Microalbuminuria: a predictor of pregnancy-induced hypertension

Plasma fibronectin concentration in obese/overweight pregnant women: a possible risk factor for preeclampsia

Plasma fibronectin (FN) levels in obese/overweight and non-obese pregnant women were evaluated as a possible risk factor for preeclampsia. A total of one hundred and sixty three pregnant women attending antenatal clinic at University of Calabar Teaching Hospital participated in the study and sixty non-pregnant women served as control. About 77 (47.24%) of the pregnant women were followed up for any subsequent development of preeclampsia during the pregnancy. Fibronectin levels in plasma were measured by ELISA assay and serum total protein, urea and creatinine were determined spectrophotometrically. The mean plasma FN concentration of non-obese pregnant women in first trimester was lower than those of the non-pregnant women by 24%, but however, increased to the non-pregnant level in second and third trimesters. Obese/overweight pregnant women had significantly (P < 0.05) higher values than non-obese pregnant women in second and third trimesters. FN in obese/overweight pregnant women correlated positively with mean arterial blood pressure (MAP: r = 0.414, P = 0.04). About 28.57% of the pregnant women with FN above cut off point of 330 μg/ml at 18-24 weeks of gestation developed preeclampsia. This value increased to 40.0% when only the obese/overweight women were considered. On analysis of both fibronectin >330 μg/ml and MAP > 90, the predictive value increased to 66.7%. We therefore conclude that elevated FN may be regarded as a risk factor of preeclampsia especially among the obese women.

Prediction of preeclampsia: can it be achieved?

In this review, the various biochemical tests that have been proposed for the prediction of preeclampsia are described and evaluated. Placenta hormone markers do not predict future disease. They denounce the early placental changes that are part of the evolving disease and only predict the imminent of preeclamptic syndrome. This explains why tests are better predictors when preeclampsia supervenes shortly, and why screening in the first trimester is unlikely to work as well as in the second trimester. The use of multiple markers in the screening should reflect different aspects of the disease process and could increase the specificity and sensitivity of the screening and work on different etiologic factors. The possible use of second-trimester biochemical screening to predict the risk of preeclampsia remains to be investigated in the high-risk population.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After completion of this article, the reader should be able to list the various theories on the etiology of preeclampsia, to relate the various risk factors for the development of preeclampsia, and to describe the various screening tests for preeclampsia.

Accuracy of urinalysis dipstick techniques in predicting significant proteinuria in pregnancy

OBJECTIVE

To estimate the accuracy of point-of-care dipstick urinalysis in predicting significant proteinuria in pregnancy.

DATA SOURCES

Literature from 1970 to February 2002 was identified via 1). general bibliographic databases, that is, MEDLINE and EMBASE, 2). Cochrane Library and relevant specialist register of the Cochrane Collaboration, and 3). checking the reference lists of known primary and review articles.

METHODS OF STUDY SELECTION

Studies were selected if the accuracy of dipstick urinalysis techniques in predicting total protein excretion was estimated compared with a reference standard (laboratory estimation of protein excretion). The tests included visually read color-change dipsticks and automated dipstick urinalysis. Study selection, quality assessment, and data abstraction were performed independently and in duplicate.

TABULATION, INTEGRATION, AND RESULTS

Data from selected studies were abstracted as 2 x 2 tables comparing the test result with the reference standard. Test accuracy was expressed as likelihood ratios. Summary likelihood ratios were generated as measures of diagnostic accuracy to determine posttest probabilities. The electronic search produced 1543 citations. After independent review of published articles, a total of 34 articles was obtained for further scrutiny, and 7 studies were considered eligible for inclusion in the review. The 6 studies evaluating visual dipstick urinalysis produced a pooled positive likelihood ratio of 3.48 (95% confidence interval 1.66, 7.27) and a pooled negative likelihood ratio of 0.6 (95% confidence interval 0.45, 0.8) for predicting 300 mg/24-hour proteinuria at the 1+ or greater threshold.

CONCLUSION

The accuracy of dipstick urinalysis with a 1+ threshold in the prediction of significant proteinuria is poor and therefore of limited usefulness to the clinician. Accuracy may be improved at higher thresholds (greater than 1+ proteinuria), but available data are sparse and of poor methodological quality. Therefore, it is not possible to make meaningful inferences about accuracy at higher urine dipstick thresholds. There is an urgent need for research in this area of common obstetric practice.

Hypertensive disorders of pregnancy in women with Type 1 and Type 2 diabetes

AIMS

Hypertensive disorders in pregnancy are common in women with Type 1 diabetes and can be associated with adverse fetal outcomes, but little is known about hypertension in pregnancy in women with Type 2 diabetes. The aim of this study was to compare the incidence and outcomes of, and risk factors for, hypertension in pregnancy in women with Type 1 and Type 2 diabetes.

METHODS

One hundred consecutive singleton pregnancies in women with Type 2 and 100 in women with Type 1 diabetes were studied. Hypertension in pregnancy was classified according to Australasian Society for the Study of Hypertension in Pregnancy guidelines. Outcomes of pregnancy examined included birth weight, rates of caesarean section, premature delivery and special care unit admission, and perinatal mortality.

