Dating of twin pregnancy

BJOG. Jul;(8) doi: /jx. Epub May First-trimester ultrasound dating of twin pregnancy: are singleton.
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Comments on a recent meta-analysis. Todas ellas aumentan la morbimortalidad perinatal. Discordance in fetal biometry and Doppler are independent predictors of the risk of neonatal morbidity in twin pregnancies. Impaired fetal growth might be better evaluated in twin pregnancies by assessing the inter-twin discordance rather than the individual fetal size. The aim of this study was to investigate the prediction of perinatal loss in twin pregnancy using discordance in fetal biometry and Doppler.

This was a retrospective cohort study in a tertiary referral centre. The estimated fetal weight EFW , umbilical artery UA pulsatility index PI , middle cerebral artery MCA PI, cerebroplacental ratio CPR and their discordance recorded at the last ultrasound assessment before delivery or demise of one or both fetuses were converted into centiles or multiples of the median MoM.

Logistic regression analysis was performed to identify, and adjust for, potential confounders. The predictive accuracy was assessed using ROC curve analysis. The analysis included dichorionic diamniotic and monochorionic diamniotic twin pregnancies fetuses. Perinatal loss of one or both fetuses complicated 16 2. The detection rate, false positive rate, positive likelihood ratio LR and negative LR were EFW discordance and CPR discordance are independent predictors of the risk of perinatal loss in twin pregnancies.

Their combination could identify the majority of twin pregnancies at risk of perinatal loss. These findings highlight the importance of discordance in Doppler indices of fetal hypoxia, as well as fetal size, in assessing the risk of perinatal mortality. Ultrasound surveillance in twin pregnancy: An update for practitioners. Ultrasound has revolutionised the management of multiple pregnancies and their complications.

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Increasing frequency of twin pregnancies mandates familiarity of all clinicians with the relevant pathologies and evidence-based surveillance and management protocols for their care. In this review, we summarise the latest evidence relating to ultrasound surveillance of twin pregnancies including first trimester assessment and screening, growth surveillance and the detection and management of the complications of monochorionic pregnancies including twin-to-twin-transfusion syndrome, selective fetal growth restriction, twin reversed arterial perfusion sequence and conjoined twinning.

The Role of Ultrasound in Twin Pregnancy. Nov Ultrasound Obstet Gynecol. This incidence has increased over the years, mainly due to the expanding use of assisted reproductive technologies. Twins may be monozygotic one egg, fertilized by one sperm cell or dizygotic two eggs, fertilized by two sperm cells. Higher order multiples can be either or, occasionally, a combination. Ultrasound plays a very important role in the diagnosis and management of these pregnancies, from very early in gestation, up the second and third trimesters and to the delivery room.

This role includes establishing the early diagnosis of the presence of a multiple gestation, accurate dating, the precise determination of chorionicity and amnionicity, and the surveillance and management of complications unique to these pregnancies, although for several of these complications such as restricted growth, twin-to-twin transfusion, preterm labor and delivery , this is, usually, less of a clinical issue of the first trimester. Sensitivity of first trimester ultrasound in the detection of congenital anomalies in twin pregnancies: Sep Acta Obstet Gynecol Scand.

The first aim of this study was to ascertain the diagnostic performance of first trimester ultrasound in detecting congenital anomalies in twins.

First-trimester ultrasound dating of twin pregnancy: Are singleton charts reliable?

The secondary aim was to explore the strength of association between different pregnancy characteristics and early detection of structural anomalies in a large unselected population of twin pregnancies. Retrospective analysis of prospectively collected data from consecutive twin pregnancies booked for antenatal care from till Detection of structural abnormalities using ultrasound was possible in the first trimester in However, their predictive accuracy was only moderate AUC: First trimester detection of structural abnormalities in twin pregnancies is possible in The likelihood for first trimester detection of structural anomalies in twins was maximum for cranial vault, midline brain and abdominal wall defects.

Monochorionicity and increasing discrepancy in crown-rump length and nuchal translucency were associated with fetal structural abnormalities, although their predictive performance was only moderately good. This article is protected by copyright. Antenatal fetal surveillance in multiple pregnancies. The presence of more than one fetus in the womb is associated with a range of possible complications, both for the mother and fetuses. Early detection of these complications followed by timely and appropriate management will reduce the risk of adverse outcomes.

