Physiology Of Normal Puerperium Pdf Downloadl
Irineo Kortig
The female body goes through immense changes during a pregnancy that involve all organ systems in the body. These changes result in physiology that differs from that of a non-pregnant female. Additionally, abnormalities in the development of pregnancy can lead to further complications for both mother and fetus. With the maternal mortality rate in the United States reaching almost 18 deaths per 100,000 live births in 2009, a drastic increase from the 7.2 deaths per 100,000 in 1987, it has become more critical for all healthcare providers to understand the typical changes that accompany pregnancy, as well as recognize changes that go beyond typical pregnancy symptoms.[1]
If we are impressed at how much the uterus has grown during the 9 months of pregnancy, we should be even more impressed with how quickly it reverses this growth. The uterus decreases from a weight of around 1 kg to less than 100 g. The uterus returns to around its pre-pregnant state in just 6 weeks. Despite this, the turnover of muscle proteins, connective tissue and cellular remodeling occurring during involution is relatively under-appreciated and under-researched, which perhaps can be said of the whole puerperium, compared with pregnancy. Much has been made of how to assess the rate of involution by palpation and tape measure to determine the distance between the symphysis pubis and uterine fundus. Deviation from accepted normal values could indicate an abnormality and the need for clinical investigation. Studies over the past 20 years or so have indicated that there is so much normal variation between women, and error in the measurements, that these manual measurements of involution are rarely worth doing..4,5 Sonographic data are more reliable, but not warranted for routine use. Palpation, however, showing an increase in fundal height needs further evaluation. Delayed involution may be a sign of retained products of conception or endometritis, or a high uterus due to pelvic hematoma or abscess.
The skin, hair, and nails rapidly reverse any changes that occurred in pregnancy. The dark pigmentation that occurs in the vulva, abdominal wall and face in some women, passes. Any edema of pregnancy is quickly dissipated. Stretch marks (striae gravidarum), become less apparent as the puerperium progresses. Most women experience hair loss over the first few months postpartum, which although potentially upsetting, is only restoring growth to non-pregnant levels. The loosening of ligaments and muscles, especially the diastasis recti, that has occurred with pregnancy, gradually reverse in the puerperium. Exercise and sporting activity should be reintroduced during the early postpartum period. This may be within a week following a normal vaginal delivery but delayed by a few weeks following a cesarean section delivery. The American College of Obstetricians and Gynecologists advises postpartum women should get at least 150 minutes of moderate-intensity aerobic activity every week.12 The general benefits of exercise on health and well-being underlie this advice, especially as a way to help increase mood, lose weight and strengthen muscle.13,14
Although respiratory problems may be common in pregnancy, the respiratory system is little affected by the puerperium. Abnormal breathing patterns should alert clinicians to postpartum complications, such as infection.
Significant changes in cardiovascular parameters occur in the puerperium and beyond. Major adaptations to the maternal cardiovascular system occur during pregnancy, which are necessary to ensure adequate blood supply to the placenta and fetus. By the third trimester of pregnancy, heart rate, stroke volume and cardiac output are increased; there is an increased plasma volume and decreased peripheral vascular resistance. Table 1 demonstrates that significant changes occur to these parameters immediately after parturition. While much of the cardiovascular system has returned to normal by 6 weeks after birth, cardiac output does not normalize until 24 weeks after birth, and peripheral vascular resistance remains elevated and is still higher than normal at 6 weeks.
Preparation for lactation occurs during puberty and pregnancy, well before puerperium and the initial latch of the newborn infant. It is important to appreciate the structure and cellular components of the lactating breast in order to fully understand the physiology of lactation (see Figure 2). During puberty, increasing estrogen and progesterone levels stimulate development of new alveolar buds from which milk-secreting mammary gland lobules will evolve. During pregnancy, the volume of breast tissue increases and formation of new alveolar-lobular structures continues alongside further maturation of the milk-producing apparatus. Estrogen, progesterone and prolactin are necessary for such development in pregnancy; however, other factors including placental lactogen and growth hormone also play a role. Little or no milk is produced during pregnancy because high levels of progesterone and estrogen block the secretory activity of the cells in the alveoli. During labor and lactation, further growth and differentiation occurs increasing the glandular component of the breast.
The consequence of high procoagulation activity is increased fibrin turnover, as indicated by increasing concentrations of D-Dimers (D-D), recognized as the most sensitive markers of secondary fibrinolytic activation, with successive trimester [3]. Changes in hemostatic systems occur gradually in normal pregnancy, reaching the highest degree of hypercoagulability in the third trimester and disappearing slowly during puerperium [2]. They should be considered an adaptive mechanism protecting a pregnant woman against delivery hemorrhage and generally do not have any clinical implications. In one recent meta-analysis, the most common complication, venous thromboembolism (VTE), was found to have low incidence, estimated at 1.2 per 1000 births [4]. However, the risk of pulmonary embolism (which often results from VTE) has been found to be higher and occurs 4-6 times more often than in nonpregnant women of similar age [5].
During normal pregnancy total body water increases by 6 to 8 liters, 4 to 6 liters of which are extracellular, of which at least 2 to 3 liters are interstitial. At some stage in pregnancy 8 out of 10 women have demonstrable clinical edema. There is also cumulative retention of about 950 mmol of sodium distributed between the maternal extracellular compartments and the product of conception. Thus, changes in factors governing renal sodium and water handling accompany alterations in local Starling forces whereby there is a moderate fall in interstitial fluid colloid osmotic pressure (COPi) and a rise in capillary hydrostatic pressure (Pc), as well as changes in hydration of connective tissue ground substance. Edema is a traditional criterion for diagnosing pre-eclampsia, but should no longer be used as its detection is not clinically useful. The role of diuretics in obstetric practice should be restricted to the management of pulmonary edema in pre-eclampsia. Volume expansion therapy in pregnancy runs the risk of pulmonary or cerebral edema, particularly in the immediate puerperium. Vulval edema and erythematous edema associated with deep venous thrombosis are rare but dangerous complications of pregnancy.
The second and third trimesters of pregnancy are associated with dramatic changes in maternal anatomy and physiology. The most obvious anatomical sign of pregnancy is the dramatic enlargement of the abdominal region, coupled with maternal weight gain. This weight results from the growing fetus as well as the enlarged uterus, amniotic fluid, and placenta. Additional breast tissue and dramatically increased blood volume also contribute to weight gain. Surprisingly, fat storage accounts for only approximately 2.3 kg (5 lbs) in a normal pregnancy and serves as a reserve for the increased metabolic demand of breastfeeding.
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