If you look closely at each baby's head you can see the ossified white outlines of the bones in the skull. What you're seeing: Now into your second trimester, your babies' bones are beginning to harden in a complex process called ossification, where inorganic and organic compounds come together to help the skeleton harden. Upper limbs are becoming proportionate to the rest of their bodies (although lower limbs are still underdeveloped). Their livers and spleens are producing red blood cells. Tissue under their faces and limbs is beginning to harden into bone. Weight, around 1 ounce.įetal development milestones: Your babies' male or female genitalia are forming. Read more about your babies in week 11.įetal size: Length, 3 1/4 to 4 inches, crown to rump.This baby has her head facing the cervix (notice the white facial bones), while baby B has her back toward the membrane that separates the two babies. Here, you can see the cervix in the lower right-hand corner of the image as the grayish form that comes near baby A. The baby marked A is always the one closest to the cervix. In this image, the sonographer has marked each twin, one with an A, the other with a B. Each baby has her own amniotic sac and umbilical cord. Where there were once only small buds, arms and legs are now growing. What you're seeing: Just 11 weeks into your pregnancy, nine from conception, your unborn babies' faces are becoming more recognizable, with ears and eyes gradually moving into the proper place. Weight, 0.25 ounces.įetal development milestones: Lots of little arms and legs are growing and elongating this week! Facial features are developing, as are fingers and toes. American Institute of Ultrasound in Medicine - įetal size: Length, 1.61 inches, crown to rump.

Twin sonogram