———————————————-
In this story you’ll be playing the role of Lara Croft, an OB/GYN who sees three patients throughout her shift. Your goal is to make the diagnosis for each emergency, and figure out which treatment option is best.
————————————————
Report to OB Triage
The OB unit you work in is located on the 1st floor of a downtown hospital. It’s just a quick little diversion for EMS to shuttle their patients from the ED bay to OB triage, which is where all pregnant patients are generally received. It’s not uncommon for EMS to receive this message over the radio: “Unit 411 we received your report - please report to OB Triage upon your arrival and advise us of any changes en route.” The OB unit then gets advised of any incoming patients that are being triaged to them.
The EMS providers know that there is a very specific kind of report that needs to be given to the clinicians who work in OB triage. They know they need to have the answers to a list of questions that is not short. In no particular order, questions like:
What prompted the call to 911 today?
What’s the expected due date?
Do you know how many weeks along you are?
Has there been any prenatal care?
Is there multiple births expected?
Are you considered ‘high risk?’
How many times have you been pregnant? (Gravida)
How many times have you given birth? (Para)
Have you ever had a C-Section or any other abdominal surgery?
Are you having contractions? How often? How long do they last?
Have you been bleeding at all?
Do you know what blood type you are?
Have you had any discharge?
Have you been feeling the baby move?
Any sudden weight gain / swelling, high blood pressure readings, bad headaches, trouble seeing, shortness of breath, trouble urinating, abdominal pain? (Assessing for preeclampsia).
Expecting to hear answers to these questions, you see your first patient in the care of EMS roll in through the security protected double-doors.
Womb Number One
As EMS comes down the hallway, you notice their patient doesn’t seem to be in any outward distress. You receive a report that goes like this:
This is Jennifer, she’s 38 years old. She’s had some spontaneous bleeding today that was not associated with any trauma. The blood is noted to be bright red in appearance, and ‘moderate’ in amount at this time. She doesn’t complain of any pain or contractions. Denies any rupture of membranes as far as she can tell.
Her expected due date isn’t for another 8 weeks or so, she’s about 32 weeks gestation at this point. Gravida 3, Para 2. She’s had 2 C-Sections before. Her abdomen is soft and non tender. And… I can give you the rest of your report over at the nurses station.
A concerned paramedic takes you away from the patient and continues in a slightly more candid manner:
Even though she’s had to have C-Sections with both of her kids, she want’s to deliver this baby at home in her bath tub… She received her initial checkup and got her due date, but she hasn’t continued with any pre-natal checkups or ultrasounds. She’s just been taking pre-natal vitamins, no other care.
You reply: Oh, interesting. We’ll have to get an ultrasound right away - thanks.
Even though this patient doesn’t seem to be in any distress, the lack of an ultrasound is concerning. That means that this baby and the placenta have developed without anyone checking on their position or orientation.
Based on the report, what do you suspect your patent is suffering from?
Womb Number Two
Your second patient by EMS comes in some time later. Again, the double doors open and security gives EMS a smile and a head nod at they pass by. This patient is different than the last - she appears to be in distress, and she has her ankle wrapped up like she was injured. EMS approaches and gives you report:
This is Emily, she’s 30 years old. She fell in her kitchen today - the dog spilled some water out of its bowl and she slipped. No loss of consciousness, no apparent neurological problems. She injured her ankle, we just have that splinted right now, it has good CMS. Some time after she fell, she felt abdominal and lower back pain, and then maybe 30 minutes after that she says she started to feel contractions. Contractions were followed by bleeding.
This is her first pregnancy - gravida 1, para 0. Emily is 3 weeks out from her due date, she’s about 37 weeks gestation. No history of abdominal surgeries or other traumas besides the fall. Denies rupture of membranes so far, She has only mentioned the bleeding.
Contractions have been between 4 and 5 minutes apart, and she notes them to be somewhat intense. Even between the contractions her abdomen seems to be rigid, and tender as well.
Emily was told that she may be considered ‘high risk’ because she is a smoker and smoked up until she realized she was pregnancy. She also has a history of asthma, as well as high blood pressure.
A high risk pregnancy with trauma and contractions all points to this being more of an emergency case than your last one. Based on the report by EMS, what do you suspect the diagnosis is?
Womb Number Three
Your third patient comes in by EMS near the end of your shift. EMS passes by the double doors and you catch sight of the patient. Just based on your view from down the hallway, you suspect that the patient is in active labor. EMS reports:
This is Jessica, she’s 20 years old and about a week out from her due date. She started having contractions earlier today and called when they got more intense. She does have some heavy vaginal bleeding occurring at this time, she has also had rupture of membranes. This is her second pregnancy. Gravida 2, Para 1. First child born vaginally. Jessica is not considered high risk as far as she knows, and she’s received pre-natal care. Contractions are about 3-4 minutes apart right now and lasting 20 - 30 seconds. The abdomen is non-tender.
We’re concerned about her amount of bleeding - her MAP has been on the low side.
