Pathophysiological and hormonal changes affecting pain during pregnancy: a review

the most common conditions of pain that present in the course of gesta- tion in the following sections. Literature review We searched for relevant publica- tions in the Pubmed database. The keywords used included the terms: pregnancy, pain, musculoskeletal, back pain, headache, migraine, anae- mia, TENS, syndrome, sciatica, pre- term labour, analgesics and transfu- sion. In addition, we reviewed the references of the initially retrieved articles to identify additional rel- evant publications. We focused on articles describing the categories, the risks, the causes, the mechanisms as well as the treatment of pain in pregnancy. We identified 383 articles with the computerised search. The information found in 14 articles of this search was used to form our nar- rative review. Discussion Pain derived from the musculoskeletal, nervous and circulatory system All pregnant women essentially re- port symptoms from the musculo- skeletal system; however, only 25% experience symptoms that have a significant impact on daily life. In 80% of all pregnant women, there is an interstitial oedema that predis- poses to compression and entrap- ment of nerves over the last 8 weeks in gestation. The basic changes that contribute to the discomfort or true pain in pregnancy are the relaxa- tion of ligaments, the increase in the body weight of the pregnant and the increase in the size of the uterus. In pregnancy, there is a relaxation of lig- aments that is considered a normal change and is due to the production of hormones such as relaxin, which is produced by the corpus luteum, and oestrogens. Relaxin exerts an effect on the morphology of the connective tissue fibres in the pelvis by reducing their diameter, which results in their degradation. There is a correlation between the mean value of relaxin plasma levels and the pain located at the joints and lower back pain in ges- tation. The peak levels of relaxin are noted at the 12th week of gestation, and subsequently there is a gradual decrease till the 17th week. The in- crease in relaxin levels reaches up to 50% the peak value. The increase in body weight during gestation is normal. However, in combination with the relaxation of ligaments this may lead to joint pain. An increase in weight by 20% may increase the pressure applied to the joints by 100% 1 . The increase in the size of the uterus may lead to hyperlordosis, pressure and forward flexion of the pelvis, against which the sacroiliac joints resist. With the progression of gestation, the above-mentioned events are aggravated due to re- laxation of the sacroiliac ligaments. These changes through a mechanical way lead to an increase in the pres- sure that is applied in the lower back, the sacroiliac joints and the pelvis 1 .