Nested case-control study on associated factors for anemia during pregnancy / 中华流行病学杂志

Objective To explore the related factors of anemia during pregnancy and provide scientific evidence for the primary prevention of anemia during pregnancy.Methods The pregnant women (≤ 12 pregnant weeks) who received the first pregnancy care in a local medical institution in Hunan province from June 2013 to November 2014 were included in this cohort study,and for them anemia had been excluded by physical examination.Baseline survey and follow up till childbirth were conducted for them.A queue-based nested case-control study (1 ∶ 2) was conducted (380 pregnant women with anemia detected in this study as case group,760 pregnant women without anemia randomly selected and matched by age,habitual residence during pregnancy as control group.And t test,x2 test and logistic regression analysis were conducted to identify related factors of anemia during pregnancy.Results Multivariate logistic regression analysis indicated that low family annual income level (net income) (OR=2.08,95％CI:1.22-3.59),low educational level (OR=2.09,95％CI:1.22-3.59),pre-pregnancy perm/hair dye (OR=2.23,95％ CI:1.63-3.05),early pregnancy vomiting (OR=2.51,95％ CI:1.56-4.03) were the risk factors for anemia during pregnancy.Intake of vitamin and trace element supplements (OR=0.69,95％ CI:0.50-0.94),frequent meat,fish,shrimp,egg intakes (OR=0.68,95％CI:0.49-0.92),frequent soy milk,milk intakes (OR=0.51,95％CI:0.27-0.95) were the protective factors for anemia during pregnancy.Conclusion A number of factors,such as family annual income level,education level,poisonous and harmful material contact,pregnancy reaction,nutrition,are related to the incidence of anemia during pregnancy,it is necessary to take preventive measures to reduce the incidence of anemia during pregnancy.

Nested case-control study on associated factors for anemia during pregnancy / 中华流行病学杂志

Objective To explore the related factors of anemia during pregnancy and provide scientific evidence for the primary prevention of anemia during pregnancy.Methods The pregnant women (≤ 12 pregnant weeks) who received the first pregnancy care in a local medical institution in Hunan province from June 2013 to November 2014 were included in this cohort study,and for them anemia had been excluded by physical examination.Baseline survey and follow up till childbirth were conducted for them.A queue-based nested case-control study (1 ∶ 2) was conducted (380 pregnant women with anemia detected in this study as case group,760 pregnant women without anemia randomly selected and matched by age,habitual residence during pregnancy as control group.And t test,x2 test and logistic regression analysis were conducted to identify related factors of anemia during pregnancy.Results Multivariate logistic regression analysis indicated that low family annual income level (net income) (OR=2.08,95％CI:1.22-3.59),low educational level (OR=2.09,95％CI:1.22-3.59),pre-pregnancy perm/hair dye (OR=2.23,95％ CI:1.63-3.05),early pregnancy vomiting (OR=2.51,95％ CI:1.56-4.03) were the risk factors for anemia during pregnancy.Intake of vitamin and trace element supplements (OR=0.69,95％ CI:0.50-0.94),frequent meat,fish,shrimp,egg intakes (OR=0.68,95％CI:0.49-0.92),frequent soy milk,milk intakes (OR=0.51,95％CI:0.27-0.95) were the protective factors for anemia during pregnancy.Conclusion A number of factors,such as family annual income level,education level,poisonous and harmful material contact,pregnancy reaction,nutrition,are related to the incidence of anemia during pregnancy,it is necessary to take preventive measures to reduce the incidence of anemia during pregnancy.

