Reference ranges for Doppler indices of umbilical and fetal middle cerebral arteries and cerebroplacental ratio: systematic review

OBJECTIVE

To assess studies reporting reference ranges for umbilical artery (UA) and fetal middle cerebral artery (MCA) Doppler indices and cerebroplacental ratio (CPR), using a set of predefined methodological quality criteria for study design, statistical analysis and reporting methods.

METHODS

This was a systematic review of observational studies in which the primary aim was to create reference ranges for UA and MCA Doppler indices and CPR in fetuses of singleton gestations. A search for relevant articles was performed in MEDLINE, EMBASE, CINAHL, Web of Science (from inception to 31 December 2016) and references of the retrieved articles. Two authors independently selected studies, assessed the risk of bias and extracted the data. Studies were scored against a predefined set of independently agreed methodological criteria and an overall quality score was assigned to each study. Linear multiple regression analysis assessing the association between quality scores and study characteristics was performed.

RESULTS

Thirty-eight studies met the inclusion criteria. The highest potential for bias was noted in the following fields: 'ultrasound quality control measures', in which only two studies demonstrated a comprehensive quality-control strategy; 'number of measurements taken for each Doppler variable', which was apparent in only three studies; 'sonographer experience', in which no study on CPR reported clearly the experience or training of the sonographers, while only three studies on UA Doppler and four on MCA Doppler did; and 'blinding of measurements', in which only one study, on UA Doppler, reported that sonographers were blinded to the measurement recorded during the examination. Sample size estimations were present in only seven studies. No predictors of quality were found on multiple regression analysis. Reference ranges varied significantly with important clinical implications for what is considered normal or abnormal, even when restricting the analysis to the highest scoring studies.

CONCLUSIONS

There is considerable methodological heterogeneity in studies reporting reference ranges for UA and MCA Doppler indices and CPR, and the resulting references have important implications for clinical practice. There is a need for the standardization of methodologies for Doppler velocimetry and for the development of reference standards, which can be correctly interpreted and applied in clinical practice. We propose a set of recommendations for this purpose. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Predictive accuracy of cerebroplacental ratio for adverse perinatal and neurodevelopmental outcomes in suspected fetal growth restriction: systematic review and meta-analysis

OBJECTIVE

The cerebroplacental ratio (CPR) has been proposed for the routine surveillance of pregnancies with suspected fetal growth restriction (FGR), but the predictive performance of this test is unclear. The aim of this study was to determine the accuracy of CPR for predicting adverse perinatal and neurodevelopmental outcomes in suspected FGR.

METHODS

PubMed, EMBASE, CINAHL and Lilacs were searched from inception to 31 July 2017 for cohort or cross-sectional studies reporting on the accuracy of CPR for predicting adverse perinatal and/or neurodevelopmental outcomes in singleton pregnancies with FGR suspected antenatally based on sonographic parameters. Summary receiver-operating characteristics (ROC) curves, pooled sensitivities and specificities, and summary likelihood ratios (LRs) were generated.

RESULTS

Twenty-two studies (including 4301 women) met the inclusion criteria. Summary ROC curves showed that the best predictive accuracy of CPR was for perinatal death and the worst was for neonatal acidosis, with areas under the summary ROC curves of 0.83 and 0.57, respectively. The predictive accuracy of CPR was moderate to high for perinatal death (pooled sensitivity and specificity of 93% and 76%, respectively, and summary positive and negative LRs of 3.9 and 0.09, respectively) and low for composite of adverse perinatal outcomes, Cesarean section for non-reassuring fetal status, 5-min Apgar score < 7, admission to the neonatal intensive care unit, neonatal acidosis and neonatal morbidity, with summary positive and negative LRs ranging from 1.1 to 2.5 and 0.3 to 0.9, respectively. An abnormal CPR result had moderate accuracy for predicting small-for-gestational age at birth (summary positive LR of 7.4). CPR had a higher predictive accuracy in pregnancies with suspected early-onset FGR. No study provided data for assessing the predictive accuracy of CPR for adverse neurodevelopmental outcome.

CONCLUSION

CPR appears to be useful in predicting perinatal death in pregnancies with suspected FGR. Nevertheless, before incorporating CPR into the routine clinical management of suspected FGR, randomized controlled trials should assess whether the use of CPR reduces perinatal death or other adverse perinatal outcomes. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Vaginal progesterone decreases preterm birth ≤ 34 weeks of gestation in women with a singleton pregnancy and a short cervix: an updated meta-analysis including data from the OPPTIMUM study

OBJECTIVE

To evaluate the efficacy of vaginal progesterone administration for preventing preterm birth and perinatal morbidity and mortality in asymptomatic women with a singleton gestation and a mid-trimester sonographic cervical length (CL) ≤ 25 mm.

