Ultrasound Evaluation During the First Trimester of Pregnancy W Bruce Clark, M.D  Vaginal ultrasound is usually superior to abdominal scanning  Resolution is superior because The transducer tip is closer to the pregnancy  This allows a higher frequency transducer   The exception being nuchal translucency  More freedom of movement on the anterior abdominal wall Gestational Sac     First ultrasound sign of pregnancy At weeks day to weeks days 2-3 mm At weeks 5mm, can be seen abdominally Beware of the pseudo sac week sac Yolk Sac  Transvaginal   Appears at to 5.5 weeks Mean Sac Diameter (MSD) 5mm to 8mm  Transabdominal  Appears at weeks  Mean Sac Diameter (MSD) 20mm Maximal Diameter 5-6mm at Crown Rump Length (CRL) of 30-45mm Visualization of Yolk Sac confirms Gestational Sac rather than a Pseudo Sac week with yolk sac Cardiac Activity  Transvaginal   Earliest seen at 34 days, CRL 1.6 mm Should be seen at 6.06.5 weeks, CRL to 5mm, or MSD 13 to 18mm  Transabdominal  Should be seen at weeks, MSD 25mm First Trimester  Gestational Age  Best predicted by the Crown Rump Measurement Signs of First Trimester Pregnancy Failure       Sac with no embryo Embryo ≥ mm with no FH Small sac size First trimester bradycardia Yolk sac too big, irregular, or calcified Slow embryo growth Ultrasound Findings of an Abnormal Sac   MSD >8 mm without yolk sac MSD > 16 mm without embryo First trimester fetal abnormalities   Fetal Abnormalities Nuchal translucency Second trimester fetal abnormalities   Anatomical Chromosomal Markers for chromosomal abnormalities      Short femur Nuchal thickness Pyelectasis Choroid plexus cyst Anatomical abnormalities Third trimester fetal well being      Growth Doppler flow of umbilical arteries Amniotic fluid volume Placental grade Fetal breathing movements [...]... Gestational Age  Likelihood of Spontaneous Abortion Signs of First Trimester Pregnancy Failure       Sac with no embryo Embryo ≥ 4 mm with no FH Small sac size First trimester bradycardia Yolk sac too big, irregular, or calcified Slow embryo growth Ultrasound Findings of an Abnormal Sac   MSD >8 mm without yolk sac MSD > 16 mm without embryo Ectopic Pregnancy Diagnosis of Pregnancy    Blood 5µ/... values to evaluate abnormalities of pregnancy    Blood 5µ/ ml ~ 3 or 4 days Urine 50µ/ ml ~ 10 days Ultrasound 1,000-1,500µ/ml ~18 – 20 days (gestational sac) First trimester fetal abnormalities   Fetal Abnormalities Nuchal translucency ULTRASOUND IN PRIVATE PRACTICE W Bruce Clark, M.D First Trimester  Gestational Age  Crown Rump Measurement First Trimester Ultrasound  Twins/Multiples  ... days Urine 50µ/ ml ~ 10 days Ultrasound 1,000-1,500µ/ml ~18 – 20 days (gestational sac) First trimester fetal abnormalities   Fetal Abnormalities Nuchal translucency Second trimester fetal abnormalities   Anatomical Chromosomal Markers for chromosomal abnormalities      Short femur Nuchal thickness Pyelectasis Choroid plexus cyst Anatomical abnormalities Third trimester fetal well being ... Chromosomal Markers for chromosomal abnormalities      Short femur Nuchal thickness Pyelectasis Choroid plexus cyst Anatomical abnormalities Third trimester fetal well being      Growth Doppler flow of umbilical arteries Amniotic fluid volume Placental grade Fetal breathing movements