Risk factors for low birth weight: results from a case-control study in southern Spain.

The main objective of this study is to examine the effect of several variables, including altitude of maternal residence, on delivering a low birth weight (LBW) newborn. A case-control study was done. Two hundred forty cases (single newborn weighing less than 2,500 g) and 374 controls (single newborn weighing more than 2,499 g) were included. Information was gathered from the clinical chart of delivering women, through a personal interview and the Spanish Census Bureau (for altitude). Predictors of LBW were assessed through stepwise logistic regression analysis. Several well-known LBW risk factors were identified: hypertension, weight gain during pregnancy, body size (mainly maternal prepregnancy weight), low social class, primiparity, and several conditions (spontaneous delivery, abruptio placentae). Altitude was an independent predictor of LBW at term (more than 37 weeks of gestational age) but not for preterm LBW. Nevertheless, a relationship between altitude and birth weight was not found in controls, although a moderate decreasing gradient with altitude was observed. The limitations of these findings are discussed.

Unplanned pregnancy as a major determinant in inadequate use of prenatal care.

BACKGROUND: Previous reports have stressed the importance of social class and education in prenatal care use. Unplanned pregnancy as a determinant of prenatal care use has been insufficiently studied. The objective of this report was to assess whether unplanned pregnancy is an independent predictor of inadequate use of prenatal care. METHODS: A 5% sample of women delivering at a hospital (409 women in the study population) was selected. Data on pregnancy were obtained by personal interview and from clinical charts. Prenatal care was considered inadequate according to the Kessner index. Relative risk (RR) and 95% confidence intervals (CI) were estimated. Stepwise logistic regression analysis was applied to select the independent predictors of inadequate prenatal care use. RESULTS: Prenatal care use was inadequate among 16.4% of the women. Pregnancy was unplanned among 42.8% of the women. Twenty-two percent of women with an unplanned pregnancy used prenatal care inadequately, while 12% of those with planned pregnancies used prenatal care inadequately (RR = 1.9, 95% CI = 1.2-2.9). In crude analysis, inadequate prenatal care use was also related to lower social class, lower education level, no employment outside the home, and multiparity. After adjustment was made for other predictors that were included in a stepwise logistic regression model (maternal education, social class, maternal occupation, parity, and pregnancy-induced hypertension), unplanned pregnancy was a significant risk factor for inadequate use of prenatal care (odds ratio = 2.1, 95% CI = 1.2-3.7) and it was an independent predictor for a delayed first prenatal care visit and for a reduced number of visits. CONCLUSIONS: The results suggest that unplanned pregnancy is a major determinant for inadequate use of prenatal care.

[Comparison of 2 indexes of prenatal care and risk of preterm delivery]. / Comparación de dos índices de asistencia a la atención prenatal y riesgo de parto pretérmino.

OBJECTIVES: A new index the adequacy of prenatal care utilization (APNCU) index, has been proposed to provide a more accurate and comprehensive measure of antenatal care use than the widely used Kessner index. To better understand the value of the two above mentioned indexes as predictors of preterm delivery, we examined their ability to predict women who will or will not deliver before 37 weeks of gestation. METHODS: A case-control study was performed, including 207 cases and 381 controls. Prenatal care was assessed on the basis of the two above mentioned indexes, both taking into account the number of prenatal care visits, the date of the first visit and gestational age. Multiple-factor adjusted odds ratios and their 95% confidence intervals were estimated using logistic regression methods. RESULTS: The Kessner index showed a lineal trend with both crude and adjusted for (the APNCU index) estimates of preterm delivery risk. The APNCU index did not show any linear trend with adjusted for (the Kessner index) estimates of preterm delivery risk. To assess whether the Kessner index added explanatory information to the APNCU index (or vice versa), the APNCU index was regressed on the Kessner index (and viceversa), and a set of residuals was computed for both indexes. In logistic regression analyses, the residuals of Kessner added meaningful information to the APNCU index, whereas the residuals of the APNCU index did not add any relevant information to the Kessner index. There results remained unchanged after controlling for several confounders. CONCLUSIONS: A variation in the definition of adequate prenatal care use changes the association between prenatal care and preterm delivery. The Kessner index showed a better ability for discriminating and predicting the risk of preterm delivery.

A comparison of two indices of adequacy of prenatal care utilization.

In a case-control study, we compared the ability of two indices of antenatal care use, the new Adequacy of Prenatal Care Utilization (APNCU) index and the Kessner index, to predict low birthweight. In crude analyses, both indices showed a linear trend with low birthweight. After controlling for confounding, however, the APNCU index was unrelated to low birthweight. To learn whether the Kessner index added explanatory information to the APNCU index (or vice versa), we regressed the APNCU index on the Kessner index (and vice versa) and computed residuals for both indices. In logistic regression analyses, the residuals of the Kessner index added meaningful information to the APNCU index, whereas the opposite did not occur.

