By virtue of the HPSP scholarship, as far as I know, you have to graduate med school on time so that you can continue on active duty or defer AD for an approved civilian residency. In other words, having a baby in med school would certainly delay graduation which would mean probably requesting waivers and such, but it something I knew involved a lot of "if's", "maybe's" and paperwork so I never entertained the idea of having additional kids in med school.
I had a 4 yr HPSP scholarship for USAF and entered med school with 1 kid already. I graduated, did an internship in the AF and then did 5 yrs of flight medicine. Because of deployments, war, etc, early on I was not one to be able to sit back and let others take my deployments...by the way, my first year on active duty was 2001 and I was at my first real AD assignment for about 6 weeks before I was deployed. It was a "trial by fire". Anyway, being in a combat squadron, being and feeling part of the team, I did not want to have more kids initially and thus jeopardize my credibility with my squadron, my commanders and the people I was working with in the med group. I didn't want to be part of a combat squadron (which I asked for) and then have to turn around and tell them, 'by the way, I'm pregnant and I can't go on this deployment'. On the other hand, I was and still am happily married so family life was also always a factor. Eventually I did burn out with the whole combat gig and needed a change of pace. I also was aging and knew I wanted more kids. So, as reassignment opportunities came up, I specifically looked for a positions with a slower combat tempo (there was never a 'no combat' choice or 'no deployment' choice). This was with the anticipation of trying to conceive and have more kids. With the knowledge I wanted more kids, I also knew that I could never feel comfortable continuing to leave my kids at home. It is HARD to leave and go to an unknown, unfriendly environment. Killed me but even worse for the family that is left at home.
So, 10 yrs after my first kid was born I was finishing up my AD commitment with the birth of my second child. There was some time that I was in the window for deployment after my 2nd was born and by then I knew I could no longer continue to entertain the idea to ever leave my children and family again. So, I got out. I miss the excitement, miss the camaraderie but I knew I could not sacrifice anymore in the way the military tends to ask one to sacrifice. To some, the military tempo is a constant and rewarding way of life but to me it was no longer palatable.
By the way, after I got out I went into an actual residency again. I had two more kids in residency. It's hard having kids in residency but it is do-able. It takes a lot of perseverance and family support.
The majority of docs I met in the military took the HPSP scholarship because of the money. But, most of them were miserable in the military. I joined for the experience. It was an awesome experience. I just had had enough.