OBSTETRICS A little bit of everything or, a whole lot of not much

1. OBSTETRICSA little bit of everything or,a whole lot of not much Holdorf

2. Second and Third Trimester Placenta

3. Placenta Development The placenta is a mateno-fetal organ which begins developing at implantation of the blastocyst and is delivered with the fetus at birth. This is a normal fetal ultrasound performed at 17 weeks gestation. In the foreground to the left and middle of the screen, you can see the placenta, following the curve of the uterus.

4. Placental Positions • Placental development may occur on any side of the gestational sac: • Anterior • Posterior • Lateral (right/left) • Fundal Fundal Posterior

5. Umbilical Cord • The umbilical cord is the life-line that attaches the placenta to the fetus. The umbilical cord is made up of three blood vessels: two smaller arteries which carry blood to the placenta and a larger vein which returns blood to the fetus. It can grow to be 60 cm long, allowing the baby enough cord to safely move around without causing damage to the cord or the placenta.

6. Placenta Abruption • When the uterus bleeds from the site where the placenta was attached. The blood typically passes through the cervix and out the vagina. Sometimes, however, the blood remains trapped behind the placenta. Left untreated, placental abruption puts both mother and baby in jeopardy.

7. Placenta Previa • The implantation of the placenta at least partially covering the cervix. • There are actually three types of previa. Complete previa where the cervical os is completely covered. Partial previa where just a portion of the cervix is covered by the placenta. And the marginal previa that extends just to the edge of the cervix.

8. Partial Placenta Previa The placenta partially covers the internal os.

9. Marginal Previa Transvaginal sagittal view which shows a posterior marginal placenta previa extending about 2 cm over the internal os.

10. Complete Previa

11. Maturity/Grading Placental Grading Based on Placental Calcification 1. Placental Grading Grade 0 No calcifications (to about 31 wk) I Scattered calcifications (31 – 36 wk) II Basal Calcifications (36 – 38 wk) III Basal and interlobar septal calcifications (38 wk to term) 2. The placenta matures considerably after the 40th week. 3. Two parts of the placenta may have different grades, in which the highest grade is assigned. 4. Most term pregnancies have grade I or II placentas. 5. Only about 10% - 15% of term placentas are grade III.

12. Grade 0 Late 1st trimester-early 2nd trimester Uniform moderate echogenicity Smooth chorionic plate without indentations

13. Grade 1 Mid 2nd trimester –early 3rd trimester (~18-29 wks) Subtle indentations of chorionic plate Small, diffuse calcifications (hyperechoic) randomly dispersed in placenta

14. Grade 2 Late 3rd trimester (~30 wks to delivery) Larger indentations along chorionic plate Larger calcifications in a “dot-dash” configuration along the basilar plate

15. Grade 3 39 wks – post dates More irregular calcifications with significant shadowing

16. Placenta Accreta • Placenta accreta is a severe obstetric complication involving an abnormal attachment of the placenta to the myometrium. • There are three forms of placenta accreta, distinguishable by the depth of penetration.

17. Placenta Accreta • The most common form of placenta accreta which is the invasion of the myometrium which does not penetrate the entire thickness of the muscle. • Placenta increta occurs when the placenta extends into the muscle of the uterine wall. • Placenta percreta, the worst form of the condition is when the placenta penetrates the entire uterine wall.

18. Placenta Accreta Typical image of massive anterior placenta percreta. US Doppler shows the newly formed vessel between uterus and the bladder.

19. Multiple Gestations

20. Diamniotic • Diamniotic pregnancy is when there are more than one amniotic sac.

21. Monoamniotic • Monoamniotic twins are identical twins who share the same amniotic sac. This very rare condition occurs in an estimated 1 in 25,000 to 1 in 60,000 pregnancies, and historically has resulted in the in-utero death of one or both babies in 50 to 70 percent of cases.

22. Complications of the Fetus and Newborn with Multiple Gestation • Preterm births. • Compared to singleton pregnancies, a twin is seven times more likely and a triplet is over 20 times more likely to die in the first month of life. • Prematurity is associated with an increased risk of respiratory distress syndrome (RDS), intra-cranial hemorrhage, cerebral palsy, blindness, low birth weight, and neonatal morbidity and mortality. • Intrauterine growth restriction, intrauterine death of one or more fetuses, miscarriage, and congenital anomalies are all more common. • Lifelong disability is over 25% for babies weighing less than 1,000 grams.

23. Maternal Complications Associated with Multiple Gestation • Preeclampsia, also called pregnancy-induced hypertension, occurs three to five times more frequently. • Premature labor requiring prolonged bed rest or hospitalization is common. • Placental abnormalities associated with maternal hemorrhage are more likely to occur. • Gestational diabetes, anemia, and polyhydramnios occur more frequently. • Cesarean section is often needed for twin pregnancies and almost always required for triplets.

24. Fetal Abnormalities

25. Cranial Abnormalities Hydrocephaly • Dilatation of ventricular system secondary to an increase in the amount of CSF. Effects include flattening of parenchyma, intraparenchymal effusions which cause demyelination and brain damage.

