Page 853 - TNFlipTest

Toronto Notes 2019 Obstetrical Hemorrhage Radiation
• ionizingradiationexposureisconsideredteratogenicathighdoses ■ if indicated for maternal health, should be done
• imagingnotinvolvingdirectabdominal/pelvichighdosageradiationisnotassociatedwithadverse effects
■ higher dosage to fetus: plain x-ray of lumbar spine/abdomen/pelvis, barium enema, CT abdomen/ pelvis/lumbar spine
• radioactiveisotopesofiodinearecontraindicated
• noknownadverseeffectsfromU/SorMRI(long-termeffectsofgadoliniumunknown,avoidif
Obstetrics OB13
possible)
Table 8. Approximate Fetal Doses from Common Diagnostic Procedures
Examination
Plain Film
Abdomen Pelvis
Lumbar spine Thoracic spine Chest (2 views)
CT
Abdomen Pelvis Lumbar spine Chest
Adapted from: Cohen-Kerem, et al. 2005 and Valentin 2000
Estimated Fetal Dose (rad)
0-14 0-11 0-17 0.009 <0.001
0-8 2-5 0-24 0.006
Number of Exams Safe in Pregnancy
35 45 29 555 5000
6
2 20 833
Radiation in Pregnancy
• bloodyshow(sheddingofcervicalmucousplug)–mostcommonetiologyinT3 • placentaprevia
• abruptioplacentae–mostcommonpathologicaletiologyinT3
• vasaprevia
• cervicallesion(cervicitis,polyp,ectropion,cervicalcancer)
• uterinerupture
• other:bleedingfrombowelorbladder,abnormalcoagulation
Table 9. Comparison of Placenta Previa and Abruptio Placentae
• Necessary amount to cause miscarriage: >5 rads
• Necessary amount to cause malformations: >20-30 rads
Obstetrical Hemorrhage
Definition
• vaginalbleedingfrom20wktoterm
Differential Diagnosis
Definition
Etiology Epidemiology Risk Factors
Bleeding
Placenta Previa
Abnormal location of the placenta near, partially, or completely over the internal cervical os
Idiopathic
0.5-0.8% of all pregnancies
History of placenta previa (4-8% recurrence risk) Multiparity
Increased maternal age
Multiple gestation
Uterine tumour (e.g. fibroids) or other uterine anomalies
Uterine scar due to previous abortion, C/S, D&C, myomectomy
PAINLESS
Abruptio Placentae
Premature separation of a normally implanted placenta after 20 wk GA
Idiopathic
1-2% of all pregnancies
Previous abruption (recurrence rate 5-16%)
Maternal HTN (chronic or gestational HTN in 50% of abruptions) or vascular disease
Cigarette smoking (>1 pack/d), excessive alcohol consumption, cocaine
Multiparity and/or maternal age >35 yr
PPROM
Rapid decompression of a distended uterus (polyhydramnios, multiple gestation)
Uterine anomaly, fibroids
Trauma (e.g. motor vehicle collision, maternal battery)
Usually PAINFUL