- When LMP and Ultrasound Dates Don’t Match: When to Redate?
- Women’s Health Care Physicians
- Committee opinion no 611: method for estimating due date.
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- Women’s Health Care Physicians
With over 1, ob-gyn related apps on the market, ACOG’s EDD Calculator is the only one that reconciles the discrepancy in due dates between the first ultrasound and the date of the last menstrual period. The EDD Calculator also recalculates the due date based on ultrasound or on assisted reproductive technology ART to assist health care providers with patients who undergo embryo transfer, or IVF, in adherence to the Committee Opinion. ACOG supports the use of the EDD Calculator and will transition away from the physical plastic wheel in favor of this modern reinvention. That’s the highest score among all of the other pregnancy wheel apps that my colleagues and I previously evaluated in our study published in Obstetrics and Gynecology in June
Wharton, MD. This document reflects emerging clinical and scientific advances as of the date issued and is subject to change. The information should not be construed as dictating an exclusive course of treatment or procedure to be followed. This information is designed as an educational resource to aid clinicians in providing obstetric and gynecologic care, and use of this information is voluntary. This information should not be considered as inclusive of all proper treatments or methods of care or as a statement of the standard of care.
It is not intended to substitute for the independent professional judgment of the treating clinician. Variations in practice may be warranted when, in the reasonable judgment of the treating clinician, such course of action is indicated by the condition of the patient, limitations of available resources, or advances in knowledge or technology.
The American College of Obstetricians and Gynecologists reviews its publications regularly; however, its publications may not reflect the most recent evidence. Any updates to this document can be found on www. ACOG does not guarantee, warrant, or endorse the products or services of any firm, organization, or person. Neither ACOG nor its officers, directors, members, employees, or agents will be liable for any loss, damage, or claim with respect to any liabilities, including direct, special, indirect, or consequential damages, incurred in connection with this publication or reliance on the information presented.
This Committee Opinion is updated as highlighted to reflect a limited, focused change in the language and supporting evidence regarding exposure to magnetic resonance imaging and gadolinium during pregnancy. Imaging studies are important adjuncts in the diagnostic evaluation of acute and chronic conditions. However, confusion about the safety of these modalities for pregnant and lactating women and their infants often results in unnecessary avoidance of useful diagnostic tests or the unnecessary interruption of breastfeeding.
Ultrasonography and magnetic resonance imaging are not associated with risk and are the imaging techniques of choice for the pregnant patient, but they should be used prudently and only when use is expected to answer a relevant clinical question or otherwise provide medical benefit to the patient. With few exceptions, radiation exposure through radiography, computed tomography scan, or nuclear medicine imaging techniques is at a dose much lower than the exposure associated with fetal harm.
If these techniques are necessary in addition to ultrasonography or magnetic resonance imaging or are more readily available for the diagnosis in question, they should not be withheld from a pregnant patient. Breastfeeding should not be interrupted after gadolinium administration. The use of X-ray, ultrasonography, CT, nuclear medicine, and MRI has become so ingrained in the culture of medicine, and their applications are so diverse, that women with recognized or unrecognized pregnancy are likely to be evaluated with any one of these modalities 1.
This document reviews the available literature on diagnostic imaging in pregnancy and lactation. Obstetrician—gynecologists and other health care providers caring for pregnant and breastfeeding women in need of diagnostic imaging should weigh the risks of exposure to radiation and contrast agents with the risk of nondiagnosis and worsening of disease. Planning and coordination with a radiologist often is helpful in modifying technique so as to decrease total radiation dose when ionizing radiation studies are indicated Table 1.
Ultrasound imaging should be performed efficiently and only when clinically indicated to minimize fetal exposure risk using the keeping acoustic output levels As Low As Reasonably Achievable commonly known as ALARA principle. Ultrasonography involves the use of sound waves and is not a form of ionizing radiation. There have been no reports of documented adverse fetal effects for diagnostic ultrasonography procedures, including duplex Doppler imaging.
The U. However, it is highly unlikely that any sustained temperature elevation will occur at any single fetal anatomic site 3. The risk of temperature elevation is lowest with B-mode imaging and is higher with color Doppler and spectral Doppler applications 4. Ultrasound machines are configured differently for different indications. Those configured for use in obstetrics do not produce the higher temperatures delivered by machines using nonobstetric transducers and settings.
Similarly, although color Doppler in particular has the highest potential to raise tissue temperature, when used appropriately for obstetric indications, it does not produce changes that would risk the health of the pregnancy. However, the potential for risk shows that ultrasonography should be used prudently and only when its use is expected to answer a relevant clinical question or otherwise provide medical benefit to the patient 5.