26. Cranial AbnormalitiesHydranencephaly • Total or near total absence of cerebral hemispheres with normally developed meninges and skull. Cerebellum and midbrain, including basal ganglia are intact. 14 weeks shows unfused thalami surrounded by fluid in this fetus with hydranencephaly. Note the lack of cerebral hemispheric tissue.

27. Cranial AbnormalitiesHoloprosencephaly • Abnormality of forebrain diverticulation leading to a single large midline ventricle. Spectrum of pathologic findings include: • Alobar: (most severe) large single cavity with minimal amount of cerebral tissue surrounding it, fused thalami, and a facial syndrome. • Semilobar: more cerebral tissue present, occipital lobe present.

28. Cranial AbnormalitiesPorencephaly • The presence of cystic areas within the cerebral parenchyma.

29. Cranial Abnormalities Dandy-Walker Syndrome • Characterized by: • Posterior Fossa Cyst continuous with 4th vent. • Posterior fossa enlargement. • Cerebellar vermian dysgenesis.

30. Cranial AbnormalitiesChoroid Plexus Cysts • The presence of simple cysts within the choroid plexus.

31. Cranial AbnormalitiesMicrocephaly • Small head greater than 3 standard deviations below normal.

32. Cranial AbnormalitiesAgenesis of Corpus Callosum • Absence of the corpus callosum resulting from a chromosomal abnormality or a chromosomal translocation. May be complete or partial.

33. Cranial AbnormalitiesIntracranial Tumors • Rare occurrence. May be cystic, solid, or complex.

34. Facial AbnormalitiesFacial Clefts • Failure of lip fusion, normally complete by 35 days of intrauterine life. Bilateral Cleft Lip

35. Facial AbnormalitiesEpignathus • A teratoma arising from the oral cavity or pharynx. May arise from the sphenoid bone, hard or soft palate, pharynx, tongue or jaw.

36. Neck AbnormalitiesCervical Teratoma • Similar to epignathus expect the tumor arises from the neck.

37. Neck AbnormalitiesNuchal Thickening • Increased soft tissue thickness over the posterior aspect of the neck.

38. Neck AbnormalitiesCystic Hygroma • Benign developmental anomaly of lymphatic origin characterized by single or multiple cystic areas within soft tissues surrounding the neck.

39. Neural Tube Abnormalities Anencephaly • Anencephaly, a congenital anomaly in which the cerebral hemispheres and overlying skull and scalp are entirely absent, is the most obvious and dramatic of the “absence” abnormalities.. Note the absence of cranial tissue.

40. Protrusions of the meninges and frequently of brain substance through a defect in the cranium. Encephaloceles contain brain tissue and cranial meningoceles do not. Although cephalocele usually result from a defect in neural tube closure, they may be seen in the amniotic band syndrome or in association with various malformation syndromes. Neural Tube Abnormalities Cephalocele/Encephaloceles

41. Neural Tube Abnormalities Spina Bifida and Meningomyelocele • Spina bifida refers to a defect in the spine resulting from a failure of the two halves of the vertebral arch to fuse. These lesions usually occur in the lumbosacral and cervical regions. If the meninges protrude through the defect, the lesion is designated a meningocele; if neural tissue is included, it is a meningomyelocele. No fusions

42. Abdominal Wall AbnormalitiesOmphalocele • Herniation of abdominal viscera into the base of the umbilical cord. May be caused by failure of fusion of the lateral ectomesodermal folds or by persistence of the body stalk in the area normally occupied by the abdominal wall.

43. Abdominal Wall AbnormalitiesGastroschisis • Smaller herniation of abdominal viscera through an off-midline defect in the abdominal wall, usually located just to the right of the umbilicus.

44. Abdominal Wall AbnormalitiesUmbilical Cord Hernia • Protrusion of a small amount of intestine at the umbilicus.

45. Abdominal Wall AbnormalitiesBladder Extrophy • Congenital failure of abdominal wall to develop over bladder; urinary bladder may protrude thorough abdominal wall. A 35 week male fetus with bladder extrophy.

46. Genitourinary AbnormalitiesUreteropelvic Junction Obstruction • Narrowing (stricture) at this junction which reduces the flow of urine from the kidney and can result in enlargement of the kidney caused by the backup of urine into the renal pelvis (hydronephrosis) and kidney damage. UPJ obstruction can be severe, minimal, or intermittent. Postnatal ultrasound confirmed the ureteropelvic junction obstruction.

47. Genitourinary AbnormalitiesUreterovesical Junction Obstruction • Rare, and is noted by dilatation of the ureter to the level of the bladder.

48. Genitourinary AbnormalitiesBladder Outlet Obstruction • Bladder outlet obstruction occurs at the base of the bladder, and reduces or prevents the flow of urine into the urethra. Keyhole Appearance

49. Genitourinary AbnormalitiesPosterior Urethral Valves • Predominantly a male abnormality because of redundant membranous folds in the posterior urethra that lead to varying degrees of GU system obstruction. Axial ultrasound image depicts a massively distended bladder with a keyhole appearance posteriorly.

50. Gastrointestinal AbnormalitiesEsophageal Atresia • Esophageal Atresia is a disorder of the digestive system in which the esophagus does not develop properly. The disorder is a congenital defect, which means it occurs before birth.