METHODS

This was an updated systematic review and meta-analysis of randomized controlled trials comparing the use of vaginal progesterone to placebo/no treatment in women with a singleton gestation and a mid-trimester sonographic CL ≤ 25 mm. Electronic databases, from their inception to May 2016, bibliographies and conference proceedings were searched. The primary outcome measure was preterm birth ≤ 34 weeks of gestation or fetal death. Two reviewers independently selected studies, assessed the risk of bias and extracted the data. Pooled relative risks (RRs) with 95% confidence intervals (CI) were calculated.

RESULTS

Five trials involving 974 women were included. A meta-analysis, including data from the OPPTIMUM study, showed that vaginal progesterone significantly decreased the risk of preterm birth ≤ 34 weeks of gestation or fetal death compared to placebo (18.1% vs 27.5%; RR, 0.66 (95% CI, 0.52-0.83); P = 0.0005; five studies; 974 women). Meta-analyses of data from four trials (723 women) showed that vaginal progesterone administration was associated with a statistically significant reduction in the risk of preterm birth occurring at < 28 to < 36 gestational weeks (RRs from 0.51 to 0.79), respiratory distress syndrome (RR, 0.47 (95% CI, 0.27-0.81)), composite neonatal morbidity and mortality (RR, 0.59 (95% CI, 0.38-0.91)), birth weight < 1500 g (RR, 0.52 (95% CI, 0.34-0.81)) and admission to the neonatal intensive care unit (RR, 0.67 (95% CI, 0.50-0.91)). There were no significant differences in neurodevelopmental outcomes at 2 years of age between the vaginal progesterone and placebo groups.

CONCLUSION

This updated systematic review and meta-analysis reaffirms that vaginal progesterone reduces the risk of preterm birth and neonatal morbidity and mortality in women with a singleton gestation and a mid-trimester CL ≤ 25 mm, without any deleterious effects on neurodevelopmental outcome. Clinicians should continue to perform universal transvaginal CL screening at 18-24 weeks of gestation in women with a singleton gestation and to offer vaginal progesterone to those with a CL ≤ 25 mm. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

First- and second-trimester tests to predict stillbirth in unselected pregnant women: a systematic review and meta-analysis

BACKGROUND

Several biophysical and biochemical tests have been proposed to predict stillbirth but their predictive ability remains unclear.

OBJECTIVE

To assess the accuracy of tests performed during the first and/or second trimester of pregnancy to predict stillbirth in unselected women with singleton, structurally and chromosomally normal fetuses through use of formal methods for systematic reviews and meta-analytic techniques.

SEARCH STRATEGY

Electronic databases, bibliographies and conference proceedings.

SELECTION CRITERIA

Observational studies that evaluated the predictive accuracy for stillbirth of tests performed during the first two trimesters of pregnancy.

DATA COLLECTION AND ANALYSIS

Two reviewers selected studies, assessed risk of bias and extracted data. Summary receiver operating characteristic curves, pooled sensitivities, specificities and likelihood ratios (LRs) were generated. Data were synthesised separately for stillbirth as a sole category and for specific stillbirth categories.

MAIN RESULTS

Seventy-one studies, evaluating 16 single and five combined tests, met the inclusion criteria. A uterine artery pulsatility index >90th centile during the second trimester and low levels of pregnancy-associated plasma protein A (PAPP-A) during the first trimester had a moderate to high predictive accuracy for stillbirth related to placental abruption, small-for-gestational-age or pre-eclampsia (positive and negative LRs from 6.3 to 14.1, and from 0.1 to 0.4, respectively). All biophysical and biochemical tests assessed had a low predictive accuracy for stillbirth as a sole category.

CONCLUSIONS

Currently, there is no clinically useful first-trimester or second-trimester test to predict stillbirth as a sole category. Uterine artery pulsatility index and maternal serum PAPP-A levels appeared to be good predictors of stillbirth related to placental dysfunction disorders.

Novel biomarkers for predicting intrauterine growth restriction: a systematic review and meta-analysis

BACKGROUND

Several biomarkers for predicting intrauterine growth restriction (IUGR) have been proposed in recent years. However, the predictive performance of these biomarkers has not been systematically evaluated.

OBJECTIVE

To determine the predictive accuracy of novel biomarkers for IUGR in women with singleton gestations.

SEARCH STRATEGY

Electronic databases, reference list checking and conference proceedings.

SELECTION CRITERIA

Observational studies that evaluated the accuracy of novel biomarkers proposed for predicting IUGR.

DATA COLLECTION AND ANALYSIS

Data were extracted on characteristics, quality and predictive accuracy from each study to construct 2×2 tables. Summary receiver operating characteristic curves, sensitivities, specificities and likelihood ratios (LRs) were generated.

MAIN RESULTS

A total of 53 studies, including 39,974 women and evaluating 37 novel biomarkers, fulfilled the inclusion criteria. Overall, the predictive accuracy of angiogenic factors for IUGR was minimal (median pooled positive and negative LRs of 1.7, range 1.0-19.8; and 0.8, range 0.0-1.0, respectively). Two small case-control studies reported high predictive values for placental growth factor and angiopoietin-2 only when IUGR was defined as birthweight centile with clinical or pathological evidence of fetal growth restriction. Biomarkers related to endothelial function/oxidative stress, placental protein/hormone, and others such as serum levels of vitamin D, urinary albumin:creatinine ratio, thyroid function tests and metabolomic profile had low predictive accuracy.

