Clinical Physiology for Paramedics, Reproduction and Pregnancy - Essay Example

?Reproduction and Pregnancy Introduction Pregnancy is one of the most natural human experiences for women. Although it is mainly under the reproductive system, its actual unfolding can involve most systems of the body in order to ensure successful and safe outcomes. To most people, the idea of pregnancy begins with conception and ends with the birth, however, the reproductive process starts even earlier for women, as early as their own conception and fetal development. This paper will discuss the normal development of pregnancy, its impact on the main body systems, as well as how the body compensates for the changes which occur during the pregnancy. It will describe the physiology of normal pregnancy, relating it to fetal development; it will also describe the changes seen in the musculoskeletal and digestive systems seen during pregnancy. This paper shall also describe the impact of pregnancy to the cardiovascular, respiratory and renal system, mostly changes in the body which are made in order to accommodate the pregnancy. Body Physiology of normal pregnancy Stages of prenatal development Marking pregnancy is mostly done from the first day when the last menstrual period is experienced, with the gestational age of the fetus being counted from that first day (Martini, et.al., 2012). The woman’s menstrual cycle is part of the changes which are taking place to accommodate possible conception. These changes include the increase of follicle stimulating hormone (FSH) which then triggers folliculogenesis and later oogenesis (Martini, et.al., 2012). Following these developments, a mature egg cell would emerge as the female gamete. Where the mature egg is fertilized by the male gamete or the spermatozoa, fetal development follows. The fertilized egg is then known as the zygote. This marks the germinal stage, which is the first stage of prenatal development. The mature egg cell and the spermatozoa normally unite in the fallopian tubes. As the egg is fertilized, it moves into the uterus (Martini, et.al., 2012). The transport usually takes up to a week. The zygote already initiates cell division within 24 to 36 hours following fertilization. The cell division is rapid, ensuring the next stage of development – the blastocyst. This blastocyst then reaches the uterus, implanting on its walls. Embryogenesis follows as the cells of the zygote form differentiate to form the different parts of the baby (Chaille, 2006). This is the second stage of prenatal development, also known as the embryonic stage. Embryogenesis unfolds in about 10 weeks of gestation. The different cells start forming the different parts of the body with basic parts including the organs and the nervous system. As embryogenesis ends, some features for the fetus can already be distinguished including the fingers, eyes, and ears (Chaille, 2006). Some structures like the placenta and umbilical cord also become more apparent. Following 10 weeks of gestation, the embryo develops more prominently into the fetus. At this point, the fetus measures about 30 mm. The illustration below shows the size of the pregnancy. This marks the last stage of prenatal development, also known as the fetal stage. Figure A (1st month of pregnancy) Placental development and function The ultrasound would also pick up fetal heartbeat with some involuntary movements of the fetus also noted (Walley, et.al., 2010). Fetal development would also include the continued development of the body systems and organs. Sex organs are already developed by the third month of development. Growth in weight and length is also sustained during fetal development. Brain activity becomes apparent at the 5th and 6th week of fetal development (Walley, et.al., 2010). No conscious thought is however notable at this stage. Synaptic formation is seen at 17 weeks with increased pace at 28 weeks, continuing up to the 3rd or 4th month following delivery. During the last few weeks of fetal development, the baby’s length and weight increases even more, reaching viable weight by delivery. The figure below estimates a viable infant at 38 weeks of gestation. Pregnancy development impact on systems Uterine changes The impact of pregnancy on the body systems shall be based on the developments and impact observed at each trimester of the pregnancy (Walley, et.al., 2010). These changes may be cardiovascular, renal, respiratory, and even metabolic. These changes are needed in order to accommodate the pregnancy, as well as prevent complications in fetal and maternal development. During pregnancy, the uterine changes include its upward growth, pushing away from the pelvis. The fundus can be palpated at 12 weeks of pregnancy and the myometrium also pushes upward (Lederman and Weiss, 2009). The growth of the uterus follows the growth of the fetus. It naturally leans to the woman’s right side with ligaments supporting its growth. Structural and functional changes Musculoskeletal changes Changes in gait and posture are observed during pregnancy in order to accommodate the growing fetus. These changes also imply the occurrence of musculoskeletal disorders and fall risks, including lower back pain, leg cramps, as well as pain in the pelvis and