Diagnostic Methods in Pregnancy - Essay Example

Diagnostic Methods In Pregnancy Affiliation Pregnancy and diagnostic methods Many physiological changes in the mother marks pregnancy. Many medical conditions and complications can arise with the changes of the haemodynamic components and volume as well as change of hormonal constituents in the body (Carlin & Alfirevic, 2008). In the event of these changes, major obstetric and non-obstetric conditions that require vigilant diagnostic methods arise. Considering pregnancy to be a possible risk to maternal health, it is important not to delay the diagnosis of any other conditions such as hemorrhagic ovarian cysts that can further deteriorate the health of the mother. With the type of diagnostics required, magnetic resonance imaging (MRI), computed tomography (CT) scan, and ultrasound (US) are used; each of these diagnostic methods has both detrimental and beneficial effects on a normal pregnancy. During the first trimester organogenesis takes place in the fetus, teratogenic substances from the environmental will cause organ agenesis and malformations, also death of the fetus is very likely (Holmes, 2011). The teratogens can be in the form of chemicals and radiations, which the mother is exposed to in the environment. With the basic knowledge on teratogenic substances and effects on the fetus, it is important that risks and benefits of any diagnostic methods are determined. Computed tomography This is a non-invasive method that uses of narrow beam x-ray to scan successive layers of tissue in the body for a cross sectional view. This diagnostic method is reliably used in diagnosing pelvic, neurological, skeletal abdominal thoracic conditions and cancers (Shetty, 2010). During pregnancy, it is used to diagnose congenital malformations such as neural tube defects tumors and hemorrhagic conditions in the fetus. However, when the CT scan is done in pregnancy it is likely to bring about the fear of teratogenic and carcinogenic effects due to the ionizing radiations to the growing fetus. The effects are more pronounced when the fetus is in the field of view during the procedure as chances of exposure to the beams are increased. Frequent exposures to the CT scans can also bring about stochastic effects through causing DNA changes in the fetus (Pommier et al., 2009). CT scan has been associated with use of contrast dyes to obtain clear images. Barium and other iodine based intravenous chemicals are used in the process; however, these chemicals have hazardous effects to the growth of the fetus and the health of the mother. Manriquez et al. (2010) also found out that the existence of maternal preeclampsia as an underlying medical condition can be worsened by anxiety and discomforts related to frequent use of computed tomography scans. The release of adrenaline and cortisol; the stress hormones, cause elevation of the blood pressure and pulse rate that can precipitate placental blood supply insufficiency. As a result, maternal and fetal distress can occur if the condition is not managed promptly. There is an increased risk of anaphylaxis with the renal function impairment during CT scan (Bae, 2010). This will consequently affect the fluid volume in the maternal body as well as accumulation of waste products causing fetal toxicity. The underlying maternal medical conditions such as asthma and hyperemesis gravidarum are aggravated by contrast anaphylaxis with laryngeal edema, bronchospasm and hypotension as well as nausea and vomiting. Major electrolyte imbalances will also be a sequel. During the process of performing a CT scan the pregnant mother is required to hold her breath for a preferred period of time, this may interfere with the normal oxygenation process thereby causing hypoxia to the fetus due to placental oxygen insufficiency (Wolthaus et al., 2006). The high doses of CT scan radiation used such as ;chest CT scan is equivalent to 350 chest x-rays and the abdominal CT scan is equivalent to 400 x-rays will increase the risk of leukemia and childhood cancers. The growing fetus tends to have an increased risk from the accumulation of radiations than it is in adults, this may lead to future cancer development upon repeated exposures. Alteration of cellular structures and component also form the path of oncogenesis occurs through time to manifest in the future years. Human and machine errors may cause a surge of energy threshold above 150mGy during a normal CT scan procedure (Yeung et al., 2013). This causes serious teratogenic effects