The techniques, skills, and experience for timely detection of complications and managing them appropriately require sufficient training and exposure. Therefore, referral of women pregnant with more than one fetus to specialized clinics is preferable. One of the most essential elements of appropriate management of multiple pregnancies is early determination of chorionicity.

Monochorionic and monoamniotic multiple pregnancies require additional surveillance for a whole range of specific complications that are unique to this group. Ultrasound and Doppler are the most important tools in the management of multiple pregnancies. This chapter will summarize the current best practice, in particular the use of ultrasound and Doppler, in the antenatal management of multiple pregnancies. The influence of chorionicity and gestational age at single fetal loss on the risk of preterm birth in twin pregnancies: Feb Ultrasound Obstet Gynecol.

Single intrauterine death sIUD in twin pregnancies is associated with a significant risk of co-twin demise and preterm birth PTB , especially in monochorionic MC twins. However, it is yet to be established whether the gestational age at loss may influence the pregnancy outcome. A cohort study of all twin pregnancies from a large regional network of 9 hospitals over a ten-year period. Ultrasound data was matched to hospital delivery records and a mandatory national register for perinatal losses CMACE.

Cases with double fetal loss at the time of the scan were not included in the analysis. The cumulative rates of PTB before 34, 32 and 28 weeks of gestation was assessed in pregnancies which did vs those which did not experience sIUD. The analysis included twin gestations DC and MC. Median gestational age at birth was lower in the pregnancies complicated by sIUD compared to those which were not This association was observed both in MC and DC twin gestations.

Twin pregnancies complicated by sIUD, regardless of the chorionicity, have a significantly higher risk of PTB before 34, 32 and 28 weeks of gestation.


Large prospective multicenter studies with shared protocols for prenatal management are needed to ascertain the actual risk of spontaneous PTB in twin pregnancies affected by sIUD. Objective This article evaluates the morbidity of infants born via assisted reproductive technology ART compared with matched naturally conceived infants. Study Design This is a retrospective review of maternal and infant data among inborn infants conceived via ART and matched control infants born at 30 to 34 weeks' gestational age GA between and Data were analyzed using paired t-test or Wilcoxo—Mann—Whitney test for continuous and Fisher's exact test for categorical variables.

Result Of study infants, 60 were conceived via ART and 60 naturally. Control infants were matched for GA, gender, race, and multiple gestations. ART infants required more respiratory support and took longer to reach full feeds compared with control infants.

Conclusion Infants born via ART are physiologically more immature with more intensive care needs than naturally conceived infants of similar gestation, potentially increasing health care costs. This immaturity should be considered when planning early delivery in these pregnancies.

The Stork Multiple Pregnancy Cohort. Objective The aim of this study was to determine the association between biometry discordance at the time of the anomaly scan and adverse perinatal outcomes in twin pregnancies. Population or samplePopulation multicentre retrospective study of all twin pregnancies booked for antenatal care in nine hospitals over a period of 10 years. Methods Logistic regression and receiver operating characteristic ROC curve analyses were performed to evaluate the association between abdominal circumference AC and estimated fetal weight EFW discordance, recorded between 20 and 22 weeks of gestation, and adverse pregnancy outcomes.

ResultsA total of twin pregnancies [ monochorionic MC and dichorionic DC ] were included in the study. The predictive accuracy of the EFW discordance was poor for fetal loss after 22 weeks of gestation area under the curve, AUC 0. There was no significant difference in the prediction of these outcomes when using EFW discordance or AC discordance. Conclusions Once structural malformations, chromosomal abnormalities, and twin-to-twin transfusion syndrome have been excluded, second-trimester EFW and AC discordance have poor predictive value for adverse perinatal outcomes in twin pregnancy.

Evaluation of measurement of fetal crown-rump length from ultrasonically timed ovulation and fertilization in vitro. To assess with accuracy the development and maturity of the fetus, we evaluated fetal growth in 46 pregnant women who had conceived subsequent to ultrasonically timed ovulation. Fetal crown-rump length CRL was measured at gestational ages that differed by about 1 day from those previously reported. The variance in CRL measurements at each gestational age was small, and the data were normally distributed.

