hi there in response to your query i will like to share the following that Pre-ejaculatory fluid is released from the male urethra in amounts of up to 4 ml during sexual arousal, prior to ejaculation. It is said to originate from Cowper’s glands and the Glands of Littre.These glands secrete an alkaline fluid containing numerous enzymes and mucus but no sperm. Despite this lack of sperm, current advice is that any fluid emanating from the penis prior to ejaculation could be contaminated with sperm and therefore should be regarded as potentially fertile and capable of resulting in an unwanted pregnancy. so in my opinion protection from Post coital pills should be taken within 72 hrs of intercourse to avoid unwanted pregnancy and this pill is highly effective with failure rate of 2 % only. Now a days single dose pills are also available and you can try that also Take Care