Prenatal care and prevention of preterm birth. A case-control study in southern Spain.

The value of prenatal care is controversial and difficult to establish. A national policy for improving perinatal outcomes was proposed and applied throughout Andalusia (Southern Spain) in 1984. Here we report the results of an evaluation of this health care program as regards the prevention of preterm delivery. Effectiveness of prenatal care was assessed on the basis of two case-control studies in a hospital setting: one performed before the program was implemented (1981-1982) and the second one six years after the program began (1990-1993). A total of 229 cases and 395 controls for the period 1981-1982, and 207 cases and 381 controls for 1990-1993 were selected. Prenatal care was assessed based on the number of prenatal care visits, the date of the first visit, and an American composite index adjusting for gestational age. Multiple-factor adjusted odds ratios and their 95% confidence intervals (CI) were estimated using unconditional logistic regression analysis. The use of prenatal care significantly improved across time: the proportion of women receiving no prenatal care decreased from over 30% to less than 5%, and the proportion of women starting prenatal care in the first trimester for 1990-1993 was three times greater than the figure for 1981-1982. In the 1981-1982 case-control study, the date of first visit and the composite index were shown to be unrelated to preterm birth risk; and the number of visits yielded a significant association, although no definite trend could be established. In the 1990-1993 case-control study, a clear and significant relationship was observed between the number of prenatal care visits, the trimester of the first visit, and the adequacy of care according to the composite index. This latter variable, reflecting a more stringent standard of prenatal care, was selected by a stepwise logistic regression analysis as the best predictor for preterm birth risk. The results suggest that the present Andalusian program helps prevent preterm delivery. Nonetheless, its minimum standards should be raised to further decrease preterm birth risk.

Recall bias in a case-control study of low birth weight.

The role of report/recall bias in case-control studies of low birth weight (LBW) was investigated in women who gave birth at a tertiary hospital. Prenatal exposure information reported at the postpartum interview was compared with that documented during pregnancy in obstetric records. 169 cases of LBW and 198 controls were selected. The two sets of information on case mothers and control mothers were compared, using the medical record as a reference. Kappa values were estimated. No trend was observed to increase/decrease the sensitivity and specificity of recall. Agreement on alcohol use was very low (kappa = 0.11 for case mothers and 0.03 for control mothers): on obstetrical records, only 12 mothers of cases reported habitual alcohol intake at the first prenatal care visit, whereas in the interview 69 said yes to the same question; in control mothers, the figures were 4 and 89 respectively. Odds ratios (ORs) of exposure estimated from the two sets of data did not differ importantly in 8 variables. Interview data yielded ORs for hypertension (8.39 versus 4.63), anemia (0.44 versus 0.99) that were farther from the null, and ORs in the opposite direction for alcohol (0.83 versus 1.61) and any drug (0.64 versus 1.42). In conclusion, given that OR figures are similar for most variables and no trend is observed in sensitivity/specificity, mothers of normal births can be an adequate reference group, using personal interviews to obtain information on lifestyle, and medical records for conditions.

[Infection by the human immunodeficiency virus among the Spanish population (I). Qualitative meta-analysis]. / Infección por el virus de la inmunodeficiencia humana en la población española (I). Metaanálisis cualitativo.

A meta-analysis of the original papers on human immunodeficiency virus (HIV) published in Spain was performed to better know the characteristics of HIV infection in Spain. Between 1985 and 1989, 67 investigations fulfilled the inclusion criteria. They were evaluated by means of a quantified questionnaire. The mean quality of the investigations was 44.65 +/- 1.5%. A bias in the selection was highly probable in 80% of the studies, whereas a bias in information and in confusion was less frequent (35.8% and 77.6%, respectively). The investigations of more quality were those carried out recently at the University in collaboration with other Institutions and with participation of sanitary personnel published in microbiologic journals.

[Infection by the human immunodeficiency virus in the Spanish population (II). A meta-analysis of the time and geographic trends]. / Infección por el virus de la inmunodeficiencia humana en la población española (II). Metaanálisis de las tendencias temporales y geográficas.

The aim of this research was to study the prevalence of infection by the human immunodeficiency virus (HIV) among the Spanish population. Due to the lack of available data we have applied meta-analysis techniques. We analyzed 67 original publications on this field appeared between 1985 and 1989. The prevalence of the illness has progressively increased among the risk groups (ADVP, homosexuals, prostitutes, heterosexual transmission) but not in hemophilic patients. The geographical distribution showed statistically significant differences being Barcelona as the province with the area of highest prevalence of the infection in ADVP and homosexuals.