Wrong due date from ultrasound scan - why it happens | MadeForMums
But my question is about early 1st trimester ultrasounds used for dating purposes. More specifically. I was supposed to be 9w2d on Tuesday. Predicting delivery date by ultrasound and last menstrual period in early gestation. Femur length was slightly less accurate than crown-rump length or BPD. I had an ultrasound at 8 weeks and 2 days which put my conception date . early on until someone gave me a probable conception date of Oct.
Results The mean age of the women was Most ultrasound scans The majority of the respondents Conclusion The worrisome confidence in ultrasound scan dating is a challenge to the prevention of prolonged pregnancy and its complications in our environment.
Antenatal health education should discourage self-referral for ultrasound scan dating and emphasize its limitations in late pregnancy as well as the perinatal effects of prolonged pregnancy. Both are important for optimal prenatal, intrapartum, and postnatal care. For instance, reliable information about gestational age and EDD is useful in assessment of fetal growth during the antenatal period.
In clinical practice, the gestational age and EDD are often determined using the LMP, except when the discrepancy between the LMP-derived gestational age or EDD and that of early pregnancy ultrasound scan exceeds 1 week; in this situation, the ultrasound scan estimates are more reliable and should be used.
Further, the rate of post-term pregnancy has been shown to decrease when early ultrasound scan is used in estimating the gestational age and EDD. The uncontrolled proliferation of ultrasound in Nigeria has further heightened the conflict between these two estimates of delivery date because pregnant women are increasingly having access to ultrasound scanning manned by various cadres of health workers, without information on its known limitations.
This scenario is a big challenge in terms of prevention of prolonged pregnancy in our environment where women register late for antenatal care 9 and rarely have reliable early ultrasound scan results.
A scenario is often created where the attending medical practitioner feels the pregnancy is prolonged based on a certain LMP-derived EDD while the client holds a different view based on her ultrasound scan-derived EDD, and therefore refuses to accept induction of labor despite counseling.
The aim of this study was to determine the perception and acceptability of menstrual dating EDD derived from LMP for timing of labor induction for postdatism by pregnant women who have a late pregnancy ultrasound scan.
Predicting delivery date by ultrasound and last menstrual period in early gestation.
Materials and methods Study area Enugu State is one of the five states in the southeast geopolitical zone of Nigeria, and its capital city is Enugu.
It has an average annual temperature of The state covers a land area of approximately 8, The Enugu State University Teaching Hospital, Parklane, is a state-owned teaching hospital located in the center of the Enugu metropolis. Both centers provide antenatal and postnatal care services to pregnant women in Enugu State.Pregnancy Tips : How to Calculate the Due Date From the Date of Conception
It has been reported that approximately one half of women accurately recall their LMP 2—4. Accurate determination of gestational age can positively affect pregnancy outcomes. For instance, one study found a reduction in the need for postterm inductions in a group of women randomized to receive routine first-trimester ultrasonography compared with women who received only second-trimester ultrasonography 5.
Methods for Estimating the Due Date - ACOG
A Cochrane review concluded that ultrasonography can reduce the need for postterm induction and lead to earlier detection of multiple gestations 6. Because decisions to change the EDD significantly affect pregnancy management, their implications should be discussed with patients and recorded in the medical record. Measurements of the CRL are more accurate the earlier in the first trimester that ultrasonography is performed 11, 15— The measurement used for dating should be the mean of three discrete CRL measurements when possible and should be obtained in a true midsagittal plane, with the genital tubercle and fetal spine longitudinally in view and the maximum length from cranium to caudal rump measured as a straight line 8, Mean sac diameter measurements are not recommended for estimating the due date.
Dating changes for smaller discrepancies are appropriate based on how early in the first trimester the ultrasound examination was performed and clinical assessment of the reliability of the LMP date Table 1.
Predicting delivery date by ultrasound and last menstrual period in early gestation.
For example, for a day-5 embryo, the EDD would be days from the embryo replacement date. Likewise, the EDD for a day-3 embryo would be days from the embryo replacement date. Clinical Considerations in the Second Trimester Using a single ultrasound examination in the second trimester to assist in determining the gestational age enables simultaneous fetal anatomic evaluation.
With rare exception, if a first-trimester ultrasound examination was performed, especially one consistent with LMP dating, gestational age should not be adjusted based on a second-trimester ultrasound examination. Ultrasonography dating in the second trimester typically is based on regression formulas that incorporate variables such as the biparietal diameter and head circumference measured in transverse section of the head at the level of the thalami and cavum septi pellucidi; the cerebellar hemispheres should not be visible in this scanning plane the femur length measured with full length of the bone perpendicular to the ultrasound beam, excluding the distal femoral epiphysis the abdominal circumference measured in symmetrical, transverse round section at the skin line, with visualization of the vertebrae and in a plane with visualization of the stomach, umbilical vein, and portal sinus 8 Other biometric variables, such as additional long bones and the transverse cerebellar diameter, also can play a role.
Date changes for smaller discrepancies 10—14 days are appropriate based on how early in this second-trimester range the ultrasound examination was performed and on clinician assessment of LMP reliability.
Because of the risk of redating a small fetus that may be growth restricted, management decisions based on third-trimester ultrasonography alone are especially problematic; therefore, decisions need to be guided by careful consideration of the entire clinical picture and may require close surveillance, including repeat ultrasonography, to ensure appropriate interval growth.
The best available data support adjusting the EDD of a pregnancy if the first ultrasonography in the pregnancy is performed in the third trimester and suggests a discrepancy in gestational dating of more than 21 days. Conclusion Accurate dating of pregnancy is important to improve outcomes and is a research and public health imperative.
- Can your pregnancy scan give the wrong due date?
- Women's Health Care Physicians
As soon as data from the LMP, the first accurate ultrasound examination, or both are obtained, the gestational age and the EDD should be determined, discussed with the patient, and documented clearly in the medical record. The American College of Obstetricians and Gynecologists, the American Institute of Ultrasound in Medicine, and the Society for Maternal—Fetal Medicine recognize the advantages of a single dating paradigm being used within and between institutions that provide obstetric care.
Table 1 provides guidelines for estimating the due date based on ultrasonography and the LMP in pregnancy, and provides single-point cutoffs and ranges based on available evidence and expert opinion. Fetal Imaging Workshop Invited Participants. A comparison of recalled date of last menstrual period with prospectively recorded dates.
J Womens Health Larchmt ; Comparison of pregnancy dating by last menstrual period, ultrasound scanning, and their combination. Am J Obstet Gynecol ; Last menstrual period versus ultrasound for pregnancy dating. Int J Gynaecol Obstet ; First trimester ultrasound screening is effective in reducing postterm labor induction rates: Ultrasound for fetal assessment in early pregnancy.
Cochrane Database of Systematic ReviewsIssue 7. Predicting delivery date by ultrasound and last menstrual period in early gestation. New charts for ultrasound dating of pregnancy and assessment of fetal growth: Ultrasound Obstet Gynecol ; First- and second-trimester ultrasound assessment of gestational age. First- vs second-trimester ultrasound: