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Study protocol. A prospective cohort study of unselected primiparous women: the pregnancy outcome prediction study.
Background:
There have been dramatic changes in the approach to screening for aneuploidy over the last 20 years. However, the approach to screening for other complications of pregnancy such as intra-uterine growth restriction, pre-eclampsia and stillbirth remains largely unchanged. Randomised controlled trials of routine application of high tech screening methods to the general population have generally failed to show improvement in outcome. We have previously reviewed this and concluded it was due, in large part, to poor performance of screening tests. Here, we report a study design where the primary aim is to generate clinically useful methods to screen women to assess their risk of adverse pregnancy outcome.
Methods/design: We report the design of a prospective cohort study of unselected primiparous women recruited at the time of their first ultrasound scan. Participation involves serial phlebotomy and obstetric ultrasound at the dating ultrasound scan (typically 10-14 weeks), 20 weeks, 28 weeks and 36 weeks gestation. In addition, maternal demographic details are obtained; maternal and paternal height are measured and maternal weight is serially measured during the pregnancy; maternal, paternal and offspring DNA are collected; and, samples of placenta and membranes are collected at birth. Data will be analysed as a prospective cohort study, a case-cohort study, and a nested case-control study.DiscussionThe study is expected to provide a resource for the identification of novel biomarkers for adverse pregnancy outcome and to evaluate the performance of biomarkers and serial ultrasonography in providing clinically useful prediction of risk.
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Nomograms of Iranian fetal middle cerebral artery Doppler waveforms and uniformity of their pattern with other populations' nomograms
Background:
Doppler flow velocity waveform analysis of fetal vessels is one of the main methods for evaluating fetus health before labor. Doppler waveforms of middle cerebral artery (MCA) can predict most of the at risk fetuses in high risk pregnancies. In present study, we tried to obtain normal values of MCA Doppler flow velocity indices and their nomograms during 20th to 40th week of normal pregnancies among Iranian population and compare their pattern with other studies' nomograms.
Methods:
During present descriptive cross-sectional study, 1037 normal pregnant women with 20th-40th week gestational age were underwent MCA Doppler study. All cases were studied by gray scale ultrasonography initially and Doppler of MCA afterward. Resistive Index (RI), Pulsative Index (PI), Systolic/Diastolic ratio (S/D ratio), and Peak Systolic Velocity (PSV) values of MCA were determined for all of the subjects.
Results:
Results of present study showed that RI, PI, S/D ratio values of MCA decreased with parabolic pattern and PSV value increased with simple pattern, as gestational age progressed. These changes were statistically significant (P=0.000 for all of indices) and more characteristic during late weeks of pregnancy.
Conclusions:
Values of RI, PI and S/D ratio indices reduced toward the end of pregnancy, but PSV increased. Despite the trivial difference, nomograms of various Doppler indices in present study have similar pattern with other studies.
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Women's attitude towards prenatal screening for red blood cell antibodies, other than RhesusD.
Background:
Since July 1998 all Dutch women (+/- 200,000/y) are screened for red cell antibodies, other than anti-RhesusD (RhD) in the first trimester of pregnancy, to facilitate timely treatment of pregnancies at risk for hemolytic disease of the fetus and newborn (HDFN). Evidence for benefits, consequences and costs of screening for non-RhD antibodies is still under discussion. The screening program was evaluated in a nation-wide study. As a part of this evaluation study we investigated, according to the sixth criterium of Wilson and Jungner, the acceptance by pregnant women of the screening program for non-RhD antibodies.
Methods:
Controlled longitudinal survey, including a prenatal and a postnatal measurement by structured questionnaires. Main outcome measures: information satisfaction, anxiety during the screening process (a.o. STAI state inventory and specific questionnaire modules), overall attitude on the screening program. Univariate analysis was followed by standard multivariate analysis to identify significant predictors of the outcome measures. Participants: 233 pregnant women, distributed over five groups, according to the screening result.
