I would like to go to synagogue,
but since I am at the beginning of my pregnancy I do not have
the strength to stand for all of the standing parts. If I
can only stand for part of them, which ones should I stand
for? thank you!

Answer from Rabbi David Sperling
A woman who does not have the strength to
stand when praying can pray the complete service sitting down.
The following is in order of preference of
when to stand:-
To bow during the silent amidah.
The first three blessings of the silent amidah.
The rest of the amidah.
When the Torah is being carried.
Kedusha.
Yishtabach.
Barachu (at least to bow slightly).
The other places where we traditionally stand.
I'm not sure if you are Ashkenazi or Sepharadi.
The Sephardim sit down lots more than the Ashkenazim ! (they
sit for most of the Kadishim). You can certainly follow that
practice if you are lacking energy. May you be well and have
a good birth, and be inscribed for a good year.