hip (Rosene-Montella and Lee, 2008). The image below highlights these changes. As the pregnancy progresses, the pelvis would tilt and the woman would arch her back to compensate and maintain balance. Poor posture may be seen as the pregnancy progresses. Muscle contraction is decreased and lower back alignment is compromised. Gait changes are often observed with their step lengthening because of the weight gain and postural adjustments (Rosene-Montella, 2008). Their foot can also increase in size, and the additional weight can decrease the arches of their feet, thereby increasing the width and length of their feet. This would explain why these women often adapt a waddling gait during their pregnancy. Their center of balance also changes and these women eventually learn to adjust their bodies in order to secure balance (Rosene-Montella and Lee, 2008). With the expanding uterus, body aches and pains in the back, the perineal area, and thighs may often manifest. Pain near the pelvic bone may also be caused by the increasing pressure of the infant’s head and increased weight (Walley, et.al., 2010). Some women also feel pain running down their back, their leg and sometimes their knees, and this phenomenon is otherwise identified as sciatica. As the uterus increases pressure on the sciatic nerve, sciatica manifests. Gastrointestinal changes Due to increased B-human chorionic gonadotrophin, pregnant women are likely to go through nausea and vomiting (Blackburn, 2012). Gastric emptying is also reduced alongside gastroesophageal sphincter strength causing acid reflux. The intestinal muscles can also have a decreased motility, often leading to constipation and higher rates of water absorption (Blackburn, 2012). Maternal Physiological Adaptations of the Cardiovascular System The plasma volume for the woman is increased as the pregnant woman is now nourishing herself and her fetus. Aldosterone also increases and with it, plasma volume elevates (Steer, et.al., 2006). Higher heart rate, stroke volume, and cardiac output also increase as a result of higher plasma volume. The vascular resistance is decreased as the smooth muscles relaxes. Dilation of the blood vessel results due to higher progesterone levels. Blood pressure therefore falls (Topol and Califf, 2007). Diastolic blood pressure falls from 12 to 26 weeks of gestation, rising again to usual levels prior to pregnancy at 36 weeks gestation. With blood pressure increasing for some women, pre-eclampsia can be considered (Topol and Califf, 2007). Cardiac functions are also changed with higher heart rates and higher stroke volume. Lower vagal tone and higher sympathetic tone is the possible cause of such phenomenon. Blood pressure for women can fluctuate with lower rates in the first trimester due to lower sensitivity for angiotensin (Elkayam and Gleicher, 1998). Haemodynamic Changes As was already mentioned above, plasma volume changes are observed during pregnancy. The red blood cells also increase about thirty percent of their usual volume. Hematocrit levels are lower because of dilution (Fortner, 2007). The white blood cells increase with platelet levels decreasing to the lower normal levels. These women have higher rates for coagulability, increasing their risk for blood clots and embolisms (Fortner, 2007). This is attributed to their liver increasing their coagulation levels, mostly fibrinogen and factor VIII. Edema is common during pregnancy as the uterus exerts pressure on the veins and affects lymphatic drainage from the legs (Otto, 2012). Dizziness and lightheadedness is also felt by these women. This may be attributed to the growth of more blood vessels during the early months of pregnancy. The fetus can also cause pressure on the blood vessels can cause decreased oxygen supply to the brain, leading to lightheadedness. In some cases, as the infant’s demands on the woman’s body increases, the woman becomes more lightheaded and dizzy (Chaille, 2006). Some women also feel tired even if they have had long hours of sleep. This is common during the first trimester as the body is prompting the body to get more rest (Martini, et.al., 2012). As the third trimester sets in, exhaustion also manifests with sleeping becoming more of a challenge and the baby’s demands on the body take its toll on the woman’s sleeping, eating, and general metabolism. Physical changes The woman’s nipples and areola usually darken immediately following conception, mostly because of fewer hormones produced by the ovaries (Pillitteri, 2007). A more visible pregnancy bump is noted by the second trimester, with breast development becoming also more visible. The women are more energized on the second trimester with additional weight often observed as morning sickness is no longer a problem (Levine and Munsch, 2010). The uterus also expands to accommodate the growing embryo. Major weight gain is observed in the third trimester. The fetus also grows at a faster pace, often up to 28 grams in a day (Levine and Munsch, 2010). The belly usually changes in shape during these last months of pregnancy, depending on the fetal positioning and movement. Stretch marks are also more apparent and may be seen on the thighs, abdomen, and breasts (Rosenberg, 2008). As the skin stretches to accommodate the