A fond "Welcome back!" to you my friend! We have missed your input on the forums...
Very good topic for this forum - I had thought of bringing it up before and you have presented a perfect opportunity. Pregnancy is a unique challenge for the female martial artist - bringing a whole new set of training challenges...I invite everyone who has experienced this to post their challenges/solutions/etc. here...I know I would have appreciated some input when I was going through it!
You don't mention the rank of your friend...this will make a difference. Her current level of conditioning, intensity, training schedule, all of these will be drastically modified in the months to come, but there is no reason why she cannot continue training in one form or another for the duration, doctor and health permitting.
First off, I hope that she has an understanding doctor/midwife! They don't have to practice martial arts to be sympathetic to the demands that karate entails. She needs to have an open enough relationship with whomever she chooses so that she can acquaint him/her with the basic demands of her training routine. Then sensible modifications can be made as needed.
Oh, yeah, and tell her to drop the stomach conditioning!
Actually, I had been doing some heavy duty conditioning for the first 2 months of my pregnancy (before I found out I was pregnant) and no harm was done, so I would tell her not to worry about what she's done so far - but lighten up (stop!) on the punches to the midsection now.
Conditioning and kumite were the two things that were primarily affected for me...sanchin checks also of course - but only in strikes to the stomach. I just let my sensei know - and he told any seniors that would be checking me to stay away from there. The farther into the pregnancy, the more limits the body imposes - but kata (albeit modified toward the last weeks) is possible all the way through. The variations that come out as the belly expands are quite interesting!
Important: Tell her to really watch for shifts in balance - even very early on as her body is going through some drastic changes right now that will really mess with her equilibrium...way before the pregnancy even becomes apparent.
I hope that others will present their thoughts here - but in the meantime - please give your friend my email address if she is so inclined as to contact me and discuss this in more detail.
Peace, (and welcome back!)