We have been half heartedly trying for the last couple of months to conceive baby number 4. We weren't actively "trying" for the other 3 so I'm not sure what works for us 
My cycle is usually about 30 days but can vary by about 2 days eaither way. According to the calendar I should be fertile this week but I'm not seeing much in the way of cervical mucous yet. Is this the most reliable indicator?