Results:
Satisfaction about the provided information was moderate in all groups. All screen- positive groups desired more supportive information. Anxiety increased in screen- positives during the screening process, but decreased to basic levels postnatally. All groups showed a strongly positive balance between perceived utility and burden of the screening program, independent on test results or background characteristics.
Conclusions:
Women highly accept the non-RhD antibody screening program. However, satisfaction about provided information is moderate. Oral and written information should be provided by obstetric care workers themselves, especially to screen-positive women.
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Fetal age assessment based on 2nd trimester ultrasound in
Africa and the effect of ethnicity
Background:
The African population is composed of a variety of ethnic groups, which differ considerably from each other. Some studies suggest that ethnic variation may influence dating. The aim of the present study was to establish reference values for fetal age assessment in Cameroon using two different ethnic groups (Fulani and Kirdi).
Methods:
This was a prospective cross sectional study of 200 healthy pregnant women from Cameroon. The participants had regular menstrual periods and singleton uncomplicated pregnancies, and were recruited after informed consent. The head circumference (HC), outer-outer biparietal diameter (BPDoo), outer-inner biparietal diameter and femur length (FL), also called femur diaphysis length, were measured using ultrasound at 12-22 weeks of gestation. Differences in demographic factors and fetal biometry between ethnic groups were assessed by t- and Chi-square tests.
Results:
Compared with Fulani women (N=96), the Kirdi (N=104) were 2 years older (p=0.005), 3 cm taller (p=0.001), 6 kg heavier (p<0.0001), had a higher body mass index (BMI) (p=0.001), but were not different with regard to parity. Ethnicity had no effect on BPDoo (p=0.82), HC (p=0.89) or FL (p=00.24). Weight, height, maternal age and BMI had no effect on HC, BPDoo and FL (p=0.2-0.58, 0.1-0.83, and 0.17-0.6, respectively).
When comparing with relevant European charts based on similar design and statistics, we found overlapping 95% CI for BPD (Norway & UK) and a 0-4 day difference for FL and HC.
Conclusions:
Significant ethnic differences between mothers were not reflected in fetal biometry at second trimester. The results support the recommendation that ultrasound in practical health care can be used to assess gestational age in various populations with little risk of error due to ethnic variation.
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Use of antenatal corticosteroids prior to preterm birth in four South East Asian countries within the SEA-ORCHID project
Background:
There is strong evidence supporting the use of antenatal corticosteroids in women at risk of preterm birth to promote fetal lung maturation and reduce neonatal mortality and morbidity. This audit aimed to assess the use of antenatal corticosteroids prior to preterm birth in the nine hospitals in four South East Asian countries participating in the South East Asia Optimising Reproductive Health in Developing Countries (SEA-ORCHID) Project. MethodWe reviewed the medical records of 9550 women (9665 infants including 111 twins and two triplets) admitted to the labour wards of nine hospitals in four South East Asian countries during 2005. For women who gave birth before 34 weeks gestation we collected information on women's demographic and pregnancy background, the type, dose and use of corticosteroids, and key birth and infant outcomes.
Results:
Administration of antenatal corticosteroids to women who gave birth before 34 weeks gestation varied widely between countries (9% to 73%) and also between hospitals within countries (0% to 86%). Antenatal corticosteroids were most commonly given when women were between 28 and 34 weeks gestation (80%). Overall 6% of women received repeat doses of corticosteroids. Dexamethasone was the only type of antenatal corticosteroid used.
Women receiving antenatal corticosteroids compared with those not given antenatal corticosteroids were less likely to have had a previous pregnancy and to be booked for birth at the hospital and almost three times as likely to have a current multiple pregnancy. Exposed women were less likely to be induced and almost twice as likely to have a caesarean section, a primary postpartum haemorrhage and postpartum pyrexia.
Infants exposed to antenatal corticosteroids compared with infants not exposed were less likely to die. Live born exposed infants were less likely to have Apgar scores of <7 at five minutes and less likely to have any lung disease.