CONCLUSIONS

None of the novel biomarkers evaluated in this review are sufficiently accurate to recommend their use as predictors of IUGR in routine clinical practice. However, the use of biomarkers in combination with biophysical parameters and maternal characteristics could be more useful and merits further research.

Systematic review of methodology used in ultrasound studies aimed at creating charts of fetal size

BACKGROUND

Reliable ultrasound charts are necessary for the prenatal assessment of fetal size, yet there is a wide variation of methodologies for the creation of such charts.

OBJECTIVE

To evaluate the methodological quality of studies of fetal biometry using a set of predefined quality criteria of study design, statistical analysis and reporting methods.

SEARCH STRATEGY

Electronic searches in MEDLINE, EMBASE and CINAHL, and references of retrieved articles.

SELECTION CRITERIA

Observational studies whose primary aim was to create ultrasound size charts for bi-parietal diameter, head circumference, abdominal circumference and femur length in fetuses from singleton pregnancies.

DATA COLLECTION AND ANALYSIS

Studies were scored against a predefined set of independently agreed methodological criteria and an overall quality score was given to each study. Multiple regression analysis between quality scores and study characteristics was performed.

MAIN RESULTS

Eighty-three studies met the inclusion criteria. The highest potential for bias was noted in the following fields: 'Inclusion/exclusion criteria', as none of the studies defined a rigorous set of antenatal or fetal conditions which should be excluded from analysis; 'Ultrasound quality control measures', as no study demonstrated a comprehensive quality assurance strategy; and 'Sample size calculation', which was apparent in six studies only. On multiple regression analysis, there was a positive correlation between quality scores and year of publication: quality has improved with time, yet considerable heterogeneity in study methodology is still observed today.

CONCLUSIONS

There is considerable methodological heterogeneity in studies of fetal biometry. Standardisation of methodologies is necessary in order to make correct interpretations and comparisons between different charts. A checklist of recommended methodologies is proposed.

Vaginal progesterone reduces the rate of preterm birth in women with a sonographic short cervix: a multicenter, randomized, double-blind, placebo-controlled trial

OBJECTIVES

Women with a sonographic short cervix in the mid-trimester are at increased risk for preterm delivery. This study was undertaken to determine the efficacy and safety of using micronized vaginal progesterone gel to reduce the risk of preterm birth and associated neonatal complications in women with a sonographic short cervix.

METHODS

This was a multicenter, randomized, double-blind, placebo-controlled trial that enrolled asymptomatic women with a singleton pregnancy and a sonographic short cervix (10-20 mm) at 19 + 0 to 23 + 6 weeks of gestation. Women were allocated randomly to receive vaginal progesterone gel or placebo daily starting from 20 to 23 + 6 weeks until 36 + 6 weeks, rupture of membranes or delivery, whichever occurred first. Randomization sequence was stratified by center and history of a previous preterm birth. The primary endpoint was preterm birth before 33 weeks of gestation. Analysis was by intention to treat.

RESULTS

Of 465 women randomized, seven were lost to follow-up and 458 (vaginal progesterone gel, n=235; placebo, n=223) were included in the analysis. Women allocated to receive vaginal progesterone had a lower rate of preterm birth before 33 weeks than did those allocated to placebo (8.9% (n=21) vs 16.1% (n=36); relative risk (RR), 0.55; 95% CI, 0.33-0.92; P=0.02). The effect remained significant after adjustment for covariables (adjusted RR, 0.52; 95% CI, 0.31-0.91; P=0.02). Vaginal progesterone was also associated with a significant reduction in the rate of preterm birth before 28 weeks (5.1% vs 10.3%; RR, 0.50; 95% CI, 0.25-0.97; P=0.04) and 35 weeks (14.5% vs 23.3%; RR, 0.62; 95% CI, 0.42-0.92; P=0.02), respiratory distress syndrome (3.0% vs 7.6%; RR, 0.39; 95% CI, 0.17-0.92; P=0.03), any neonatal morbidity or mortality event (7.7% vs 13.5%; RR, 0.57; 95% CI, 0.33-0.99; P=0.04) and birth weight < 1500 g (6.4% (15/234) vs 13.6% (30/220); RR, 0.47; 95% CI, 0.26-0.85; P=0.01). There were no differences in the incidence of treatment-related adverse events between the groups.

CONCLUSIONS

The administration of vaginal progesterone gel to women with a sonographic short cervix in the mid-trimester is associated with a 45% reduction in the rate of preterm birth before 33 weeks of gestation and with improved neonatal outcome.

Novel biomarkers for the prediction of the spontaneous preterm birth phenotype: a systematic review and meta-analysis

BACKGROUND

Being able to predict preterm birth is important, as it may allow a high-risk population to be selected for future interventional studies and help in understanding the pathways that lead to preterm birth.

