It depends on what type of birthing classes you want to take. I suggest Hypnobabies which you would need to start by 7 months.
Other classes last between 8 and 12 weeks on adverage and they need to be finished by 36 weeks gestation.
A few classes that include nutrition and pregnancy info so they start in the first or second trimester.
at 7:39 PM on Apr. 6, 2009
The only birthing classes avaliable to us was given through our hospital, so we were completely dependant on their schedule. And of course making sure we were finished before the baby was due!! LOL! So you might just want to check with whatever establishment you are going to go through and what their recommendations are. GOOD LUCK WITH YOUR DELIVERY!! =)