Breast Cancer Care advises all women to be "breast aware" and report changes to their GP, but during pregnancy (and afterwards) breasts can do odd - often perfectly healthy - things. They may:
1 Feel weird. Tenderness, tingling and soreness of the nipple and breast is normal. This is caused by increased levels of the hormone progesterone and the growth of the milk ducts.
2 Expand. Inflation varies widely. Some of us turn into Dolly Parton; others see hardly any change in size.
3 Change colour. As pregnancy progresses, the nipples and areolae get darker, and surface veins on the breast grow more noticeable. The large glands under the areola that produce fluid to lubricate and protect the nipple also get bigger towards the end of pregnancy.
4 Leak. From about 16 weeks into pregnancy, breasts may leak small amounts of straw-coloured fluid. This is colostrum - your baby's first milk - full of special nutrients and antibodies for the first few days. Occasionally, nipples can leak blood in pregnancy because of the increased number and sudden growth of blood vessels. Though this can be normal in pregnancy, you should see your GP anyway, just to check.
5 Get lumpy. Breast lumps sometimes appear in pregnancy. Usually they are cysts (fluid-filled sacs), galactoceles (milk-filled cysts) or fibroadenomas (fibrous tissue). If you already have fibroadenomas, they may enlarge. The vast majority of breast lumps in pregnancy are non-cancerous, but do get any new lump or any growing lump checked out by your GP just to be sure.
For a leaflet on breast changes during and after pregnancy see breastcancercare.org.uk, or call 0808 800 6000.