infant, scars on the skin form and are seen as stretch marks. Some women declare that they may also observe darker nipples and may observe a dark line on their skin from their belly button to their pubic area (linea nigra as seen on Figure below). Some darkening in the skin may also be seen on their cheeks, nose, and upper lip (Chaille, 2006). Some patches (Figure 2) known as melasma are also observed on both sides of their face and mostly seen on darker skinned women. Maternal Physiological Adaptations of the Respiratory System Respiratory changes are observed with minute ventilation increased by 40% in the first trimester. This is attributed to higher progesterone levels (White and Portenfield, 2013). There is hyperemia during pregnancy, as well as higher phagocytic activity, often alongside epistaxis and rhinitis. The thorax and abdomen also adjust due to growing fetus, the subcostal angle increasing to as much as 103 degrees (White and Portenfield, 2013). Diaphragmatic excursion is also observed. All these changes may cause these women to appear barrel chested during pregnancy. Maternal Physiological Adaptations of the Renal System Due to the expansion of the embryo and the belly, weaker bladder control is noted for the woman, often prompting frequent urination and causing backaches (Chaille, 2006). With better fetal viability, the movements of the fetus become even more regular, sometimes stronger. This can also cause pain the ribs and spinal area. As the head descends into the pelvic area, the cervix and the perenium areas becoming flatter and the head of the infant is now felt by the mother in her vaginal area. A lighter feeling for the mother is felt at this point with breathing becoming easier as the pressure of the infant is not anymore on the upper abdomen (Martini, et.al., 2012). However, the bladder capacity is decreased as the pressure is now transferred to the pelvic area and rectum. Sometimes mothers feel like the fetus would likely drop out of their abdomen at any time during these times. Maternal activity becomes more limited with their sleep positions often impacting on the development of the fetus based on lesser blood flow. Fluid and electrolyte balance Fluid requirements are increased by pregnancy, with urine outputs sometimes decreasing. As a result, fluid retention may be experienced. Electrolyte intake is increased and net retention of sodium, chloride, and potassium observed until the final week of pregnancy with urinary output decreasing (Atherton, et.al., 1982). Summary These changes in the women’s body are all attributed to the infant’s growing impact on the woman. As it continues to grow, it impacts on the surrounding organs and systems, decreasing their normal capacity and functions. The body makes the necessary adjustments to accommodate the growing infant. In general, these changes are seen on the GI tract, the respiratory system, and the renal system as these are the systems pressed into by the growing infant. After delivery, the normal functions of the woman’s body are gradually restored. References Atherton J, Dark J, Garland M, Pidgeon J & Soni S, 1982, Changes in water and electrolyte balance, plasma volume and composition during pregnancy in the rat, J Physiol, 330: 81–93. Blackburn S, 2012, Maternal, Fetal, & Neonatal Physiology4: Maternal, Fetal, & Neonatal Physiology, Elsevier Health Sciences, New York. Chaile P 2006, Characterization of developmental changes during the establishment and progression of pregnancy in viviparous nearshore rockfish (sebastes spp.) And the determination of patterns of post-natal growth, ProQuest, New York. Elkayam U & Gleicher N, 1998, Cardiac Problems in Pregnancy: Diagnosis and Management of Maternal and Fetal Heart Disease, John Wiley & Sons, London. Fortner K, 2007, The Johns Hopkins Manual of Gynecology and Obstetrics, Lippincott Williams & Wilkins, New York. Lederman R & Weis K, 2009, Psychosocial Adaptation to Pregnancy: Seven Dimensions of Maternal Role Development, Springer, California. Levine L & Munsch J 2010, Child development: An active learning approach, SAGE, California. Martini F, Nath J & Bartholomew 2012, Fundamentals of anatomy & physiology, 9th edn, Pearson Benjamin Cummings, San Francisco Otto C, 2012, Practice of Clinical Echocardiography, Elsevier Health Sciences, New York. Pillitteri A, 2007, Maternal & Child Health Nursing: Care of the Childbearing & Childrearing Family, Lippincott Williams & Wilkins, London. Riley L 2006, Pregnancy: The ultimate week-by-week pregnancy guide, New York, Meredith Books. Rosenberg S 2008, Natural pregnancy, natural baby: Natural remedies for pregnancy, birth and post-partum discomforts, Xlibris Corporation, California. Rosene-Montella K & Lee R, 2008, Medical Care of the Pregnant Patient, ACP Press, London. Steer P, Gatzoulis M, & Baker P, 2006, Heart Disease and Pregnancy, RCOG, New York. Topol E & Califf R, 2007, Textbook of Cardiovascular Medicine, Volume 355, Lippincott Williams & Wilkins, London. Walley J, Simkin P, Keppler, A 2010, Pregnancy, childbirth, and the newborn: The complete guide, Simon and Schuster, New York. White B & Portenfield S, 2012, Endocrine and Reproductive Physiology, Mosby Physiology Monograph Series, Elsevier Health Sciences, New York. Read More