In a case of alleged infanticide, autopsy of a newborn shows aerated lungs that float in water (hydrostatic lung test positive) and diatoms in lung tissue matching the water body. The MOST appropriate medico-legal conclusion regarding live birth is:

• A The infant was definitely born alive and breathed, based on the lung float test alone
• B The infant was stillborn; diatoms entered passively after death
• C The infant likely breathed air after birth; diatoms in lungs support live birth but the float test has limitations including decomposition and maceration artefacts ✓
• D The float test is only valid for infants older than 28 weeks gestation

Explanation

The hydrostatic lung test (Breslau's second life test) is positive (lungs float) when air has entered the alveoli via breathing; however, artificial respiration, decomposition with gas formation, and maceration can cause false positives. Diatoms entering the lungs require active respiratory effort (diaphragm movement aspirating water) providing strong corroborative evidence of live birth and subsequent submersion. Combining a positive float test with diatom evidence (showing vital reaction of breathing) strengthens the inference of live birth. The test is not restricted by gestational age but requires interpretation with caution.

Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.