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Normal fetal biometry of a 16 weeks' gestational age

Diagnosis certain

Presentation

Healthy pregnant woman in a routine ultrasound at 16 weeks and 5 days gestation.

Patient Data

Age: 30 years
Gender: Female
  • Gestational age (GA) based on last menstrual period (LMP): 16w5d
  • Number of fetuses: 1
  • Head circumference (HC): 128.8 mm
  • Occipitofrontal diameter (OFD): 46.3 mm
  • Biparietal diameter (BPD): 34.3 mm
  • Abdominal circumference (AC): 103.3 mm
  • Femur length (FL): 22.8 mm
  • Fetal heart rate (FHR): 146 b/min
  • Estimate of fetal weight (EFW): 161.2 g
  • Arithmetic ultrasound age (AUA): 16w4d

Case Discussion

Initially, the GA informed by our pregnant patient was of 16 weeks and 5 days, which was calculated based on LMP. The final gestational age calculation (the AUA) resulted only in 1 day discrepancy with LMP, and this is within the acceptable margin of error.

The selected images demonstrate a 16 weeks' gestational age ultrasound and its appropriate measurements of fetal biometry.

Contributed by Dr. Guilherme Pioli Resende M.D., Dr. Rebecca Carolina Silva Lins M.D. and Dr. Arthur Ataide Lopes M.D.

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