Sociodemographic determinants of low birthweight in Greece: a population study.

A total population sample of 10,654 singleton births from the Greek National Perinatal Survey of April 1983 was analysed to identify factors independently associated with low birthweight (LBW). The sample was divided into two groups according to the gravidity of the mothers (3368 primigravidae and 7286 multigravidae). Data examined included regional characteristics, marital status, age at and duration of marriage, parental ages at delivery, crowding in the home, insurance status, parental occupational classification and parental education levels. Logistic regression was used to define the socio-economic and demographic characteristics independently associated with the delivery of an LBW singleton baby. Significantly different LBW rates were found among the two groups: 4.3% in the primigravidae and 5.2% for multigravidae. For primigravidae significant associations were found with marital status, maternal occupation and father's education, while for multigravidae significant features were mother's education and place (region) of residence. The study showed little to assist in devising strategies of primary prevention of LBW in Greece.

PIP: This study examines the sociodemographic determinants of low birth weight (LBW) in Greece. The study population comprised 10,654 singleton births (3368 primigravid and 7286 multigravid mothers) from the Greek National Perinatal Survey of April 1983 was used to identify factors associated with LBW. The study considered classifications based on parental occupations, educational levels, marital status and parental ages, with the ultimate aim of providing clues about causal etiology. The results indicated no significant correlation with paternal occupation group. There was, however, a significant association with maternal occupation group. The housewife, whether primigravid or multigravid, had the lowest risk of having an LBW baby as compared to laborers and commercial workers. In Greece, paternal and maternal education showed a significant relationship with LBW. Unmarried primigravidas had a significant residual risk of LBW; however, marital status was not an independent risk factor for multigravidas. The mother's age was significantly associated with LBW among multigravidas, the highest rate being found among the oldest group of mothers. Paternal age was also significantly related to LBW among multigravidas, with women whose husband was either a teenager or age 45 or older being most at risk. In conclusion, factors such as maternal age and social class based on the father's occupation are not independently associated with LBW in Greece. For primigravidas significant associations were found with marital status, maternal occupation and father's education, while for multigravidas significant features were the education and place of residence of the mother.

The risk of teen mothers having low birth weight babies: implications of recent medical research for school health personnel.

This article reviews recent medical research on the relationship between young maternal age and the incidence of low birth weight infants. One line of research, "nature," emphasizes biological factors in early adolescence such as immaturity of the female reproductive system and inadequate prenatal weight gain. "Nurture," another research focus, stresses sociocultural attributes of teen mothers such as poverty and minority status. Young maternal age alone does not explain the higher rates of low birth weight infants born to adolescent females. Both biological and sociocultural factors, plus lifestyle choices made by adolescents, combine to raise or lower the risk of delivering a low birth weight infant. School health personnel need to link their health promotion efforts to those of other community organizations serving adolescents and their families.

PIP: This paper reviews a medical study on the relationship between low birth weight babies and young maternal age, and examines the biological and sociocultural factors that put female adolescents at risk for delivering a low birth weight infant. Young female adolescents are not uniformly at risk for having low birth weight infants. The incidence of low birth weight in younger adolescents can be explained in part by biological factors such as immaturity of the female reproductive system and inadequate prenatal weight gain, and in part by sociocultural and life style factors such as race and poverty. The poor and minority groups are at greatest risk. The school health personnel can help reduce the risk of teen mothers of having low birth weight babies by exerting joint efforts with teachers, students, parents, and community organizations and agencies in implementing school-wide environments that support healthy lifestyle choices, postponing first pregnancies, and reducing unwanted pregnancies.

Low birth weight in China and Finland.

