Lubricants and Fertility

Vaginal Dryness - A Common Problem

Almost every woman will experience vaginal dryness sometime during her life. Half of all women of reproductive age report the need to use artificial lubricants occasionally or regularly. For women trying to conceive, vaginal dryness can become even more of a problem, with over 75% of 'trying-to-conceive' couples reporting this problem, due to stress factors and/or fertility medications.

In relieving vaginal dryness, couples do not want to create another problem. However, numerous studies have shown that most of the commonly available personal lubricants and even saliva can harm sperm.

In fact, several studies show that several well-known products, including KY Jelly, Astroglide and Replens actually KILLED SPERM EQUIVALENTLY TO CONTRACEPTIVE GELS.

For example, this graph shows sperm motility at ZERO after contact with three popular lubricants as reported by investigators at the University of Texas Southwestern Medical Center (Kutteh, et al., 1996).

Resent research has also shown an actual and severe decline in the ability of embryos to form when sperm are exposed to one of the leading personal lubricant brands during in vitro studies using a bovine model. (View abstract here)

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How Do Lubricants Damage Sperm

The reason for sperm damage from most products can be seen when data on product pH and osmolarity are compared as in the table 1 below.

The optimum pH value for sperm migration and survival in the cervical mucus is between 7.1 and 8.5 (according to the World Health Organization Manual 4th edition, 2000). Sperm are very sensitive to low (acidic) pH and, to a lesser extent, elevated (alkaline) pH. Below pH levels of 6.9, sperm die at a rate that increases with lowering pH.

Sperm are also sensitive to both high and low osmolarities (ion concentration in solution) because these can cause them to either shrink or swell beyond their "critical volume limits". A physiologic osmolarity between 260-360 mOsm/kg (that of semen) is best for sperm function.

Usually ingredients like glycerin or propylene glycol (in most lubricants), are what result in these high osmolarities.  If any glycols or mineral oils are in the lubricant you are using, you can pretty much assume the formula will be damaging to sperm.

Water also kills sperm on contact because it has no salt solution. Some people will tell you to use a little warm water--- don’t’!

Likewise, saliva has digestive enzymes in it that stop sperm from swimming on contact—not so good if you want them to reach the egg!

Even mineral oil which some doctors recommend, has been shown to limit the ability of sperm to penetrate eggs in laboratory studies (likely due to the high osmolarity as shown in the Table). 

Table 1: pH and Osmolarities for Popular Vaginal Lubricants