25 weeks (from Babygaga.com)

Fetal development in pregnancy week 25:fetus in sixth month Your little grower’s physical proportions are evening out at this point and most of their remaining development will largely be weight gain and lots and lots of nervous system development. The good news is: if your child is born premature now they’ll be more likely to survive without too much trauma as their lungs began to produce “surfactant” last week, which means their tiny respiratory system is getting stronger with each passing day. Yes, now’s a good time for a minor sigh of relief and a quick pat on the back. All that hard work and conscientious living is really getting your child prepared for a healthy delivery. Keep up the fabulous work mama! This week they’ll be scootching slowly out of the old breech position and start rotating (already!) into a better position for exit during their birth. Their head and feet are slowly rotating so that the head is pointed down towards the birth canal. Time is short (or really long, depending on who you ask)—just (still!) 14 weeks left before you can go back to being a single-resident human.