Conclusion:
In this survey the use of antenatal corticosteroids prior to preterm birth varied between countries and hospitals. Evaluation of the enablers and barriers to the uptake of this effective antenatal intervention at individual hospitals is needed.
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Multi-level modeling of social factors and preterm delivery in Santiago de Chile
Background:
Birth before the 37th week of gestation (preterm birth) is an important cause of infant and neonatal mortality, but has been little studied outside of wealthy nations. Chile is an urbanized Latin American nation classified as "middle-income" based on its annual income per capita of about $6000.
Methods:
We studied the relations between maternal social status and neighborhood social status on risk of preterm delivery in this setting using multilevel regression analyses of vital statistics data linked to geocoded decennial census data. The analytic data set included 56,970 births from 2004 in the metropolitan region of Santiago, which constitutes about 70% of all births in the study area and about 25% of all births in Chile that year. Dimensionality of census data was reduced using principal components analysis, with regression scoring to create a single index of community socioeconomic advantage. This was modeled along with years of maternal education in order to predict preterm birth and preterm low birthweight.
Results:
Births in Santiago displayed an advantaged pattern of preterm risk, with only 6.4% of births delivering before 37 weeks. Associations were observed between risk of outcomes and individual and neighborhood factors, but the magnitudes of these associations were much more modest than reported in North America.
Conclusion:
While several potential explanations for this relatively flat social gradient might be considered, one possibility is that Chile's egalitarian approach to universal prenatal care may have reduced social inequalities in these reproductive outcomes.
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Obstetric risk indicators for labour dystocia in nulliparous women: A multi-centre cohort study
Background:
In nulliparous women dystocia is the most common obstetric problem and its etiology is largely unknown. The frequency of augmentation and cesarean delivery related to dystocia is high although it is not clear if a slow progress justifies the interventions. Studies of risk factors for dystocia often do not provide diagnostic criteria for the diagnosis. The aim of the present study was to identify obstetric and clinical risk indicators of dystocia defined by strict and explicit criteria.
Methods:
A multi-centre population based cohort study with prospectively collected data from 2810 nulliparous women in term spontaneous labour with a singleton infant in cephalic presentation. Data were collected by self-administered questionnaires and clinical data-records. Logistic regression analyses were used to estimate adjusted Odds Ratios (OR) and 95% confidence intervals (CI) are given.
Results:
The following characteristics, present at admission to hospital, were associated with dystocia during labour (OR, 95% CI): dilatation of cervix < 4 cm (1.63, 1.38–1.92), tense cervix (1.31, 1.04–1.65), thick lower segment (1.32, 1.09–1.61), fetal head above the inter-spinal diameter (2.29, 1.80–2.92) and poor fetal head-to-cervix contact (1.83, 1.31–2.56). The use of epidural analgesia (5.65, 4.33–7.38) was also associated with dystocia.
Conclusion:
Vaginal examinations at admission provide useful information on risk indicators for dystocia. The strongest risk indicator was use of epidural analgesia and if part of that is causal, it is of concern.
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Maternal risk factors for abnormal placental growth: The national collaborative perinatal project
Background:
Previous studies of maternal risk factors for abnormal placental growth have focused on placental weight and placental ratio as measures of placental growth. We sought to identify maternal risk factors for placental weight and two neglected dimensions of placental growth: placental thickness and chorionic plate area.
Methods:
We conducted an analysis of 24,135 mother-placenta pairs enrolled in the National Collaborative Perinatal Project, a prospective cohort study of pregnancy and child health. We defined growth restriction as < 10th percentile and hypertrophy as > 90th percentile for three placental growth dimensions: placental weight, placental thickness and chorionic plate area. We constructed parallel multinomial logistic regression analyses to identify (a) predictors of restricted growth (vs. normal) and (b) predictors of hypertrophic growth (vs. normal).