Study on the determinants of intrauterine growth restriction / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the intrauterine growth retardation (IUGR) and its determinants so as to provide evidence for maternal and child health care programs to be carried out.</p><p><b>METHODS</b>Fourteen townships were selected by cluster random sampling from 37 townships in Liuyang. A total of 6 105 pregnant women who had established their health care programs during April 2008 and March 2011, were recruited in this study. Records on pregnancy care manual and delivery were collected. 6 105 single live births were divided into two groups (IUGR group and control group). Those whose birth weight was below the 10th percentile for mean weight corrected for gestation age were grouped as IUGR group. Chi-square test and Multivariate logistic Regression method were used to estimate the determinants of IUGR.</p><p><b>RESULTS</b>A total of 6 105 women, pregnant with a singleton gestation were enrolled in the study: 528 of these pregnancies were complicated with IUGR (8.65%). Data from the multivariate logistic regression analysis showed that maternal age less than 25 (OR = 1.268), prim parity (OR = 1.706), BMI less than 18.5 kg/m² at first obstetrical examination (OR = 1.709), deficiency in weight gain during pregnancy (OR = 1.576) and pregnancy-induced hypertension syndrome (OR = 1.698) were related risk factors to intrauterine growth retardation.</p><p><b>CONCLUSION</b>Maternal age, prim parity, BMI, weight gain during pregnancy and pregnancy-induced hypertension syndrome were factors associated to the intrauterine growth retardation. Effective measures in reducing the intrauterine growth retardation should include factors as monitoring maternal weight and the change of weight during pregnancy in order to maintain the weight at normal ranges. Prevention and therapy for pregnancy-induced hypertension syndrome, should also be strengthened.</p>

Incidence and risk factors for postpartum hemorrhage in Liuyang, China / 中南大学学报(医学版)

OBJECTIVE@#To investigate the incidence and risk factors of postpartum hemorrhage in Liuyang City, Hunan Province.@*METHODS@#This was a nested case-control study. A total of 14 townships were randomly selected by cluster random sampling method from 37 townships in Liuyang City, Hunan Province. All women who got pregnant and childbirth from January 2010 to December 2011 in the above 14 townships were selected and followed up at first-trimester, second trimester, third trimester and each delivery period. Data were collected directly from maternal care manuals and the clinical records from the subjects' delivery hospitals. These whose postpartum bleeding was more than 500 mL were selected as cases, and the same amounts of normal maternal in the same cohort study whose postpartum bleeding was less than 500 mL were selected as controls. χ2 test and unconditional logistic regression analysis were applied to identify the determinants.@*RESULTS@#A total of 5 933 women were included in our study. The incidence of postpartum hemorrhage was 2.22%. Unconditional logistic regression analysis showed that the risk factors for postpartum hemorrhage mainly included anemia (OR=3.940, 95% CI: 2.100-7.389), scarred uterus (OR=2.730, 95% CI: 1.198-6.220), placenta previa (OR=10.665, 95% CI: 1.142-99.566), placental factors (OR=4.332, 95% CI: 1.004-18.692), and prolonged pregnancy (OR=5.899, 95% CI: 2.602-13.376).@*CONCLUSION@#Postpartum hemorrhage is caused by complicated factors. Comprehensive measures should be taken to reduce postpartum hemorrhage.

Postpartum change of blood pressure and its risk factors in patients with hypertensive disorders in pregnancy / 中南大学学报(医学版)

OBJECTIVE@#To investigate the change of blood pressure in patients with hypertensive disorders in pregnancy after delivery and the risk factors.@*METHODS@#In a retrospective cohort study, we collected subjects from villages and towns in Liuyang by cluster sampling method. Before enrolling in this cohort, all had established health records from January 2010 to December 2011. We collected the medical records and maternal health care manuals of this cohort as our data materials, focusing on the blood pressure records as well as related features. We compared the differences of recovery rate of postpartum blood pressure in different kinds of antenatal blood pressure groups with χ2 test. In order to explore the main factors influencing the recovery rate of blood pressure of patients with hypertensive disorders in pregnancy, we conducted univariate and multivariate analysis by χ2 test and unconditional logistic regression analysis.@*RESULTS@#Among the 460 women with hypertensive disorders in pregnancy in our analysis, the recovery rate of postpartum blood pressure reached 88.7%. Multivariate analysis showed that the risk factors influencing the recovery rate of postpartum blood pressure included advanced age (OR=0.436), higher degree of hypertensive disorders in pregnancy (OR=0.436), and hypertension with simultaneously high systolic and diastolic blood pressures (OR=0.192).@*CONCLUSION@#For most patients with hypertensive disorders in pregnancy, the blood pressure may decrease to normal level 42 days after delivery. Women with advanced age, higher degree of hypertensive disorders in pregnancy and hypertension with simultaneously high systolic and diastolic blood pressures should be given more attention.

