Irregular periods dating scan
My husband and I have been trying for a baby for a long time as I have very irregular periods. I have a dilemma in that I had sex with another man. It was only once, the date was 4th October. It was after that I discovered my pregnancy a few weeks later. With the given due date, could this man be the father of my child or is it more likely to be my husband's?
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. Accurate dating of pregnancy is important to improve outcomes and is a research and public health imperative. As soon as data from the last menstrual period, the first accurate ultrasound examination, or both are obtained, the gestational age and the estimated due date EDD should be determined, discussed with the patient, and documented clearly in the medical record.
Subsequent changes to the EDD should be reserved for rare circumstances, discussed with the patient, and documented clearly in the medical record. When determined from the methods outlined in this document for estimating the due date, gestational age at delivery represents the best obstetric estimate for the purpose of clinical care and should be recorded on the birth certificate. For the purposes of research and surveillance, the best obstetric estimate, rather than estimates based on the last menstrual period alone, should be used as the measure for gestational age.
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:. An accurately assigned EDD early in prenatal care is among the most important results of evaluation and history taking. This information is vital for timing of appropriate obstetric care; scheduling and interpretation of certain antepartum tests; determining the appropriateness of fetal growth; and designing interventions to prevent preterm births, postterm births, and related morbidities.
Appropriately performed obstetric ultrasonography has been shown to accurately determine fetal gestational age 1. A consistent and exacting approach to accurate dating is also a research and public health imperative because of the influence of dating on investigational protocols and vital statistics. This Committee Opinion outlines a standardized approach to estimate gestational age and the anticipated due date.
However, there is great usefulness in having a single, uniform standard within and between institutions that have access to high-quality ultrasonography as most, if not all, U. Accordingly, in creating recommendations and the associated summary table, single-point cutoffs were chosen based on expert review. Because this practice assumes a regular menstrual cycle of 28 days, with ovulation occurring on the 14th day after the beginning of the menstrual cycle, this practice does not account for inaccurate recall of the LMP, irregularities in cycle length, or variability in the timing of ovulation.
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.
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. For instance, the EDD for a pregnancy that resulted from in vitro fertilization should be assigned using the age of the embryo and the date of transfer. 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. 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. 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.
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. For the purposes of research and surveillance, the best obstetric estimate, rather than estimates based on the LMP alone, should be used as the measure for gestational age. 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. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, posted on the Internet, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher.
Methods for estimating the due date. Committee Opinion No. American College of Obstetricians and Gynecologists. Obstet Gynecol ; Women's Health Care Physicians. Recommendations 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: As soon as data from the last menstrual period 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.
Introduction An accurately assigned EDD early in prenatal care is among the most important results of evaluation and history taking. 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.
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.
Conclusion Accurate dating of pregnancy is important to improve outcomes and is a research and public health imperative. Fetal imaging: 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 Reviews , Issue 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: Br J Obstet Gynaecol ; Fetal crown—rump length: Radiology ; Gestational age in pregnancies conceived after in vitro fertilization: Ultrasound dating at 12—14 weeks of gestation. A prospective cross-validation of established dating formulae in in-vitro fertilized pregnancies. Accuracy of gestational age estimation by means of fetal crown—rump length measurement.
Estimation of gestational age by transvaginal sonographic measurement of greatest embryonic length in dated human embryos. Ultrasound Obstet Gynecol ;4: Underestimation of gestational age by conventional crown—rump length dating curves. New crown—rump length curve based on over pregnancies. Standardization of sonar cephalometry and gestational age. Sonographic prediction of gestational age: Conceptional age, menstrual age, and ultrasound age: Estimating fetal age: Commit-tee Opinion No.
I informed the midwife that my periods are irregular and that my last period according to the dating scan that I conceived prior to the 27th Feb?. As soon as data from the last menstrual period, the first accurate ultrasound . dating by last menstrual period, ultrasound scanning, and their combination.
Pregnancy math can be a little murky. After all, unless you went the IVF-route, your physician has no way of knowing the exact time of conception. Because of this, pregnancy is calculated from the first day of your last menstrual period or LMP.
Pettker, MD; James D.
A dating scan is an ultrasound examination which is performed in order to establish the gestational age of the pregnancy. Most dating scans are done with a trans-abdominal transducer and a fullish bladder. If the pregnancy is very early the gestation sac and fetus will not be big enough to see, so the transvaginal approach will give better pictures.
Am I expecting my husband's baby or my lover's?
