Home stretch ladies! Second to last week of discussion boards. I think this is a valuable opportunity to share tips and tricks that we have learned in clinicals. Has anyone had the opportunity to scan multiple gestations? As we discussed today, there is an increased risk of morbidity and mortality with multiple gestations, which is why they are all typically considered high risk by default.

I also think pathologies can be a challenge, and I trust all of you will show up with great additional resources (team visual learners!) as we start to explore the things that can go wrong in a twin pregnancy. I'll be adding my own post later today, but feel free to post any questions you have in addition to your responses to the prompt. I will try to answer what I can, and know that my awesome sono sisters will also be able to chime in.

I think it's important to treat multifetal exams just as you would a singleton pregnancy, but of course times two or even maybe three! I think the best approach for me would be to begin with the maternal assessment. I would take a detailed look at the placenta(s) to see where it may be implanted, cord insertions into the placenta, how close it may be in relation to the cervix, and thorough examination of the cervix to ensure it's both long and closed.

Once I have finished the cervix I can move onto fetal anatomy. I know whichever fetus presents closest to the cervix will be labeled as Twin/Triplet A and will have my sole focus until I have obtained all necessary images. It's really important not to jump around to different fetuses as this can create confusion and lead to errors in labeling. Extra time is allotted for these studies so it is best we take our time and be accurate rather than simply taking images as they may come into view. A check off list would be extremely helpful in ensuring all required images have been taken and will provide reassurance that I can move onto the next closest fetus.

Some pathologies or conditions we may see with multifetal pregnancies include twin-to-twin transfusion syndrome (TTTS) where one twin is considered a donor and the other a recipient when it comes to circulation. Depending on how early the pregnancy is documented there may also be a vanishing twin. This can be observed by the presence of two embryos in the initial scan and only one embryo on follow-up examination!

The best way to document this is by labeling correctly, attempting to identify fetal gender,looking for intertwining membranes, and biometry. We know one fetus may be falling behind if the measurements are too far apart from each other or where they should be measuring for their gestational age.

The first thing I will want to do when scanning a multiple gestation pregnancy is determine which baby is baby A, which is baby B, and so on. This is really important to keep straight because if one baby ends up having an anomaly, we will want to be able to follow it and track it throughout the pregnancy. The fetus that is closest to the internal cervical os is termed “Baby A” or the presenting fetus. I think it would be helpful to follow Dr. Wilson’s method of labeling images of baby A with “AAA femur” and so on. This way the radiologist knows exactly which fetus the image belongs to.

Most of the protocol for scanning twins or higher multiple gestations is similar to the protocol for scanning a singleton. The maternal anatomy still needs to be assessed and biometry needs to be performed on each fetus. Something I would pay more attention to with twins is fetal gender. Typically this is not definitively determined until later in gestation, but during the first trimester it can be helpful to see if the genital tubercle is showing signs of male or female anatomy. This can help with deciphering if the twins are going to be identical (monozygotic) or fraternal (dizygotic).

Since we know that twins often have higher rates of anomalies and mortality issues, this would make me want to scan even more meticulously. Twins have higher chances of neural tube defects so I would definitely want to pay attention to the cerebellum and spinal cord to look for conditions like Chiari malformation type 2 and spina bifida. Multiple gestation pregnancies also have higher risks for diaphragmatic hernias so I would also want to pay attention to the diaphragm and make sure it is continuous. In addition to congenital anomalies, I would also definitely want to assess the placenta and see if there is one or two. A single placenta for twins can often lead to Twin to Twin Transfusion Syndrome. This can lead to one twin not receiving enough blood and therefore not developing correctly. It is important to compare the sizes of the fetuses in this case.

It’s also important with twins to look for any signs of them being conjoined. With a singleton pregnancy you are just concerned with the one fetus and their anatomy, but with twins you are looking at their anatomy and how the two fetuses are related to each other. I would watch to see if the fetuses move away from each other during the exam to determine if they are conjoined.

I’ve attached an image of how to label the fetuses and what TTTS looks like.

