While nothing is 100% I would pay more attention to Diet, PH and your biorhythms and moon signs!
I have seen tons of girl sways fail because of the woman's biorhythms and the moon signs! Mine included, even though I only swayed with DS3!
If you go to cycletourist.com and put in your info it will give you your biorhythm.
For a girl - you want the RED line at the top and the BLUE at the bottom, that is Strong girl! It would even be better if the day you conceive has a RED vertical line, but avoid the BLUE lines going down!
With this pregnancy I was in Strong girl AND a female moon sign, but coincidentally conceived on a BLUE critical day and now I having my 4th son! This one was a major surprise though, as DS3 was only 7 wks old when I got pregnant!
Hope i didn't just confuse (or scare) you.. Lol
Learning all this stuff over the last year or so has made my head spin! LOL