Patient cohort
In this study, a cohort of women diagnosed with PE who underwent cardiovascular health screening at 6 months postpartum was assembled from two study centres (Kingston and Ottawa, ON, Canada). In Kingston, women who develop a pregnancy complication are referred to the Maternal Health Clinic (Kingston General Hospital) for postpartum cardiovascular health screening at 6 months postpartum as part of routine, standard of care. Assessments and evaluations, including the calculation of a lifetime cardiovascular risk score, conducted at the Maternal Health Clinic have been previously described.28 From this clinic, we recruited eligible study participants at the time of their 6-month postpartum visit (between 2011 and 2017). Women diagnosed with PE who had placenta pathology performed at delivery of the index pregnancy (PE diagnosis) were approached to participate in the study.
In Ottawa, women were recruited to participate in the study as part of the DREAM Study research protocol designed to emulate the Maternal Health Clinic. Women diagnosed with PE prior to delivery were recruited from inpatient services at The Ottawa Hospital, General Campus between 2013 and 2018. Placentas from each participant were sent to Anatomical Pathology at the Children’s Hospital of Eastern Ontario. Six months after delivery, participants returned to the Ottawa Hospital for cardiovascular health screening performed by the research study nurse. The assessments performed at this study visit were identical to those performed at the Maternal Health Clinic and a lifetime cardiovascular risk score was calculated for each participate as described previously.28 At both sites, all women provided written informed consent to participate in the study.
PE was defined according to the contemporaneous Society of Obstetricians and Gynaecologists of Canada criteria including hypertension (blood pressure ≥140/90 mmHg, on at least two occasions >15mins apart after 20 weeks’ gestation) with new proteinuria (≥0.3g/day by 24h urine collection, ≥30mg/mmol by protein:creatinine ratio, or ≥1+ by urinary dipstick), or one or more adverse conditions (e.g., headache/visual symptoms, chest pain/dyspnea, nausea or vomiting, right upper quadrant pain, elevated WBC count) or one or more severe complications (e.g., eclampsia, uncontrolled severe hypertension, platelet count <50x109/L, acute kidney injury).30 Women with chronic hypertension, known CVD prior to pregnancy, known kidney disease prior to pregnancy, or diabetes (type I, type II, gestational) were excluded. Small-for-gestational age (SGA) status of the infant was determined if birthweight was <5th percentile for gestational age and sex.31 Clinical data including medical and family history, pregnancy outcome and postpartum cardiovascular health results were collected by chart review following 6 months postpartum cardiovascular screening.