Although a developing country, China has a lower occurrence of low birth weight (LBW) than many developed countries. This study of two population-based one-year birth cohorts, from Finland in 1985-86 and China in 1992, shows the occurrence of low birth weight (LBW) (1000- < 2500 g) among singletons to be 2.6 percent in the Chinese cohort and 3.0 percent in the Finnish one, and that of preterm births (28- < 37 weeks) 2.7 percent and 4.5 percent, respectively. The main component of LBW is term LBW (57.4 percent) in the Chinese case and preterm LBW (64.7 percent) in the Finnish case. The perinatal mortality rate (PMR) was twice as high in the Chinese cohort (13.0 vs. 5.9 per thousand). The occurrence of LBW in the Finnish cohort decreased to 2.3 percent after crosstabulation of the Finnish mothers to conform in structure to the population of Chinese mothers in terms of maternal age, marital status and maternal smoking. The result suggests that the lower incidence of LBW in the Chinese cohort seems to be a reflection of the Chinese socio-cultural environment, which provides Chinese mothers with favourable characteristics. The Finnish excess LBW would have disappeared if the mothers had possessed those characteristics as well. The excess perinatal deaths in the Chinese series might be explained by the different levels of perinatal health care in the two countries.

PIP: Even though China is a developing country, it has a lower occurrence of low birth weight (LBW) than many developed countries. The incidence of LBW, preterm births, and perinatal mortality was assessed in a cohort of 9391 children born in 1992 in Qingdao, China, and a cohort of 9479 children born in 1985-86 in Northern Finland. 2.6% of the singleton children in the Chinese cohort and 3.0% in the Finnish one were born LBW, while the occurrence of preterm births was 2.7% and 4.5%, respectively. The main component of LBW is term LBW (57.4%) in the Chinese cohort and preterm LBW (64.7%) in the Finnish cohort. The perinatal mortality rate (PMR) was 13.0/1000 in the Chinese cohort compared to 5.9/1000 in the Finnish cohort. However, after cross-tabulating the population of Finnish mothers to conform in structure to the population of Chinese mothers in terms of maternal age, marital status, and maternal smoking, the occurrence of LBW in the Finnish cohort decreased to 2.3%. The lower incidence of LBW in the Chinese cohort therefore seems to be a reflection of the Chinese sociocultural environment, which provides Chinese mothers with favorable characteristics in terms of age, marital status, and smoking. The excess perinatal mortality in the Chinese cohort may be explained by the different levels of perinatal health care in the two countries.

Physical abuse and low birthweight: a case-control study.

OBJECTIVE: To examine whether physical abuse of a woman by her partner was associated with low birthweight. DESIGN: A case-control study. SETTING: Department of Gynaecology and Obstetrics, University Hospital of Trondheim, Norway. PARTICIPANTS/SAMPLE: Eighty-six women who were delivered of a low birthweight (< 2500 g) infant (cases) and 92 women who were delivered of an infant with birthweight > or = 2500 g (controls). METHODS: An in-depth interview, either postpartum at the maternity ward or one year after delivery. Information about abuse was obtained by direct questioning and a modified version of the Conflict Tactics Scales. RESULTS: A total of 17% of the women had experienced abuse by a partner. While 7% had been abused by their current partner before the index pregnancy only one woman reported abuse during pregnancy. Relatively more mothers of low birthweight infants were abused (20%) compared with controls (15%), but the association was not statistically significant (OR 1.37, 95% CI 0.63-2.99). Abused women reported a higher consumption of alcohol and cigarettes in pregnancy compared with nonabused women. CONCLUSION: Abuse was not found to be a risk factor for low birthweight in this study.

PIP: A case-control study conducted at the University of Trondheim, Norway, in 1992-94 investigated the association between physical or sexual abuse by a male partner and low birth weight. 86 infants who weighed less than 2500 g at delivery were enrolled as cases, while 92 infants with a birth weight of 2500 g or above served as controls. Both the conflict tactics scale and direct questioning in the postpartum period or one year after delivery were used to measure domestic violence. A total of 31 women (17%) reported physical and/or sexual abuse by a current or former partner. Abused women were significantly more likely than their nonabused counterparts to be unemployed, to smoke, and to consume alcohol during pregnancy, but there were no differences between groups in terms of education, marital status, income, mean age at delivery, or mean pre-pregnancy weight. Relatively more mothers of low-birth-weight infants were abused than controls (20% and 15%, respectively), but the association was not statistically significant (odds ratio (OR), 1.37; 95% confidence interval (CI), 0.63-2.99). The association remained nonsignificant even after adjustment for potentially confounding factors such as cigarette smoking and alcohol consumption during pregnancy (OR, 1.35; 95% CI, 0.62-2.98).

The association between birthweight, sociodemographic variables and maternal anthropometry in an urban sample from Dhaka, Bangladesh.

The relationship between birthweight, sociodemographic variables and maternal anthropometry was examined in a sample from an inner urban area of Dhaka, Bangladesh. About 21% of babies were of low birthweight (LBW) using the World Health Organization cut-off of < 2500 g. LBW was more common in younger (< 20 years) and older (> 30 years) mothers, the low-income group and those with little or no education. The mean birthweights of the higher-educated, higher-income group and male children were on average 290, 260 and 120 g, respectively, higher than uneducated, lower-income groups and female children. The best cut-offs for detecting LBW and normal-weight infants was maternal weight of 50 kg (odds ratio = 4.6), maternal arm circumference of 23 cm (odds ratio = 5.0) and body mass index of 20.5 (odds ratio = 6.5). The sensitivity and specificity were best for maternal weight (69% and 68%, respectively). Logistic regression analyses show that mothers' weight at term was the best single predictor of LBW (31%), while maternal weight along with age, educational level and income group correctly predicted just over 35% of LBW. Regression analyses also confirmed that mothers' weight at term was the best predictor of birthweight, with a correlation coefficient of 0.49.

PIP: The relationship between birth weight, sociodemographic variables, and maternal anthropometry was examined in a sample of mothers and infants from an inner urban area of Dhaka, Bangladesh. 253 pregnant women aged 17-35 years, of whom 251 gave birth to live children, participated. Of the surviving children, 1 died within 7 days of birth and 2 were hospitalized after birth; these latter children were excluded from the study. 55% of babies were male, 92% were born vaginally without intervention, and 86% of the deliveries occurred at home. About 21% of babies were of low birth weight (LBW) according to the World Health Organization cut-off of less than 2500 g. LBW was more common among mothers under age 20 years and over age 30, those of low income, and those with little or no education. The mean birth weights of the higher-educated, higher-income group, and male children were 290, 260, and 120 g, respectively, higher than those of uneducated, lower-income group, and female children. The best cut-offs for detecting LBW and normal-weight infants were maternal weight of 50 kg, maternal arm circumference of 23 cm, and body mass index of 20.5. The sensitivity (69%) and specificity (68%) were best for maternal weight. Regression analyses found that mother's weight at term was the best predictor of LBW, while maternal weight combined with age, educational level, and income group correctly predicted slightly more than 35% of LBW.

Assessing the impact of adolescent pregnancy and the premarital conception stress complex on birth weight among young mothers in Gibraltar's civilian community.

PURPOSE: The objective of this study was to assess the impact of young maternal age and the timing of conception on birth weight among primiparous women living in Gibraltar. METHODS: The data for this study were derived from a population of 295 primiparous women who gave birth under 25 years of age. Only married women who had no previous maternal history and delivered live singleton newborns between 1980 and 1984 were included. The confounding effects of gestation length, sex, and socio-economic status on birth weight were taken into account using the multivariate technique of multiple classification analysis. A conception timing variable was constructed and partitioned into four groups which represented the separate and joint effects of maternal age and prenuptial stress on birth weight. RESULTS: The overall mean birth weight was 3344.15 g. After controlling for the specified factors and covariate, the infants of older mother (> 19) who conceived after marriage weighed 57.78 g above the referent group mean. Older mothers who conceived a child before marriage delivered infants weighing 75.67 below the grand mean. Young mother (< 20) who conceived within marriage had infants who weighed 37.32 g less than the grand mean. Infants delivered by young mothers who conceived before marriage weighed 133.66 g less than the overall mean birth weight. The only significant group difference detected within the conception timing variable was between young mothers who conceived before marriage versus older mothers who conceived after marriage. CONCLUSIONS: Premarital conception is identified as a risk factor for lower infant birth weights among mothers under 20 years of age. This study emphasizes the need to take into account the effects of culturally mediated behavior on the pregnancy experience of young women.

PIP: The impact of young maternal age and the timing of conception relative to marriage on birth weight was assessed in a sample of 295 primiparous married women from Gibraltar, who gave birth before 25 years of age. Mean birth weight was 3344.15 g. After controlling for sex, gestational age, and socioeconomic status, the infants of mothers 20 years of age and over who conceived after marriage weighed 57.78 g above the referent group mean. Older mothers who conceived a child before marriage delivered infants weighing 75.67 g below the group mean. Mothers under 20 years of age who conceived within marriage had infants who weighed 37.32 g less than the mean, while those delivered by young mothers who conceived before marriage had infants weighing 133.66 g less than the overall mean birth weight. The only significant group difference by conception timing was between young mothers who conceived before marriage and older mothers who conceived after marriage. This finding suggests that conception prior to marriage in traditional small-scale communities such as Gibraltar can be a behavioral risk factor, termed the premarital conception stress complex, that contributes to reduced birth weight. During the interval between conception and marital resolution, the effects of increased stress, heightened anxiety, and reduced nutritional intake are hypothesized to coalesce and adversely affect maternal health and fetal development in the crucial first trimester of pregnancy.

Low birthweight, preterm births and intrauterine growth retardation in relation to maternal smoking.

The association between the intensity and duration of cigarette smoking during pregnancy and the frequency of low birthweight, preterm births and intrauterine growth retardation was investigated in a historical cohort. All 5166 livebirths occurring in the city of Pelotas, Brazil, during 1993 were identified and mothers interviewed soon after delivery. Children whose mothers smoked during pregnancy had a birthweight 142 g lower than those of non-smoking mothers. The odds ratio for low birthweight among children of smokers was 1.59 [95% CI 1.30-1.95]. There was no association between smoking and preterm delivery assessed by the Dubowitz score. In relation to intrauterine growth retardation, smoking was associated with an odds ratio of 2.07 [95% CI 1.69-2.53]. There was a direct dose-response association between the number of cigarettes smoked and the risk of growth retardation. Women whose partner smoked were also at higher risk of having a child with growth retardation. All the above results were adjusted for confounding factors. The effect of maternal smoking on low birthweight seems to be attributable to intrauterine growth retardation rather than preterm delivery.

PIP: Although the deleterious effect of maternal smoking on birth weight has been well documented, no study has investigated the impact of smoking on the different combinations of low birth weight (LBW), preterm delivery, and intrauterine growth retardation (IUGR). The present study addressed these associations through a cohort analysis of virtually all 5166 live births occurring in Pelotas, Brazil, in 1993. Mean birth weight was 3169 g; the prevalences of LBW, preterm birth, and IUGR were 9.1%, 8.0%, and 8.9%, respectively. The prevalence of smoking at conception was 33.2%; 26.2% of mothers smoked during the entire pregnancy; and 43% of mothers' partners smoked. The infants of mothers who smoked during pregnancy weighed an average of 142 g less at birth than those of nonsmokers. Logistic regression analyses of LBW were adjusted for social class, maternal education, parity, pregnancy interval, prior LBW, maternal height, and number of antenatal care visits. Mothers who smoked for part or all of the pregnancy were 1.59 times more likely to deliver a LBW infant than nonsmokers. There was no association between maternal smoking and preterm delivery. The risk of IUGR was 2.07 times higher in mothers who smoked; women who stopped smoking during the first trimester, however, had a risk similar to that of nonsmokers. Smoking by the mother's partner also increased the risk of IUGR (odds ratio, 1.33). Smoking was associated with at least a doubling of risk of IUGR, whether or not LBW or preterm birth was also present, suggesting that IUGR is the key factor mediating the effect of smoking on birth weight.

Some obstetric and foetal correlates in association with anemia in pregnancy.

PIP: Anemia is one of the most common complications encountered during pregnancy, contributing directly or indirectly to maternal and perinatal mortality and morbidity. Hemoglobin level was estimated by photometric calorimetry in 1902 pregnant women attending the antenatal clinic of the Maternal Health Unit of the Department of Community Medicine Institute of Medical Sciences, Srinagar, between December 1992 and December 1993 for antenatal care and eventually admitted to deliver. An overall anemia prevalence of 58.99% was observed in the cohort, mild anemia in 36.70%, moderate in 17.98%, and severe in 4.31%. The lowest concentrations of hemoglobin were observed among women under age 20 and over age 25 years. Mothers with second gravida enjoyed the highest concentration of hemoglobin relative to mothers of other gravida. Also, women with a pregnancy interval of more than 24 months had the highest mean concentration level compared to women with shorter intervals. The incidence of low-birth-weight babies was 32.11%, 49.80%, and 69.05% in mild, moderate, and severely anemic pregnant women, respectively. Finally, early neonatal mortality was observed at the level of 0.87% among normal women, 1.84% among mildly anemic women, 6.72% among moderately anemic women, and 28.57% among severely anemic women.^ieng

Factors influencing adolescent birth outcome.