I would first sweep through each baby to see get my bearings, then I will move to moms anatomy including, cervix, ovaries, uterus, and placenta. Then I would continue to treat a multiple gestation pregnancy just as a single pregnancy. Taking one at a time, starting with baby A (the one closest to the cervix) and then moving to baby b and c and so on, making sure to labeled each fetus correctly as I move along. I think this would help me stay consistent and on track with what I'm scanning. Jumping around from baby to baby would be extremely confusing and I would most likely forget things. The radiologist also has to be able to understand the scan so being consistent is really important for their sake as well. I would stick to my same protocol for a singleton, and just double or triple it. 

Twin to Twin Transfusion Syndrome, where twins share one placenta  and one of the twins ends up being a donor for the other because the vessels are not evenly dispensed between the 2 fetuses. The donor ends up giving away more blood than it receives and is at risk for malnourishment and the recipient is at risk for receiving too much blood and can overwork the heart. 

Twin Embolization Syndrome is a complication of monozygotic twinning following in utero demise of the co-twin. Passage of thromboplastic material into the circulation of the surviving twin results in ischemic structural defects in various organs 

Twin Reversed-Arterial Perfusion arises when the cardiac system of one twin (pump twin) does the work of supplying blood for both twins. The increased pumping of the heart puts this twin at risk for cardiac failure. The receiving twin (acardiac twin) lacks a heart or has one that is not fully formed. 

Documenting these pathologies is extremely important and can cause so many other issues down the line so being precise and accurate is so so important. It's also important to be consistent like I mentioned before because if someone comes behind you to scan this patient again, and they can't be sure which baby is which from your scan, it's will go downhill and the tech doing the follow up will have an extremely hard time. The pathologies I mentioned are vascular anomalies so throwing on color will be very important to prove the  diagnoses, rather than with something like conjoined twins I would want to clearly see the attachment site and also include color to see if any vascularity is attaching them as well like we saw in the power point today. 

Within the last decade, our generation has experienced an increase in multiple gestation pregnancies mainly due to assisted reproductive technology, maternal age, and genetics. As we learned in class, Nailah shared a diagram that showed an complete OB fetal scan protocol that neatly had everything within segments. From cervix and placenta placement to the biometric. measurements to the fetal hands and feet. For me-- in clinicals, it's important to scan within segments so that 1) I don't forget to scan anything, as the fetus may switch to a great position to take fetal heart images while I am imaging another segment 2) to ensure that I correctly documented a complete routine survey for Baby A/ B/ C/ etc.

As we scan a multiple gestation pregnancy, during its first trimester, its important to note:

• # of gestational sacs
• # amniotic cavities
• # embryos/ sac
• # yolk sac

As we scan a multiple gestation pregnancy, during its second trimester, its important to note:

• # of fetuses
• fetal lie
• # of placentas
• presence or absence of membranes
• qualitative assessment of amniotic fluid of maximal vertical pocket
• pulsed/ color Doppler 

In addition to repeating a OB complete fetal survey for each fetus, I would also attempt to image the # fetuses all together (coronal? plane). With this image, I would also be able to evaluate other pathologies, besides congenital anomalies, that we might be dealing with. The pathologies I would keep in mind is:

• "vanishing twin"
  • conduct a through sweep through in TRV and LONG of the uterus to ensure the # of fetuses
• vasa previa 
  • examining normal the insertion of the fetuses umbilical cord insertion to the placenta, rather than  into the amniotic membrane 
• TRAP sequence (monochorionic/ monoamniotic)
  • use of color Doppler may show a reversal of flow in the umbilical cord of the "acardiac" twin than in the "pump" twin
  • visual of arterial to arterial anastomoses
  • visual of venous to venous anastomoses
• TTTS (monochorionic/ diamniotic)
  • identify if same gender
  • seeing if there is a fetal weight discordance of 20% of greater between the fetuses
  • identifying a major difference in the amount of amniotic fluid between the amniotic sacs.
  • visual of a "stuck" twin
  • use of color Doppler (stage 3) shows an absent OR reversed end- diastolic flow in the donor's umbilical arteries or pulsatile flow in the umbilical vein 
  • visual of arterial to venous anastomoses

I think the way I would approach a multiple gestation pregnancy would be similar to my approach for a singleton. I would start with maternal anatomy. Next I would determine amnionicity and chronicity if the exam took place during the 10-14 week timespan where this determination is more accurate. Then I would determine which fetus was baby A, baby B and so on. Baby A is of course the one that would present first and is closest to the cervix. Once that was determined, I would continue to scan as I would with a singleton and complete my protocol for one fetus before moving to the other.

