Abnormalities of the Amnion, Placenta, and Umbilical Cord Part 1

by Peter Ward, PhD

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    00:01 Another set of problems that can occur in this process a little bit later on are called amniotic bands.

    00:07 If the amnion develops tears or little strips of tissue that come loose, these bands may be floating freely within the amnion.

    00:16 As fetal movements occur, the fetus' limbs can get tied up with these bands and they can constrict the fingers or other parts of the limbs and actually lead to amputation or constriction of the portions of the body that are tied up.

    00:32 So amniotic bands are very problematic and may have to be dealt with with an intrauterine procedure if they are detected.

    00:39 Another set of problems that can occur is when the amniotic fluid is present in too much quantity or too little quantity.

    00:47 Now, the amniotic fluid is typically between 700 and 1000 milliliters in volume and the amniotic fluid does a variety of interesting things besides as simply cushioning the developing embryo and fetus.

    01:00 The fetus breathes in amniotic fluid and expels it.

    01:04 This allows the lungs to develop properly and also strengthens the respiratory muscles so that when we're born, instead of breathing in resistance heavy fluid, we're breathing in relatively light resistance air and it allows us to breathe far more easily once we're out of the womb.

    01:23 Amnion is also swallowed and the embryo will absorb some of the amnion in the intestines and the kidneys will filter fluid in the body, release it as urine which will be taken back and put back into the amnion.

    01:37 So even though we're urinating into the amnion, most of our body's wastes are recycled through the placenta so that urine does not pollute the amnion even though it is being released throughout the fetal period.

    01:50 If we have too much amniotic fluid, we will refer to this as polyhydramnios, and this can be as much as 2,000 milliliters, almost double the normal amount.

    02:00 This can occur because the intestines have not formed properly and there's a blockage so the amnion that would normally be swallowed and then filtered by the kidneys and the placenta is building up around the body.

    02:13 If the fetus cannot swallow the amnion, it builds up and is going to put pressure on the embryo.

    02:19 On the opposite extreme, there is olygohydramnios which is too little amniotic fluid.

    02:24 This often results in what's called Potter Sequence.

    02:28 Without lack of buoyancy causes flattening of the facial features, dislocation of the hips or clubbing of the feet due to the fact that the embryo is not floating as freely as it should be within the amniotic fluid.

    02:42 Another problem that can develop is lung hypoplasia because the lungs are not developing enough because they're not breathing in enough fluid to expand properly and workout the respiratory muscles.

    02:53 Problems that can occur with the placenta itself include placenta accreta, and placenta increta, and placenta percreta.

    03:04 The main thing I want you to know about this is that they go in alphabetical order and in order of severity.

    03:10 So placenta accreta is going to happen when the placenta, instead of being strictly within the endometrium, the inner lining of the uterus, extends into the myometrium or the muscles of the uterus.

    03:23 Placenta increta is the same, only more so and has a significant attachment into the muscle of the uterus, the myometrium.

    03:33 And finally, placenta percreta is going to be when the uterus is completely or should I say invaded by the placenta from the endometrium, myometrium and even all the way out to the series lining of the uterus we have placenta percreta anchoring the placenta very firmly to all of those tissues.

    03:55 And the problem with all of these conditions is that if the placenta is forcibly removed during the after birth portion of delivery, it can cause massive maternal hemorrhaging.

    04:05 So this is a major problem and should be detected early so it can be dealt with and the hemorrhage controlled readily in the operating room.

    About the Lecture

    The lecture Abnormalities of the Amnion, Placenta, and Umbilical Cord Part 1 by Peter Ward, PhD is from the course Conception, Implantation and Fetal Development.

    Author of lecture Abnormalities of the Amnion, Placenta, and Umbilical Cord Part 1

     Peter Ward, PhD

    Peter Ward, PhD

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