Multiples Pathology

congenital anomalies of twins

-NTD

-hydrocephalus

-congenital heart disease

-urogenital sinus malformation

-chromosomal abnormalities

-single umbilical artery

syndromes are specific to

monochorionic twins

twin to twin transfusion

abnormal arterial to venous anastomoses through a common placenta

TTTS prognosis

poor prognosis

donor twin

-twin on the arterial side of the communication, shunting blood to recipient twin

-severe risk for intrauterine death, pulmonary hypoplasia due to oligohydramnios

-hypovolemia

-anemia

-severe growth restriction

-fetal compromise (absent movement)

-poor renal perfusion (absent bladder)

-oligohydramnios ("stuck twin") - fixed position against uterine wall (only possible in diamniotic twinning)

recipient twin

-receives blood from donor

-constant state of diuresis leading to polyhydramnios/large bladder

-untreated leads to premature labor or loss of pregnancy

-hypervolemia

-plethoric-beefy red colartion, increased RBCs - leads to CHF

-hyrops

-fetal death

TTTS treatment options

-selective feticide

-laser ablation of surface chronic vessels

-therapeutic amniocentesis

selective feticide risks

death or embolization syndrome to remaining twin because of shared placenta

therapeutic amniocentesis

reduce poly, relief of pressure improves circulation in donor twin

twin embolization

-in utero death of one twin followed by the development in the remaining twin of neurologic damage or injury to organs

-including small intestines and kidneys

-due to passage of thrombosis from dead twin through intraplacental vascular communication

-injury depends on the degree of embolization

-associated with hydrops, poly, intracranial findings, intraperitoneal calcificiations, enlarged echogenic kidneys

acardiac parabiotic twinning

-a severely malformed fetus with an absent heart that continues to grow throughout the pregnancy

three names for acardiac parbiotic twinning

-acardiac or monster twinning

-parabolic twinning

-TRAP syndrome/sequence

acardiac mechanism of perfusion

-deoxygenated blood from pump twin is sent to acardius fetus

-upper body and head receive blood with little to no oxygen

sonographic appearance of acardiac parabiotic twinning

-grossly malformed

-limited development of upper half of body

-head absent or small with holoprosencephaly

-arms and ribs are absent to hypoplastic

-lungs and abdominal viscera are absent

pump twin

-added perfusion burden on cardiovascular system - chief cause for morbidity/mortality

-only potential member of pregnancy

-constant high cardiac output leads to high renal perfusion and diuresis

-lead to poly, CHF, hydrops, death

treatment of acardiac parabolic twinning

embolization of acardiac twin

fetus in fetu

-parasitic twin develops within the abdomen of the other twin

-more common in upper retroperitoneum, microscopic or radiographic evidence of vertebral column

heterotopic twin

-increasing incidence with assisted fertility

-one twin in utero

-one twin out of uterus

superfetation

-successful fertilization of a second ovum released during an ongoing pregnancy

-not the same cycle

-results in twins of nonequal age

superfectation

-fertilization of two ova within a short interval by separate acts of coitus

-same cycle

-not detectable by sonography, not same father

-detailed genetics may prove fetuses have different fathers

method of selective reduction

transcervical aspiration of intracardiac injection of potassium chloride

method of selective termination

-intracardiac puncture/exsanguination

-embolization or air embolization via umbilical

risk of selective termination

-wrong baby

-uterine contractions may begin and loss of entire pregnancy

-long term damage to surviving fetus