If the fetuses were mono/di or mono/mono, I would evaluate their cord insertion sites in the placenta to see if they are close to one another and assess if there are vascular anastomoses. This could lead to twin to twin transfusion syndrome, where one fetus receives more of the fetal blood circulation than the other. In the case of mono/mono, I'd also check if the cords are twisted or knotted with each other. Twists or knots can block obstruct the blood circulation in one or both fetuses, leading to growth disparities or death. Color and spectral Doppler would be helpful in assessing these situations.  

I would also assess the size of the fetuses relative to one another. If the difference in biometrics shows a fetal weight difference of greater than 20% or measurements for gestational age show a difference greater than 5 days, then there is abnormal growth with at least one of the fetuses. These can be related to anemia, IGUR, placental insufficiency, TTTS, and other conditions related to the gestational environment. 

Below is a link to a Radiopaedia entry about twin growth discordance.

https://radiopaedia.org/articles/twin-growth-discordance?lang=us

Also, here is video that explains TTTS and the fetoscopic laser surgery that can be performed to help the mitigate the unequal transfusion between the twins.

When scanning multigestational pregnancies, I think it can become overwhelming thinking about everything you have to keep track of, so I think remembering that it’s not all that different from scanning singletons, is important. We will still assess the placentas implant location, how close it is to the cervix,  and determine if the cervix is long and closed. 

We will determine which fetus is presenting closest to the cervix, and label it twin A, and the other B, C, D, and so on depending on how many are present. We’ll complete biometry  on each fetus, one at a time in order to avoid confusion. Careful scanning needs to be completed in order to not mislabel fetal parts. I thought it was a great idea that Michelle mentioned labeling them “AAA” and “BBB” in order to make it even more clear, and also that Paris mentioned that even if on a prior scan, a sonographer mislabeled the fetuses, it’s recommended to keep the labels as such, in order to avoid further confusion. 

We want to determine the chorionicity and amnionicity, and take a look at the placenta as well. Since we know multigestational pregnancies have higher morbidity and mortality rates, we want to be even more thorough with these scans. Twin to twin transfusion syndrome can occur when there is a shared placenta. The blood flows unevenly, one twin receives too much blood (recipient), and the other receives too little (donor). The receipt can experience heart failure and the donor can experience life threatening anemia, insufficient nutrition and oxygen. We also want to look at the genders, and look out for discrepancies that are too large between the fetal  measurements, which could mean one fetus isn’t developing as it should. 

I think the first thing I will need to do when scanning a multiple gestation pregnancy is take a deep breath. It can be very easy to get overwhelmed in a normal singleton scan, let alone multiples! However as my brilliant classmates have already started discussing, if you can scan a singleton, you can scan a multiple gestation. You just approach it one fetus at a time. Hence the importance of identifying and documenting each fetus. 

Because of the increased risk of complications, it is even more crucial that we assess the fetal environment and maternal components in addition to standard protocols and biometry. By correctly identifying the type of pregnancy (di-di, mono-di, mono-mono) we can help guide the care plan for mom and fetuses. According to radiopaedia.org, mono-mono twins often have 50%+ rate of perinatal mortality (vs 10% for di-di, and 20% for mono-di).

A lot of people have already started discussing the big twin pathologies that are most often seen, such as TTTS, TAPS, and TRAPS. These are all hemodynamic complications found in monochorionic twins (due to shared placenta). Monoamniotic twins can have cord entanglement in addition to the hemodynamic complications listed.

