It was concluded that presence ofcannabinoids in urine or blood is not unequivocal proof of active cannabissmoking. Giardino 25 26 found THC-acid levels of up to 30-50ng/ml from passive-exposed subjects, and recommended a threshold of 65ng/ml to differentiatebetween active and passive smoking of cannabis.ticht & Kaferstein 20 estimated that the blood THC concentrationsproduced in a 70kg person smoking 15mg THC would peak at 7-8 minutes,after 30 minutes between 14-42ng/ml, and at 60 minutes between 7.5-14ng/ml.3.3 McBay 21 compared THC and THC-COOH levels in a study involving smokedmarijuana cigarettes.
Calculation Using An ovulation Calendar: 1  The first day of a period is considered as day 1. 2  Usually on day 14, the egg is released and is waiting for the sperm to fertilize it. 3  The egg has a lifespan of just 12 to 24 hours whereas a sperm can last for about 72 hours in a woman.
1 4. Know When You Ovulate: Chart your basal body temperature and your cervical mucus. 2  You might also use an over-the-counter ovulation predictor kit (OPK) to check for hormonal changes in your urine before ovulation. 3  5. 4  De-Stress: Try yoga, meditation, or long walks to reduce stress.enstrual periods vary from woman to woman and month to month. Use this calculator to help determine the timing of your ovulation and peak fertility. CAUTION: This tool cannot and should not be used to prevent pregnancy. 1  1.