The Science Behind Abortion Pills

In recent years, the debate on the validity of abortion has grown increasingly prevalent. The federal right to abortion was repealed after Roe v. Wade was overturned in the June 2022 court ruling of Dobbs v. Jackson Women’s Health Organization. Fourteen states banned abortion altogether, and even more have established heavy restrictions. Since then, there has been national controversy over the definition of life and what this means for legal regulations on abortion.

 Abortion is scientifically defined as the termination of a pregnancy before the fetus is considered “viable,” which in New York, is after 24 weeks of age. There are many different methods of abortion, but there are two main categories: in-clinic medical procedures or medication abortions. Medication abortions use abortion pills and can be done at home or at hospitals under medical supervision. 

 Abortion pills were first developed in France during the 1980s, but usage in the U.S. was only approved by the Federal Drug Administration (FDA) in September 2000. French scientist Dr. Étienne-Émile Baulieu is credited for developing the modern abortion pill alongside manufacturing company Roussel-Uclaf in the late 20th century. Baulieu began his studies on the cell biology of the female hormones estrogen and progesterone in the 1960s, from which followed many labs that eventually led him to identify progesterone’s cell receptors. Investigating the role of progesterone receptors in pregnancy led to the creation of the drug RU-486, the active synthetic steroid hormone antagonist that is used in abortion pills today. According to data collected by the Guttmacher Institute, medical abortions have grown more popular in recent years due to their safety and accessibility relative to surgical procedures, with the numbers jumping from 39% of all U.S. abortions in 2017 to 53% in 2020 and 54% in 2022. After Roe v. Wade was overturned, this number jumped to 63% nationwide, a 10% increase from the year before.

A medication abortion happens in two steps. Patients first take a 200 milligram dose of mifepristone, a synthetic steroid which is administered orally in the form of a Mifeprex pill. Mifepristone occupies receptors in the body where the hormone progesterone would normally bind, making it so that the body can no longer use progesterone. At the beginning of a pregnancy, progesterone levels increase to prevent the uterine wall from breaking down as it would during a normal menstrual cycle to protect the embryo that has nested there. By reducing progesterone levels, mifepristone makes it so that the embryo can no longer stick to the lining, which would have shed as it does in a normal menstrual cycle.

After the mifepristone takes its effect (typically 24 to 48 hours after taking the pill), patients are administered four tablets of the drug misoprostol. The misoprostol tablets are used to help the detached embryo exit the body. When combined with mifepristone, the effectiveness of misoprostol increases by 10% because the drugs reinforce each other and help ensure that the abortion goes to completion. Mifepristone alone does not always ensure an abortion, and it’s been proven possible for pregnancy to resume after taking only mifepristone. Misoprostol, also used to induce labor, is classified as a prostaglandin, which means that it causes the cervix to dilate and the uterus to contract so that the embryo can be passed through the birth canal. 

The mifepristone-misoprostol combination is officially approved by the World Health Organization. Studies show it is the safest and most effective abortion option. Nevertheless, some women have opted to use misoprostol on its own by taking four tablets every three hours to a total of 12 tablets. The method is marginally less effective than the combination and is not FDA approved, but it is often a more accessible option because misoprostol has no prescriber requirements while prescribers of mifepristone must be certified under the Mifepristone REMS program. However, states with near-total abortion bans since the overturning of Roe v. Wade have made it illegal for pharmacies to dispense abortion pills of any kind regardless of certification. Even in states where abortion is allowed, restrictions on who can prescribe and distribute abortion pills and where medical abortions can take place have become tighter and created new barriers for women living in those states. 

After misoprostol is taken, the abortion takes effect in two to six hours. However, this process has a few common side effects—for example severe cramping. This is because misoprostol induces strong uterine contractions, which manifest through painful stomach cramps. In addition, mifepristone may lead to side effects such as QT prolongation, an irregular change in heartbeat. The heart consists of a complex electrical system which allows it to contract and expand. The electrical signals are categorized into five waves—P, Q, R, S, and T. Waves Q through T represent the activity in the heart's lower chambers, so a QT interval is the time it takes for the heart to refill with blood before it contracts again. Drugs such as mifepristone may bind to certain cardiac cells and disrupt the flow of ions through the heart, causing the electrical current to be prolonged. Prolonged QT intervals are longer than normal QT intervals and may increase risk of seizures. Those with pre-existing health conditions, especially heart rhythm disorders, are more susceptible to experiencing those side effects.

Despite these negative side effects, medication abortions are still verifiably safe: there is only a 0.4% risk of serious complications like QT prolongation. In general, medication abortions are 91.6% to 99.7% successful when taken before 64 days of pregnancy. However, the risk of complications and failure increases with gestational age - how far along a pregnancy is - because the pregnancy becomes more complex with increased gestational age. The abortion itself has very little risk of harmful, long-term consequences—most risk is due to external complications.

Those complications are often found in patients with minimal access to medical oversight who carry out unsafe, self-managed abortions. Abortions with improper medical treatment may lead to physical complications such as incomplete abortion, which is the failure of all tissue to be expelled from the womb. Patients with incomplete abortions require professional assessment and often undergo surgical treatment. This condition is entirely treatable if detected early by a doctor but if left untreated may lead to a severe bacterial infection called uterine sepsis. Any retained tissue may decay and create ideal conditions for bacterial growth. In turn, the immune system attacks its own tissues to stop the infection, increasing the risk of organ failure and death. While the abortion medication is fundamentally safe to use, restrictions on abortion care lead some to improperly self-administer it or fail to seek medical supervision when needed. 

The political response to abortion is still evolving. Restrictions are being continuously enacted and adjusted. While there are no current regulations on the distribution of misoprostol, mifepristone has more strict restrictions. In recent years, the availability of abortion medication has expanded dramatically. Previously, those seeking at-home abortions had to receive medication directly from certified doctors or clinics. In early 2023 after the overturning of Roe v. Wade, retail pharmacies received permission from the FDA to sell mifepristone to patients with a prescription from a healthcare provider. This means that pharmacies like CVS and Walgreens can carry mifepristone and misoprostol. However, bans—which already exist in a third of the states—could make it illegal, or extremely difficult, for pharmacies to sell abortion medication. This is concerning for the millions of women living in those states that rely on this critical medication, as seen by the recent increase in medication abortions. 

As the limitations on abortion clinics increase, the increased use of abortion pills has made them a vital point of contention in the conversation about reproductive rights. Scientific studies have proven medication abortions to be a safe and effective alternative to the medical procedures that continue to grow inaccessible, exemplifying the growing desperation that women are facing in the wake of the recent political turmoil over abortion.