OBJECTIVE

To investigate the accuracy of novel biomarkers to predict spontaneous preterm birth in women with singleton pregnancies and no symptoms of preterm labour.

SEARCH STRATEGY

Electronic searches in PubMed, Embase, Cinahl, Lilacs, and Medion, references of retrieved articles, and conference proceedings. No language restrictions were applied.

SELECTION CRITERIA

Observational studies that evaluated the accuracy of biomarkers proposed in the last decade to predict spontaneous preterm birth in asymptomatic women. We excluded studies in which biomarkers were evaluated in women with preterm labour.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data on study characteristics, quality, and accuracy. Data were arranged in 2 × 2 contingency tables and synthesised separately for spontaneous preterm birth before 32, 34, and 37 weeks of gestation. We used bivariate meta-analysis to estimate pooled sensitivities and specificities, and calculated likelihood ratios (LRs).

MAIN RESULTS

A total of 72 studies, including 89,786 women and evaluating 30 novel biomarkers, met the inclusion criteria. Only three biomarkers (proteome profile and prolactin in cervicovaginal fluid, and matrix metalloproteinase-8 in amniotic fluid) had positive LRs > 10. However, each of these biomarkers was evaluated in only one small study. Four biomarkers had a moderate predictive accuracy (interleukin-6 and angiogenin, in amniotic fluid; human chorionic gonadotrophin and phosphorylated insulin-like growth factor binding protein-1, in cervicovaginal fluid). The remaining biomarkers had low predictive accuracies.

CONCLUSIONS

None of the biomarkers evaluated in this review meet the criteria to be considered a clinically useful test to predict spontaneous preterm birth. Further large, prospective cohort studies are needed to evaluate promising biomarkers such as a proteome profile in cervicovaginal fluid.

Evidence-based intrapartum care in Cali, Colombia: a quantitative and qualitative study

OBJECTIVES

To measure the rate of use of selected intrapartum obstetric practices and to explore the factors associated with their use.

DESIGN

Prospective quantitative and qualitative study.

SETTING

Fifteen public and private hospitals in Cali, Colombia.

SAMPLE

Quantitative arm: 1,767 low-risk women delivering a single live baby; qualitative arm: 36 intrapartum care providers.

METHODS

Quantitative analysis of women's clinical charts for measuring the rates of obstetric practices. Qualitative analysis of audiotaped semi-structured interviews with intrapartum care providers.

MAIN OUTCOME MEASURES

Rates of use of ten intrapartum obstetric practices and associated factors and intrapartum care providers' views on evidence-based obstetric practice.

RESULTS

Rates for the ineffective practices of enema use, perineal/pubic shaving, and routine intravenous infusion during labour were around 75%. Episiotomy rates for primiparae and multiparae were 70 and 22%, respectively. Rates for the beneficial practices of active management of the third stage of labour and allowing women's choice of position during the first stage of labour were around 45%. Companionship during labour, external cephalic version for breech presentation at term, and absorbable synthetic sutures for episiotomy showed rates of utilisation lower than 15%. Hospital characteristics, type of intrapartum care provider, and women's medical insurance status were associated with use of selected practices. Barriers and opportunities for implementing evidence-based practices in routine obstetric care were identified.

CONCLUSIONS

Intrapartum care in Cali, Colombia, is not guided by the best available evidence. Effective change strategies should be undertaken to encourage the adoption of obstetric practices clearly demonstrated as effective and to discard those that are ineffective.

Effect of the interpregnancy interval after an abortion on maternal and perinatal health in Latin America

OBJECTIVE

To investigate whether the length of the interval between an abortion and the next pregnancy is associated with increased risks of adverse maternal and perinatal outcomes in Latin America.

METHOD

Retrospective cross-sectional study using information from 258,108 women delivering singleton infants and whose previous pregnancy resulted in abortion recorded in the Perinatal Information System database of the Latin American Centre for Perinatology and Human Development, Montevideo, Uruguay, between 1985 and 2002. Adjusted odds ratios were obtained through logistic regression analysis.

RESULT

Compared with the post-abortion interpregnancy intervals of 18 to 23 months, intervals shorter than 6 months were significantly associated with increased risks of maternal anemia, premature rupture of membranes, low birth weight, very low birth weight, preterm delivery, and very preterm delivery.

CONCLUSION

In Latin America, post-abortion interpregnancy intervals shorter than 6 months are independently associated with increased risks of adverse maternal and perinatal outcomes in the next pregnancy.

DEFINITION

Post-abortion interpregnancy interval (PAII): the time elapsed between the day of the abortion and the first day of the last menstrual period for the index pregnancy.

