Interesting responses...seems like a lot of you had similar birth experiences to your moms/sisters. I wonder why it's not considered "a thing"? Maybe too hard to prove empirically?

Hard to say, I was breech so my mother had a c section. My labor was 30 hours, sunny side up, baby got stuck, 5 doctors worked to rotate him, head rotated 180degrees but turned out his body only did 90 degrees. Baby turned purple, I got ripped to pull the baby out, baby was bruised and suffered a dislocated shoulder. Thank god no arm nerve damage and baby recovered fine. I got plenty of stitches and am still recovering.

At my lamaze class this week, our teacher said that fast labors (specifically something she called "favorable cervix") are hereditary, so if your mom or sisters had exceptionally fast labors you should discuss with your doctor whether they want you to go to the hospital earlier than you would otherwise. Long labors, though, she said are not hereditary.

My sister's and my labor's were very similar. We simply did not dilate. She eventually dilated after petocin. I never got past 3 cm after 27 hours and petocin. C-section for me.

It's genetic (It's certainly not nurture) but the genes involved are your mother's PLUS your father's PLUS the father of the baby's AND the way the father's genes mix with yours.

The placenta plays an important role in the "management" of a pregnancy, so the heredity could involve the baby's father as well.

My mom and I had very similar labor stories. I was the oldest and she barely got to the hospital in time. She says I was nearly born in the elevator (probably an exaggeration) and that I was 4 weeks early. My son was born 45 minutes after we arrived at the hospital, and he was 3+ weeks early.

I asked my doctor about it after the fact. He said it isn't "hereditary" but the length of labor can be considered "familial". I'm currently expecting my second, and am preparing myself in case he comes early as well, but who knows!