Yes, a lack, or an insufficient quantity of fertile mucus may make it difficult for you to become pregnant. Not only does fertile mucus help the sperm in the journey to meet the egg cell, it also allows it to survive in the otherwise unfriendly, acidic environment of the vagina. If there is no mucus, the spermatozoids are unable to survive very long while waiting for the egg cell, decreasing the chances of fertilization. That is why, when there is an insufficient amount of mucus, it's very important to plan intercourse as close to ovulation as possible. You may also try to reduce the acidity of the vagina (an unfriendly environment for the sperm) by eating more foods that have an alkaline pH (fruits and vegetables) and less products that acidify the body (sweets, coffee, alcohol, meat). Also, try some natural means of increasing the fertile mucus. If none of these methods work, and you have been trying to become pregnant for a couple of cycles without success and you do not notice any fertile mucus even if ovulation takes place (OvuFriend marks ovulation on your chart), you should consult your doctor.