Study on the influence of pregnancy-induced hypertension on neonatal birth weight and its interaction with other factors / 中华流行病学杂志

<p><b>OBJECTIVE</b>To research the influence of pregnancy-induced hypertension (PIH) on neonatal birth weight and its interaction with other factors.</p><p><b>METHODS</b>A retrospective cohort study was conducted in this study. 14 townships were randomly selected by cluster random sampling method from 37 townships in Liuyang city, Hunan province. All pregnant women from these 14 townships with pregnancy care manual and delivery record, during April 1st, 2008 to March 31st, 2011 were selected as subjects of this study. Blood pressure during pregnancy and neonatal birth weight were recorded. Multinomial logistic regression model was used to adjust the confounding factors. Addictive effects model was used for interaction analysis.</p><p><b>RESULTS</b>Data from 6 102 subjects were collected, including 418 (6.9%) pregnant women with PIH, 166 (2.7%) infants with low birth weight and 333 (5.5%) with fetal macrosomia. Results from the Multinomial logistic regression analysis showed significant association between neonatal birth weight and PIH, premature birth, BMI <18.5 before pregnancy, and weight gain ≥ 16 kg during pregnancy. Data from the Interaction analysis showed that there was strong positive interactions between PIH and premature birth to low birth weight infants (RERI = 35.08, API = 0.435, S = 1.7), and between PIH and BMI<18.5 before pregnancy to low birth weight infants. However, no significant interaction was found between PIH and weight gain.</p><p><b>CONCLUSION</b>Factors as PIH, premature birth, BMI before pregnancy and weight gain showed impact on low birth weight or fetal macrosomia. PIH also showed significant interaction on neonatal birth weight with premature birth as well as BMI before pregnancy, respectively.</p>

Study on the application of Back-Propagation Artificial Neural Network used the model in predicting preterm birth / 中华流行病学杂志

<p><b>OBJECTIVE</b>To establish a practical and effective model in predicting the premature birth, using the Back-Propagation Artificial Neural Network (BPANN).</p><p><b>METHODS</b>This was a prospective cohort study. Data was gathered from pregnant women selected by cluster sampling method from 2010 to 2012 in Liuyang city, Hunan province and was randomly divided into training sample (to establish the prediction models), validation sample (to select the optimal network) and testing sample (to evaluate the prediction models) by ratio of 2:1:1. BPANN and logistic regression analysis were used to establish models while ROC was applied to evaluate the 'prediction models'.</p><p><b>RESULTS</b>Among the 6 270 pregnant women, 265 premature births were seen, with the premature incidence as 4.22%. The 7 variables which entered into the forecasting model would include abnormal uterine or uterine deformity, parity, number of pregnancies, gestational hypertension, placenta previa, premature rupture of membrane and regular prenatal examination. Sensitivity, specificity, agreement rate and area under the ROC curve of BPANN were 67.65% , 84.87%, 84.12% and 0.795, respectively. However, the sensitivity, specificity, agreement rate and area under the ROC curve of logistic regression were 64.71%, 85.60%, 84.69% and 0.783, respectively.</p><p><b>CONCLUSION</b>The newly established BPANN model was practical and reliable, which proved that this model was slightly better than the logistic regression in the prediction of premature birth.</p>

A population based study on incidence and determinants of preterm birth in Liuyang Hunan / 中南大学学报(医学版)

