Lumps are also known as nodules, pregnancy breasts with nodules may be the cause of Montgomery’s nodules, breast hyperplasia, breast fibroids and so on. 1. Montgomery’s nodule: after pregnancy, the level of each hormone in the body will change, the sebaceous glands at the periphery of the areola hypertrophy to form a nodular bulge, observe the chest will have a small nodule, this is a normal Montgomery’s nodule during pregnancy. 2. Breast hyperplasia: patients with breast hyperplasia may lead to enlargement of breast glands and feel nodules on the chest when touching. Nodules caused by breast hyperplasia are usually widespread, often occurring with menstruation, and after menstruation, the breast nodules will be reduced or disappear, and there is swelling and pain or pins and needles pain in the breast during the attack. 3. Breast fibroma: in patients with breast fibroma, the epithelium of the breast is fibrotic, forming benign tumors, and the nodules can be felt in the chest, which are generally hard and have clearer boundaries and better mobility. There are many reasons for having nodules in the chest after pregnancy, so it is recommended to consult a doctor for a clear diagnosis.