In spite of a growing concern about adolescent pregnancy, factors that influence its birth outcome have remained inadequately defined. Data on sociodemographic variables, maternal health habits, medical and obstetric complications, and neonatal outcome measures were collected between October 1993 and May 1994. A total of 212 (110 adolescent and 102 non-adolescent) mothers and their newborns were included in the study. The data were analyzed using the EPI Info and the Statistical Analysis System softwares. Adolescent pregnancy was found to be associated with significantly higher rates of premature and low birth weight infants (p < .001). Newborns of adolescent mothers were also lower in other anthropometric parameters-length less than 45 cm (p < 0.001) and head circumference less than 32 cm (p < 0.003)- and had lower Apgar scores (< 7) at 1 and 5 minutes (p < 0.001). Gestational age was strongly and independently associated with birth weight. Low parity, lack of antenatal care, and young maternal age also had positive contributions to birth weight in descending order of strength. The findings of the present study suggest that factors other than young maternal age are strongly associated with poor adolescent birth outcome.

PIP: The impact of age factors on birth outcome was investigated in a comparative study of 212 deliveries occurring at Ethiopia's Tikur Anbessa Hospital during October 1993 to May 1994. 110 of these deliveries involved adolescent mothers, while the remaining 102 were to women 20-29 years of age. Adolescent mothers were significantly more likely than their older counterparts to be single and primiparous. Adolescent mothers missed significantly more prenatal visits and received less tetanus toxoid than non-adolescents. Although gestational ages and the frequency of small-for-age infants were comparable in both groups, adolescents had newborns with significantly lower anthropometric parameters. They were significantly more likely to be premature, low birth weight, and to have asphyxia. There were also more breech, instrumental, and Cesarean section deliveries among the adolescents. Gestational age was strongly and independently associated with birth weight. Multiple linear regression identified gestational age, low parity, lack of prenatal care, and young maternal age as significant predictors of birth weight. These findings suggest that factors other than young maternal age contribute to adverse pregnancy outcomes.

Trend of birthweights of African newborns: an overview.

Birthweight remains a good index for defining health care delivery as well as the status of the mother prenatally and during pregnancy. Birthweight is also an important assessor of neonatal viability. It varies from each community, region or nation with a 17% incidence of low birthweight in west Africa; 13.5% in east Africa; 6.8% in western Europe and 6.1% in east Asia.

PIP: Birth weight is a good indicator of maternal health and nutrition during pregnancy and the quality of the health care services, as well as a predictor of neonatal viability. The literature suggests that the incidence of low birth weight ranges from 6.8% in western Europe and 6.1% in east Asia to 17.0% in west Africa and 13.5% in east Africa. Although numerous studies have indicated that the mean birth weights of African infants are significantly lower than those of European or US infants, the African data largely reflect hospital and not home deliveries. Thus, a comprehensive assessment of low birth weight in Africa requires mandatory birth registration and centralized records to bridge the gap between the various tiers of the health care delivery system. On the other hand, several community-based studies conducted in countries such as Nigeria have provided compelling evidence for a strong link between low birth weight in Africa and malarial infection of the placenta, a high rate of twinning, low socioeconomic status, and poor maternal nutrition.

Calf circumference as a predictor of low birth weight babies.