Methodological and technical issues related to the diagnosis, screening, prevention, and treatment of pre-eclampsia and eclampsia

In contrast with advances made in treating or eliminating many other serious disorders, severe morbidity and mortality associated with pre-eclampsia/eclampsia remain among the leading problems that threaten safe motherhood, particularly in developing countries. This article reviews technical issues related to diagnosis, screening, prevention, and treatment of pre-eclampsia and identifies corresponding needs. The authors stress the lack of standardized definitions of pre-eclampsia and eclampsia and discuss problems in blood-pressure measurements and assessment of urinary protein. They summarize the evidence for prevention strategies and screening tests for early detection. For treatment, magnesium sulfate has been proven effective, but not widely used. The authors outline priorities for narrowing the identified gaps and emphasize the need for coordinated efforts to reduce the morbidity and mortality due to pre-eclampsia/eclampsia. They conclude that the mystery of this disease must be resolved to achieve primary prevention of it.

Kangaroo mother care to reduce morbidity and mortality in low birthweight infants

BACKGROUND

Kangaroo mother care (KMC), defined as skin-to-skin contact between a mother and her newborn, frequent and exclusive or nearly exclusive breastfeeding, and early discharge from hospital, has been proposed as an alternative to conventional neonatal care for low birthweight (LBW) infants.

OBJECTIVES

To determine whether there is evidence to support the use of KMC in LBW infants as an alternative to conventional care after the initial period of stabilization with conventional care.

SEARCH STRATEGY

We used the standard search strategy of the Neonatal Review Group of the Cochrane Collaboration. MEDLINE, EMBASE, LILACS, POPLINE and CINAHL databases (to December 2002), and the Cochrane Controlled Trials Register (The Cochrane Library), were searched using the key words terms "kangaroo mother care" or "kangaroo care" or "kangaroo mother method" or "skin-to-skin contact" and "infants" or "low birthweight infants".

SELECTION CRITERIA

Randomized trials comparing KMC and conventional neonatal care in LBW infants.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed and data were extracted independently by two reviewers. Statistical analysis was conducted using the standard Cochrane Collaboration methods.

MAIN RESULTS

Three studies, involving 1362 infants, were included. All the trials were conducted in developing countries. The studies were of moderate to poor methodological quality. The most common shortcomings were in the areas of blinding procedures for those who collected the outcomes measures, handling of drop outs, and completeness of follow-up. The great majority of results consist of results of a single trial. KMC was associated with the following reduced risks: nosocomial infection at 41 weeks' corrected gestational age (relative risk 0.49, 95% confidence interval 0.25 to 0.93), severe illness (relative risk 0.30, 95% confidence interval 0.14 to 0.67), lower respiratory tract disease at 6 months follow-up (relative risk 0.37, 95% confidence interval 0.15 to 0.89), not exclusively breastfeeding at discharge (relative risk 0.41, 95% confidence interval 0.25 to 0.68), and maternal dissatisfaction with method of care (relative risk 0.41, 95% confidence interval 0.22 to 0.75). KMC infants had gained more weight per day by discharge (weighted mean difference 3.6 g/day, 95% confidence interval 0.8 to 6.4). Scores on mother's sense of competence according to infant stay in hospital and admission to NICU were better in KMC than in control group (weighted mean differences 0.31 [95% confidence interval 0.13 to 0.50] and 0.28 [95% confidence interval 0.11 to 0.46], respectively). Scores on mother's perception of social support according to infant stay in NICU were worse in KMC group than in control group (weighted mean difference -0.18 (95% confidence interval -0.35 to -0.01). Psychomotor development at 12 months' corrected age was similar in the two groups. There was no evidence of a difference in infant mortality. However, serious concerns about the methodological quality of the included trials weaken credibility in these findings.

REVIEWER'S CONCLUSIONS

Although KMC appears to reduce severe infant morbidity without any serious deleterious effect reported, there is still insufficient evidence to recommend its routine use in LBW infants. Well designed randomized controlled trials of this intervention are needed.

Maternal morbidity and mortality associated with interpregnancy interval: cross sectional study

OBJECTIVE

To study the impact of interpregnancy interval on maternal morbidity and mortality.

DESIGN

Retrospective cross sectional study with data from the Perinatal Information System database of the Latin American Centre for Perinatology and Human Development, Montevideo, Uruguay.

SETTING

Latin America and the Caribbean, 1985-97.

PARTICIPANTS

456 889 parous women delivering singleton infants.

MAIN OUTCOME MEASURES

Crude and adjusted odds ratios of the effects of short and long interpregnancy intervals on maternal death, pre-eclampsia, eclampsia, gestational diabetes mellitus, third trimester bleeding, premature rupture of membranes, postpartum haemorrhage, puerperal endometritis, and anaemia.

RESULTS

Short (<6 months) and long (>59 months) interpregnancy intervals were observed for 2.8% and 19.5% of women, respectively. After adjustment for major confounding factors, compared with those conceiving at 18 to 23 months after a previous birth, women with interpregnancy intervals of 5 months or less had higher risks for maternal death (odds ratio 2.54; 95% confidence interval 1.22 to 5.38), third trimester bleeding (1.73; 1.42 to 2.24), premature rupture of membranes (1.72; 1.53 to 1.93), puerperal endometritis (1.33; 1.22 to 1.45), and anaemia (1.30; 1.18 to 1.43). Compared with women with interpregnancy intervals of 18 to 23 months, women with interpregnancy intervals longer than 59 months had significantly increased risks of pre-eclampsia (1.83; 1.72 to 1.94) and eclampsia (1.80; 1.38 to 2.32).

