Term
| Twin pregnancies are divided according to ___ or ___ as these have important implications for pregnancy and infant outcome. |
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Definition
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Term
| Zygosity refers to whether twins arose from one __ __, called ___, or from two __ __, called ___. |
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Definition
- one fertilized egg, monozygous
- two fertilized eggs, dizygous |
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Term
| Chorionicity refers to ____. |
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Definition
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Term
| Chorion is the ___ of the ___ ___ of land vertebrates, contributing to the formation of the ____ in placental mammals. |
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Definition
- outermost of the extraembryonic membranes
- formation of the placenta |
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Term
| Amnionicity refers to ___ __ that __ or __ __ __ the __ __ of twins. |
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Definition
| - membrane layers that do or do not separate the gestational sacs of twins |
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Term
| ___ ____ twins have NO separating membrane. |
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Definition
| - Monochorionic Monoamniotic (MC/MA) |
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Term
| __ ___ twins have a separating membrane consisting of 2 layers of amnion only. |
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Definition
| Monochorionic Diamniotic (MC/DA) |
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Term
| ___ ____ twins have a separating membrane consisting of both chorion and amnion. They may or may not have __ or __ placenta. |
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Definition
Dichorionic Diamniotic (DC/DA)
separate or fused placenta |
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Term
| Dizygotic twins occur when __ __ __ were fertilized by __ __. |
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Definition
- 2 separate ova
- 2 sperm |
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Term
| 2/3 of the twins in the United States are ___. |
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Definition
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Term
| Monozygotic twins occurs when there is division of a __ __ fertilized by a __ __. This accounts for 1/3 of the twins in the United States. |
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Definition
- single ova
- single sperm |
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Term
| With dizyogtic twinning aka __ __ there are two distinct pregnancies. There is a separate __, __, and __. |
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Definition
- Fraternal twinning
- chorion, amnion, and placenta |
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Term
| two or more ovum fertilized in a single menstrual cycle: |
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Definition
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Term
| Factors that influence dizygotic twinning: |
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Definition
- race
- hereditary/family history
- maternal age
- parity
- fertility drugs
- geography
- maternal weight and height (heavier more likely to have twins)
- diet |
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Term
| What maternal ages have the greatest incidence of twins: |
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Definition
| - both extremes of the reproductive ages (14-15) and (48-50) |
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Term
| What races are most and least likely to have dyzogtic twins? |
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Definition
- Nigeria has the highest rate of natural twinning
- Japan has the lowest rate of natural twinning |
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Term
| Monozygotic twinning aka __ __ twinning aka __ __. Cleavage of the fertilized egg happens at various stages during embryogenesis. |
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Definition
- single ovum twinning
- embryo splitting |
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Term
| The rate for monozygous twinning is __ at __ in __ births. |
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Definition
| - constant at 1 in 250 births |
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Term
| Monozygotic twinning is INdependent of __, __, __, and __. __ and __ __ double the risk of embryonic splitting. |
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Definition
- independent of race, heredity, age, and parity
- Fertility drugs and ART DO double the risk |
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Term
| If embyronic splitting occurs from __ to __ hours, the monozygotic twins will be Diamniotic, Dichorionic. This occurs 30% of the time. |
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Definition
- 0-72 hours
- Diamniotic, Dichorionic
- 30% of the time |
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Term
| If embryonic splitting occurs in __ to __ days, the monozygotic twins will be Monochorionic Diamniotic. This occurs 68% of the time. |
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Definition
- 4 to 8 days
- Monochorionic, Diamniotic
- 68% of time |
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Term
| If embryonic splitting occurs from __ to __ days the monozygotic twins will be Monochorionic Monoamniotic. This happens 2% of the time. |
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Definition
- 8 to 13 days
- Monochorionic, Monoamniotic
- 2% of the time |
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Term
| If embryonic splitting after greater than 13 days, the monozygotic twins will be ___. |
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Definition
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Term
0-72hrs Diamniotic, Dichorionic 30%
4-8days Monochorionc, Diamniotic 68%
8-13days Monochorionc, Monoamniotic 2%
>13 days Conjoined Twins |
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Definition
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Term
| Early assessment of ___ by ___ is essential in the management of multiple pregnancies as the distinguishing features are more difficult to ascertain later on. |
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Definition
| - chorionicity by ultrasound |
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Term
| Female external genitalia on the left and male external genitalia on the right, confirming dichorionic twin gestation with certainty |
