2nd and 3rd Trimester Bleeding

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  • Placenta previa - when the placenta partially or totally covers the internal cervical os. Defined as edge of placenta <10 mm from internal cervical os 

    • Occurs approximately 4/1000 births, but varies world wide. Increased risk associated with history of previous placenta previa, previous C-section, and multiple gestation 

    • Approximately 90% of placenta previa identified on ultrasound <20 weeks → resolve before delivery 

    • Painless vaginal bleeding can occur up to 90% of persistent cases 

    • 10-20% of women present with uterine contractions, pain, and bleeding 

    • Why we care: can lead to catastrophic bleeding, need for transfusion, and delivery. Can lead to stillbirth  

  • Placenta accreta spectrum 

  • Vasa previa 

    • What it is: when fetal vessels run within the membranes over the internal os of the cervix 

    • Very rare. Has been quoted 1/2500 deliveries 

    • Painless bleeding usually 

    • Two types: 

      • Velamentous cord insertion and fetal vessels that run freely within the amniotic membranes overlying the cervix or in close proximity of it (2 cm from os); usually pregnancies with low lying placenta or resolved placenta previas are at risk 

      • Succenturiate lobe or multilobe placenta and fetal vessels connectin both lobes course over or in close proximity of cervix (2 cm from os)   

    • Other risks: IVF 

    • Why we care: increased risk of fetal hemorrhage, exsanguination, and death 

  • Placental abruption

    • What it is: Separation of the placenta from the inner wall of the uterus before birth 

    • Usually painful bleeding 

    • Incidence: 2-10/1000 births in the US 

    • Risk factors: hx of fabruption, cocaine use, tobacco use, hypertension, uterine abnormalities (ie. fibroids, bicornuate uterus) 

    • Why we care: can lead to catastrophic bleeding, need for transfusion, and delivery. Can lead to stillbirth. 

  • Uterine rupture 

    • What it is: significant uterine disruption. Usually will occur along a previous uterine scar 

    • Very painful bleeding (pain is usually more significant than bleeding) 

    • Risk factors: previous uterine rupture, previous uterine scar, especially if a fundal or vertical scar (ie. cesarean delivery, myomectomy), induction, labor 

    • Why we care: very high incidence of morbidity and mortality for both mom and baby 

  • Less dangerous causes:

    • Labor - “bloody show” with labor

    • Cervicitis 

      • Can be caused by infection (ie. BV, candida infection, trichomonas, chlamydia, gonorrhea) 

    • Cervical polyp 

    • Vaginal laceration 

Doing a Workup for Bleeding in the 2nd and 3rd Trimester

  • History 

    • How much bleeding? (soaking through clothes? Passing clots?)

      • Passing tissue? 

      • Remember: just because someone has light bleeding does not mean that they don’t have something life-threatening for them or their fetus   

    • Is there pain? 

    • How long has the bleeding been happening? 

  • Exam 

    • After your physical exam, do an abdominal and pelvic exam 

      • Lift the sheet: how fast is the patient bleeding? 

      • Abdominal exam: is there tenderness to palpation anywhere? Over the uterus? How pregnant does the patient appear to be (if no records?) 

        • Patients with rupture will be very tender to palpation 

        • Less likely to be tender to palpation with something like placenta or vasa previa 

      • Start with a speculum exam - if passing tissue, that should be sent to pathology 

        • Look for vaginal laceration, neoplasms, discharge, evidence of cervicitis, cervical polyps, fibroids, ectropion 

        • Send testing for cervicitis and vaginitis (ie. wet mount, as well as chlamydia/gonorrhea) 

      • Do not do a digital cervical exam without confirming where the placenta is located!

  • Labs and Imaging 

    • Pregnancy test if not confirmed (just a urine pregnancy test!) 

    • Type and screen, CBC, coagulation profile

    • Putting the baby on the monitor 

      • Consider doing so if the fetus is viable 

      • Sometimes, the only way to tell if someone is abrupting or rupturing their uterus (other than having abdominal pain) is seeing non-reassuring fetal heart tracing 

      • Watch contraction pattern - can discern if someone is contracting with bleeding or now. Also, there may be evidence of abruption on monitor (small amplitude, frequent contractions) 

    • Ultrasound 

      • Usually, transabdominal is enough, but if you think that there is a placenta previa, placenta accreta, or vasa previa, you should do a transvaginal ultrasound 

      • Color and pulsed Doppler should be used to help in diagnosis 

      • Remember that placental abruption is a clinical diagnosis: you may not always see a blood clot or an area that appears “abrupted” on the placenta

      • Usually, placenta previa, placenta accreta, and vasa previa are diagnosed at the mid-trimester ultrasound and will require clinical follow-up 

Management 

  • Depending on the amount of bleeding: 

    • Vital signs 

    • Two large bore IVs 

    • Resuscitation - fluids vs. blood products

  • If there is less bleeding and you think you have more time:

    • Blood type and Rh status - administer Rhogam if it is indicated 

    • Management otherwise depends on reason for bleeding - will discuss briefly some of the more dangerous things 

  • Placenta previa:

    • Usually will trigger an admission for monitoring 

    • If preterm, usually recommend steroids, and if <32 weeks, can discuss magnesium for CP prophylaxis 

    • Pending the stability of mom and fetus, may require emergent delivery via cesarean section 

    • Certain locations may have a “threshold” for prolonged admission - ie. three strikes = three bleeds and admission for the rest of pregnancy 

    • If otherwise stable, can usually be delivered between 36w0d - 37w6d via c-section

    • Usually can have vaginal delivery if >2 cm from os, but some institutions may discuss if >1 cm 

  • Placenta accreta spectrum:

    • Will usually also trigger an admission for monitoring, and can also lead to emergent delivery + hysterectomy pending stability 

    • Steroids and mag if indicated 

    • If stable, recommend delivery between 34w0d-35w6d, and usually this will be done at tertiary care center with multi-disciplinary team 

  • Vasa previa:

    • There is usually a lower threshold for bleeding and contraction in vasa previa because the bleeding could come from the fetus 

    • While an adult human has 5-6L of blood, a fetus has much less. A term fetus+placenta can have up to 500mL of blood (baby may have 250-300cc). Usually describe to patients in measurements of a soda can (355 mL). 

    • For this reason, many places will hospitalize vasa previa between 28-34w0d and monitor 

    • Recommend delivery between 34w0d-37w0d pending stability of mom and baby