The CRL growth curves of this and previous studies were tested using measurements from 7 pregnancies derived from in vitro fertilization IVF. The data from IVF pregnancies were consistent with our curve, having 1 day difference to those previously reported. The gender of the fetus did not influence the CRL during the first trimester. The results suggest that fetal growth is uniform during the first trimester. A critical evaluation of sonar crown-rump length measurement. Sep Br J Obstet Gynaecol. In a study to evaluate the reproducibility and accuracy of the sonar technique of measurement of the in vivo fetal crown-rump length Robinson, , a series of in vivo and in vitro experiments was performed in which the random and systematic errors inherent in the technique were assessed.

The potential sources of random error were those of operator judgement, movement of the fetus and mother, machine sensitivity settings and measurement from the photograph; while the sources of systematic error were those of oscilloscope scale factor, and velocity calibration inaccuracies, and the effect of beam width. The overall effect of the random errors, that is, the reproducibility of the technique, was assessed in an in vivo blind trial in which three independent measurements were made of the fetus.

In a series of 30 experiments the average standard deviation of the three readings was found to be 1. Evaluation of the systematic errors by in vivo experimentation, on the other hand, showed that the basic sonar measurements were in error by an overestimate of 1 mm for the beam width effect and 3. A weighted non-linear regression analysis of measurements was performed in order to obtain a "curve of best fit" for the period covering 6 to 14 weeks of menstrual age. The values obtained were corrected for the systematic errors and compared with widely quoted anatomical figures.

In the second part of this investigation the original data was further analyzed to determine on a statistical basis the accuracy of the technique as a method of estimating maturity. It was shown that such an estimate could be made to within 4. The ultrasonic measurement of fetal crown-rump length as a method of assessing gestational age. The fetal crown-rump length CRL was measured by means of pulsed ultrasound, and the normal values between 47 and days from the onset of the last menstrual period were determined from cross-sectional data in patients.

For any given CRL, the range was found to be within three days of the menstrual age with a maximum variation for a given occasion of three days.

4.1. Gestational age

Detailed statistical analysis showed that the acceleration in the rate of change in the CRL was a constant and that the intrapatient variability, where measured, was low. A close correlation between the measurement and the date of ovulation was demonstrated in a further 40 patients. Ultrasound for fetal assessment in early pregnancy. Advantages of early pregnancy ultrasound screening are thought to be more accurate calculation of gestational age, earlier identification of multiple pregnancies, and diagnosis of non-viable pregnancies and certain fetal malformations.

Check-ups and scans in a twin pregnancy

The objective of this review was to assess the use of routine screening ultrasound compared with the selective use of ultrasound in early pregnancy ie before 24 weeks. Adequately controlled trials of routine ultrasound imaging in early pregnancy. One reviewer assessed trial quality and extracted data.

Study authors were contacted for additional information. Nine trials were included. The quality of the trials was generally good. Routine ultrasound examination was associated with earlier detection of multiple pregnancies twins undiagnosed at 26 weeks, odds ratio 0. There were no differences detected for substantive clinical outcomes such as perinatal mortality odds ratio 0. Where detection of fetal abnormality was a specific aim of the examination, the number of terminations of pregnancy for fetal anomaly increased.

Routine ultrasound in early pregnancy appears to enable better gestational age assessment, earlier detection of multiple pregnancies and earlier detection of clinically unsuspected fetal malformation at a time when termination of pregnancy is possible. However, the benefits for other substantive outcomes are less clear. Relationship of intertwin crown—rump length discrepancy to chorionicity, fetal demise and birth-weight discordance. To study the frequency and clinical significance of crown-rump length CRL discrepancy at weeks of gestation in twin pregnancies from an unselected population.

This was a retrospective analysis of all twin pregnancies that underwent a routine week scan at a large teaching hospital. Fetal loss was defined as fetal demise of one or both twins after 14 weeks. A total of twin pregnancies were studied; The 95 th and 99 th centile for CRL discrepancy in twins was In 39 twin pairs, there was subsequent intrauterine death of one or both twins.

Fetal loss is significantly associated with discrepancy in CRL at the week scan in monochorionic twins and discordance in birth weights is significantly associated with discrepancy in CRL in dichorionic twins. However, intertwin CRL discrepancy is of limited value in screening for these adverse events.