When used in this manner and with machines that are configured correctly, ultrasonography does not pose a risk to the fetus or the pregnancy. The principal advantage of MRI over ultrasonography and computed tomography is the ability to image deep soft tissue structures in a manner that is not operator dependent and does not use ionizing radiation.
There are no precautions or contraindications specific to the pregnant woman. Magnetic resonance imaging is similar to ultrasonography in the diagnosis of appendicitis, but when MRI is readily available, it is preferred because of its lower rates of nonvisualization 6. Although there are theoretical concerns for the fetus, including teratogenesis, tissue heating, and acoustic damage, there exists no evidence of actual harm.
With regard to teratogenesis, there are no published human studies documenting harm, and the preponderance of animal studies do not demonstrate risk 1. Finally, available studies in humans have documented no acoustic injuries to fetuses during prenatal MRI 1. In considering available data and risk of teratogenicity, the American College of Radiology concludes that no special consideration is recommended for the first versus any other trimester in pregnancy 8.
However, there are diagnostic situations in which contrast enhancement is of benefit. Two types of MRI contrast are available: Gadolinium-based agents are useful in imaging of the nervous system because they cross the blood—brain barrier when this barrier has been disrupted, such as in the presence of a tumor, abscess, or demyelination 9.
Although gadolinium-based contrast can help define tissue margins and invasion in the setting of placental implantation abnormalities, noncontrast MRI still can provide useful diagnostic information regarding placental implantation and is sufficient in most cases 7. Even though it can increase the specificity of MRI, the use of gadolinium-based contrast enhancement during pregnancy is controversial.
Uncertainty surrounds the risk of possible fetal effects because gadolinium is water soluble and can cross the placenta into the fetal circulation and amniotic fluid. Free gadolinium is toxic and, therefore, is only administered in a chelated bound form. In animal studies, gadolinium agents have been found to be teratogenic at high and repeated doses 1 , presumably because this allows for gadolinium to dissociate from the chelation agent.
In humans, the principal concern with gadolinium-based agents is that the duration of fetal exposure is not known because the contrast present in the amniotic fluid is swallowed by the fetus and reenters the fetal circulation. The longer gadolinium-based products remain in the amniotic fluid, the greater the potential for dissociation from the chelate and, thus, the risk of causing harm to the fetus 8.
The only prospective study evaluating the effect of antepartum gadolinium administration reported no adverse perinatal or neonatal outcomes among 26 pregnant women who received gadolinium in the first trimester More recently, a large retrospective study evaluated the long-term safety after exposure to MRI in the first trimester of pregnancy or to gadolinium at any time during pregnancy This study interrogated a universal health care database in the province of Ontario, Canada to identify all births of more than 20 weeks of gestation, from to The risk also was not significantly higher for congenital anomalies, neoplasm, or vision or hearing loss.
Limitations of the study assessing the effect of gadolinium during pregnancy include using a control group who did not undergo MRI rather than patients who underwent MRI without gadolinium and the rarity of detecting rheumatologic, inflammatory, or infiltrative skin conditions Given these findings, as well as ongoing theoretical concerns and animal data, gadolinium use should be limited to situations in which the benefits clearly outweigh the possible risks 8, To date, there have been no animal or human fetal studies to evaluate the safety of superparamagnetic iron oxide contrast, and there is no information on its use during pregnancy or lactation.
Therefore, if contrast is to be used, gadolinium is recommended. The water solubility of gadolinium-based agents limits their excretion into breast milk. Less than 0. Although theoretically any unchelated gadolinium excreted into breast milk could reach the infant, there have been no reports of harm. Therefore, breastfeeding should not be interrupted after gadolinium administration 13 , Commonly used for the evaluation of significant medical problems or trauma, X-ray procedures are indicated during pregnancy or may occur inadvertently before the diagnosis of pregnancy.
In addition, it is estimated that a fetus will be exposed to 1 mGy of background radiation during pregnancy 2. Various units used to measure X-ray radiation are summarized in Table 1. Concerns about the use of X-ray procedures during pregnancy stem from the risks associated with fetal exposure to ionizing radiation. The risk to a fetus from ionizing radiation is dependent on the gestational age at the time of exposure and the dose of radiation If extremely high-dose exposure in excess of 1 Gy occurs during early embryogenesis, it most likely will be lethal to the embryo Table 2 15, However, these dose levels are not used in diagnostic imaging.
