Cardio-metabolic characteristics of women in south-western Uganda from pre-pregnancy to the postpartum period: A feasibility study

Abstract

Introduction Normal pregnancy is associated with cardiovascular changes that enable adaptation to the pregnancy state. Pregnancy complications, such as preeclampsia, are associated with maladaptation to pregnancy, and are a female-specific risk factor for chronic hypertension postpartum. I sought to determine the proportion and risk factors for persistent hypertension at three months postpartum, to describe the haemodynamic and metabolic changes from pre-pregnancy to postpartum among women planning to conceive, and to describe the healthcare providers’ and postpartum mothers’ barriers and facilitators to attending preconception clinics in south-western Uganda. Methods I conducted three sub studies at Mbarara Regional Referral Hospital in south-western Uganda. In sub study one, I conducted a prospective cohort study of women with new onset hypertensive disorders of pregnancy and followed them up three months postpartum. Women with persistent hypertension were those with high blood pressure and or on anti-hypertension medication at three months postpartum. Multivariable logistic regression was used to determine the risk factors for persistent hypertension. Sub study two was a feasibility prospective cohort study where I enrolled women in south-western Uganda that were planning to conceive. Haemodynamic and haematological characteristics were assessed pre-pregnancy, throughout pregnancy and repeated at twelve weeks postpartum. Metabolic and biochemical characteristics were assessed pre-pregnancy and twelve weeks postpartum. Analysis was done using paired t-test and repeated measures analysis of variance. Sub study three, was a qualitative study using in-depth interviews among postpartum mothers and health care workers. Analysis was done using thematic analysis to identify the barriers and facilitators to preconception clinic attendance. Results There were 111 pregnant women with hypertensive disorders of pregnancy enrolled in study one and 49% (54/111) were seen at 3 months postpartum. The proportion of women with persistent hypertension was 39% (21/54) and elevated serum creatinine (>106.08 µmol/L (>1.2mg/dL)) at admission for delivery was an independent risk factor for persistent hypertension. In study two, 239 women were enrolled with a conception rate of 60.7%. The incidence of preeclampsia was 1.1%. The systolic blood pressure (SBP) decreased to reach its lowest level in the third trimester (SBP ∆7±11 mmHg, p<0.001) while the diastolic blood pressure (DBP) was lowest in the second trimester (DBP ∆10±8 mmHg, p<0.001) and both returned to the pre-pregnancy level by 12 weeks postpartum (SBP ∆-0.3±10 mmHg, p=0.779, DBP ∆-0.3±8 mmHg, p=0.675). The peripheral vascular resistance decreased through pregnancy reaching its lowest level in the second trimester (∆245±315 dynes.s-1. cm-5, p<0.001) and returned to the pre-pregnancy state at 12 weeks postpartum (∆-23±362 dynes. s-1. cm-5, p=0.613). The cardiac output increased through pregnancy and was highest in the second and third trimester (∆-0.5±1 L/min, p<0.001) and returned to the pre-pregnancy state at 12 weeks postpartum (∆-0.1±1 l/min, p=0.717). Total cholesterol (∆-0.9mmol/l, 95% CI -1.1, -0.6), triglycerides (∆-0.2 mmol/l, 95% CI -0.4, -0.04) and serum creatinine (∆-11.2 µmol/L, 95% CI -14.4, -8) were elevated postpartum compared to pre-pregnancy levels while HbA1c (∆0.8%, 95% CI 0.3, 1.2), was lower postpartum. The red blood cell indices including haemoglobin (∆1.5±2.1 (g/dL) p <0.001), haematocrit (∆ 6.8±4.5 (%) p <0.001) and red blood cells (∆ 0.4±0.3 (10^6/µL) p <0.001) decreased during pregnancy with the lowest values of haemoglobin observed in the second and third trimester. However, haemoglobin then increased (∆ 0.4±2.1 (g/dL) p =0.194) to reach pre-pregnancy levels by 12 weeks postpartum while the haematocrit decreased (∆ 2.1±4.3 (%) p=0.002) and red blood cells increased (∆-0.3±0.4 (10^6/µL) p <0.001) postpartum compared to pre-pregnancy. The mean corpuscular volume (MCV) (∆8.7±8.0 (fL) p <0.001) and mean corpuscular haemoglobin (MCH) decreased (∆3.8±7.4 (pg) p =0.001) through pregnancy to a nadir postpartum while the mean corpuscular haemoglobin concentration (MCHC) gradually increased throughout pregnancy. The white cell count increased in pregnancy starting in the second trimester while the platelets decreased throughout pregnancy. In study 3, the participants reported that preconception clinics provided an opportunity to screen for maternal risk factors. The barriers to clinic attendance were lack of awareness about preconception services, limited accessibility of the clinics and cultural beliefs of traditional medicine over contemporary medical interventions. However, recognition of the benefits of preconception care, supportive social networks and positive perceptions of preconception care were facilitators to clinic attendance. Conclusion Approximately 4 in 10 women whose pregnancies were complicated by hypertensive disorders of pregnancy remained hypertensive at three months postpartum. Conducting a longitudinal pre-pregnancy study is feasible in south-western Uganda and the incidence of preeclampsia was low. Significant haemodynamic, metabolic and haematological changes occur during pregnancy and after pregnancy. Majority of these changes occur in very early pregnancy. Understanding women’s pre-pregnancy health by leveraging preconception clinics may be possible through enhancing awareness and making the clinics accessible. Implementation of preconception clinics may provide opportunities to design pre-pregnancy observational studies and interventional studies aimed at reducing the incidence of pregnancy complications such as preeclampsia and reducing the risk of future cardiovascular disease.