Answer: 34 weeks.
Explanation: A developing baby goes through important growth throughout the pregnancy. This includes the last months and weeks. As a demonstration, the brain, lungs, and liver require the concluding weeks of pregnancy to fully grow. Babies born 32+ weeks early often time have a higher chance of disease, deformity, and death.
Fun fact: Studies have shown that 16% of babies born early (who live) have breathing problems, feeding difficulties, cerebral palsy, developmental delay, vision problems, and/or hearing problems.