<prompt> Most sensitive test for assessment of fetal well being isBiparital diameterArm circumferenceAbdominal circumferenceHead circumference  <response>: Biparietal diameter 85-Dutta 6thReal ultrasound measurement of fetal growth First trimester - Crown - rump length Second trimester - Biparietal diameter BPD Third trimester - Multiple foetal growth parameters are considered together. These are- Prior to 36 weeks - Combination of biparietal diameter, abdominal circumference and femur length FL- After 36 weeks - Combination of head circumference, abdominal circumference and femur lengthA- BPD greater than 9.2 cm indicates foetal pulmonary maturity corroborated by L:S ratio Early measurement of BPD and FL are the most useful in establishing gestational age Later measurement of fetal growth are best achieved by measurement of the head circumference and the abdominal circumference G. chamberlain 7th Foetal head: abdominal circumference ratioMaximum - 1.29 at 12 weeksEqual - 1.00 at 36 weeksMinimum - 1.00 after 37 weeks Bishop score is used for induction of labour Manning score is most sensitive reliable test for fetal well beingDifferent diameter of skull in newborn are Suboccipito-bregmatic 9.5cm Suboccipito-frontal 10cm Occipito frontal 11.5cm Mento vertical 14cm Sub mento vertical 11.5cm Sub mento-bregmatic 9.5cm Biparietal diameter 9.5cm Super-subparietal 8.5cm Bitemporal diameter 8cm Bimastoid diameter 7.5cm Twin peak sign - Ultrasonography shows extension of placental tissue into the inner twin membrane in diaminiotic dichorionic DD 