leading to the fetal death as well. It is therefore recommended that the medical practioners weighs the risks and benefits of performing a CT scan and discusses them with the client most preferably bearing in mind the gestation period. The patient must be shielded to avoid excessive exposure to radiations. It is also important that the anatomic coverage be limited to the region of interest avoiding unnecessary exposure of the fetus to the radiations. To avoid excessive exposure of the fetus to the teratogenic radiation, a limit must be place on the number of times a pregnant mother is taken for a CT scan (Boutis et al., 2013). Table 1 Advantages of CT scan Disadvantages of CT scan 1. non-invasive diagnostic method 1. teratogenic and carcinogenic effects due to the ionizing radiations 2. diagnose congenital malformations such as neural tube defects tumors and hemorrhagic conditions in the fetus 2. stochastic effects through causing DNA changes in the fetus 3.risk of leukemia due to ionizing radiations 4. use of intravenous contrast complicate underlying medical conditions Anaphylaxis from the contrast dyes Magnetic Resonance Imaging (MRI) This is a diagnostic method that uses the magnetic fields and radiofrequency signals to create and show different tissue compositions, the powerful magnetic field is useful in dispersing the nuclei in the body (Bulas & Egloff, 2013). This method if preferred because it presents images in their axial, sagittal and coronal planes hence the most difficult to see body parts are viewed. MRI has been used to evaluate placental and fetal anomalies as well as obstetric conditions. Regardless of the benefits elicited in using the MRI, several other unwanted effects have been identified. There is the risk of acoustic damage from the MRI during the first trimester of pregnancy, the loud sound and noise of 80-130 dB from the MRI machine are generated by the MR scanners that are under the direct effect of oscillating electromagnetic waves (Levine, 2006). Sound generated is considered detrimental to hearing ability of the fetus since excess sound wave frequencies interfere with the normal development and functioning of internal ear structures. During the imaging procedure there is increased heating of maternal tissues, which impacts on the overall body temperature causing maternal hyperthermia. The fetus can be affected indirectly through placental blood insufficiency as the intracellular and extracellular fluid balance is affected through loss of water by increased diaphoresis. Inadequate blood supply to the placenta consequently deprives the fetus of oxygen and nutrients required to sustain normal fetal development. Physical trauma is a risk especially when the environment in which the MRI is conducted has a lot of metallic equipment such as oxygen gas cylinders. The strong electromagnetic field created can easily pull the equipment and even the client’s bed and wheel chair since they are made of metallic materials. The impact created causes injury to the mother and by extension fetal trauma. According to Hu, Song, Chen & Chen (2014), the mandatory use of intravenous gadolinium in MRI is found to have teratogenic effects to fetal growth. Since gadolinium enhances clarity of imaging for maternal tumors or placental abnormalities, its use is preferred for accurate findings. This dye crosses the placenta and may cause fetal organ malformations and agenesis if used during the first trimester. Fetal kidneys are overworked since the dye is excreted through these organs; the nephrons are adversely affected since they have not attained the maturity state to handle heavy chemical substances in the body. The health facility must observe the safety guidelines in performing an MRI to a pregnant patient. The intravenous gadolinium is made a contraindication in pregnancy unless it is necessary to use. The risks and benefits associated with the use of gadolinium must be discussed with the expectant mother. The mother must be protected from loud noise by use of earphones and pads. The time of exposure to the MRI machine must be limited and MRI to be used only if other nonionizing diagnostic methods proof inefficient. Before MRI procedure all jewelry and other metallic equipment that are in contact with the client must be removed to avoid electromagnetic accidents. Table 2 Advantages of MRI Disadvantages of MRI 1.Enhances viewing of hard to see body parts 1. risk of acoustic damage with sound and noise of 80-130 dB 2. used in diagnosing fetal and placental abnormalities. 