Finasteride, commonly known by brand names like Propecia or Proscar, is a widely used medication for managing male pattern baldness and benign prostatic hyperplasia (BPH). While it is generally a safe and effective treatment for the man taking it, its systemic presence raises concerns when a couple plans for pregnancy. This medication circulates throughout the body, and its presence can raise questions about the safety of a developing fetus. Therefore, understanding the necessary precautions and the timeline for stopping the drug is a central consideration for men planning to conceive.
The Safety Concern: Understanding Finasteride’s Risk
Finasteride functions as a 5-alpha reductase inhibitor, blocking the enzyme that converts testosterone into dihydrotestosterone (DHT). DHT is a powerful androgen that plays a necessary role in the development of male characteristics, both during puberty and in the womb.
The potential for harm arises because DHT is essential for the normal formation of external genitalia in a male fetus during the first trimester, specifically between the 8th and 12th weeks. Disrupting this process by inhibiting 5-alpha reductase can lead to birth defects known as teratogenicity. Animal studies have demonstrated that exposure to finasteride during this window can cause abnormalities such as hypospadias, a condition where the urethral opening forms on the underside of the penis instead of at the tip.
Although the amount of finasteride that enters a man’s semen is extremely low, the drug is detectable in seminal fluid. Due to the potential severity of the birth defects and the established mechanism of action, medical guidance remains highly conservative. Even with minimal exposure through semen, the theoretical risk to a male fetus is enough to warrant strict caution and drug cessation for any couple trying to conceive.
Official Guidance on Stopping Before Conception
The duration required for the medication to clear the system is a primary concern for men planning a family. Finasteride has a relatively short terminal half-life in the bloodstream, typically around five to six hours, but its biological effect on DHT suppression can last much longer. Suppressed DHT levels typically return to normal within about two weeks after stopping the medication.
Despite the relatively quick clearance from the blood, medical professionals recommend a significantly longer washout period. Many authoritative sources suggest that men should discontinue finasteride for a minimum of one month before attempting conception to ensure the drug is fully eliminated and undetectable. However, a more conservative and widely cited recommendation is to stop the medication for three months, or approximately 90 days, prior to trying to conceive.
This three-month timeline is rooted in the biology of male reproduction, specifically the cycle of spermatogenesis. It takes approximately 74 days for a new sperm cell to fully mature, meaning a 90-day cessation period ensures that the sperm used for conception was produced entirely after the drug was stopped. This extended waiting period guarantees the drug is completely cleared from the man’s system. It also allows for the reversal of any potential, though rare, finasteride-associated adverse effects on sperm quality, such as reduced sperm count or motility.
Safety Protocols During the Cessation Period
Stopping the medication requires additional safety protocols to mitigate all routes of exposure. A major concern is the risk of a pregnant partner absorbing the drug through the skin. Women who are pregnant or who may become pregnant must never handle crushed or broken finasteride tablets, as the drug can be absorbed transdermally.
If a tablet is accidentally broken or crushed, the affected area should be immediately and thoroughly washed with soap and water. During the recommended washout period of one to three months, barrier contraception, such as condoms, should be used if the couple is sexually active before the planned conception date. While the risk from semen exposure is considered remote, using a barrier method provides an absolute guarantee against the transfer of any residual medication.
Men should also avoid donating blood while taking finasteride and for at least one month after stopping the treatment. This restriction prevents the inadvertent transfusion of the drug to a pregnant recipient. If accidental conception occurs while the man is still taking the medication, he should stop the drug immediately and consult with a healthcare provider to discuss the situation and receive appropriate counseling.