The breast is highly sensitive to touch. The areola, i.e. the ring around the nipple, becomes progressively darker and its diameter grows. The darker areola is believed to be a visual signal to the newborn in order to identify it more easily. Small lumps around the nipple, the Montgomery glands, start to protrude. Their main function is to secrete an oily substance that lubricates and protects the area from any contamination. Because this substance contains another substance, similar to the amniotic fluid, it is believed that the infant feels immediately familiar with the nipple during the first moments of his life and is encouraged to breastfeed. It is preferable during breastfeeding to avoid washing the nipples with soap so as to avoid an alteration of the substance.
Womb and uterine cervix
From the first moment of implantation of the fetus, the walls of the uterus begin to soften and dilate. Muscle fibers increase 5 to 10 times in size and the diameter of the blood and lymphatic vessels also increases. During the first trimester though, the size of the womb does not change significantly. During early pregnancy the uterus finds itself low in the pelvis. As it increases in size and weight, it presses the bladder causing the – well known to pregnant women - urinary frequency. The cervix softens significantly and has a protective covering of mucus, which will remain in this place until delivery, to protect the uterus from the entrance of bacteria.
Blood circulation and heart
During the first trimester of pregnancy, the blood volume as well as the red blood cells that carry oxygen to all body cells, increase significantly. The walls of the blood vessels, always thanks to hormones, soften and widen so blood can move more quickly in order to feed the baby and your vital organs with more oxygen and nutrients. From the ninth week, your heart increases the amount of blood sent to the uterus, placenta and your vital organs by 40% per minute.
Respiration and metabolism
The progesterone hormone increases the rate of respiration. You now inhale more oxygen to furnish your tissues and the fetus with additional quantities of oxygen and exhale more carbon dioxide. The activity of your metabolism increases by 10-25%.
Throughout pregnancy, the average weight of a pregnant woman increases approximately by 12 kilos. Of these 12 kilos, one third, approximately 4,5 kg, corresponds to the weight of the fetus, placenta and amniotic fluid. The uterus weighs 1 kilogram and your breast about 400 grams. The remaining 6 kilos come from water retention and fat deposition in the body.