You are now 29 weeks pregnant, which is the beginning of week 30. Your baby now weighs about 1,350 grams (approximately 3 lbs) and measures about 40 cm in length (or 15.75 inches). Many women now find their posture noticeably changes to compensate for the increasing size of their belly. This can affect your centre of gravity and balance as well as possibly leading to backache. Try to maintain a straight posture and avoid high heels if possible.
Your baby's bones are now mature enough to start producing their own blood supply from their bone marrow, taking over this task from their liver and spleen. During the last 3 months unborn babies begin to store iron in their liver (supplied from their mother's body). This is Nature's way of meeting their iron requirements until they start eating solids, about 4 to 6 months after birth. You can read more in iron and iron supplements.
From week 30 your baby develops a special layer of fat called 'brown adipose tissue' (or BAT). This is similar to the kind of fat found in hibernating animals. BAT is your baby's main source of heat production after birth, because newborn babies have a limited ability to shiver, sweat or move to regulate their own body temperature. By 40 weeks, BAT will make up about 2 to 7 % of your baby's total body weight. Premature babies can have trouble keeping warm after birth because they lack BAT. This is one of the reasons why they are cared for with overhead heaters or humidicribs in intensive care nurseries.
Your baby's brain is increasing in size and complexity and the pupils of their eyes can now respond to light, allowing your baby to focus more readily and see dim shapes.
About 11% of all premature babies are born between 28 and 31 weeks gestationand are regarded as being 'moderately preterm'. Babies born at around 29 to 30 weeks have about a 90% chance of survival.