Many people know that aspirin, as a painkiller and anti-inflammatory drug, is known as a “miraculous drug” for its ability to relieve pain, reduce inflammation, lower fever, treat diabetes, and Alzheimer’s disease, as well as prevent secondary strokes and heart attacks.
Therefore, during the assisted reproductive cycle, when patients are prescribed aspirin by reproductive specialists, they may wonder: I came to treat infertility and undergo in vitro fertilization, why am I being prescribed an anti-inflammatory painkiller?
Today, I will explain the application of aspirin in the in vitro fertilization cycle.
First, let’s talk about the mechanism of action.
As currently understood, the main mechanism of action of aspirin is its ability to inhibit the activity of cyclooxygenase (COX), ultimately suppressing the synthesis of prostaglandins (PG) and thromboxane A2 (TXA2). COX helps the body produce PG and TXA2, both of which are major culprits causing discomfort in the body.
Prostaglandin PG is present in many organs and plays an important role; for instance, in the ovaries, PG promotes follicular development, enhances hormone secretion from the ovaries, and is involved in inducing ovulation, luteinization, and the dissolution process. During menstruation, the synthesis of PG in the endometrium causes the spiral arterioles in the endometrium to constrict, speeding up the onset of menstruation; elevated levels of PG may be a cause of dysmenorrhea.
TXA2 is a potent agent that induces platelet aggregation and aids in thrombus formation. In certain women who experience repeated in vitro fertilization failures or recurrent spontaneous abortions, there is an increase in platelet count and activity, along with elevated PG levels, resulting in a blood state that is more prone to coagulation—known medically as “hypercoagulable state,” which can lead to failure in embryo implantation or miscarriage.
With the above principles in mind, let’s look at how aspirin is used in the field of reproduction.
First, for women with thin endometrium. The reproductive medicine community currently defines a thin endometrium as being less than 7 mm, which may lead to failure in embryo implantation or miscarriage. Aspirin can help improve uterine artery blood flow, thereby enhancing the blood supply to the endometrium, with the aim of improving its status and thickness.
Secondly, for women with positive autoimmune antibodies, especially those with repeated embryo transfer failures or recurrent spontaneous abortions. Clinically, for conditions like infertility, “test tube” assistance, repeated embryo transfer failures, and recurrent miscarriages, doctors will test for various autoantibodies, such as thyroid antibodies, antiphospholipid antibodies, and anti-β-2-GP-1 antibodies, among others. These antibodies can contribute to a hypercoagulable state of the blood and reduce the endometrium’s ability to accept embryos. Although there is currently insufficient high-level evidence from evidence-based medicine supporting any particular method’s effectiveness, clinical observations suggest that aspirin may be effective, especially when combined with medications like prednisone.
Then, there are women with ovarian hyperstimulation syndrome. Ovarian hyperstimulation syndrome is a common complication in “test tube baby” technology, primarily manifested by ascites and a hypercoagulable state. Aspirin’s antiplatelet action can help prevent the tendency for thrombosis associated with ovarian hyperstimulation syndrome.
Finally, it can also be used for women with complications during pregnancy, such as pregnancy-induced hypertension (particularly preeclampsia), intrauterine growth restriction, diabetes, and autoimmune diseases. Many complications during pregnancy arise due to arterial spasms, leading to elevated blood pressure and poor blood supply to the fetus.
Side effects of aspirin
In conclusion, while aspirin has benefits, it is not suitable for everyone, and it is essential to follow medical advice when taking it. The main side effects of aspirin are gastrointestinal mucosal irritation, which may lead to stomach discomfort, hidden pain, nausea, vomiting, and loss of appetite. Consequently, patients with gastric diseases, particularly those with gastric ulcers, should avoid aspirin. Also, patients with gout, asthma, and hepatic or renal insufficiency should refrain from using it. Pregnant and breastfeeding women are generally not advised to use it.