One pathology that I came across in the chapter for this week was fetus papyraceus. This is a rare condition in which there is a case of fetal demise. However instead of "vanishing", it becomes mummified and compressed between the surviving fetal membranes and the uterine wall. 
A sequelae of this is twin embolization syndrome, which is a complication of MZ twins when there is a demise of one twin and affects circulation of the surviving twin. It is important to look for other signs in the surviving twin such as gastroschisis, microcephaly, ventriculomegaly, etc. which help aid in a diagnosis of twin embolization syndrome. 

Hello everyone,

So the first thing I would do when scanning a multiple gestation pregnancy is scan the cervix to make sure that the placenta (or placentas in some cases) is not too close to it, hopefully ruling out previa. If it is a first trimester pregnancy then I will check chorionicity and amnionicity by checking the number of gestational sacs and amniotic membranes. I will also check to make sure that there is a yolk sac and fetal pole in each (or however many) sacs. I would document a twin peak sign or T sign as well if the pregnancy is far along enough. Once the babies have gotten older, like around 20 weeks, I will label the baby closest to the cervix as Fetus A and begin taking its survey. I will label everything that has to do with Fetus A with an A as well. For example, "A. FEMUR" so that the radiologist can tell both of the babies apart and appropriate follow up can be done. While I am scanning the babies, I will check to make sure they are not conjoined in any part and for a monoamniotic case, I will check the umbilical cords to make sure the blood flow is okay for both the babies.

There are many different pathologies to keep in mind when scanning multiple gestational pregnancies, including intrauterine growth restriction (IUGR), twin to twin transfusion syndrome (TTTs) and twin reversal arterial perfusion (TRAP). For IUGR, we would need to make sure all the babies are growing as they should according to the LMP. We need to pay attention to the biometric measurements of both of the babies, such as femur length and biparietal diameter. Twin To Transfusion Syndrome is when blood returning from one fetus ends up being sent to the other fetus. This would lead to polyhydramnios and excessive growth in the baby receiving all of the extra blood. We can get an appearance called the "stuck twin", as shown in the picture below.

The last pathology I will be discussing that we could potentially see in multiple gestational pregnancies is Twin Reversed Arterial Perfusion Sequence (TRAPs), or acardiac twinning. This occurs in monochorionic pregnancies and in this, one twin is referred to as the "pump" twin and the other is the "acardiac" twin. Doppler would show reversal of blood flow in the umbilical arteries and vein of the acardiac twin. This is because the acardiac twin is receiving its blood from the pump twin via the umbilical arteries and this places a huge load on the pump twins heart, putting it at risk for heart failure, polyhydramnios, and nonimmune hydrops fetalis. On sonography, the pump twin may appear normal or have signs of hydrops and the acardiac twin will not have cardiac structures.

I would scan multiple gestation with the same protocal as just double it up with a few adjustment to accommodate for there being two fetus. I would label the twins to be able to track each fetus’s individual progress. In the first trimester scan, I would be mindful of size discrepancy between CRL of the fetuses because this can provide information on fetal viability. I would also assess and document chorionicity and amnionicity. For second trimester, I would perform the 20-week anatomy routine scan for each fetus; assessing: chorionicity and amniocity and if symmetrical growth is present between fetuses. It is important to be mindful of evaluating each fetus’s umbilical cord insertion site as well; especially in mochorionic gestations because the fetuses are at risks for things such as umbilical cord knots because they share a chorion. In third trimester, I would do biometry checks on all fetuses; keeping in mind that after 30 weeks twins do not grow at the same rate as singletons and the rate of growth discreases as the gestational number increases. Furthermore, multiple gestations have to be scanned more frequently than singletons. Monochorionic gestations are at higher risk for complications than dichorionic so they need to scanned more frequently. Uncomplicated dichorionic gestations should have a routine first and second trimester scans and then be scanned every 4 weeks following. Uncomplicated monochorionic gestations should have a routine first trimester scan and then be scanned every two weeks after 16 weeks to monitor for twin-to-twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS), and other complication where one fetus may not be receiving proper nutrients. In the event one of these complications were present I would document it with measurements and multiple images to track whether or not progression is occuring throughout the pregnancy. 

