On average, 1.37 million abortions are performed each year in the United States, with over 45 million since 1973. The most common reasons women choose abortion are that they cannot afford a baby, are too young or in school, or are not ready due to their relationship status or partner's wishes. Most abortions, 88%, occur in the first trimester. While abortion laws and availability vary worldwide, it is estimated that about 46 million abortions occur globally each year, with 20 million done illegally. Medical abortions involve medication to induce abortion, while surgical abortions are performed using suction or dilation and evacuation depending on the gestational period. Complications are rare but can include heavy bleeding or infection.