Cervical Mucus and Sperm- Don’t Stop Their Journey!
After ejaculation, sperm have to be able to swim through the cervix to reach the Fallopian Tube where fertilization of the egg occurs. However, the interactions of sperm and cervical mucus (CM) that allow this migration are often disrupted in fertility patients. It is thought that at least a third (if not more) of subfertile couples have some disruption of sperm-cervical mucus interactions that limit sperm transport to the tubes.
The importance of normal CM in natural reproduction is widely recognized. For most of a woman�s cycle the CM is a thick gel and hostile to sperm, with a low pH and a structure that stops sperm transport by the presence of closely spaced microfibers. During ovulation, however, the CM becomes more alkaline (higher pH), and the fibers align in parallel with an expanded distance between them. This allows the sperm to swim through the mucus. Normally, the volume of daily CM also increases 5 fold at ovulation. CM is a hydrogel of 90% water, and its primary function appears to be bathing sperm in a fluid medium to protect them during transport The presence of sugar-proteins in the gel that hold the water is controlled by hormone changes at ovulation (especially the presence of estrogen). These sugars increase the mucus gel’s capacity to hold water, expand fiber spacing, & allow sperm migration. Taken together, these changes permit sperm to rapidly swim through the cervix and proceed to the Fallopian tube for fertilization.
In women with poor sperm-CM interaction there is a reduction in CM fiber spacing making sperm travel difficult, a primary cause of which in many women may be not enough water in the gel. This may be caused by advancing age (with low grade hormonal disruptions); and following the use fertility medication such as clomiphene citrate (or clomid). Clomid is a widely prescribed fertility drug. In fact, it has become increasingly used as a first line therapy for couples with fertility issues. With easy internet access, many women are also taking Clomid without doctor oversight. Estimates are that 40% of couples with fertility problems utilize Clomid at some point for the woman. Although it�s wide spread use has helped many couples conceive, it does cause significant problems with vaginal dryness and CM production and function. Specifically, numerous studies have shown that Clomid causes decreases in: volumes of CM; quality of CM (”egg-white like appearance”); and sperm ability to swim into CM. In fact, women on Clomid are seven times more likely to have “hostile” CM that is difficult for sperm to penetrate than are women not on the medication.
Women on Clomid also have an increased prevalence of vaginal dryness, which can cause pain at intercourse and decrease enjoyment for the man (which can decrease sperm counts). Many women on Clomid (which is already making them prone to poor sperm-cervical mucus penetration) are therefore also using lubricants that can harm sperm such as KY, Astroglide and Replens. These women may be creating a vaginal environment that limits sperm transport. Pre~Seed “fertility-friendly” Intimate Moisturizer can replenish vaginal moisture without harming sperm. We are planning on a clinical trial to evaluate the effect of Pre~Seed on sperm and cervical mucus interactions, especially for women on Clomid.
Happy baby-making!
Dr. E
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