https://www.hopkinsmedicine.org/health/conditions-and-diseases/twintotwin-transfusion-syndrome-ttts

https://www.hopkinsmedicine.org/health/conditions-and-diseases/twin-anemia-polycythemia-sequence-taps

How I would scan a multiple gestation pregnancy would be a bit different than a singleton. For the first trimester I would evaluate the uterus, cervix and adnexa. Then I would examine how many gestational sacs are present and how the fetuses are separated. If 2 sacs are present I would want to see thick walls(lambda) between the fetuses. If 1 sac is present but 2 amnions are present I would see a very thin wall between the fetuses(t -sign). If there is only sac and no wall in between fetuses or fetuses are fused this would for sure be something that would need to be followed closely and also the monochorionic/diamniotic pregnancy. If prior to 7 weeks I would look for 2 yolk sacs. If after 7 weeks I would then look for the presenting fetus or baby A and document the CRL, heart rate. Then I would do the same for baby B. 

For the second trimester I would do all the same steps as in the first trimester now adding identification of each baby's gender to further determine if they are monochorionic or dichorionic. Next I would look for the locations of the placentas. For a dichorionic pregnancy I would note the location of each placenta. For monochorionic pregnancies I would document the location of the placenta and the insertion of each umbilical cord into the placenta. If the umbilical cords seem to interconnect this would need to be documented well and is an indication of mono/mono twins. If the scan is a full anatomy scan then I would start with baby A and take all the same images as I would a singleton pregnancy then do all the same for baby B. 

Besides congenital anomalies, with twins we could be dealing with 

Twin to Twin Transfusion Syndrome- Abnormal blood vessel connections form in the placenta and blood flows unevenly between fetuses. One twin is the donor and becomes dehydrated. The other is the recipient and develops high blood pressure and produces too much urine leading to polyhydramnios 

• We would look for discordant growth

• Fetal Weight <  10th percentile 

• Fetal Weight Difference > 20%

• AC difference > 20mm 

• CRL difference > 3 days at 11-14weeks 

• Ogliohydramnios in smaller twin 

• Polyhydramnios in bigger twin

• Unequal bladder filling (too much or none)

• Unequal umbilical cord thickness

Twin Embolization Syndrome- Demise of 1 twin leads to thromboplastic material passing into the surviving twins circulation which could lead to ischemic defects of the CNS, gastrointestinal tract and genitourinary system

• We would need to look for CNS anomalies like

• Ventriculomegaly, Porencephalic cyst, Fetal cerebral atrophy, Cystic encephalomalacia, Microcephaly

• GI anomalies such as Hepatic and Splenic infarcts, Small bowel atresia, Gastroschisis 

• Genitourinary anomalies such as Renal Cortical Necrosis, Horseshoe Kidneys 

Twin Reversed Arterial Perfusion - Cardiac system of one twin does the work of supplying for both twins

These findings would be seen in the acardiac twin

• Cyst formation in soft tissues

• No cardiac or cranial structures

• Unrecognizable lower extremities

• Polyhydramnios

This slideshare is amazing for twins and the anomalies that may occur 

https://www.slideshare.net/drthiyaga/twin-embolization-syndrome/28

Scanning a multiple gestation pregnancy would be much more difficult than scanning a singleton already is. There is much to look for, and so much more to document. Whatever vast list of things you would need to measure and image on one baby, the list grows in multiple depending on how many twins are involved.

How I would approach this is starting off as usual, scanning mother and making sure all is well with cervix, ovaries, adnexa, etc. Next, I would move on by sweeping in both planes to really quantify the number of fetuses, yolk sac, etc seen. Once sure, I would label alphabetically starting by the fetus closest to cervix to keep future scans orderly and cohesive. 

After counting and labelling, I would then start checking for chorionicity and amnionicity, looking for the Twin Peak sign or the T sign. This is very important because monochorion and especially monoamnion is subject to much higher rates of complications. For example, something to really pay attention to is the shared placenta, as TTTS could cause fetal demise. Another thing to look for, while noting if twins are sharing everything, is whether or not they are conjoined. If not, is one CRL or gestational age measured at a way different date than another? These are all extra things to look out for when it comes to multiple gestations.

