I think expecting pregnant women to work extra on calls is unreasonable. It is incredibly tiring being pregnant, even a normal schedule is very tough. Stress can cause problems in pregnancy, some of you are seriously expecting women to risk the health of their child? If anyone even suggested to me that I should ever do anything that could potentially hurt my child I would never speak to them again. I have had very bad experiences though so am probably far more touchy/concerned about risks than most people. I also think asking someone with a 6 week old baby at home to work extra on calls is unreasonable, male or female. I'm sure many people to try to arrange pregnancies around lighter schedules but some desperately struggle to get pregnant so can't necessarily do it when it's most convenient. There are obviously time limits on getting pregnant, you absolutely cannot expect anyone to potentially risk never having a baby so as not to interfere with work schedules.
Saying "everyone has a family" doesn't really fly with me. Ask anyone that has a child who they would rather die, their child, or literally anyone else in the world and you can bet no one would say their child. A parent, sibling, or spouse is just not the same. Obviously other people are important, but it's not the same.
To those super hard core people saying you shouldn't have kids in residency or should go into lifestyle specialties, medicine is a calling, it should be your only priority etc when covering for others why aren't you thinking, "great, more work, more time to learn, this is why I went into surgery, to see everything and do as much as I can"? One could argue that those taking leave are actually giving you what you claim to want, every patient is a learning experience.
I am in an incredibly tough surgical specialty and a few years ago would have had a very different response to this thread but being pregnant changes you. Those saying they would simply have an abortion (something I used to say) have no idea how they would really respond if they got pregnant, a hypothetical, and reality are different.
Despite the above, I do think it is unfair that the extra on calls are forced onto others and working outside of the US find it a bit shocking that this is the way your system is set up. In the UK most doctors take several months, if not a year off after delivery, and don't work right up to it, regardless of specialty. Taking a full year is actually preferable in terms of work in many ways so you complete training at the normal time, just a year later. Any time off is added to the end of training but that is just the norm and accepted. The 6 weeks off you get in the US would mean extra training time for us anyway. Beyond the first 2 years, you can only take 2 weeks out for sickness etc without extending your training. For us no one is forced to do extra work to cover, the hospital will simply hire a locum if needed. So getting pregnant actually benefits other people, you give someone a job they otherwise wouldn't have had! I would be very angry about being forced to do extra cover with no compensation, they should at the very least pay you extra.