Twin Gestation Part II



hi I am Ajith Mirkwood professor of obstetrics and gynecology from Mumbai hello citizens of the internet this is the second part of my lecture on twin gestation in which I will discuss the diagnosis of twin gestation please watch part 1 before watching this video Ghana the days when an obstetrician would deliver a baby and walk away from the labor ward only to be told by the midwife doctor hurry up come back there is another baby coming in modern of statics ultrasound has revolutionized the way we diagnose and manage multiple gestation this is what I am going to discuss in detail in this video the key to successful clinical diagnosis of multiple gestation is to think twins family history of multiple pregnancy especially on maternal side and or recent intake of ovulation inducing drugs should make one suspect the possibility of it being a multi fetal gestation on examination clinical findings that point to a plural pregnancy are barrel-shaped abdomen abdominal girth greater than 100 centimetres fundal height greater than period of amenorrhea too many fetal parts felt or 3 fetal poles or to fetal heads are felt little hearts heard with maximum intensity in two separate areas by two observers with a minimum difference of 10 beats per minute suggests twins however this is not practical and never used for diagnosis of twins in the modern era occasionally the superimposition of to feed large sounds produces a gallop rhythm this is known as our knocks sign which is more useful for diagnosis it is important on abdominal palpation to know the lie and presentation of the twins especially near term as the management depends on it vertex vertex is the commonest type which is seen in 45% of twins the next common combination is vertex breach or breech vertex seen in 35% cases in another 10% cases it may be breeze peach and another 10% it may be transverse breech or transverse vertex transverse transverse is the rarest combination of twins and now I am going to discuss the role of ultrasonography in diagnosis of multiple pregnancy in modern aesthetics most multiple gestation are diagnosed by ultrasonography from the first trimester until delivery of the second twin the use of ultrasound in the management of twins is both ubiquitous and indispensable in early pregnancy transfer gional ultrasonography helps in early first trimester diagnosis of twins determination of Coriana city and a municipality of anning twins later in pregnancy ultrasonography helps in detection of congenital fetal anomalies detection of lie and position of fetuses for intrapartum management assessment of growth to rule out introduces diction and amniotic fluid to rule out poly arameans rule out placenta previa diagnosis of discordant twins and measurement of cervical length to diagnose preterm labor I am going to discuss these indications for ultrasound in detail transvaginal Sur ography is essential for early diagnosis of twins twins can be suspected as early as seven weeks when two separate gestational sacs are identified on transfer channel ultrasonography but this needs further confirmation it is prudent to wait until two separate embryos and heartbeats are visible to determine the number of fetuses in a pregnancy a repeat ultrasonography at eight weeks will show separate fetal bodies at 12 weeks separate heads can be distinguished if routine scanning of all pregnant women is carried out at at least 60 weeks twins should rarely be missed the optimal time for determining Coriana city and ammunition transvaginal ultrasound is between 6 to 10 weeks before 10 weeks gestation several sonographic findings can help determine curiosity first the number of gestational sacs the presence of two gestation sacs implies a die chorionic pregnancy while a single gestational sac with two identified heartbeats implies a monochorionic twin pregnancy number of amniotic sacks if two separate and distinct immured are identified before ten weeks on ultrasound it suggests diagnosis of diagnostic twins number of yolk sacs the number of yolk sacs is an accurate method of determining a me honesty before the amnion can be visualized mono amniotic means have a single yolk sac whereas diametric twins usually have two after ten weeks following new set of sonographic findings will help determine em jnana city and Coriana city first is gender discordance while different fetal gender identifies dyke Orianna city in all but the rarest cases concordance of gender phenotype does not rule out dyke Orianna city the number of distinct placentas seem will also help a single placental mass likely indicates monochorionic city whereas the presence of two distinct separate placentas identifies die Coriana city careful sonographic examination may help distinguish a single placenta from two placentas in abetment the most widely used sign for determining Coriana city is the twin p or lambda sign it is a projecting zone of tissue of similar echo texture to the placenta triangular in cross-section and wider at the chorionic surface of the placenta extending into and tapering to a point within the intervene membrane as seen here the twin peak sign most often identifies dyke Orianna city monochorionic City on the other hand can be determined by the absence of the twin peak sign the inter twin membrane