Here is an image of fetal papyraceus, a fetal demise that happens with TTTS. The fetus that does not survive ends up compressed and "paper-like." Sonographic images are much easier to digest than the real life pictures that google can pull up. Next to it is a happy image of quadruplets, where one pair is monochorionic!

.                           

Article on Fetus Papyraceus or Vanishing Twin: https://sonoworld.com/fetus/page.aspx?id=296

I would complete a multiple gestational pregnancy exam similarly as I would a singleton pregnancy by first imaging the maternal anatomy.  If this was the first trimester between weeks 10-14, I would establish chorionicity, amnionicity and take all proper images. Also I would look for the T sign or lambda sign to be present. With a 20 week anatomy scan, I would label the location of each fetus starting with baby A which is the fetus closest to the cervix. I would take all proper images of baby A by labeling at the top of my images "AAA" so there is never any confusion by the reading radiologist. During the exam I will be sure to assess the placental cords/ cord insertion/ and blood flow. I would then move to baby B and so forth if more that 2 babies. Also I will look for the babies being conjoined which would be evident if the babies weren't visualized on their own but stayed attached and other anomalies that can present with multiple gestations.

There are many complications that can been seen while scanning multiple gestations and I will discuss vasa previa vs previa, twin to twin transfusion, and twin reversal arterial perfusion. Vasa previa is when the placenta and umbilical cord are lying infront of the cervical os which is very dangerous for mom and baby when it comes time to deliver. A C-section is needed in these cases if diagnosed. Also these cases are sent to a perinatology clinic for close evaluations and care up until birth. Previa is when the placenta is covering the cervical os and is monitored up until birth to make sure it retracts so a natural birth is possible or if not then a c section is warranted. Twin to twin transfusion is when blood returning from one fetus is being sent to the other fetus, which could lead to polyhydramnios which could lead to fetal death if untreated. Fetoscopic laser surgery can help the unequal transfusion occurring. Twin reversal arterial perfusion (Arcardiac twinning)  occurs with monochorionic twins and arises when the cardiac system of one twin does the work of supplying the blood for both twins. The twin who supplies the blood is known as the pump twin and develops normally. However the increased pumping of the heart puts the twin at risk for cardiac failure. The other twin is known as the arcardiac twin and it lacks a heart or has one not fully formed. It's body may be poorly developed or some parts may be missing altogether. 

Great video on Twin reversal arterial perfusion:

https://www.hopkinsmedicine.org/health/conditions-and-diseases/twintotwin-transfusion-syndrome-ttts

Images of vasa previa showing the umbilical cord lit up by color doppler and it lying infront of the cervical os:

Short answer: CAREFULLY

Long answer: I will definitely take Dr. Wilson's advice on triple labeling (AAA,BBB) each twin and following prior exams for which baby is A or B to show consistency with size/dates. We actually had a twin OB last week that had two prior ultrasounds that contradicted each other's baby labeling. We ended up sticking with the more recent labels since the first one was very early pregnancy when there were not as many measurements. It was good to see how confusing it can get though, so now I know to really assess which baby is closer to the cervix if/when I am the first one documenting it. I've also noticed that twin OB scans say which baby is maternal right and which is left!

In addition to congenital anomalies, which are at heightened risk with multiple gestations, we should also be on the lookout for one baby measuring bigger than the other. I've been told at my site that we want the babies within 2 weeks of the gestational age and also within 2 weeks of each other. For example, if baby A is measuring two weeks larger than GA, and baby B is at two weeks smaller than GA, they are both within the 2 week GA window, but not within the range we want compared to one another (one month size difference). This can be caused by a monochorionic pregnancy's vascular anastomoses giving on twin (recipient) more blood flow/nutrition than the other(donor). We may be able to see this in the vascularity like in the picture below, where the cord does not show the typically candy cane flow appearance.

Hi class,

With twin (and higher) pregnancies the risk to mom and babies is much higher than with singles. I'm going to focus on placenta a little bit more - trying to ensure each baby is getting enough good stuff from mom. The same holds true with the cord. I'll double and triple check that each cord has 2 arteries, one vein, and that blood is flowing nicely.

