involution of the uterus, its weight decreases to 500 g, by the end of the 2nd week - to 350 g, the 3rd - to 200-250 g. By the end of the postpartum period, it weighs the same as in a state outside of pregnancy - 50-60 g.

The mass of the uterus in the postpartum period decreases due to constant tonic contraction of muscle fibers, which leads to a decrease in blood supply and, as a consequence, to hypotrophy and even atrophy of individual fibers. Most of the vessels are obliterated.

During the first 10 days after birth, the fundus of the uterus descends daily by approximately one transverse finger (1.5-2 cm) and on the 10th day is at the level of the pubis.

Involution of the cervix has some peculiarities and occurs somewhat more slowly than the body. Changes begin with the internal os: already 10-12 hours after birth, the internal os begins to contract, decreasing to 5-6 cm in diameter.

The external os remains almost the same due to the thin muscular wall. The cervical canal therefore has a funnel shape. After 24 hours, the canal narrows. By the 10th day, the internal os is almost closed. The external os forms more slowly, so the cervix is finally formed by the end of the 13th week of the postpartum period. The initial shape of the external os is not restored due to overstretching and ruptures in the lateral sections during labor. The cervix has the appearance of a transverse slit, the cervix is cylindrical, not conical, as before labor.

Simultaneously with the contraction of the uterus, the restoration of the uterine mucosa occurs due to the epithelium of the basal layer of the endometrium, the wound surface in the area of the parietal decidua is completed by the end of the 10th day, with the exception of the placental site, the healing of which occurs by the end of the 3rd week. The remnants of the decidua and blood clots are melted under the action of proteolytic enzymes in the postpartum period from the 4th to the 10th day.

In the deep layers of the inner surface of the uterus, mainly in the subepithelial layer, microscopy reveals small-cell infiltration, which forms on the 2nd-4th day after birth in the form of a granulation ridge. This barrier protects against the penetration of microorganisms into the wall; in the uterine cavity, they are destroyed by the action of proteolytic enzymes of macrophages, biologically active substances, etc. During the process of uterine involution, small-cell infiltration gradually disappears.

The process of endometrial regeneration is accompanied by postpartum discharge from the uterus - lochia (from the buckwheat lochia - childbirth). Lochia consists of admixtures of blood, leukocytes, blood serum, and remnants of the decidua. Therefore, the first 1-3 days after childbirth are bloody discharge (lochia rubra), on the 4th-7th day lochia become serous-sanguineous, have a yellowish-brownish color (lochia flava), on the 8th-10th day - without blood, but with a large admixture of leukocytes - yellowish-white (lochia alba), to which mucus from the cervical canal is gradually mixed (from the 3rd week). Gradually, the amount of lochia decreases, they acquire a mucous character (lochia serosa). On the 3rd-5th week, discharge from the uterus stops and becomes the same as before pregnancy.

The total amount of lochia in the first 8 days of the postpartum period reaches 500-1500 g; they have an alkaline reaction, a specific (musty) smell. If for some reason lochia is retained in the uterine cavity, then lochiometra is formed. In case of infection, an inflammatory process may develop - endometritis.

During pregnancy and childbirth, the fallopian tubes are thickened and elongated due to increased blood filling and edema. In the postpartum period, hyperemia and edema gradually disappear. On the 10th day after childbirth, complete involution of the fallopian tubes occurs.

In the ovaries, the regression of the corpus luteum ends in the postpartum period and the maturation of the follicles begins. As a result of the release of a large amount of prolactin, menstruation is absent in nursing women for several months or for the entire period of breastfeeding. After lactation ceases, most often after 1.5-2 months, the menstrual function resumes. In some women, ovulation and pregnancy are possible during the first months after childbirth, even while breastfeeding.

Most non-breastfeeding women will resume menstruation 6-8 weeks after giving birth.

The vagina is wide open after childbirth. The lower sections of its walls protrude into the gaping genital slit. The vaginal walls are edematous, blue-purple in color. Cracks and abrasions are visible on their surface. The lumen of the vagina in primiparous women, as a rule, does not return to its original state, but remains wider; the folds on the vaginal walls are less pronounced. In the first weeks of the postpartum period, the volume of the vagina decreases. Abrasions and tears heal by the 7th-8th day of the postpartum period. Papillae (carunculae myrtiformis) remain from the hymen. The genital slit closes, but not completely.

The ligamentous apparatus of the uterus is restored mainly by the end of the 3rd week after birth.

The perineal muscles, if they are not injured, begin to restore their function in the first days and acquire normal tone by the 10th-12th day of the postpartum period; the muscles of the anterior abdominal wall gradually restore their tone by the 6th week of the postpartum period.

Mammary glands

The function of the mammary glands after childbirth reaches its highest development. During pregnancy, milk ducts are formed under the influence of estrogens, proliferation of glandular tissue occurs under the influence of progesterone, and increased blood flow to the mammary glands and their engorgement occurs under the influence of prolactin, which is most pronounced on the 3rd-4th day of the postpartum period.