In humans, growth restriction, microcephaly, and intellectual disability are the most common adverse effects from high-dose radiation exposure Table 2 2, With regard to intellectual disability, based on data from atomic bomb survivors, it appears that the risk of central nervous system effects is greatest with exposure at 8—15 weeks of gestation. It has been suggested that a minimal threshold for this adverse effect may be in the range of 60— mGy 2, 18 ; however, the lowest clinically documented dose to produce severe intellectual disability is mGy 14, Even multiple diagnostic X-ray procedures rarely result in ionizing radiation exposure to this degree.
Fetal risk of anomalies, growth restriction, or abortion have not been reported with radiation exposure of less than 50 mGy, a level above the range of exposure for diagnostic procedures In rare cases in which there are exposures above this level, patients should be counseled about associated concerns and individualized prenatal diagnostic imaging for structural anomalies and fetal growth restriction Table 3 The risk of carcinogenesis as a result of in-utero exposure to ionizing radiation is unclear but is probably very small.
A 10—20 mGy fetal exposure may increase the risk of leukemia by a factor of 1. Thus, pregnancy termination should not be recommended solely on the basis of exposure to diagnostic radiation. Should a pregnant woman undergo multiple imaging studies using ionizing radiation, it is prudent to consult with a radiation physicist to calculate the total dose received by the fetus. The Health Physics Society maintains a website with an ask-the-expert feature: There is no risk to lactation from external sources of ionizing radiation diagnostic X-rays Use of CT and associated contrast material should not be withheld if clinically indicated, but a thorough discussion of risks and benefits should take place 8.
In the evaluation for acute processes such as appendicitis or small-bowel obstruction, the maternal benefit from early and accurate diagnosis may outweigh the theoretical fetal risks. If accessible in a timely manner, MRI should be considered as a safer alternative to CT imaging during pregnancy in cases in which they are equivalent for the diagnosis in question. Radiation exposure from CT procedures varies depending on the number and spacing of adjacent image sections Table 2.
For example, CT pelvimetry exposure can be as high as 50 mGy but can be reduced to approximately 2. In the case of suspected pulmonary embolism, CT evaluation of the chest results in a lower dose of fetal exposure to radiation compared with ventilation-perfusion scanning 2. With typical use, the radiation exposure to the fetus from spiral CT is comparable with conventional CT.
Oral contrast agents are not absorbed by the patient and do not cause real or theoretical harm. The use of intravenous contrast media aids in CT diagnosis by providing for enhancement of soft tissues and vascular structures. The contrast most commonly used for CT is iodinated media, which carries a low risk of adverse effects eg, nausea, vomiting, flushing, pain at injection site and anaphylactoid reactions 9. Although iodinated contrast media can cross the placenta and either enter the fetal circulation or pass directly into the amniotic fluid 22 , animal studies have reported no teratogenic or mutagenic effects from its use 8, Additionally, theoretical concerns about the potential adverse effects of free iodide on the fetal thyroid gland have not been borne out in human studies Despite this lack of known harm, it generally is recommended that contrast only be used if absolutely required to obtain additional diagnostic information that will affect the care of the fetus or woman during the pregnancy.
Traditionally, lactating women who receive intravascular iodinated contrast have been advised to discontinue breastfeeding for 24 hours. Therefore, breastfeeding can be continued without interruption after the use of iodinated contrast 1, 9, 13, 16, This type of imaging is used to determine physiologic organ function or dysfunction rather than to delineate anatomy. Hybrid systems, which combine the function of nuclear imaging devices with computed tomography, improve the quality of information acquired and can help to correct artifacts produced by nuclear medicine imaging alone 9.
In pregnancy, fetal exposure during nuclear medicine studies depends on the physical and biochemical properties of the radioisotope.
Pettker, MD; James D. Goldberg, MD; and Yasser Y. This document reflects emerging clinical and scientific advances as of the date issued and is subject to change. The information should not be construed as dictating an exclusive course of treatment or procedure to be followed.
Calculate Due Date from Ultrasound Report.
Wharton, MD. This document reflects emerging clinical and scientific advances as of the date issued and is subject to change.
Ultrasound is energy in the form of sound waves. During an ultrasound exam , a transducer sends sound waves through the body. The sound waves come into contact with tissues, body fluids, and bones. The waves then bounce back, like echoes. The transducer receives these echoes, which are turned into images.
