Haemodynamic adjustments in third trimester, among pregnant women undergoing antenatal care at a tertiary hospital in Sokoto, Nigeria

Third trimester of pregnancy is characterised by profound changes in the haemodynamic system, predicated by the climax of the pregnancy hormones profiles. The blood pressure (BP) is lower and the haemoglobin levels are lower, necessitating an increased circulatory work to maintain tissue perfusion of the new maternal-fetal placental bed and for the expectant blood loss during childbirth. However, the mechanisms by which this is achieved is poorly understood. The present study aimed to assess the mechanisms by which the mother’s systems adjust to meet its haemodynamic gaps at the third trimester of a normal pregnancy. One hundred and fifty normal third trimester pregnant women undergoing antenatal care at the State Specialist Hospitalist Sokoto were assessed for blood pressure, haemoglobin concentration and anthropometries and the results compared with those of a group comprising 115 non-pregnant control women. While the pregnant group had lower BP parameters, it has significantly higher PR (P<0.0001). The pregnant group also demonstrated higher rate pressure product (RPP) (10,196±1,292bpm.mmHg v 9,429±1,469bpm.mmHg, P=0.0000). However, the non-pregnant group showed significantly higher heart rate reserve (HRR) (108.0±13.0bpm.mmHg/year), compared to the pregnant group (96.0±12bpm.mmHg/year, P=0.0000). Although, after adjusting for age, the pregnant group maintained a significantly higher RPP (397±120bpm.mmHg/year v 358±139bpm.mmHg/year, P =0.0156), the non-pregnant group after adjustment for age failed to maintain a higher HRR, instead the pregnant group showed (4.0±1.0bpm/year v 4.0±2.0bpm/year, P=0.0328). In conclusion, the pregnant woman can adjust haemodynamically by mechanisms of RPP and HRR independent of age, to cope with the stress and requirements of pregnancy. This, in addition to supplementation of haematenics, appropriate treatment of common infections and better nourishment of the pregnant mother, to help improve the anemia during pregnancy.