During the postpartum period, the following processes occur in the mammary glands:

• mammogenesis - development of the mammary gland;
• lactogenesis - initiation of milk secretion;
• galactopoiesis - maintenance of milk secretion;
• galactokinesis - removal of milk from the gland,

Milk secretion occurs as a result of complex reflex and hormonal effects. Milk formation is regulated by the nervous system and prolactin. Thyroid and adrenal hormones have a stimulating effect, as well as a reflex effect during the act of sucking,

Blood flow in the mammary gland increases significantly during pregnancy and later during lactation. There is a close correlation between the blood flow rate and the rate of milk secretion. Milk accumulated in the alveoli cannot passively flow into the ducts. This requires contraction of the myoepithelial cells surrounding the ducts. They contract the alveoli and push milk into the duct system, which facilitates its release. Myoepithelial cells, like myometrium cells, have specific receptors for oxytocin.

Adequate milk secretion is an important factor for successful lactation. Firstly, it makes alveolar milk available to the baby and, secondly, it removes milk from the alveoli so that secretion can continue. Therefore, frequent feeding and emptying of the mammary gland improves milk production.

Increasing milk production is usually achieved by increasing the frequency of feeding, including feeding at night, and in the case of insufficient sucking activity in a newborn, by feeding alternately from one mammary gland to the other. After lactation has ceased, the mammary gland usually returns to its original size, although the glandular tissue does not completely regress.

Composition of breast milk

The secretion of the mammary glands, released in the first 2-3 days after birth, is called colostrum, the secretion released on the 3-4th day of lactation is transitional milk, which gradually turns into mature breast milk.

Colostrum

Its color depends on the carotenoids contained in colostrum. The relative density of colostrum is 1.034; dense substances make up 12.8%. Colostrum contains colostrum corpuscles, leukocytes, and milk globules. Colostrum is richer in proteins, fats, and minerals than mature breast milk, but poorer in carbohydrates. The energy value of colostrum is very high: on the 1st day of lactation it is 150 kcal/100 ml, on the 2nd - 110 kcal/100 ml, on the 3rd - 80 kcal/100 ml.

The amino acid composition of colostrum occupies an intermediate position between the amino acid composition of breast milk and blood plasma.

The total content of immunoglobulins (which are mainly antibodies) of classes A, C, M and O in colostrum exceeds their concentration in breast milk, due to which it actively protects the newborn's body.

Colostrum also contains a large amount of oleic and linoleic acids, phospholipids, cholesterol, triglycerides, which are essential structural elements of cell membranes, myelinated nerve fibers, etc. In addition to glucose, carbohydrates include sucrose, maltose, and lactose. On the 2nd day of lactation, the largest amount of beta-lactose is noted, which stimulates the growth of bifidobacteria, preventing the proliferation of pathogenic microorganisms in the intestine. Colostrum also contains a large amount of minerals, vitamins, enzymes, hormones, and prostaglandins.

Breast milk is the best type of food for a child in the first year of life. The amount and ratio of the main ingredients in breast milk provide optimal conditions for their digestion and absorption in the child's digestive tract. The difference between breast milk and cow's milk (the most commonly used for feeding a child in the absence of breast milk) is quite significant.

Proteins of human milk are considered ideal, their biological value is 100%. Breast milk contains protein fractions identical to blood serum. Breast milk proteins contain significantly more albumins, while cow's milk contains more caseinogen.

The mammary glands are also part of the immune system, specifically adapted to provide immune protection to the newborn against infections of the digestive and respiratory tracts.

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Cardiovascular system

After delivery, the BCC decreases by 13.1%, the volume of circulating plasma (VCP) - by 13%, the volume of circulating erythrocytes - by 13.6%.

The decrease in BCC in the early postpartum period is 2-2.5 times greater than the amount of blood loss and is caused by the deposition of blood in the abdominal organs with a decrease in intra-abdominal pressure immediately after childbirth.

Subsequently, the BCC and BCP increase due to the transition of extracellular fluid into the vascular bed.

The circulating hemoglobin level and the circulating hemoglobin content remain reduced throughout the postpartum period.

The heart rate, stroke volume and cardiac output remain elevated immediately after delivery and in some cases are higher for 30-60 minutes. During the first week of the postpartum period, the initial values of these indicators are determined. Up to the 4th day of the postpartum period, a transient increase in systolic and diastolic pressure of approximately 5% may be observed,

Urinary system

Immediately after delivery, hypotension of the bladder and a decrease in its capacity are observed. Hypotonia of the bladder is aggravated by prolonged labor and the use of epidural anesthesia. Hypotonia of the bladder causes difficulty and disruption of urination. The mother may not feel the urge to urinate or it may become painful.

Digestive organs

Due to some atony of the smooth muscles of the digestive tract, constipation may be observed, which disappears with a balanced diet and an active lifestyle. Hemorrhoids (if they are not strangulated), which often appear after childbirth, do not bother women in labor much.