O And G Guidelines

Question 1

When will you see gestation sac, yolk sac and embryo and heartbeat

Answer 1

5, 5 1/2 and 6 weeks respectively

Question 2

Crl to see fetal hb

Answer 2

Should see when crl 7mm

Question 3

Early preg loss parameters

Answer 3

Msd 25mm no YS
Crl 7mm no HB
No development of HB in embryo already seen 7 days prior
No development of YS in sac >12mm see 7 days prior
No development YS in sac seen 14 days prior
No embryo with HB 11 days after a YS is seen
Absent previous HB

Question 4

Timing NT

Answer 4

Crl 45 (ideally 56) - 84
Gestation 12-13.6 weeks
Above this do mss2 or nips
Abnormal >3 but need to plot

Question 5

Short cervix

Answer 5

<25mm at 24 weeks

measure 2 weekly from 16-24 weeks if prior preterm, 2nd TM loss, uterine anomaly or LLeTZ

Question 6

Anatomy scan

Answer 6

19+ weeks
NF <6mm
LV <10
CM <10

Insignificant in isolation: choroid plexus cyst, echogenic cardiac focus, single umbilical artery, sandal gap toes, clinodactyly - dont report these but look closely for other markers. Report if there are 2+

Real markers:
NF>6, absent of hypop;astic nasal bone (but this is not part on TM1 screening), ventriculomegaly, clenched hand, rocker bottom feet, echogenic bowel, pleural effusion or ascites, pericardial effusion >2mm, perimembranous vsd, arsca