For example if you are trying to avoid pregnancy it is essential to know when your natal lunar fertile time occurs so you are prepared. If you are trying to fall pregnant, synchronising your cycle maximises your chance of falling pregnant at your fertile time. If you have your natal lunar phase, you can check our ready reckoner to see when that phase will be repeated each month, approximately. Please note, this does not provide you with an exact time for individual conception or contraception purposes, but rather simply gives you an idea of where you, the moon and your cycle are for awareness purposes only. We are considering introducing a more exact reporting service to this site if we get enough demand for it.
Hormones are the key.