Thanks for your post which is truly informative for us and we will surely keep visiting this website. May Accurate gestational dating of pregnancy is very important for optimal maternal and fetal outcome. Throughout pregnancy decisions like ordering and interpreting lab tests, determining fetal growth and performing intervention to prevent preterm births or post-term pregnancies and associated morbidities are based on accurate dating. Estimated Due Date EDD and current gestational dating should be documented on medical records and discussed with the patient as early as possible based on dates of Last Menstrual Period LMP and earliest available ultrasound in pregnancy. Many women have irregular cycles, or falsely recall the date of LMP or have irregular ovulation, which is not considered when calculating the EDD by traditional method. The American College of Obstetricians and Gynecologists, the American Institute of Ultrasound in Medicine, and the Society for Maternal—Fetal Medicine make the following recommendations regarding the method for estimating gestational age and due date: If the pregnancy is the result of successful ART procedure, then the EDD is calculated based on age of embryo and day of transfer. As soon as LMP and results of first trimester ultrasound are known, EDD should be calculated and recorded in medical records. It should also be told to patient and discussed with her.
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Multivariable linear regression was conducted to determine the extent to which ultrasound GA predicted LMP dating and to correct for systematic misclassification that results after applying standard guidelines to adjudicate differences in these measures. With adjustment for maternal age, smoking, and first-trimester vaginal bleeding, standard guidelines for adjudicating differences in ultrasound and LMP dating underestimated SGA birth by This methodological approach can be applied by researchers using different study populations in similar research contexts. Accurate gestational age GA dating of pregnancies is vital to public health surveillance and research investigating the causes of small-for-gestational-age SGA birth and preterm delivery PTD.
The date your baby is due—your estimated due date EDD —is calculated from the first day of your last menstrual period LMP. An ultrasound exam often is used to confirm the due date. Your obstetrician—gynecologist ob-gyn will evaluate the dating from your ultrasound exam and compare it with your due date based on your LMP. Once a due date has been selected, it does not change no matter how many additional ultrasound exams you may have during your pregnancy. The average length of pregnancy is days, or 40 weeks, counted from the first day of your LMP. The causes of postterm pregnancy are unknown, but there are several factors that may increase your chances of having a postterm pregnancy. These factors include the following:. The health risks for you and your fetus may increase if a pregnancy is late term or postterm, but problems occur in only a small number of postterm pregnancies. Most women who give birth after their due dates have uncomplicated labor and give birth to healthy babies. Risks associated with postterm pregnancy include the following:.
Committee on Practice Bulletins—Gynecology. This information is designed as an educational resource to aid clinicians in providing obstetric and gynecologic care, and use of this information is voluntary. This information should not be considered as inclusive of all proper treatments or methods of care or as a statement of the standard of care. It is not intended to substitute for the independent professional judgment of the treating clinician. Variations in practice may be warranted when, in the reasonable judgment of the treating clinician, such course of action is indicated by the condition of the patient, limitations of available resources, or advances in knowledge or technology.
Name the time in gestation when ultrasound is most accurate 2. Discuss the ACOG recommendations for redating a pregnancy based on trimester. Postgraduate Institute for Medicine PIM requires instructors, planners, managers and other individuals who are in a position to control the content of this activity to disclose any real or apparent conflict of interest COI they may have as related to the content of this activity. PIM is committed to providing its learners with high quality CME activities and related materials that promote improvements or quality in healthcare and not a specific proprietary business interest of a commercial interest. Susan J.
Miller, MD, and R. Phillips Heine, MD. This document reflects emerging clinical and scientific advances as of the date issued and is subject to change. The information should not be construed as dictating an exclusive course of treatment or procedure to be followed. The American College of Obstetricians and Gynecologists considers first-trimester ultrasonography to be the most accurate method to establish or confirm gestational age.
Чатрукьян вдруг обрел прежнюю уверенность. – Цепная мутация, сэр. Я проделал анализ и получил именно такой результат – цепную мутацию. Теперь Сьюзан поняла, почему сотрудник систем безопасности так взволнован. Цепная мутация. Она знала, что цепная мутация представляет собой последовательность программирования, которая сложнейшим образом искажает данные.
Это обычное явление для компьютерных вирусов, особенно таких, которые поражают крупные блоки информации.
Сьюзан, извини. Это кошмар наяву. Я понимаю, ты расстроена из-за Дэвида. Я не хотел, чтобы ты узнала об этом. Я был уверен, что он тебе все рассказал. Сьюзан ощутила угрызения совести.
How accurate is a due date that is determined by ultrasound?