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Definition
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Term
| The most important step after determining there is multiple gestation, is determining ___. |
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Definition
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Term
| Reasons to determine zygosity: |
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Definition
- assess obstretical risks
- guide management |
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Term
| Ways to determine zygosity: |
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Definition
- ultrasound
- examine placenta |
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Term
| Twin peak aka __ __ is a __ projection of __ tissue emanating from ___ __ placentas and extending between layers of the intertwin membrane. This is characteristic of a __ __ pregnancy. |
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Definition
- lambda sign
- triangular projection
- chorionic tissue
- fused dichorionic placentas
- Dichorionic,Diamniotic pregnancy |
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Term
| Baby A is the baby that is: |
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Definition
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Term
| Diagnosis of Multiple Gestations when U/S unavailable: |
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Definition
- family or personal history of twins
- excessive weight gain
- enlarged fundal height
- fertility drugs |
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Term
| Definitive way to diagnose multiple gestations: |
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Definition
| - ultrasound (best in the 1st trimester) |
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Term
| Maternal Complications of multiple gestations: |
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Definition
- Anemia- 2.5 fold increase
- Hydramnios
- Hypertension, Preeclampsia- 2.5 fold
- Premature labor
- Cesarean delivery
- Abruption- 3 fold
- Urinary tract infections- 1.5 fold
- Postpartum hemorrhage
- Postpartum atony |
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Term
| Discrepancy b/w plasma rise and hematocrit just in normal pregnancy. This discrepancy doubles with twins. |
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Definition
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Term
| Hydramnios: many chambers so uterus is expanding more, uterus with twins at 25 weeks is same size a singleton full term uterus |
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Definition
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Term
| Maternal Adaption to twins: |
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Definition
- increase serum level of hormones (progesterone, estrodiol, estriol, hPL, hCG, a-FP)
- Heart rate and stroke volume increase> leading to increased cardiac output
- Systolic and Diastolic Pressure mirror the changes seen in singleton pregnancy
but an even greater drop in the 2nd tri-mester with twins
At the time of delivery the mean pressure is higher in multiple pregnancies
- Plasma volume increases by 50-100%
Leading to increased dilutional anemia
- Uterine volume increases rapidly
- Increase in the Tidal Volume and Oxygen consumption
- Increase in GFR
- Caloric intake increases from 2400 kCal to 3000 kCal/day |
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Term
| Fetal complications of multiple gestations: |
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Definition
- Malpresentation
- Placenta Previa
- Abruption
- Premature Rupture of Membranes
- Prematurity
- Umbilical cord prolapse
- Intrauterine growth retardation |
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Term
| Unique fetal complications of multiple gestations: |
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Definition
- monoamniotic monochorionic twins, only happens 1% of the time, mortality rate is 50%
- conjoined twins
- acardiac twins
- twin-twin transfusion syndrome
- discordant twins
- intrauterine demise of one fetus (vanishing twin) |
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Term
| Of liveborn twins, 70-75% are dichorionic diamniotic, and 25-30% are monochorionic diamniotic. Only 1% are monoamniotic. |
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Definition
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Term
| With Monochorionic Diamniotic placentas there is lots of vessel communication between the two sides. |
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Definition
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Term
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Definition
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Term
| Conjoined twins occur when there is cleavage after day __ when the embryonic __ is formed. Separation is incomplete. |
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Definition
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Term
| Conjoined twins are categorized by the anatomic location of incomplete splitting: |
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Definition
- Thoracopagus (anterior)- most common
- Pyopagus (posterior)
- Craniopagus (cephallic)
- Ischiopagus (caudal) |
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Term
| Siamese twins are __ twins. |
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Definition
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Term
| Acardiac twins occurs in __ twins when there is a placental __ __ anastomosis. This leads to inadequate pefusion of one twin resulting in lethal anomolies. The pump twin is __, the recipient acardiac twin has ___. You treat this by __ __ __. |
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Definition
- monozygotic
- arterial arterial anastomosis
- pump twin is normal
- recipient acardiac twin has anomalies
- interrupting vascular communication |
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Term
| The acardiac fetus has an unusually long umbilical cord. It had been seen to move sonographically; it had a spinal cord but no brain. |
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Definition
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Term
| Normally there should be an __ __ connection between twins, but with Twin Twin Transfusion Syndrome there is an __ __ connection. This means one twins circulation perfuses the other twin. This occurs in 10% of monozygotic twins. |
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Definition
- arterial arterial
- arterial venous |
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Term
| Outcome of donor twin with Twin Twin Perfusion Syndrome: |
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Definition