PIP: To identify an inexpensive, reliable predictor of low birth weight capable of being utilized by untrained personnel, anthropometric measures were performed on 1600 newborns in Kanpur, India. This analysis indicated that, for a birth weight of 2500 g, the critical limit of calf circumference was 10.8 cm or less. Critical limits for crown-heel length, head circumference, chest circumference, midarm circumference, and thigh circumference were equal to or less than 45.2 cm, 32.2 cm, 30.1 cm, 9.0 cm, and 15.4 cm. All these measurements were significantly correlated with birth weight. This correlation was highest for calf circumference (r = 0.98), thigh circumference (r = 0.93), and chest circumference (r = 0.86). The highest sensitivity of detecting low-birth-weight infants was found for calf circumference (98.4%), followed by thigh circumference (91.6%) and head circumference (76.7%); specificity was 98.2% for thigh circumference and 90.0% for calf circumference. Traditional birth attendants can be trained easily to screen out high-risk newborns by measuring calf circumference.^ieng

Anthropometric indices, cord length and placental weight in newborns.

A study on the anthropometric indices of 3835 singleton newborn babies was conducted over a four months period at Sree Avittom Thirunal Hospital, Trivandrum. Of these, 1921 (50.1%) were male babies and 1914 (49.9%) were female babies. The majority of infants (43%) were born to the middle socio-economic groups and the mean birth weight of babies was high among the high-income groups. Five hundred and ninety six (15.5%) babies weighed less than 2500 g; of these 121 (20.2%) were preterm and 477 (79.8%) were full term. The prevalence of low birth weight (LBW) was high (22.0%) among the mothers aged between 15 and 19 years. There was a significant difference (p < 0.001) in the mean birth weight (BW) of term male and female babies but there was no significant differences in their body length, head circumference and cord length. The mean ponderal index of term newborn babies was 2.3 g/cm3. The mean placental weight of LBW term and preterm babies was less than that of the corresponding normal weight babies. The birth weight of babies was directly proportional to their placental weight.

PIP: A study of the 3835 singleton infants delivered at Sree Avittom Thurunal Hospital in Trivandrum, India, over a 3-month period in 1993 sought to identify correlates of low birth weight (LBW, defined as under 2500 g). The mean birth weight among these infants was 2821 +or- 479.8 g. 125 babies (3.3%) were preterm and 596 (15.5%) were LBW. Mean birth weight increased with increases in maternal socioeconomic status; 17.9% of infants with mothers with low socioeconomic status compared to 11.1% of those with mothers in the highest socioeconomic category were LBW. The prevalence of LBW was 22% among mothers aged 15-19 years compared to 11.5% among those 35-39 years of age. The mean birth weight of male term infants was significantly higher than that of female term infants (2905.2 +or- 431.4 g and 2819.7 +or- 410.9 g, respectively). There were no significant differences in mean body length, head circumference, or cord length by sex. Birth weight was directly proportional to placental weight and, in both LBW full-term and preterm infants, the placental weight was less than that of corresponding normal weight infants. Finally, the mean ponderal index of LBW term babies (1.86 g/cu. cm) and LBW preterm babies (1.37 g/cu. cm) was less than that of normal-weight term babies (2.32 g/cu. cm) and preterm babies (1.78 g/cu. cm). Overall, these findings are consistent with those of other studies conducted in India.

Determinants of term intrauterine growth retardation: the Saudi experience.

In a clinical study from an unselected Saudi obstetric population, the incidence of and risk factors for intrauterine growth retardation among live births were investigated. From a total study group of 4578 consecutive live births, 76 (1.7%) infants were found to be growth retarded. These infants were then compared with a randomly selected control group of 76 term newborns with appropriate birthweight for their gestational ages. Delivery at term of a growth-retarded infant was significantly associated with maternal age under 20 years, maternal body mass index less than 23, first degree consanguinity, poor housing, primiparity, and inadequate prenatal care in univariate analysis. When considered jointly in multivariate logistic regression analysis, the significant determinants were reduced to primiparity, first degree consanguinity, and poor housing. These risk factors correctly predicted 63% and 71% of the intrauterine growth-retarded infants or normal birthweight infants, respectively.

PIP: In Saudi Arabia, physicians compared data on 76 term intrauterine growth retardation (IUGR) infants with data on 76 randomly selected term newborns of appropriate birth weight to study the determinants of term IUGR. The term IUGR rate was 1.7% (76/4578 consecutive live births). The univariate analysis found significant risk factors to be a maternal age of less than 20 years (odds ratio [OR] = 4.89), a maternal body mass index of less than 23 (OR = 2.86), first degree consanguinity (OR = 3.1), living in a mud house (OR = 5.10), primiparity (OR = 3), and inadequate prenatal care (OR = 2.86). A stepwise multiple logistic regression model revealed that the significant risk factors of term IUGR included primiparity (OR = 3.3), first degree consanguinity (OR = 3.4), and living in a mud house (OR = 7.5). These three risk factors correctly predicted 63% and 71% of the IUGR and normal-birth-weight infants, respectively. These findings suggest that health care providers may be able to identify pregnancies at risk of IUGR and can thus prevent and manage IUGR births.

