part of
immediately_preceded_by
life cycle stage
20th week post-fertilization stage
21st week post-fertilization stage
140.0
147.0
EV:0300029
Fetal stage when the fetus is over 20 and under 21 weeks of development.
HsapDv:0000058
The lungs gain some ability to breathe air. This stage is considered the age of viability because survival outside the womb becomes possible for some fetuses (see http://ehd.org/resources_bpd_documentation_english.php).
human_developmental_stage
sixth LMP month stage