I'll also pay close attention to growth/baby sizing. Are both babies the same size? Is one bigger than the other? Are they both too small or too large? Depending how many chorions there are I'll be extra concerned with checking for severe anastomosis.

Check out this little blurb on Twin to Twin Transfusion Syndrome. I'm sure it's more common than we realize!

https://www.ssmhealth.com/cardinal-glennon/fetal-care-institute/twin-abnormalities/twin-twin-transfusion-syndrome

Sarah

Given that there is a higher prevalence of anomalies in River today and mortality issues in multiple gestational pregnancies I would begin my exam by examining fetal heartbeat and making sure both fetuses or each of the fetuses have a fetal heart rate from then on I would begin with the fetus closest to the cervix also known as fetal a.  It is important to check feral heart rate before beginning the exam because more mortality rate among singleton to multiple gestation is five to ten times more likely making it highly dangerous. I barely remember when my mom was pregnant with my twin sisters but I remember they stayed at the hospital for a long time after they were born. They were born with pneumonia and the labor put my mom in a coma which I am not sure is one of the risk factors with high risk pregnancies.  

After ensuring that the mother and each of the fetuses are well and alive it is important to compartmentalize each exam and make sure we hit everything we need to.  However I would just perform the same singleton exam to each of the fetuses. 

Conjoined twins is an anomaly that we might keep an eye for and it is in which the zygote splits after 13 days.  This is when the fetus does not split completely and grow conjoined to each other.  I will make sure to examine the chorion and amnions and see if there is only one amnion which could potentially mean that the fetuses are living together and if they are this could be an indication that the fetuses could be conjoined. 

Due to multiple gestation pregnancies being higher risk, it's very important for us as sonographers to pay special attention to these little cuties and be as diligent as possible while documenting them. The first thing I would do when I put that probe down is see which baby is baby A, being the one closest to the cervix and which one is baby B and label them as such. Once this is completed we can properly investigate these babies for any anomalies without confusing them. 

The major things I'm looking for would allow to use a protocol as if I was looking at a singleton pregnancy but just twice.

I thought of twin transfusion syndrome that multiple gestation pregnancies might encounter. This occurs in pregnancies where twins share one placenta, blood vessels, and oxygen needed for growth. In this case, one of the babies get all the nutrients while the other hardly gets any. The exact cause is unknown. Paying attention to each babies amniotic fluid levels in this case is very important or just in general when scanning twin pregnancies. We want to keep this possible anomalies in the back of our minds and always be on the lookout for them!

TGIF ladies! Great job on the boards this week. This week we looked at how to approach scanning a multiple gestation pregnancy, from techniques and mindset to protocols and procedure. We also started diving into some pathology beyond congenital anomalies and what to look for when scanning those.

Some of the main/recurring topics included (but were by no means limited to):

• Fetus identification, with baby A being closest to the cervical os
• Maternal anatomy and the importance of assessing everything from cervix to placenta
• The differences in separate gestational sacs and the sonographic signs to look for
  • Di/di – “Lambda sign”
  • Mono/di – “T sign”
  • Mono/mono – no separating membrane
• The potential risks of a shared placenta (TTTS, TAPS, TRAP)
• Conjoined twins in mono/mono gestations
• Other pathologies, such as Twin Embolization Syndrome, Fetus Papyraceus, Vasa Previa, IUGR

Everyone did a great job engaging with each others posts and sharing experiences from clinical sites. Different challenges were brought up and discussed with lots of encouragement from the group. As usual, you all brought excellent insight and helpful illustrations to the conversation. The sonogram examples were all relevant and educational.

It sounds like there hasn’t been too much exposure to multiple gestations at clinical sites so far, so I would encourage anyone who gets the opportunity to practice as much as possible while we are still students. Review your sites specific protocols for twins and keep working on the singleton scans.

As a class, we have always done a great job with sharing resources, and I think if we continue to do so, we will just get stronger as sonographers in the field. The internet was scoured for resources, and radiopaedia.org came through again as a strong favorite. There were also some fantastic educational videos from youtube.com that were shared.