When do you give birth to a baby? Is it after the completion of nine months, or 40 weeks; are both the same or different? If you have just tested positive for pregnancy, you might be doing those calculations already, trying to figure out the due date for your delivery. MomJunction understands the difficulty in narrowing down on the exact weeks of pregnancy and thereby the due date. Therefore, we will tell you how to calculate pregnancy weeks and months.
When and Why Your Doctor May Change Your Due Date
Pregnancy is connected with many signs and symptoms that are associated with the body adjusting to housing a fetus. These symptoms include morning sickness, putting on weight, cravings and food aversions among others. The very important symptom is a lack of menstrual periods. The calculation of the due date from this symptom, however, depends on if you have regular or irregular menstrual cycles. It is easier to calculate a due date when you have regular cycles. A regular menstrual cycle is one where the duration between menstrual cycles is 28 days. But in case of irregular cycles, the following methods can be applied. This is a prepared wheel that matches the dates of your last menstrual period with a due date. The estimates for the due date are done by locating the date of the last menstrual period on the wheel, which is in turn matched with a due date. If you have menstrual cycles that are longer than 28 days, which is considered to be an irregular cycle, you need to perform some simple calculations to come up with a proper last monthly period date.
This is a scan done early in pregnancy before 12 weeks of gestation. It is only natural to be curious and concerned about pregnancy and early pregnancy scans can give you peace of mind. What are the advantages of having an early pregnancy scan? How is the early pregnancy scanning done?
Can your pregnancy scan give the wrong due date?
During the course of the pregnancy, every mother should have at least two scans. These help to ensure the pregnancy goes smoothly, and to identify any problems ahead of time. The dating scan is generally the first ultrasound that every mother-to-be will have. While many women will have a good idea of when they had their last menstrual period, another portion will be far less certain. This can be due to a number of factors, including whether the pregnancy was planned or not, and if the mother often has irregular periods. The scan also gives a due date, which is sometimes a small range of dates due to a difference with your own dating attempt. An accurate due date is crucial so that, in the event of being overdue, your doctor knows whether you are drastically overdue or simply a few days late. Your doctor will ask you questions about when you had your last menstrual period, and estimate that ovulation occurred 14 days into the cycle, but some mothers may be unsure. However this is not usually a problem, as the best time for a dating scan falls between 8 and 12 weeks, a month-long period. Dating scans are much less reliable after 13 weeks because at this stage babies often start growing at different rates.
Every pregnant woman wants to know her due date , and a due date that is calculated from her last menstrual period with a due date calculator often doesn't match the due date that is estimated by her first ultrasound also known as a sonogram. During an ultrasound, a technician will spread a warm gel over the lower part of your abdomen and then press a tool called a transducer against your belly to examine your fetus using sound waves. An image of your fetus will appear on an accompanying computer screen and while looking at this image, the technician will take some standard measurements from different angles and listen for a heartbeat. Don't worry: This type of exam is painless and risk-free, and seeing your baby for the first time will likely be an enjoyable experience. Naturally, one of the most common questions asked about ultrasound accuracy is: Just how accurate are the due dates that are predicted by an ultrasound?
A podcast about pregnancy and drug use, Native people and tribal sovereignty. When people discuss how far along in pregnancy someone is, they tend to do so in general terms: Medical professionals use a standard set of up to three methods to date pregnancies: That way, regardless of where they trained or where they practice, any two doctors dating a pregnancy will predict the same due date or gestational age. However, the timing of the actual delivery is not so predictable.
Pregnancy lasts an average of days 40 weeks from the first day of your last menstrual period LMP. Read our report on the 13 best pregnancy iPhone and Android apps of the year here. Add seven days to the first day of your LMP and then subtract three months. The other way to calculate your due date is to use a pregnancy wheel. This is the method that most doctors use. The first step is locating the date of your LMP on the wheel. When you line up that date with the indicator, the wheel displays your due date. Remember that the due date is only an estimate of when you will deliver your baby.
This scan is carried out from 11 weeks to 13 weeks and six days. The scan is usually performed transabdominally but in a few cases it may be necessary to do the examination transvaginally. If you want to visit your own FMF page please click here. Aims of the nuchal scan To date the pregnancy accurately. This is particularly relevant for women who cannot recall the date of their last period, have an irregular menstrual cycle, or who have conceived whilst breastfeeding or soon after stopping the pill.
MFM mums share their stories plus expert sonographers explain why it happens and what to do if you're told your due dates are wrong. By Rachel Mostyn. Original date given was 18 December but at the scan it was moved to 31 Dec. Unless you have an early pregnancy scan most of you will be given your estimated due date at the week scan. Of course you have probably already used an online due date calculator. Weird huh?The best time to get Pregnant specially in irregular periods - Dr. Suhasini Inamdar