directly inserts on the placenta without any wedge tissue and some people refer to it as the inverted T sine s see here the characteristics of inter twin membrane can also help determine coriolis City the inter twin membrane of a die chorionic pregnancy consists of two layers of a Mian and two layers of chorion it is thicker and more reflective than the monochorionic diameter attic membrane a membrane thickness of greater than two millimeters identifies Dyke orianna city whereas membrane thickness less than two millimeter suggests monochorionic City the membrane should be imaged perpendicularly to the ultrasound beam after magnification in the second trimester sometimes the number of membranes can be counted and if there are more than two then Dyke Orianna city is strongly suggested this is known as the split membrane sign as seen here in this ultrasound picture determination of gestational age from fetal biometry in twin pregnancies is a dilemma which one to take as the correct gestational age when you find different fetal sizes when using ultrasonography for determining gestational age most experts use the larger of the two fetuses to date a pregnancy erroring on the side of over estimation of gestational age and lessening the chances of missing intrauterine growth restriction in the smaller twin artisan ography plays an important role in the diagnosis of discordant twins this Gordon C in the twins is defined by the following formula using the larger of the twins as the denominator it is given by the formula expected fetal weight of the larger twin minus the expected fetal weight of the smaller twin divided by the expected fetal weight of the larger twin in 200 there is no single definition of growth discordance in twins clinically significant birth weight threshold definitions in the literature based on morbidity and mortality in the postnatal population range from 15 to 30% we adopt a 20% t-shirt as a reasonable option another definition of significant growth discordance includes abdominal circumference measurement and a difference of greater than 20 millimeters between the two twins suggests fetal discordance mono my honesty occurs in approximately 1% of all monozygotic twin pregnancies these pregnancies are at an elevated risk of fetal death because of cord entanglement therefore it is important to rule out mono mu olicity on ultrasound ultrasound findings suggestive of mono amniotic twins are non visualization of inter tween membrane entanglement of cords conjoined twins and single umbilical cord containing more than three vessels what about the role of Doppler velocimetry in winds umbilical artery doppler should not be routinely offered in uncomplicated twin pregnancies serial doppler studies may be done however for early diagnosis of intrauterine growth restriction when ultrasound shows discordance ii in multiple pregnancies aneuploidy screening using nuchal translucency and maternal serum alpha-fetoprotein measurements should be offered an elevated maternal serum alpha-fetoprotein value that is four point five times the median in an uncomplicated with gestation is abnormal and requires further testing if ultrasound is not available plain x-ray of the abdomen can be used to confirm the diagnosis of twins or multiple pregnancies during my OBGYN residency and early clinical practice there was no ultrasone we used to rely only on plain x-ray of the abdomen or diagnosis of multiple pregnancies and we were quite good at it using plain x-ray of the abdomen one can not only confirm the diagnosis in later stage of pregnancy but also know the lie and presentation diagnose conjoined twins accidentally triplets rule out major congenital fetal anomalies and look for polyhydramnios one more thing the twins are baptized before they are born the twin which lies lower into the pelvis or tends to enter it first is known as the first of the twin or twin a and the twin which is at a higher level is known as the second of the twin or 12e both the accept leads seen here are of twin gestation the x-ray plate on the Left shows both the twins are at the same level and therefore one cannot say which is in a and which is Queen B both are of breech presentation in the exit plate on the right the first pin that is twin a is in cephalic presentation probably vertex and twin B is a breech presentation there are no obvious feeding schedule abnormalities and liker appears adequate this is the end of Part two of my lecture on twin presentation and in the third part I will discuss the management of twins for further reading on this topic and other topics in obstetrics and gynecology refer to following books written by me practical obstetrics and gynecology modern aesthetics modern and ecology clinical cases in Australia questions and answers clinical cases in gynecology questions and answers and pelvic reconstructive surgery if you have found this video useful and informative please subscribe to my youtube channel by clicking here

13 Replies to “Twin Gestation Part II”

  1. Hi Sir…I am amazed by the fact that during you practise, USG was still not there and only depend on Xray modalities to diagnose twins… can you please upload part 3 sir, regarding the management of twins based on their lie and presentation…

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