CONCLUSIONS

Interpregnancy intervals less than 6 months and longer than 59 months are associated with an increased risk of adverse maternal outcomes.

Maternal morbidity and mortality associated with multiple gestations

OBJECTIVE

To test the hypothesis that women with multiple gestations are at increased risk of adverse maternal outcomes.

METHODS

We studied the association between multiple gestation and frequency of adverse maternal outcomes in 885,338 pregnancies recorded in the Perinatal Information System database of the Latin American Center for Perinatology and Human Development, Montevideo, Uruguay, between 1985 and 1997. Relative risks (RRs) were adjusted for 14 potential confounding factors through multiple logistic regression models.

RESULTS

There were 15,484 multiple gestations. Among parous women, multiple gestation was associated with a twofold increase in risk of death compared with singleton gestations [adjusted RR 2.1; 95% confidence interval (CI) 1.1, 3.9]. Compared with singleton gestations, women with multiple gestations had adjusted RRs of 3.0 (95% CI, 2.9, 3.3) for eclampsia, 2.2 (95% CI, 1. 9, 2.5) for preeclampsia, and 2.0 (95% CI, 1.9, 2.0) for postpartum hemorrhage. Likewise, there was significant association between multiple gestation and increased incidence of preterm labor, anemia, urinary tract infection, puerperal endometritis, and cesarean delivery. The incidences of premature rupture of membranes, third-trimester bleeding, and gestational diabetes mellitus were not statistically different for singleton and multiple gestations.

CONCLUSION

Multiple gestation increases the risk of significant maternal morbidity and mortality.

Epidemiology of fetal death in Latin America

BACKGROUND

To identify risk factors associated with fetal death, and to measure the rate and the risk of fetal death in a large cohort of Latin American women.

METHODS

We analyzed 837,232 singleton births recorded in the Perinatal Information System Database of the Latin American Center for Perinatology and Human Development (CLAP) between 1985 and 1997. The risk factors analyzed included fetal factors and maternal sociodemographic, obstetric, and clinical characteristics. Adjusted relative risks were obtained, after adjustment for potential confounding factors, through multiple logistic regression models based on the method of generalized estimating equations.

RESULTS

There were 14,713 fetal deaths (rate=17.6 per 1000 births). The fetal death risk increased exponentially as pregnancy advanced. Thirty-seven percent of all fetal deaths occurred at term, and 64% were antepartum. The main risk factors associated with fetal death were lack of antenatal care (adjusted relative risk [aRR]=4.26; 95% confidence interval, 3.84-4.71) and small for gestational age (aRR=3.26; 95% CI, 3.13-3.40). In addition, the risk of death during the intrapartum period was almost tenfold higher for fetuses in noncephalic presentations. Other risk factors associated with stillbirth were: third trimester bleeding, eclampsia, chronic hypertension, preeclampsia, syphilis, gestational diabetes mellitus, Rh isoimmunization, interpregnancy interval<6 months, parity > or =4, maternal age > or =35 years, illiteracy, premature rupture of membranes, body mass index > or =29.0, maternal anemia, previous abortion, and previous adverse perinatal outcomes.

CONCLUSIONS

There are several preventable factors that should be dealt with in order to reduce the gap in fetal mortality between Latin America and developed countries.

Intrafascial abdominal hysterectomy: outcomes and complications of 867 operations

OBJECTIVE

To prospectively evaluate the results and complications of the surgical technique of intrafascial abdominal hysterectomy.

METHODS

From March 1993 to February 1998, 867 women at four institutions from the Department of Valle del Cauca, Colombia, underwent intrafascial abdominal hysterectomy. Information on sociodemographic and clinical characteristics before hysterectomy, indications for hysterectomy, surgical outcomes and intra- and post-operative complications were collected. Patients were evaluated at 1, 3, and 12 months post-operatively and annually thereafter.

RESULTS

The follow-up period ranged from 6 to 63 months (median=45 months). The mean blood loss was 286+/-112 ml. Operative time averaged 71+/-11 min. The overall operative site infection rate was 4%. Intra- and post-operative hemorrhage occurred in 0.2 and 1.0% of patients, respectively. The transfusion rate was 0.7%. The incidences of ureteral, bladder, and bowel injury were 0.1, 0.4 and 0.0%, respectively. To date, none of the patients followed up between 1 and 5 years have had evidence of vaginal vault prolapse.

CONCLUSIONS

Intrafascial abdominal hysterectomy is a safe technique with a low rate of complications.

Risk factors for pre-eclampsia in a large cohort of Latin American and Caribbean women

OBJECTIVE

To study risk factors for pre-eclampsia in a large cohort of Latin American and Caribbean women.

DESIGN

Retrospective cross-sectional study from the Perinatal Information System, the database of the Latin American Center for Perinatology and Human Development, Montevideo, Uruguay.