EMS goes on to tell you about the vital signs, the IV access, and so on. You are immediately thinking about the viability of this pregnancy and know you need to act quickly. Based on the report by EMS, what do you suspect the diagnosis is?
The Anatomy
When we talk about fetal circulation, we usually focus on the fetal circulation that’s occurring inside of the baby. We talk about the foramen ovale, the ductus arteriosus, and the ductus venosus. Connected to that circulation is the umbilical cord, and connected to that is the placenta, and connected that placenta is the mother. The interface between placenta (basically the baby) and mom is what we are looking at above.
Of note is the decidua basalis. The decidua basalis and the placental septum are the parts of the endometrium that forms the mothers side of the mom-placenta interface. On the placental side of this interface we have the chorionic plate and main stem villus. Generally these anatomical structures are shortened to just the decidua basalis and the chorion to describe the connection between the womb and the placenta. You can think of this connection between the mother and the fetus as they are holding hands - the fingers of the mother being the placental septal outshoots, and the fingers of the fetus being the main stem villus that branch off from the chorionic plate.
Just looking at the picture above, doesn’t it just seem like a bleed would be catastrophic? This is a very circulation / vessel rich area.
Occurrence
Bleeds do occur in this mother-placenta interface, and they’re scary. How often do these problems actually occur? Let’s take a quick look at the numbers.
Placenta previa occurs in approximately 5 per 1000 pregnancies, but seems to vary by region.
According to Cresswell et al (2013), North America has an occurrence of ~3 per 1000 pregnancies. In patients with advanced maternal age, multiparity, previous Cesarean delivery and abortion, smoking and cocaine use during pregnancy, and male fetuses all had increased risk of developing placenta previa (Faiz & Ananth, 2013).
Placental abruption occurs between in approximately 3-10 births per 1000, with smoking and maternal age being a major contributing factor of whether the placenta will detach. (Ananth et al, 2015).
Vasa previa occurs in approximately 1 per 2500 births, but can reach as high as 1 per 202 births if the mother used assisted reproductive technologies (Schachter et al, 2002).
While these conditions are not what we would consider common, who do you think is going to get the call to take care of these patients when they start bleeding? You. So we should be very aware of the seriousness of these sources of bleeding.
Diagnosis
So, which one of the patients above has which condition? Let’s revisit the cases and figure it out.
Womb Number One Diagnosis:
The first case was a 38 year old who presented with spontaneous bright red bleeding. The bleeding was not associated with trauma, nor was the patient in any discomfort. This type of presentation should make us think Placenta Previa. Placenta previa occurs when the placenta grows over the cervical opening - preventing the baby from being born vaginally. We notice symptoms when the placenta starts to detach form the wall of the endometrium and begins bleeding. Not that acronyms are usually very helpful, but there is one to describe the signs and symptoms of placenta “PREVIA.”
P = Painless, bright red bleeding.
R = Relaxed, soft uterus - non tender.
E = Episodes of bleeding that can range from mild to profuse.
V = Visible bleeding.
I = Intercourse caused bleeding.
A = Abnormal fetal position.
What else was concerning about this patient? She had skipped pretty much all of her prenatal appointments she should have went to. If she would have been getting ultrasounds performed, there is a very high chance that the placenta previa would have been recognized, and that she would have been scheduled for another C-Section- which she likely needs now. The placenta has partially detached and the baby may not be getting enough oxygen.
Thinking back on her case, she’s a prime candidate for placenta previa. The mother is her late 30’s, and she’s had two previous C-Sections. The scarring caused by C-Sections increases the risk that a future growing placenta will detach at an abnormal location (such as causing a placenta previa).
Womb Number Two Diagnosis:
The second patient was pretty worrisome as well. A first time expecting mother who fell, and is now having vaginal bleeding, pain, and contractions. This traumatic cause of distress and bleeding is a classic presentation of Placental Abruption. Placental abruption occurs when there is premature detachment of the placenta from the uterine wall. The degree of detachment can vary quite a bit - and the bleeding can either be concealed or apparent. These patients experience pain and contractions because the blood from the detachment irritates the uterus and makes it hard and contractile.There is another acronym that does try to condense the characteristics of this process: “DETACHED.”
D = Dark Red Bleeding
E = Extended fundal height
T = Tender uterus
A = Abdominal pain / contractions
C = Concealed bleeding (possibly)
H = Hard abdomen
E = Experience DIC
D = Distressed baby
Thinking back on the medical history of the mother, the detachment of her placenta due to a fall isn’t surprising. She smoked up until she realized she was pregnant, and she has high blood pressure and asthma. All three of these things weaken the bond between the placenta and the uterus due to vasoconstriction and other mechanisms. Without strong bonds between the mother and the placenta, the chances of that placenta staying attached throughout the whole pregnancy aren’t nearly as good.
The bleeding caused by this detachment can be concealed or apparent. Concealed bleeding is all contained by the placenta, so there is no outward vaginal bleeding. Concealed bleeding is very worrisome because healthcare providers may not take the patient as seriously if there is no outward vaginal bleeding. But, these patients are every bit as sick as a patient with obvious vaginal bleeding. Not only is a placental abruption classified into concealed or apparent bleeding, but it’s also classified by the amount of the placenta that is detached. If the whole placenta no longer has communication with the uterus, this is a complete detachment. If some of the placenta still communicates with the uterus, that would be a partial detachment.
