The Common Medication To Be Very Careful About Taking Before A Flight

When preparing for air travel, passengers often consider factors like packing, security checks, and ensuring they reach the airport on time. However, one essential item on the pre-flight checklist that might not come to mind is the medication they take before take-off. Among these, birth control pills stand out as a common medication that requires some special attention due to potential health risks associated with air travel.

Birth control pills are a widely used form of contraception, relied upon by millions of women globally. While safe for daily use under most circumstances, they carry a risk factor that becomes particularly pronounced when combined with the sedentary nature of long-haul flights: an increased likelihood of developing blood clots, known medically as venous thromboembolism (VTE). VTE encompasses conditions such as deep vein thrombosis (DVT), where blood clots form in the deep veins of the legs, and pulmonary embolism (PE), where a clot travels to the lungs, as per the Centers for Disease Control and Prevention (CDC).

Birth control pills, especially those that are classified as a combined hormonal contraceptive (CHC), containing both the hormones estrogen and progesterone, can elevate clotting factors in the blood, slightly increasing the risk of developing these conditions. When you add prolonged periods of immobility during flight, the risk escalates. Deep vein thrombosis and pulmonary embolism are life-threatening conditions. 

The science behind the risk

Combined contraceptives increase the levels of plasma, protein, and coagulation factors in the blood, which promote clotting while decreasing inhibitors of blood coagulation, according to a 1987 study. In a sedentary situation, such as sitting in a cramped airline seat for several hours, blood flow in the lower limbs slows down. This reduced circulation, combined with increased clotting factors, creates a perfect storm for the development of blood clots and, in turn, VTE.

According to a 2011 study published in the Canadian Medical Association Journal, the risk of VTE, while still relatively low, is three to five times higher in women who take birth control pills compared to those who do not. The risk is further magnified for flights longer than four hours, making it a significant concern for international travelers. According to Dr. Unnati Desai, "The estimated risk of a VTE from a long-haul flight is one case per 106,667 flights of less than four hours, one case per 4656 flights of more than four hours, and one case per 1264 flights of more than 16 hours" (via NZ Herald). 

Symptoms of deep vein thrombosis include swelling, pain, cramping, redness, and discomfort around the leg area. The skin may also change color in the leg, turning red or purple. However, some people may not present any visible symptoms of DVT. More severe symptoms of pulmonary embolism include a sudden onset of shortness of breath, chest pain, heart palpitations, low blood pressure, and feelings of dizziness, sweating, and anxiety. 

Preventative measures

While all individuals taking a birth control pill should be aware of this issue, certain groups are at higher risk. Per a 1999 study published in GeneReviews, this includes women over the age of 35, smokers, those with a family history of blood clots, individuals with obesity, and people with underlying health conditions that predispose them to clotting, such as Factor V Leiden thrombophilia. Pregnant travelers are at an even higher risk of VTE.

For those taking birth control and planning to fly, several steps can be taken to mitigate the risk of VTE. Drinking plenty of water before and during the flight helps prevent dehydration, which can contribute to blood clot formation. As tempting as it can be, avoid alcohol and caffeine. Perform leg exercises such as calf raises in your seat, engage in gentle stretching, and walk around the cabin every hour or so to improve circulation.

It's also wise to book an aisle seat. According to the CDC, travelers sitting in the window seat are twice as likely to be at risk for VTE than those in the aisle seat. Another tip is to wear compression stockings, which help promote blood flow in the legs, reducing the risk of clotting. They usually cost between $10 and $100 per pair, but insurance may cover the cost if your doctor prescribes them. Discuss your travel plans with your healthcare provider if you have multiple risk factors for VTE. They may recommend switching to a different contraceptive method temporarily or taking other precautionary measures.