SETTING

Latin America and the Caribbean, 1985-1997. Population 878,680 pregnancies at 700 hospitals; of these 42,530 were complicated by pre-eclampsia and 1,872 by eclampsia.

MAIN OUTCOME MEASURES

Crude and adjusted relative risks (RR) of risk factors for pre-eclampsia. Adjusted relative risks were obtained after adjustment for potential confounding factors through multiple logistic regression models based on the method of generalised estimating equations.

RESULTS

The following risk factors were significantly associated with increased risk of pre-eclampsia: nulliparity (RR 2 x 38; 95% CI 2 x 28-2 x 49); multiple pregnancy (RR 2 x 10; 95% CI 1 x 90-2 x 32); history of chronic hypertension (RR 1 x 99; 95% CI 1 x 78-2 x 22); gestational diabetes mellitus (RR 1 x 93; 95% CI 1 x 66-2 x 25); maternal age > or = 35 years (RR 1 x 67; 95% CI 1 x 58-1 x 77); fetal malformation (RR 1 x 26; 95% CI 1 x 16-1 x 37); and mother not living with infant's father (RR 1 x 21; 95% CI 1 x 15-1 x 26). Pre-eclampsia risk increased according to pre-pregnancy body mass index (BMI). In comparison with women with a normal pre-pregnancy BMI (19 x 8 to 26 x 0), the RR estimates were 1 x 57 (95% CI 1 x 49-1 x 64) and 2 x 81 95% CI 2 x 69-2 x 94), respectively, for overweight women (pre-pregnancy BMI = 26 x 1 to 29 x 0) and obese women (pre-pregnancy BMI > 29 x 0). Cigarette smoking during pregnancy and a pre-pregnancy BMI < 19 x 8 were significant protective factors against the development of pre-eclampsia. The pattern of risk factors among nulliparous and multiparous women was quite similar.

CONCLUSIONS

Risk factors for pre-eclampsia observed among Latin American and Caribbean women are similar to those found among North American and European women.

Cigarette smoking during pregnancy and risk of preeclampsia: a systematic review

In this systematic review of the existing evidence regarding the relationship between cigarette smoking during pregnancy and preeclampsia, studies were found through searches of MEDLINE (1966-October 31, 1998), Embase, Popline, CINAHL, Lilacs, bibliographies of identified studies, and proceedings of meetings on preeclampsia, and also through contact with relevant researchers. No language restrictions were imposed. Only cohort and case-control studies dealing with the relationship between cigarette smoking and preeclampsia were considered. Assessment of methodologic quality and data extraction of each study were carried out by 2 authors working independently. Typical relative risks and odds ratios with 95% confidence intervals were calculated for cohort and case-control studies, respectively, with both fixed and random effects models. Twenty-eight cohort studies and 7 case-control studies including a total of 833,714 women were included. All cohort studies reported an inverse association between cigarette smoking during pregnancy and incidence of preeclampsia (typical relative risk, 0.68; 95% confidence interval, 0.67-0.69). The findings were similar for case-control studies (typical odds ratio, 0.68; 95% confidence interval, 0.57-0.81). An inverse dose-response relationship was also found. Pooled data from cohort and case-control studies showed a lower risk of preeclampsia associated with cigarette smoking during pregnancy.

Cervical cerclage: an alternative for the management of placenta previa?

OBJECTIVE

Our purpose was to determine whether cervical cerclage reduces the maternal and neonatal morbidity in women with placenta previa.

STUDY DESIGN

Thirty-nine pregnant women with an initial diagnosis of placenta previa at 24 to 30 weeks' gestation were randomly assigned to cervical cerclage (n = 19) or conservative management (n = 20). Subjects were followed up until delivery. Primary outcome measure was gestational age at delivery. Secondary outcome measures were prolongation of pregnancy, number of patients bleeding after being randomly assigned, units of blood transfused, birth weight, hospital stay and costs, and admission to neonatal intensive care unit. Statistical significance was calculated by the Student t test, Fisher's exact probability test, and the chi2 with Yates' correction factor.

RESULTS

No statistically significant differences were observed between the two groups studied.

CONCLUSION

Cervical cerclage does not appear to be an adequate alternative for the management of placenta previa.

Triple-marker test as screening for Down syndrome: a meta-analysis

The effectiveness of triple-marker testing as screening for Down syndrome needs to be evaluated by means of formal meta-analytic techniques. We did a MEDLINE search to identify studies evaluating the detection of Down syndrome by use of the triple-marker test. Reference lists of articles were also checked. Papers published in either English, French, or German from 1966 to November 1996 were eligible for this review. Twenty cohort studies were identified. Results of sensitivities and false-positive rates from different subgroups of the study sample were compared by using summary receiver-operating characteristic curve analysis. Medians of sensitivities and false-positive rates were also estimated. A total of 194,326 patients were included. In women of all ages, the medians for sensitivities were 67, 71, and 73 percent when the cutoffs used were 1:190-200, 1:250-295, and 1:350-380, respectively. The median false-positive rates fluctuated between 4 and 8 percent. For women at or above 35 years old, the medians of sensitivity and false-positive rate were 89 and 25 percent, respectively, when the chosen cutoff was 1:190-200. In patients below 35 years old, the median sensitivity was 57 percent if the cutoff used was 1:250-295. Summary receiver-operating characteristic curves showed that 1:190 was the best cutoff for predicting Down syndrome. The triple-marker testing is an effective screening method of detecting Down syndrome pregnancies. It is less effective in younger than in older age groups and may be offered as an alternative to amniocentesis to pregnant women over 35.