OBJECTIVE@#To describe the incidence and to discuss the risk factors of premature birth in rural areas of Liuyang.@*METHODS@#We collected subjects from villages and towns in Liuyang through cluster sampling method. Before enrolling in this cohort, all of them had established health records from January 2010 to December 2011. We followed up the early, middle and late stages of pregnancy until delivery, and collected medical records and maternal health care manual of this cohort as our data materials. We explored the main influence factors of premature delivery by χ2 test and unconditional logistic regression analysis for single factor and multivariate analysis.@*RESULTS@#Among 6270 women who enrolled in our cohort, 259 were diagnosed as premature birth. The incidence (4.13%) was lower than the national average level. Non-conditional logistic regression analysis showed that the risk factors of premature birth were as follows: OR of placental abruption was 7.678 (95% CI: 2.249-26.215), that of premature rupture of fetal membranes (PROM) was 5.177 (95% CI: 3.945-6.793), that of uterine abnormal and deformity was 2.675 (95% CI: 1.007-7.107), that of placenta anomaly was 2.633 (95% CI: 1.666-4.162), that of hypertension in pregnancy was 2.172 (95% CI: 1.044-4.521), that of pregnancy complications was 1.806 (95% CI: 1.033-3.157), that of male fetus was 1.429 (95% CI: 1.086-1.881). Protective factors of preterm birth were too frequent prenatal examination (OR=0.502, 95% CI: 1.033-3.157) and single pregnancy (OR=0.155, 95% CI: 0.075-0.319).@*CONCLUSION@#Preterm delivery is caused by complicated factors, such as placental abruption, PROM and male fetus. Comprehensive measures should be taken to reduce preterm birth.

Complications and related determinants in 13669 pregnant women / 中南大学学报(医学版)

OBJECTIVE@#To investigate pregnancy complications and related determinants, and provide scientific evidence for maternal health care.@*METHODS@#A total of 13669 pregnant women who planned to deliver in the hospital were randomly identified and surveyed by questionnaire. Chi-square test and logistic regression models were used to screen the influencing factors for pregnancy complications.@*RESULTS@#The incidence of pregnancy complication was 13.94%. The following diseases had higher incidence than others: anemia (2.95%), premature rupture of membranes (2.51%), diabetes (1.92%), severe preeclampsia (1.43%), mild preeclampsia (1.27%), and hypertensive disorder complicating pregnancy (1.27%). Data from logistic regression models showed that pregnancy complications were related to maternal age, education level, number of caesarean sections, ways to terminate pregnancy, gestation weeks and number of fetuses.@*CONCLUSION@#The rate of pregnant complication is high, which should be treated in time to ensure the safety of pregnant women.

Pre-conception factors for intrauterine growth retardation / 中南大学学报(医学版)

OBJECTIVE@#To analyze the pre-conception factors for intrauterine growth retardation.@*METHODS@#A nested case-control study was conducted in a cohort of 1368 women from 14 Child and Maternity Health Care Departments by cluster sampling method in Liuyang City, Hunan Province. Following-up until delivery, we collected their medical records and maternal health care manual materials. All neonates with intrauterine growth retardation were detected in the follow-up (the case group) and another 186 neonates without intrauterine growth retardation, matched with gender and mother's age, were randomly selected from the cohort as controls. χ2 test and multiple conditional logistic regression were used to investigate the determinants of intrauterine growth retardation.@*RESULTS@#Intrauterine growth retardation was associated with BMI (OR=64.775), waist circumference (OR=0.166), abortion (OR=6.997), level of total cholesterol (OR=0.045), folic acid (OR=0.077), and cortisol (OR=9.164).@*CONCLUSION@#Intrauterine growth retardation is associated with BMI, waist circumference, abortion,level of total cholesterol, folic acid, and cortisol. Effective measures to reduce intrauterine growth retardation in children include strengthening the detection of pre-pregnancy blood biochemical indicators to guide health care during pregnancy, and increasing nutrition during pregnancy according to pre-pregnancy BMI and waist circumference.

Cost-benefit of expanding cervical cancer screening / 中南大学学报(医学版)

OBJECTIVE@#To estimate the benefit and cost of increasing the coverage of cervical cancer screening.@*METHODS@#Using an eleven year conventional screening data (universal strategy) and a representative population sample (expanding strategy) to analyze the health and economic impact.@*RESULTS@#The screening coverage for all 30-59 women in Liuyang was increased from 7.20% to 66.67%. Early detection cases were increased from 20 to 45, and life years saved in one screening term increased from 103.46 years to 925.83 years with expanding strategy as compared with the conventional strategy. The incremental cost per life year saved was 6 917.07 Yuan. The benefit/cost ratio was 1.80:1 at the screening coverage of 66.67%, which was higher than that of the conventional strategy (1.40:1). Both strategies were cost-effective.@*CONCLUSION@#With various uncertainties and data limitations, expanding screening coverage is more effective than conventional strategy, and more benefit is obtained when the number of early detection cases increases.