- hypovolemia
- hypotension
- anemia
- oligohydramnios
- growth restriction |
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Term
| Outcome of recipient twin with Twin Twin Transfusion Syndrome: |
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Definition
- hypervolemia
- hydramnios
- hyperviscosity
- thrombosis
- hypertension
- cardiomegaly
- polycythemia
- edema
- CHF |
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Term
| Twin Twin Transfusion Syndrome treatment: |
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Definition
- therapeutic amniocentesis, laser
VERY POOR OUTCOMES |
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Term
| If there is a vascular connection across a monochorionic twin placenta, then a twin-twin transfusion syndrome can develop. In this condition, there is diminished blood flow to one twin (the "donor") and increased blood flow to the other twin (the "recipient"). The pale appearing donor is smaller and may die for lack of sufficient blood flow. More commonly, the larger plethoric recipient may die from congestive heart failure. |
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Definition
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Term
| __ __ is the most accurate way to assess fetal growth. |
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Definition
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Term
| __ to __% difference in fetal weight suggests clinically significant growth discordance. |
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Definition
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Term
| Weight discordance of __% or more is associated with a __ fold increase of stillbirth. |
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Definition
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Term
| Intrauterine demise of one fetus (vanishing twin) occurs in __% of twin pregnancies. There is usually __ __ injury to the surviving twin. "Monochorionic twin" as ealry as 12 weeks gestation. List complications of surviving twin: |
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Definition
- 21%
- profound neurological injury
- cerebral palsy, cortical necrosis, small bowel atresia, multicystic encephalomalacia
USUALLY SIGNIFICANT HYPOTENSION AT THE TIME OF DEATH OF THE CO-TWIN. |
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Term
| Antepartum management goals of multiple gestations: |
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Definition
- prolong gestation
- increase birth weight
- decrease perinatal morbidity and mortality |
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Term
| Antepartum management during 1st and 2nd trimester of multiple gestations: |
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Definition
- cervical assessment
- nutritional counseling |
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Term
| 3rd trimester antepartum management: |
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Definition
- cervical assessment
- monitor for signs of preeclampsia
- antenatal testing (biophysical profile)
- monitor fetal growth |
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Term
| Do NOT treat for preterm labor after __ weeks. |
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Definition
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Term
| Intrapartum management for preterm labor includes ___ ___ and ___. |
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Definition
- Antenatal steroids
- Tocolytics: Magnesium sulfate, Terbutaline, Procardia, Toradol |
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Term
| calcium channel blocker to stop uterine contractions in preterm labor: |
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Definition
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Term
| Most common presentation for twin delivery: |
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Definition
| - vertex-vertex> delivery vaginally if possible with double set up |
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Term
| Any presentation other than vertex-vertex twins, a __ should strongly be considered. |
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Definition
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Term
| A 36 year old female presents for her initial prenatal appointment. She was treated with Clomiphene citrate for infertility. Her initial ultrasound reveals a twin gestation. This type of twinning is usually: |
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Definition
| Diamniotic, Dichorionic b/c fertility drugs make you release more than one egg |
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Term
| A 20 year old female presents for her prenatal appointment at 21 weeks gestation. She has a known twin gestation. Fundal height has increased 10 cm from the last visit 2 weeks ago. Ultrasound reveals excessive amniotic fluid around the first twin and the second twin has only a small pocket of fluid. This complication of twins is: |
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Definition
| Twin-Twin Transfusion syndrome |
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Term
| The incidence of monozygotic twins is : |
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Definition
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Term
| Which two factors are associated with the highest rate of twinning? |
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Definition
- Infertility agents
- Maternal age |
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Term
| At the onset of labor the most common presentation for twin gestation is |
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Definition
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Term
| If division of the zygote occurs on the fifth day after conception the fetuses will have: |
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Definition
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Term
| The most common type of conjoined twin is: |
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Definition
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Term
| A 24 year old G1P0 has just delivered twins, both male, at 37 weeks. On your initial assessment, you notice the “A” twin is large and plethoricand the “B” twin is small and pale. A CBC is the next most appropriate step because: |
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Definition
| "A" twin is at risk for polycythemia |
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Term
| Discordance in twins is best measured by: |
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Definition
- Biparietal diameter
- Abdominal circumference
- Femur length |
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