Epidemiology of eclampsia in Colombia

OBJECTIVE

To measure the incidence of eclampsia, its maternal and perinatal outcomes and patterns of presentation of this disease in our environment.

METHOD

Retrospective descriptive study of 164 cases of eclampsia managed at the Hospital Universitario del Valle, Cali, Colombia from September 1993 to August 1995. Information was collected from reviews of hospital case-notes.

RESULTS

The incidence of eclampsia was 8.1/1000 deliveries. Maternal mortality was 6.1%. Fifty-seven percent of seizures occurred antepartum, 22% during labor, and 21% after delivery. Sixty-nine cases (42%) presented preterm. Ninety-eight women (60%) were nulliparous. Approximately one quarter of the women did not have hypertension or significant proteinuria at the time of seizures. Twenty percent of all women had at least one major complication. Perinatal mortality was 12.8%. Antepartum and postpartum cases were more severe than intrapartum cases.

CONCLUSION

Eclampsia occurs in one in 124 deliveries in Cali, Colombia and is associated with high maternal and perinatal morbidity and mortality.

Case-control study of risk factors for complicated eclampsia

OBJECTIVE

To identify risk factors associated with complicated eclampsia.

METHODS

Twenty-four patients with eclampsia complicated by intracerebral hemorrhage, pulmonary edema, renal, hepatic, or respiratory failure, disseminated intravascular coagulation, abruptio placentae, pulmonary aspiration, or hemolysis, elevated liver enzymes, low platelets syndrome were compared retrospectively with 101 uncomplicated eclamptic controls. Information on maternal demographic factors, medical and obstetric histories, and maternal and perinatal outcomes was retrieved and analyzed by univariate and multivariate analysis.

RESULTS

By multiple logistic regression, the only risk factors associated with the development of complicated eclampsia were maternal age over 26 years (adjusted odds ratio [OR] 6.3, 95% confidence interval [CI] 2.17, 18.48), multiparity (adjusted OR 4.5, 95% CI 1.55, 13.60) and no prenatal care (adjusted OR 3.3, 95% CI 1.25, 9.60).

CONCLUSION

Maternal age above 26 years, multiparity, and no prenatal care are the maternal risk factors identified for the development of complicated eclampsia.

Evaluation of methods used in the prediction of hypertensive disorders of pregnancy

Several methods used in the prediction of hypertensive disorders of pregnancy (HDP) were evaluated with statistical techniques. Only cohort studies were considered. The data reviewed show that platelet count, hematocrit, serum uric acid, and microalbuminuria are poor predictors of HDP. Mean arterial pressure predicts transient hypertension rather than preeclampsia. Fibronectin, urinary calcium excretion, roll-over test, and Doppler ultrasound showed contradictory and nonconclusive findings among the different authors. Isometric exercise test showed high predictive values but only two studies have been performed. Angiotensin II sensitivity was the test that showed the best predictive values but it is useless in clinical practice. In conclusion, currently, there is no test that fulfills all criteria established to be a good predictor of hypertensive disorders of pregnancy. The search for an adequate method for the screening of HDP with a high sensitivity, inexpensive, and easy to perform should still be a priority in future investigations.

What does an elevated mean arterial pressure in the second half of pregnancy predict--gestational hypertension or preeclampsia?

OBJECTIVE

The purpose of this study was to determine the predictive value of elevated mean arterial pressure in the second half of pregnancy for both preeclampsia and gestational hypertension.

STUDY DESIGN

This was a cohort of 588 nulliparous pregnant women studied prospectively from the twentieth week until delivery. Mean arterial pressure was obtained by means of a random-zero sphygmomanometer at 20, 26, and 31 weeks of gestation. The best cutoff point for the determination of predictive values was established by a receiver-operator characteristic curve.

RESULTS

Patterns of mean arterial pressure throughout pregnancy were different between preeclamptic and gestational hypertensive women. Receiver-operator characteristic curves for mean arterial pressure showed better predictive capacity for gestational hypertension than for preeclampsia. Sensitivity of mean arterial pressure to predict preeclampsia ranged between 39% and 48%, whereas for prediction of gestational hypertension it varied from 72% to 92%. Specificities for both groups were moderate (60% to 86%). Positive predictive values were low for all groups (5% to 33%).

CONCLUSION

Elevated mean arterial pressure in the second half of pregnancy is a good predictor of gestational hypertension but is a poor predictor of preeclampsia.