Significant changes in the postpartum period occur in the reproductive system of the woman, especially in the uterus.
Involution of the uterus
In the first hours after the period, there is a significant tonic contraction of the uterus. Against the background of increased tone, peripheral muscle contraction (contraction of the contraction) occurs, contributing to a decrease in the size of the uterus. In this case, the walls of the uterus thicken, it acquires a spherical shape, slightly flattened in the front-back direction.
The uterine base at the beginning of the postpartum period is 13-15 cm above the pubic symphysis, the length of its cavity (from the outer opening of the cervical canal to the bottom) reaches 15-20 cm, the thickness of the walls in the bottom is 4-5 cm. The transverse size of the uterus immediately after birth is 12-13cm, weight - 1000g. The anterior and posterior walls of the uterus are adjacent to each other.
The uterus decreases in the direction from the bottom to the neck. The contractility of the lower part and cervix is much lower, therefore in the lower part the wall of the uterus is thinner. The vaginal part of the cervix hangs down into the vagina, its edges are refined, often have lateral ruptures and superficial injuries (tears). Due to the contraction of the uterus body and the circular layer, the myometrium, located around the inner throat, indicates the boundary between the upper and lower uterine regions. The bottom of the uterus in the first days of the postpartum period touches the abdominal wall, an angle is formed between the body and the cervix of the uterus, which is opened forward (antlexio uteri). This is facilitated by the relaxation of the ligament apparatus and the fact that the woman in bed lies on her back. In the first days after delivery, the uterine mobility is increased, which is also explained by the stretching and lack of tonus of its ligamentous apparatus. The uterus easily shifts upwards, especially when the bladder is overloaded.
Reducing the size and mass of the uterus contributes to the reduction of its muscles and the morphological changes that occur while doing so. Muscles that contract, compress the walls of the blood and lymph vessels. The lumen of the vessels narrows, many of them are closed and subjected to obliteration. As a consequence, there is a sharp restriction of the nutrition of myometrium cells, their fatty degeneration, decay and resorption.
The state of contraction of the uterus is judged by the level of standing of its bottom. During the first 10-12 days after birth the bottom of the uterus descends daily by approximately 1-1.5 cm. On the first day after birth, the uterus's bottom is at the level of the navel (due to the increase in the pelvic floor muscle tone), which is higher than immediately afterwards childbirth. In each subsequent day, the level of standing of the uterine fundus decreases by one transverse finger. On the second day the bottom of the uterus is located above the pubic symphysis by 12-15 cm, on the fourth day by 9-11 cm, on the sixth day by 8-10 cm, on the eighth day by 7-8 cm, on the tenth day by 5-6 cm and the twelfth by the fourteenth day is in the bosom. By the end of the 6-8th week after delivery, the uterus in size corresponds to that of a non-pregnant woman (lactating mothers may even be less). The weight of the uterus by the end of the first week decreases by more than half (by 500-600g), the second week to 350g, the third week to 200g, and at the end of the postpartum period 60-70g.
Involution of the uterus depends on the general condition of the woman's organism, age, the number of previous births, the peculiarities of the course of pregnancy and childbirth. In case of multiple pregnancy, polyhydramnios, large fetus and anomaly of labor, the involution of the uterus is delayed (subinvolution of the uterus).
In a peculiar way, the inner surface of the uterus is healing, which, after separation of the placenta and membranes, is a vast wound surface, especially in the placental area, because during the delivery the surface part of the visible form of the mucous membrane is separated. On the outcrops of the uterine wall, only the basal layer of the epithelial tissue of the endometrium and the remains of the deep glandular layer of the palpation can be detected. A large number of small cells that appear among the residues of decidual tissue form a layer of granulation tissue - the granulation shaft. The latter is quickly covered with an epithelial layer, which is formed from the remains of glands. The proliferation of the epithelium leads to the regeneration of the wound surface and its transformation into a typical mucous membrane. The wound surface in the placental area is completely covered with a thin layer of mucosal cells on the tenth day of the postpartum period. Renewal of the full-fledged endometrium is completed only eight weeks after delivery.
In the process of healing of the inner surface of the uterus, postpartum discharge appears. Fragments of decidual tissue, fragments of fetal membranes, blood clots undergo phagocytosis and active proteolysis with the formation of a wounded secretion (lochia). The character of lousy changes in accordance with the processes of cleaning and healing of the inner surface of the uterus. In the first 2-3 days after delivery, the lochia have a bloody character (lochia rubra), starting from the 3rd day they become bloody-serous with a predominance of leukocytes (lochia rubro-serosa), on the 7-9th day after birth - serous (lochia serosa ). The total number of suckers in the first eight days reaches 500-1500g.
Lochia have a neutral or alkaline reaction and a specific smell. From ten days after the birth, the lochia acquire a serous-clyseal character (lochia alba). There is no excretion from the uterus for 5-6 weeks. Sexual life is not permitted until the eighth week of the postpartum period.
The involution of the cervix lags in intensity from the involution of the uterus body. Immediately after delivery, the cervical canal freely passes the hand. 10-12 hours after birth, the canal becomes conical, the inner throat passes 2-3 fingers, the day after the birth, due to the contraction of the circular muscles surrounding the inner opening of the cervical canal, the inner shed passes two fingers, the cervical canal is funnel-shaped. On the third day, only one finger passes through the inner pharynx. Until the tenth day, the cervical canal is formed. The outer eye is closed in the third week of the postpartum period. The cervix acquires a cylindrical shape instead of conical before delivery, the external suture becomes slit-shaped in the transverse direction.
The ligamentous apparatus, which was in the first days after childbirth, in a state of relaxation, gradually acquires the usual tone and for the third week becomes the same as before pregnancy.
Changes in the ovaries
Ovaries in the postpartum period undergo significant changes. The regress of the yellow body ends and the maturation of the follicles begins. In most (55-60%) of women who do not breast-feed, menstruation occurs 6-8 weeks after delivery. In most nursing mothers (80%), menstruation is inhibited for several months or for the entire breastfeeding period.
The first menstruation after childbirth is often "ANOVULATIVE", i.e. The follicle ripens, but ovulation does not occur and the yellow body does not form. The follicle undergoes regression, and at the present time the disintegration and separation of the mucous membrane of the uterus begins, in which processes of proliferation have occurred (under the influence of estrogen hormones), but there is no secretory transformation of the endometrium. Over time, the process of ovulation, and with it the menstrual function is completely restored.