Cystic fibrosis (CF) is a disease caused by the dysfunction of the cystic fibrosis transmembrane regulator (CFTR) protein.

The function of the CFTR protein is critical in secretory cells that produce mucus. By allowing the transport of chloride ions across the cell membranes, this protein is responsible for maintaining the required salt gradient important for proper movement of water across cell membranes. This  ensures the mucus-producing cells lining tissues can secrete a thin, watery mucus.

This mucus is responsible for many functions, a prime example being the trapping of airborne pathogens by mucus-producing goblet cells in the lungs. Another function of mucus-producing cells is to facilitate the movement of sperm cells.

Functional disturbances in the CFTR protein in the mucus-producing cells can compromise the transport of water by this channel, resulting in the production of a thick, sticky, and obstructive mucus. In contrast to thin, watery mucus, which can flow easily within the body cavities, thick mucus can clog up tissues, ducts, and organs, leading to a range of problems. Common symptoms of CF include respiratory system problems such as persistent coughing, increased susceptibility to lung infections like pneumonia, bronchitis, wheezing, and shortness of breath, digestive system problems, such as diarrhea, severe constipation, or foul-smelling and greasy stools, and malnutrition, and reproductive system problems in most male and some female patients.

CF-associated reproductive problems in men

Vas deferens is a duct that transports sperm from the epididymis, where it is stored prior to ejaculation. In CF, this duct can get blocked with thick mucus. Due to this blockage, the passage of sperm can be blocked and lead to infertility. Some male patients with CF also can be affected by a condition called congenital bilateral absence of the vas deferens, in which the vas deferens is completely absent.

Sperm production is normal in most male CF patients. So, male CF patients wanting to have children may opt for assisted reproductive technologies (ART) such as surgical sperm retrieval or testicular sperm aspiration (also known as MESA or TESA), followed by in-vitro fertilization (IVF). Male CF patients wanting to become a parent should consult their urologist to identify the best options for them.

CF-associated reproductive problems in women

Although much less common in comparison to males, female CF patients also can be affected by reproductive problems. The thickening of cervical mucus can affect the movement of sperm across the cervix making it difficult for sperm cells to reach the egg.

Overall changes in female physiology caused by CF-induced nutritional deficiencies and lung abnormalities also can cause irregularities in ovulation and reduce fertility. Taking proactive steps to boost the body’s nutritional supply can solve many problems associated with irregular ovulation.

Although CF can bring about reproductive challenges for some women, most women with the disease often conceive without a problem. When they cannot  there are other options, such as ART, that can help patients become parents.

The risk of passing CF to future generations

CF is inherited in an autosomal recessive manner. This means that for a patient to develop CF, they must have two faulty copies of the CFTR protein-encoding gene. People with one healthy and one faulty copy of the gene do not develop the disease but are so-called called carriers of disease.

A child can inherit a faulty copy of the disease-causing gene from each parent, if they are both carriers, and develop CF. The risk of this happening is 25 percent and the risk of the child of two carriers also being a carrier is 50 percent

Prenatal genetic testing and genetic counseling are offered at many reproductive and gynecology clinics. Couples who suspect or know about their CF status should seek these services when they plan to have children. For people who are not aware of their CF disease status, prenatal genetic testing for CF is offered routinely as an “opt-in” or “opt-out” choice at most clinics and the decision is left to the couple.

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Cystic Fibrosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health providers with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.