Womb Number Three Diagnosis:
This disease process is a little less known than either placenta previa or placental abruption - it’s called Vasa Previa. Vasa previa is similar to placenta previa, except only an abnormal prolonged portion of the placenta extends over the cervical opening. This condition can be missed even if the patient has received pre-natal ultrasounds because the cord can be difficult to see on ultrasound - it’s not as obvious as a placenta over the cervical opening (using color doppler to assess for blood flow has been documented to help greatly in identification of via previa).
This unprotected portion of the umbilical cord can become compromised, essentially cutting the baby off from any nutrients from the mother. This condition is more common in those who choose to use assisted reproductive technologies - which it turns out our patient did use. The compromise of the fetal circulation can be from compression or rupture. Since the umbilical vessels are rather unprotected, they’re easily compressed. The vessels also rupture more easily for the same reason. The term to describe the umbilical vessels being exposed by this abnormal anatomy between the placenta and the protected umbilical cord is called a velamentous umbilical cord. A velamentous umbilical cord is usually associated with marginal cord insertion, which means the cord is inserted close to the side of the placenta rather than in the middle where it would normally be.
Conclusion
Third trimester bleeding is a scary situation. The bleeding usually indications one of the conditions above, which means compromise for both mother and fetus. Any interruption in the uterus-placental connection, or issue with the umbilical cord can mean the mother is losing blood, and the fetus isn’t getting enough. Recognition of these problems and having a high index of suspicion is important, and we need to maintain that suspicion high because internal bleeding is not always going to present with obvious vaginal bleeding. We have a responsibility to these patients to convey the seriousness of their condition to the receiving hospital so that they can be ready for emergency cesarian section delivery if needed.
The course of action by the receiving facility is dependent on several factors. How far along is the mother? How severe is the bleeding? What is the hemodynamic status of the mother and fetus? What is the source of the bleeding? The answer to those questions is going to determine if the birth is delayed with tocolytics and corticosteroids are given for lung development, or if a cesarian section needs to happen immediately.
Regardless of what the receiving facility plans to do, our job is to stabilize the mother, which in turn will give the fetus the best chance at surviving. We may have to deliver the child if vaginal delivery in imminent, replace volume, administer oxygenation/ventilation support, and keep the mother in a position to perfuse the uterus (left-lateral recumbent). If you suspect tocolytics might be indicated, I would recommend consulting with some form of medical control. The decision to administer something like magnesium sulfate may help or hurt the situation. On one hand, the magnesium may lessen contractions (therefore lessening further uterine separation). On the other hand, Magnesium administration may induce hemodynamic instability and weaken the uterus’ ability to clamp down on its own vessels to lessen bleeding.
————————————————
As your shift comes to an end you reflect back on the patients you had during the day.
Jennifer, the placenta previa patient, did not need to have another cesarean section today. While she did have a placenta previa, her bleeding was not severe enough to warrant delivery. The baby had good fetal heart rate and variability, and there were no signs of fetal distress. Steroids were administered to help with lung development in case of delivery, and Jennifer was admitted for observation. Of note, her baby was indeed in the breech position.
Emily, the first time mother who slipped in her kitchen and suffered a placental abruption, did need a cesarian section. The abruption was both apparent and partial, which give enough time to deliver the baby.
Jessica, the vasa previa patient who had rapture of membranes, ending up losing her baby. The velamentous cord was unfortunately torn during the beginning of labor prior to arrival at the hospital, resulting in no fetal circulation for a prolonged time. Upon your initial assessment there were no fetal heart tones. Jessica ended up receiving a blood transfusion as part of her resuscitation.
————————————————
References
Cresswell, J. A., Ronsmans, C., Calvert, C., & Filippi, V. (2013). Prevalence of placenta praevia by world region: a systematic review and meta-analysis. Tropical medicine & international health : TM & IH, 18(6), 712–724. https://doi.org/10.1111/tmi.12100
Faiz AS, Ananth CV. Etiology and risk factors for placenta previa: an overview and meta-analysis of observational studies. J Matern Fetal Neonatal Med. 2003;13(3):175-190. doi:10.1080/jmf.13.3.175.190
Ananth, C. V., Keyes, K. M., Hamilton, A., Gissler, M., Wu, C., Liu, S., Luque-Fernandez, M. A., Skjærven, R., Williams, M. A., Tikkanen, M., & Cnattingius, S. (2015). An international contrast of rates of placental abruption: an age-period-cohort analysis. PloS one, 10(5), e0125246. https://doi.org/10.1371/journal.pone.0125246
Schachter M, Tovbin Y, Arieli S, Friedler S, Ron-El R, Sherman D. In vitro fertilization is a risk factor for vasa previa. Fertil Steril. 2002;78(3):642-643. doi:10.1016/s0015-0282(02)03253-3