The patient went into the clinic to receive a nutritional shot, South Korean news agency Yonhap reported.
Instead of the nurse giving her the shot, she injected the women with anaesthesia after failing to check her identity.
South Korea legalised abortions in April this year where the country's constitutional court ruled that lawmakers will revise the current laws by December 31, 2020.
The current existing laws make the practice of abortion illegal and is technically punishable by up to a year in prison. Excepts can be made when the mother is sick, the pregnancy is due to a rape or incest, or the fetus is fatal to the mother's life.