RESULTS

The overall incidence of hypertension in pregnancy was similar in Type 2 and Type 1 diabetes (41% vs. 45%), but the distribution of subtypes differed (P = 0.028). Women with Type 2 diabetes had more chronic hypertension (diagnosed at < 20 weeks gestation), but less preeclampsia than women with Type 1 diabetes. Hypertension in pregnancy was strongly associated with a number of adverse outcomes, but the impact of hypertension was significantly less for Type 2 diabetes than it was for Type 1 (premature delivery, P < 0.005; admission to Special Care Unit, P < 0.01; caesarean section, P = 0.05). This was, in part, because the frequency of adverse outcomes was greater in women with preeclampsia. Nulliparity, poor glycaemic control at presentation, and early pregnancy blood pressure and not smoking were risk factors for hypertension of similar magnitude in both types of diabetes. Significant effects of duration of diabetes and obesity were not seen in Type 2 subjects, but were in Type 1 (P < 0.01, P < 0.05, respectively). Early pregnancy albumin excretion rate was increased more frequently in Type 2 subjects than in Type 1 (P < 0.035), but was less strongly associated with the development of preeclampsia (P < 0.035).

CONCLUSIONS

The incidence of hypertension in pregnancy is similar in Type 2 and Type 1 diabetes, but the different population characteristics are reflected in a significantly different pattern of types of hypertension. Hypertension has less impact on adverse outcomes in Type 2 diabetes. Some risk factors for hypertension also differ between Type 2 and Type 1 diabetes.

The clinical value of microtransferrinuria and microalbuminuria in the prediction of pre-eclampsia

The aim of this study is to determine whether the presence of microtransferrinuria and microalbuminuria detected in pregnant women who are free of symptoms can predict the subsequent development of preeclampsia. One hundred fifty five pregnant women were successfully followed from 10 weeks gestation up till delivery. Pre-eclampsia developed in 31 women (17 mild and 12 severe pre-eclampsia), and eclampsia developed in two cases, whereas 124 women remained normotensive (controls). First morning urine specimens were collected during 10 to 12 weeks gestation and analyzed for microalbuminuria by a specific immunochemical test strip method. Mid-trimester mean arterial blood pressure (MAP) was also measured. Urinary microtransferrin levels in pregnant women who subsequently developed severe pre-eclampsia and eclampsia were significantly higher than those of pregnant women who remained normotensive. Microtransferrinuria as a predictor for pre-eclampsia had a sensitivity 93.5%, specificity 65%, positive predictive value 83% and negative predictive value 98.4%, whereas these values for microalbuminuria were: 50%, 58%, 50% and 91%, respectively. Urinary microtransferrin levels were significantly elevated in women with elevated MAP and in women who delivered low birth weight and low Apgar score babies. In conclusion, microtransferrinuria is a potentially more sensitive predictor of pre-eclampsia than microalbuminuria. Moreover, microtransferrinuria in early pregnancy might be a negative marker of fetal outcome in pre-eclampsia.

Clinical value of detecting microalbuminuria as a risk factor for pregnancy-induced hypertension in insulin-treated diabetic pregnancies

OBJECTIVE

We evaluated the role of clinical non-overt stage III diabetic nephropathy concerning the development of more frequent hypertensive complications during pregnancies of women requiring insulin.

METHODS

122 unselected pregnant women treated with insulin were enrolled in the study, of whom 56 were type-1 diabetic patients and 66 patients had gestational diabetes. In 24-h urine samples, excretion rates of albumin (UAE) and beta(2)-microglobulin were determined by nephelometric analysis and a radioimmunoassay, respectively. These parameters were also measured in the serum as well as HbA(1c), fructosamine and daily blood glucose profiles.

RESULTS

Sixteen (15.7%) women had an elevated UAE (>30 mg/24 h), of whom three had macroalbuminuria (UAE>300 mg/24 h). Thirteen (12.7%) insulin-treated women showed microalbuminuria during pregnancy, eight with type-1 diabetes and five with gestational diabetes requiring insulin. In the entire group hypertension was observed in seven (6.9%) women of whom six had microalbuminuria. The sensitivity and specificity were 85.7% and 92.6%, respectively. The positive predictive value reached 46.2%, whereas the negative predictive value was 98.9%.

CONCLUSION

Measurement of UAE in diabetic pregnancies seems to be an useful additional parameter for risk evaluation of hypertensive disorders.

Hypertension and pregnancy-related hypertension

Pregnant women with hypertension can be divided into two groups: normotensive women who develop the uniquely pregnancy-related syndrome of preeclampsia, which is characterized by hypertension, proteinuria, and edema; and women with chronic hypertension who become pregnant and are at increased risk for developing superimposed preeclampsia. Preeclampsia is a syndrome of generalized endothelial dysfunction initiated by abnormal placentation and consequent placental under-perfusion, release of cytokines and other toxins, and vasoconstriction and platelet activation. Preeclampsia is the major cause of both maternal and fetal morbidity and mortality and may be complicated by eclampsia (seizures) and hepatic and renal failure. The process is completely reversible by delivery of the fetus and placenta, but intrauterine growth retardation and premature delivery pose major threats to the fetus and may require care in tertiary care center. Treatment of preexisting or pregnancy-induced hypertension does not prevent or reverse the process, but is justified to prevent maternal cardiovascular complications, especially during labor and delivery.