2. increased heating of maternal tissues casing hyperthermia 3. noninvasive diagnostic procedure Physical trauma from strong magnetic field pulls on metallic equipment. 4. no ionizing radiation involved 3.risk of teratogenicity from use of intravenous gadolinium contrast 5.provides unique clinical images of high soft-tissue contrast Ultrasound This is the use of sound to locate the depth and structure within soft tissues and fluid medium. Waves generated by the ultrasound machine are reflected back as an echo that forms images of the internal organs. During pregnancy ultrasound is used to determine the growth status of the fetus and to locate the position of the fetus in utero (Hsu & Euerle, 2012). Fetal defects can be detected using this diagnostic method. Of all the uses, the most important function of the ultrasound is in determining the age of the fetus, the placental attachment, fetal position, movement breathing and heart rate as well as the amount of amniotic fluid (Kus & Juliano, 2014). Ultrasound has been found to cause insignificant harm to the growing fetus and the mother during pregnancy. However, there is a possibility of damage depending on the type of ultrasound conducted during pregnancy; the use of trasnsvaginal ultrasound is said to cause increased exposure of the embryo in the first trimester during which organogenesis is taking place. Abramowicz (2013) also found out that the high level of thermal effect and radiation stress is considered to affect the cell differentiation and migration during organ formation in the first trimester. Thermal effects are more pronounced with the use of Doppler ultrasound (Alfirevic, Stampalija, & Gyte, 2010). The Doppler ultrasound with stronger acoustic output and high frequency pulses is generally hazardous in the first trimester during which the fetus tissues are more sensitive and apparently loose. It is for this reason that use of Doppler ultrasound is contraindicated in the first trimester of pregnancy. Other effects of exposure to prenatal ultrasound include; intrauterine growth restriction, dyslexia, delayed speech and left-handedness associated with the sonar effects of the ultrasound machines. It is important to observe the following measures to avoid possible fetal harm: the acoustic output per session must be regulated, the length of exposure to the ultrasound machine must be brief enough, and vaginal ultrasound must be avoided during the first trimester to prevent fetal exposure to harmful energy forms (Salvesen & Lees, 2009). Table 3 Advantages of ultrasound Disadvantages of ultrasound 1.a noninvasive procedure 1. Fetal acoustic damage may occur with excessive sound energy. 2.gives clear picture of soft tissues and amniotic fluid 2. Excessive thermal energy affects normal cell differentiation and migration. 3.uses sound effect other than ionizing radiations Delayed speech and dyslexia may occur 4. Preferred modality for diagnosis and monitoring of pregnancy. Conclusion Throughout pregnancy, it is important that the health of both the mother and the developing fetus be not compromised. It is the responsibility of the health care provider to ensure that the diagnostic methods ordered and performed at this stage of life are safe and only those considered harmful in the event of absolute necessity. Even though some diagnostic methods such as ultrasound pose a constricted range of adverse effects, unnecessary and frequent exposure of the mother to ionizing radiations and strong sound waves must be avoided (Halligan & Zecevic, 2011). The susceptibility of the embryo to various forms of energy and radiations must be considered in choosing the diagnostic method to be used. To effect these requirements, the health institutions must develop protocols and policies governing the indications for ultrasound, MRI and CT scans during pregnancy. References Abramowicz, J. S. (2013). Benefits and risks of ultrasound in pregnancy. Seminars In Perinatology, 37(5), 295-300. doi:10.1053/j.semperi.2013.06.004 Alfirevic, Z., Stampalija, T., & Gyte, G. M. (2010). Fetal and umbilical Doppler ultrasound in normal pregnancy. Cochrane Database of Systematic Reviews (Online), CD001450. doi:10.1002/14651858.CD001450.pub3 Bae, K. T. (2010). Intravenous contrast medium administration and scan timing at CT: considerations and approaches. Radiology, 256, 32–61. doi:10.1148/radiol.10090908 Boutis, K., Cogollo, W., Fischer, J., Freedman, S. B., David, G. B., & Thomas, K. E. (2013). 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