Early Pregnancy

• Should see yolk sac by 5.5 w gestation
• Always when mean diameter of gestational sac is 10 mm
• Can have ectopic pregnancy at HCG levels below detectable limit of urine pregnancy (~25) so always complete US if there is concern
• Should see FHR once CRL > 5 mm
• Normal FHR usually 110 – 160
• Normal FHR can be as low as 80 if CRL < 5 mm