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Glossary of Terms
(also commonly referred to as "amnio") is a common prenatal test. During the procedure, an ultrasound device is used to determine the baby's position, and then a long hollow needle is introduced to withdraw amniotic fluid from around the fetus. (The baby is not touched.) The particles of the baby's sloughed-off skin cells floating in the water are then tested in a lab for fetal abnormalities. Results are usually back in 8-10 days. Amnios are also used to determine fetal lung maturity when preterm labor has been recommended.
relating to the period before parturition (action or process of giving birth); before childbirth
(latin name: placentae bilobata) - To be classified as bipartite or tripartite the two or three lobes of a placenta should be separated by a membrane and be of equal or near equal size. There is no certain information on how multilobed placentas are formed. A bipartite placenta in one pregnancy may be followed by greater-than-expected frequency of bipartite placenta in the next pregnancy. This raises the possibility that some multilobed placentas have genetic origin. The umbilical cord most often inserts into the membranes between the two lobes of bipartite placentas but in about one-third of cases it inserts into the larger of the two lobes. The two clinical manifestations of multilobed placetas most often cited are bleeding in the first trimester of pregnancy, and a failure of one of the lobes to separate at delivery with consequent postpartum hemorrhage.
Color Doppler Ultrasound
used to measure the velocity of blood flow. Doppler ultrasound can be used to listen to the fetal heart beat, examine the fetal heart for effects and estimate placental blood flow. This special type of ultrasound shows different rates of blood flow in different colors blue and red on a monitor in real time. One color goes from the placenta to the baby and the other one from the baby to the placenta. This way the location of the fetal vessels can be detected and the suspected diagnosis vasa previa can be confirmed or rejected.
Level II (targeted) Ultrasound
involves the use of sophisticated ultrasound equipment along with specially trained physicians to obtain a detailed look at fetal anatomy. Targeted Ultrasound is recommended when there is an increased risk of birth defects in the fetus either due to previous pregnancy history, family history, medical complications, or advanced maternal age.
early in pregnancy, the zygote (fertilized egg) implants in the uterus and forms a placenta. Implantation that occurs low in the uterus may result in a placenta that is close to or covers the cervical os (birth canal). Most low-lying placentas migrate (move) during later pregnancy towards the fundus (top of the uterus) and away from the cervix.
A low placenta has four degrees of severity:
Low-lying placenta: The placenta is implanted low in the uterus close to the cervix but the edge of the placenta does not reach the cervical os.
Marginal placenta previa: The edge of the placenta is at the margin of the cervical os.
Partial placenta previa: The cervical os is partially covered by the placenta.
Total placenta previa: The cervix is completely covered by the placenta.
A Maternal-Fetal Medicine Specialist is an Obstetrician who specializes in High-Risk Pregnancies, Prenatal Diagnosis and Medical Complications of Pregnancy. While some obstetricians have the experience and training to handle complicated pregnancies, Maternal-Fetal Medicine specialists can provide consultation and co-management of high-risk patients.
a pregnancy of twins, triplets and beyond
test used to determine presence of fetal blood. The test will detect fetal hemoglobin down to a concentration of 20%
obstetricians who specialize in high-risk pregnancies. (Peri = around; natal = birth.)
A high-risk pregnancy might mean that the mother has:
a medical problem such as gestational diabetes (diabetes of pregnancy) or high blood pressure
a pregnancy complication such as a multiple birth or preterm labor
a history of pregnancy complications.
an abnormal implantation of the placenta at or near the internal opening of the uterine cervix so that it tends to precede the child at birth usually causing severe maternal or fetal hemorrhage
administered when fetal lung maturity needs to be accelerated for early delivery prescribed when continuing pregnancy to term would compromise baby’s healthy outcome.
Succenturiate Lobed Placenta
A succenturiate (accessory) lobe is a second or third placental lobe that is much smaller than the largest lobe. Unlike bipartite lobes, the smaller succenturiate lobe often has areas of infarction or atrophy. The risk factors associated are advanced maternal age, primigravida, proteinuria in the first trimester of pregnancy, and major malformations in the fetus. The membranes between the lobes in such placenta can be torn during delivery, and the extra lobe can be retained after rest of the placenta has been delivered, with consequent postpartum bleeding.
A targeted ultrasound, or Level II ultrasound examination provides a greater assessment of fetal anatomy, using top of the line ultrasound equipment and performed by specialists in prenatal diagnosis. This is recommended for women with personal or family histories of birth defects, medication exposures, abnormal serum screening tests, or advanced maternal age.
Denoting any pharmacological agent used to arrest uterine contractions: often used in an attempt to arrest premature labor contractions.
Small device which is used within the vagina that utilizes high frequency (5.0-7.5 MHz) transducers, which offers improved resolution of normal anatomy and pathology in the female pelvis when compared to the transabdominal approach. This advantage is particularly apparent in the obese patient, the patient with a retroflexed/retroverted uterus and in identification of anatomy too small to be visualized transabdominally or that which cannot be palpated on manual exam.
(Theory developed by Dr. Harris Finberg, M.D.) trophotropism in placental tissue can be compared to the tendency of a plant to lean towards the sun to get the light it needs to survive. Since the lower segment of the uterus is not as nourishing as the upper segment, the placenta will grow upwards to reach more nourishing tissue.
(latin name: Vasa Praevia) Vasa previa is a rarely reported condition in which fetal blood vessel(s) from the placenta or umbilical cord traverse the fetal membranes between the baby’s presenting part and the entrance to the birth canal (cervical os). The vessels are unsupported by placenta or umbilical cord and are at risk of compression or rupture. The condition has a high fetal mortality rate (50-90%) when not prenatally diagnosed. This can be attributed to rapid fetal exsanguination resulting from the vessels tearing when the cervix dilates, membranes rupture or if the vessels become pinched off as they are compressed between the baby and the walls of the birth canal.
Velamentous Insertion of the Cord
When a cord is velamentous, the fetal vessels exit the protective covering of the umbilical cord and travel through the amniotic membranes, unsupported by either placenta or Wharton’s Jelly before inserting into the placenta, leaving a portion unprotected and exposed.
2018 International Vasa Previa Foundation, Inc.