Abortion

Abortion was a procedure in which a fetus was terminated within the mother's womb.

In 2153, the Triannon female Indava asked Doctor Phlox to terminate her pregnancy, as she did not want her child to become a soldier in D'Jamat's war. Phlox did not perform the procedure because he was not finished "studying their physiology." 

In 2365, Deanna Troi became pregnant from a non-corporeal lifeform. Lieutenant Worf proposed aborting the fetus as it may have been a threat to the crew. Troi refused, and carried the child to term, which lasted just over a day. 

In 2368, Geordi La Forge commented that had he been conceived on Genome colony, he would have been terminated as a fertilised cell due to his blindness.