Abnormal Placentation

by Veronica Gillispie, MD, FACOG

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    00:00 Let's discuss placental abnormalities.

    00:03 Before we discuss what's abnormal, let's discuss what normal placenta looks like.

    00:08 When we talk about the anatomy of normal placenta, we notice the placenta disc.

    00:13 And that's divided into the basal plate which is the maternal side of the placenta.

    00:17 And the chorionic place that's the fetal side of the placenta as you can see here.

    00:21 We have the membranes.

    00:23 And then we have a three vessel umbilical cord.

    00:25 Now unlike the other structures in the human body, this three vessel cord, has two arteries and one vein.

    00:32 Now let's talk about some of the placental structural abnormalities.

    00:37 First let's talk about succenturiate lobe.

    00:40 So this abnormality is one in which an extra lobe separates from the placenta.

    00:46 The clinical manifestation of this can be postpartum hemorrhage.

    00:51 At times that extra lobe can separate.

    00:54 And when you're delivering the placenta, that extra lobe does not come out.

    00:58 And it can be a cause of postpartum hemorrhage because of retained products.

    01:02 Next let's talk about velamentous insertion.

    01:06 So with the velamentous insertion the umbilical vessels traverse the membranes.

    01:11 As you can see here.

    01:13 The vessels are easily compressible.

    01:16 And so that's the clinical manifestation.

    01:18 Also it can be associated with placenta previa.

    01:22 Vasa previa.

    01:26 So with vasa previa the vessels traverse the cervical os.

    01:30 So you can see here in the picture that the vessels are in front of the fetal head.

    01:35 Now that can be problematic.

    01:36 If those vessels lacerated during the cervical exam, or artificial rupture of membranes, the baby can exsanguinate.

    01:43 So it's important to know if the patient has a vasa previa prior to delivery.

    01:50 Let's go through a question abnormal placentation.

    01:52 A patient is known to have a velamentous insertion.

    01:56 What is the most likely fetal abnormality to be seen on fetal heart tracing while in labor? A. Late decelerations B. Recurrent variable decelerations C. End-stage bradycardia or D. Recurrent accelerations Well, the answer is recurrent variable decelerations.

    02:15 Remember those vessels are easily compressed.

    02:18 And we have compression of vessels that causes recurrent variable decelerations.

    02:24 Now that we've talked about abnormal placental structure, now let's talk about abnormal placental location.

    02:31 So we have Placenta previa, Placenta accreta, Placenta increta or Placenta percreta.

    02:39 Let's start with placenta previa.

    02:40 So this is a situation in which the placenta is located near or over the cervical os.

    02:47 If disrupted in pregnancy, it can cause significant antipartum hemorrhage.

    02:52 It can actually cause death of the baby.

    02:54 And C-section is usually the recommended route of delivery.

    02:58 You can imagine if the placenta is covering the cervix than the fetus is not able to come through that, through the cervical os.

    03:04 Now placenta accreta.

    03:08 So with placenta accreta, the placental trophoblasts invade to the myometrium.

    03:15 We notice the absence of Nitabuch's layer when we look on ultrasound.

    03:19 That's how we diagnose it.

    03:20 It can be associated with placenta previa.

    03:23 And the placenta can be very difficult to remove at the time of delivery.

    03:28 That can make this a cause of postpartum hemorrhage because of retained products of conception.

    03:33 Now, increta.

    03:36 Placenta increta is a condition in which the placental trophoblasts invade through the myometrium.

    03:43 Remember accreta were just to the myometrium.

    03:46 Now we're talking about through the myometrium.

    03:48 It can also be associated with placenta previa, just as a creta can.

    03:53 And the placenta is usually adherent during delivery.

    03:56 And this can be a cause of postpartum hemorrhage.

    03:58 Usually C-section with hysterectomy is the management option because we're unable to physically remove the placenta.

    04:06 So the whole uterus has to be removed.

    04:08 Now percreta.

    04:11 In placenta percreta, the placental trophoblasts are through the serosa.

    04:17 So remember with accreta we were to the myometrium.

    04:20 With increta we were through the myometrium.

    04:23 In percreta we are completely through the myometrium and through the serosa.

    04:27 So now we're going outside of the uterus.

    04:29 The placental tissue can be in various places outside of the uterus.

    04:33 Most commonly the bladder or the rectum.

    04:36 And this causes severe hemorrhage at the time of delivery.

    04:40 Because of this we don't try to remove the placenta.

    04:42 And you can imagine we can't remove the placenta if it's into the bladder or if it is to the rectum.

    04:48 And so a lot of times we do C-section with hysterectomy and we use some of the placental in-situ.

    04:54 Again we can't remove it from the bladder or the rectum if it has invaded that far.

    04:57 So, let's talk about another question.

    05:02 What ultrasound finding is seen in placenta accreta? Is it A. Lambda sign Is it B. Absence of Nitabuch's layer C. The double peak sign or D. Tri Laminar layer.

    05:15 You remember this from the lecture that's why the answer is B.

    05:20 Absence of Nitabuch's layer.

    About the Lecture

    The lecture Abnormal Placentation by Veronica Gillispie, MD, FACOG is from the course Antenatal Care. It contains the following chapters:

    • Placenta
    • Abnormal Placenta Presentation
    • Abnormal Placental Location

    Included Quiz Questions

    1. Velamentous cord insertion
    2. Succenturiate placental lobe
    3. Vasa previa
    4. Placenta increta
    5. Placenta previa
    1. Cesarean section
    2. Cesarean section and hysterectomy
    3. Normal vaginal delivery of fetus and placenta
    4. Normal vaginal delivery of fetus followed by operative delivery of the placenta
    5. Induction of labor at 35 weeks gestation
    1. Delivery by cesarean section followed by hysterectomy
    2. Delivery by cesarean section only
    3. Normal vaginal delivery followed by hysterectomy
    4. Normal vaginal delivery only
    5. Normal vaginal delivery followed by operative delivery of the placenta
    1. Placental previa
    2. Placental accreta
    3. Placental increta
    4. Placental procreta
    5. Placental succenturiate lobe
    1. Placenta percreta
    2. Placenta increta
    3. Placenta accreta
    4. Placenta previa
    5. Placental abruption

    Author of lecture Abnormal Placentation

     Veronica Gillispie, MD, FACOG

    Veronica Gillispie, MD, FACOG

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