Abnormal Fetal Dev, Ectopic Preg, Screening for genetic dz Flashcards
Causes of sporadic and recurrent pregnancy loss
- Sporadic: most are chromosomal abnormalities; most common of which is aneuploidy; 1st most common aneuploidy is Tri16, 2nd is Tri21
- Recurrent:
• insufficient cervix: loss in 2nd trimester
• uterine anomalies: ex: T-shaped uterus
• antibody syndromes: like antiphospholipid Ab syndrome
• parent is a carrier of a balanced translocation
Presentation of pregnancy loss
- bleeding and cramping (25% of women experience bleeding in 1st trimester, but with cramping = worrisome)
- TAUS can detect gestational sac when hCG is 2000, TVUS can detect when hCG is 1000
- progesterone
Types of congenital anomalies
- chromosomal anomalies - assoc. with maternal age
- single gene defects/mutations - i.e., SCD, or CF
- structural anomalies - usually sporadic or due to teratogen, polygenic/multifactorial
* All women should have US at 18-20wks, some anomalies may be detectable by then
Anencephaly
failure of the rostral end of the neural tube to close, resulting in absence of a major portion of the brain, skull, and scalp
Cystic nuchal translucency
- an enlarged nuchal space on US which may be related to a cystic hygroma (lymph accumulation in neck region due to obstruction) or mesenchymal edema
- associated with aneuploidy, as well as with cardiac and neural tube defects
Ventriculomegaly
- results from hydrocephalus
- will see on US
- head circumference may not be enlarged, but there will be marked enlargement of the ventricle(s)
Gastroschisis
- ventral wall hernia where the guts are outside the abdomen, no enclosed in peritoneum like an omcephelocele
- this can be seen on US at 20 weeks
How many cases of twins are... present at the start of pregnancy? monozygotic? dizygotic? liveborn?
at start of pregnancy: 1/30
monozygotic (identical): 1/3 dizygotic (fraternal): 2/3
liveborn: 1/76
Risk factors for dizygotic and monozygotic twins
- Dizygotic: black, maternal family hx, young maternal age
- Monozygotic twinning: sporadic/random, only RF is IVF (because they use it as a technique to inc. embryos)
Chorionicity and Amnionicity
Chorionicity: refers to placental development; can be seen on US
- monochorionic: one placenta, two babies
- dichorionic: two placentas, two babies
Amnionicity: refers to amniotic sac
- monoamniotic: one amniotic sac
- diamniotic: two amniotic sacs
*These can be in any combination except dichorionic/monoamniotic
Complications with twins
- prematurity: avg delivery age is 36wks
- maternal DM, maternal hemorrhage
- twin-twin transfusion: in monochorionic/diamniotic twins one dies as the fluid is shunted to the other; only happens in monozygotic twins
Malpresentation
- when the baby’s head isn’t first down the birth canal, happens in 5% of cases
- requires c-section
- could be arm, foot, face, cord (cord prolapse), breech (butt), or placenta previa instead of vertex
Growth disturbances: small for gestational age
- Intrauterine growth restriction can be dx’d with serial US
- if symmetric, usually from chromosomal abnormality
- if asymmetric (that means that the head is growing normally but not the rest), often due to placental insufficiency (doesn’t deliver adequate Oxygen/nutrients), such as when the mother smokes
Growth disturbances: large for gestational age
- maternal DM can cause macrosomic babies as Glu crosses placenta; at risk for shoulder dystocia (birth injury)
- Beckwith-Wiedemann syndrome = syndrome characterized by macrosomia, macroglossia, midline abdominal wall defects, ear creases/ear pits, neonatal hypoglycemia
- Can determine estimated weight and develop birth plan (CD vs. vaginal)
What is the most common cause of maternal death in the first trimester?
Ectopic pregnancy