The impact of crown-rump length measurement error on combined Down syndrome screening: May Ultrasound Obstet Gynecol. To evaluate the impact of a 5-mm error in the measurement of crown-rump length CRL in a woman undergoing ultrasound and biochemistry sequential combined screening for Down syndrome.

Based on existing risk calculation algorithms, we simulated the case of a year-old-woman undergoing combined screening based on nuchal translucency NT measurement and early second-trimester maternal serum markers human chorionic gonadotropin hCG and alpha-fetoprotein AFP expressed as multiples of the median MoM.

Four different values for each maternal serum marker were tested 1, 1. In all cases the ratio between the risk as assessed with or without the measurement error was calculated measurement error-related risk ratio MERR. Over simulated cases, MERR ranged from 0. In simulations This would go up to 33 Down syndrome screening may be highly sensitive to measurement errors in CRL. Quality control of CRL measurement should be performed together with quality control of NT measurement in order to provide the highest standard of care.

Fetal volume and crown-rump length from 7 to 10 weeks of gestational age in singletons and twins.

We intend to verify if fetal volume and crown-rump length were different between singletons and twins in pregnancies aged from 7 to 10 weeks and to evaluate if fetal volume is more accurate to determine the gestational age than crown-rump length at this gestational age. From 52 days 7 weeks and 3 days to 73 days 10 weeks and 3 days weekly three-dimensional ultrasonography was performed in 20 twin fetuses and 20 singletons.

The 'true' gestational age was based on oocyte retrieval. At the age of 52 days, the crown-rump length was At the gestational age of 73 days, the crown-rump length was The total relative increase observed was much higher for fetal volume than for CRL: No significant difference was identified between singletons and twins for both fetal volume and crown-rump length. Twins and singletons had similar fetal volume and crown-rump length between the 7th and 10th week of gestational age.

Additionally, fetal volume assessed by VOCAL was better than crown-rump length to estimate the gestational age at the evaluated period. However, the improvement was small and probably without clinical significance. Fetal volume and crown-rump length were similar between singletons and twins. Fetal volume relative increase was higher and the predicted gestational age was better.

First-trimester screening in pregnancies conceived by assisted reproductive technology: Significance of gestational dating by oocyte retrieval or sonographic measurement of crown-rump length. Oct Ultrasound Obstet Gynecol. To evaluate, in pregnancies conceived by assisted reproductive technology, whether determination of gestational age GA by date of oocyte aspiration DOA or crown-rump length CRL at first-trimester screening influences the distribution of serum and sonographic markers or the performance of first-trimester screening for chromosomal abnormalities.

The reverse was the case for mean log MoM pregnancy-associated plasma protein-A.

Antenatal care with twins - NHS

The correct method of GA dating for other purposes e. This is referred to as vanishing twin syndrome and has no physical effect on the surviving baby. For medical purposes, there are three types of twins. These apply to triplets too, although a triplet pregnancy will be more complex than a twin one. The three types are:. The percentages of identical and non-identical twins born in the UK aren't routinely recorded, but according to the Multiple Births Foundation about one third of twins are identical. These types of twins are rare and you can expect to receive specialist care and close monitoring.

You should be seen by a foetal medicine specialist who has cared for MCMA twins before. This type of twins are usually delivered at 32 to 33 weeks pregnant. If your babies are DCDA, the risks to their health in the womb are much lower. You'll usually be scanned every four weeks. It's important to attend all your appointments, so any problems can be picked up early and treated if necessary. Find out more about antenatal checks and tests.

While most multiple pregnancies are healthy and result in healthy babies, there are more risks to be aware of when you are pregnant with two or more babies. Make sure you go to all your antenatal appointments, so any problems can be picked up early and treated if necessary. Twins and triplets have a higher risk of being born prematurely before 37 weeks and having a low birth weight of under 2. Being premature increases the risk of problems after birth, such as breathing difficulties.

Your obstetric team will work closely with you throughout your pregnancy and after your babies are born to help make sure you and your babies are safe and healthy. TTTS affects identical twins who share a placenta monochorionic. This results in an imbalanced blood flow from one twin known as the donor to the other recipient , leaving one baby with a greater blood volume than the other.

You'll need to discuss your individual case with your doctor, as what works in one TTTS pregnancy may not be appropriate in another. Skip to main content. Your pregnancy and baby guide.