ASYMPTOMATIC BACTERIURIA AS A PREDICTOR OF PRE-ECLAMPSIA: A CASECONTROLLED STUDY

---

A.A. Adeyemo¹, O.O. Bello^1,2, O.C. Idowu¹

1. Department of Obstetrics and Gynaecology, University College Hospital, Ibadan, Nigeria.
2. Department of Obstetrics and Gynecology, College of Medicine, University of Ibadan, Nigeria.

Abstract

Background: Pre-eclampsia, an important cause of maternal and perinatal morbidity and mortality world-wide has been linked to subclinical infections, with maternal infection and inflammation postulated in its aetio-pathogenesis including asymptomatic bacteriuria which is common in pregnancy. The Obejctive of the study is to determine the relationship of asymptomatic bacteriuria as a risk factor for pre-eclampsia.

Methodology: A hospital-based case-control study among 28 pre-eclamptic pregnant women (cases) and 56 healthy pregnant women (controls) at gestational age of at least 28 weeks at the University College Hospital, Ibadan, between January 2019 and August 2019. Controls were matched with cases in age, parity and gestational age.Asymptomatic bacteriuria was determined with mid-stream urine analysis for microscopy and culture and data collected using an interviewer administered questionnaire with other details from medical records extracts. Chi- square, and multivariate regression analysis were used to assess statistical significance, odds ratio and adjusted odds ratio respectively, with P-value <0.05 and 95% confidence interval (CI).

Results: There was a significant association between asymptomatic bacteriuria and pre-eclampsia. The rate of asymptomatic bacteriuria was about three times higher in women with pre-eclampsia compared to those without pre-eclampsia and 1.23 times higher after adjusting for confounders (OR: 2.9, AOR:1.23). There was no significant relationship between sterile pyuria and pre-eclampsia (p-value: 0.92)

Conclusion: This study supports the proposition that asymptomatic bacteriuria is a risk factor for pre-eclampsia. It has not however shown whether the association is causal or casual. Further studies will be needed to explain this.

Introduction

Pre-eclampsia is a pregnancy-specific disorder characterized by hypertension, significant proteinuria, with or without edema.¹ It is a progressive multisystemic disease occurring between 20 weeks gestation to 6 weeks post-partum with potentially grave maternal and perinatal complications. Pre-eclampsia may progress to eclampsia or may be result in an array of complications such as pulmonary edema, cerebral hemorrhage, hepatic failure, renal failure, preterm delivery and perinatal and maternal mortality. Sadly, it remains a disease of theories despite the plethora of global research works, as the specific etiology is still elusive.

Pre-eclampsia is an important cause of maternal and perinatal morbidity and mortality globally, affecting 2-10% of pregnancies.² Preeclampsia and eclampsia account for up to 63,000 maternal deaths annually worldwide.³ Its greatest burden is in the developing nations, and the prevalence varies across different zones. In Nigeria, it has a wide variation as low as 0.03 per 100 deliveries in Calabar to as higher as 9 per 100 deliveries in Birin Kudu.^4.5

Different maternal infections have been linked with the development of pre-eclampsia. However, chronic subclinical infection causes endothelial dysfunction by decreasing nitric oxide which is a crucial event in the development of pre-eclampsia. ⁶ Asymptomatic bacteriuria is a subclinical urinary tract infection that is common in pregnancy. It is defined as the presence of at least 105 colony forming units of a single bacterium per milliliter of two consecutive clean catch urine specimens or a single catheter specimen in absencev of urinary symptoms⁷.

Screening for asymptomatic bacteriuria and prophylactic treatment in pregnancy is important to prevent adverse feto-maternal outcomes.⁸ World-wide, its incidence in pregnancy is 2-10%⁹. Studies conducted in Nigeria revealed an incidence of 28.8% in Ibadan and 86.6% in Benin.^10,11 It usually develops more in the third trimester and is much commoner in multiparous women.

Prior research works have shown dissenting conclusions about the association between asymptomatic bacteriuria and pre-eclampsia. Considering the higher prevalence of asymptomatic bacteriuria in pregnancy and the proposed central role of infection in the pathogenesis of pre-eclampsia, it is worthwhile conducting this study. This is because prophylactic treatment of asymptomatic bacteriuria can be a simple and cheap way of preventing pre-eclampsia.