Results:
Black race was associated with an increased likelihood of growth restriction for placental weight, thickness and chorionic plate area, but was associated with a reduced likelihood of hypertrophy for these three placental growth dimensions. We observed an increased likelihood of growth restriction for placental weight and chorionic plate area among mothers with hypertensive disease at 24 weeks or beyond. Anemia was associated with a reduced likelihood of growth restriction for placental weight and chorionic plate area. Pre-pregnancy BMI and pregnancy weight gain were associated with a reduced likelihood of growth restriction and an increased likelihood of hypertrophy for all three dimensions of placental growth.
Conclusion:
Maternal risk factors are either associated with placental growth restriction or placental hypertrophy not both. Our findings suggest that the placenta may have compensatory responses to certain maternal risk factors suggesting different underlying biological mechanisms.
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A population-based study of race-specific risk for placental abruption
Background:
Efforts to elucidate risk factors for placental abruption are imperative due to the severity of complications it produces for both mother and fetus, and its contribution to preterm birth. Ethnicity-based differences in risk of placental abruption and preterm birth have been reported. We tested the hypotheses that race, after adjusting for other factors, is associated with the risk of placental abruption at specific gestational ages, and that there is a greater contribution of placental abruption to the increased risk of preterm birth in Black mothers, compared to White mothers.
Methods:
We conducted a population-based cohort study using the Missouri Department of Health's maternally-linked database of all births in Missouri (1989–1997) to assess racial effects on placental abruption and the contribution of placental abruption to preterm birth, at different gestational age categories (n = 664,303).
Results:
Among 108,806 births to Black mothers and 555,497 births to White mothers, 1.02% (95% CI 0.96–1.08) of Black births were complicated by placental abruption, compared to 0.71% (95% CI 0.69–0.73) of White births (aOR 1.32, 95% CI 1.22–1.43). The magnitude of risk of placental abruption for Black mothers, compared to White mothers, increased with younger gestational age categories. The risk of placental abruption resulting in term and extreme preterm births (< 28 weeks) was higher for Black mothers (aOR 1.15, 95% CI 1.02–1.29 and aOR 1.98, 95% CI 1.58–2.48, respectively). Compared to White women delivering in the same gestational age category, there were a significantly higher proportion of placental abruption in Black mothers who delivered at term, and a significantly lower proportion of placental abruption in Black mothers who delivered in all preterm categories (p < 0.05).
Conclusion:
Black women have an increased risk of placental abruption compared to White women, even when controlling for known coexisting risk factors. This risk increase is greatest at the earliest preterm gestational ages when outcomes are the poorest. The relative contribution of placental abruption to term births was greater in Black women, whereas the relative contribution of placental abruption to preterm birth was greater in White women.
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The difficulties of conducting maternal death reviews in Malawi
Background:
Maternal death reviews is a tool widely recommended to improve the quality of obstetric care and reduce maternal mortality. Our aim was to explore the challenges encountered in the process of facility-based maternal death review in Malawi, and to suggest sustainable and logically sound solutions to these challenges.
Methods:
SWOT (strengths, weaknesses, opportunities and threats) analysis of the process of maternal death review during a workshop in Malawi.
Results:
Strengths: Availability of data from case notes, support from hospital management, and having maternal death review forms. Weaknesses: fear of blame, lack of knowledge and skills to properly conduct death reviews, inadequate resources and missing documentation. Opportunities: technical assistance from expatriates, support from the Ministry of Health, national protocols and high maternal mortality which serves as motivation factor. Threats: Cultural practices, potential lawsuit, demotivation due to the high maternal mortality and poor planning at the district level. Solutions: proper documentation, conducting maternal death review in a blame-free manner, good leadership, motivation of staff, using guidelines, proper stock inventory and community involvement.
Conclusion:
Challenges encountered during facility-based maternal death review are provider-related, administrative, client related and community related. Countries with similar socioeconomic profiles to Malawi will have similar 'pull-and-push' factors on the process of facility-based maternal death reviews, and therefore we will expect these countries to have similar potential solutions.
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