The study was conducted at Mettu Karl referral hospital found in Metu (also Mettu) which is a market town and separate woreda in South West Ethiopia, Oromia region, Ilu-Ababor Zone. It is located 600 km from the capital city of Ethiopia, Addis Ababa. Mettu, located in the Illubabor Zone of the Oromia Region along the Sor River, this town has a latitude and longitude of 8°18′N 35°35′E and an altitude of 1605 m. This hospital is being given different services for clients referred from health centers around Illubabor. It also gives service for mothers who suffer from fistula at its fistula center. Generally the hospital can give service for around 1.4 million clients. Regarding the delivery information, the average annual number of delivering mothers is estimated to be 3602.
Study design, period and population
Institutional based cross sectional study design was conducted among women whose age was greater or equal to eighteen from March to April 2018. Selected pregnant women who gave at least one child birth and those who were above 20 weeks of gestation for current pregnancy were included.
Sample size determination
The sample size was determined using single population proportion formula using the following assumptions; the magnitude of preeclampsia, which is 8.4% in Dessie referral hospital , confidence interval 95%, the margin of error d = 0.05, Za/2 = 1.96 and with 10% non-respondent rate the final sample size was 129.
Sampling procedure and data collection instrument
First, we obtained the annual report of the pregnant mothers with gestational age of greater than 20 weeks in ANC then we divide by 12 to get the flow of pregnant mothers per month. Then finally we found about 139 pregnant mothers who come for ANC follow up. Then the total sample size required was collected consecutively within the given period.
The questionnaire is adopted and modified from reviewing different literatures and scientific facts [1, 13,14,15,16]. Data were collected by face to face interview technique using structured and pretested questionnaire. Medical records were also reviewed for some clinical and laboratory results, including proteinuria and blood pressure measurement.
Data quality control
A questionnaire was first prepared in English and then translated to national language (Amharic) and was translated back to English by another individual in order to check and maintain its consistency.
After necessary modifications and correction was made and ensured its reliability by the pre-test, the actual data were collected by four midwife nurses. To maintain the quality of the data the 3 days of training was given for the data collectors. Questionnaires which were collected were checked for its completeness and consistency of the filled questionnaires on a daily basis. Blood pressure was taken under standard operating procedure by two data collectors for each participant, to keep its reliability of measurement and to correctly diagnose preeclampsia. Current multiple pregnancy was also confirmed by both the physical examination and ultrasound evaluation. The medical registration numbers of the participants who were involved in the study were recorded on a separate sheet to avoid repeated recruitment of the study participants who come for the next visit.
In addition, the data were thoroughly cleaned and carefully entered into computer for beginning of analysis.
Gestational age: is calculated from the last normal menstrual period (LNMP) and for those women who didn’t recall their last menstrual period, fundal height and/or ultrasound result was used.
Gravidity: the total number of pregnancies, including abortion, ectopic pregnancy and any other pregnancies documented on the chart.
Parity: the number of deliveries after 28 weeks of gestation including IUFD and still birth documented in the chart.
Pre-eclampsia: denotes for women with blood pressure of ≥140 mmHg systolic or ≥ 90 mmHg diastolic on two separate readings taken at least four to six hours apart after 20 weeks gestation in an individual with previously normal blood pressure and proteinuria in pregnancy [1, 17].
Proteinuria: is assessed using the urine dipstick method. Those women levels of + 1 and above are classified as having proteinuria.
Data processing and analysis
Data was entered using epi-data manager and exported, cleaned and analyzed using statistical package for social science (SPSS) version 21.
The multicollinarity between the variables were checked and there were no interaction among independent variables. We also checked the linear relationship between the continuous variable age and its logit transformation and finally we found that there was no linear relationship. As a result the independent variable age was categorized. Each independent/ predictor variables and outcome variable was investigated using bivariate logistic regression model. The independent variables that were statistically significant with p value < 0.05 and 95% CI at bivariate analysis was included in multivariate logistic regression model using enter method to control for potential confounder variables. Finally, variables (age, current multiple pregnancy and participant history of diabetic mellitus) with p value < 0.05 were taken as strong predictor variables of preeclampsia.
Approval letter was obtained from Mizan-Tepi University, college of medicine and health sciences. The necessary information regarding to the importance of the study was addressed for each participant. Written consent was taken from each participant and their confidentiality and privacy was maintained.