Intermediate variables as determinants of adverse pregnancy outcome in high-risk inner-city populations.

A probability sample survey of high-risk inner-city women with a live birth in the last 3 years shows that maternal medical risks and health behaviors during pregnancy are important intermediate variables influencing preterm delivery and birthweight. Women who developed two or more medical risks had about three-and-a-half times the risk of preterm delivery and two-and-a-half times the risk of low birthweight compared to those without such risks. Women with prior fetal loss had twofold increase in the risk of preterm delivery and low birthweight. Unintended pregnancy resulted in one-and-a-half to twofold increase in preterm delivery and low birthweight, respectively. Inadequate gestational weight increased the risk of preterm delivery by about 50%. Smoking during pregnancy raised the risk of low birthweight slightly more than one-and-a-half times.

PIP: A probability sample survey of 1004 women from Pittsburgh, Pennsylvania, who had a live birth in the preceding three years indicated that the impact of poverty on pregnancy outcome is mediated by maternal medical risk factors and health behaviors during pregnancy. Study subjects were predominantly Black and drawn from inner-city areas with high poverty rates. None of the sociodemographic or economic variables included in the analysis (e.g., maternal age, race, household income, education, and marital status) was a significant predictor of the two adverse pregnancy outcomes considered: deliveries under 37 weeks' gestation and birth weights under 2500 g. Women with two or more medical problems during pregnancy had a 3.5 times greater risk of preterm delivery and twice the risk of low birth weight than those with no such problems. There was a two-fold increase in the risk of both adverse outcomes among the 22% of respondents who had experienced a prior pregnancy loss. Among the 54% of respondents who indicated the most recent pregnancy was unwanted, the risk of these outcomes was increased by 1.5-2.0 times. Maternal weight gain during pregnancy of less than 25 pounds was associated with a two-fold increase in low birth weight, while smoking during pregnancy increased this risk by 1.6 times.

Determinants of low birth weight: a community based prospective cohort study.

The study aimed at identifying and quantifying determinants of low birth weight (LBW) by following a community based prospective cohort of pregnant women in 45 villages in Pune district. In the 1922 live births born to mothers without a chronic illness, in whom birth weight was available within 24 hours, the cumulative incidence of LBW (< 2500 g) was 29%. The unadjusted relative risks for LBW were significantly higher for lower socio-economic status (RR = 1.71), maternal age less than 20 years (RR = 1.27), primiparity (RR = 1.32), last pregnancy interval less than 6 months (RR = 1.48), non-pregnant weight less than 40 kg (RR = 1.3), height below 145 cm (RR = 1.51), hemoglobin less than 9 g/dl (RR = 1.53) and third trimester bleeding (RR = 1.87). Multivariate logistic regression analysis showed that the adjusted odds ratio for LBW decreased with increasing gestational duration, non-pregnant weight, parity and rising education level of the mother. Socio-economic status, non-pregnant weight, maternal height, and severe anemia in pregnancy had substantial attributable risk per cent for LBW (41.4%, 22.9%, 29.5% and 34.5%, respectively). The findings suggest that selectively targetted interventions such as improving maternal education and nutrition, specifically anemia, wider availability of contraception to delay the first pregnancy and to increase pregnancy intervals may help in identifying and ensuring adequate care for those women at greatest risk of LBW.

PIP: In India, medical social workers followed a cohort of 1922 pregnant women in 45 contiguous villages in Pune District at monthly intervals so researchers could identify and quantify risk factors of low birth weight (LBW: 2500 g). 29% of the infants were LBW infants. LBW infants were significantly more likely to be born to mothers of very low socioeconomic status (unadjusted relative risk [RR] = 1.71), aged less than 20 (RR = 1.27), pregnant for the first time (RR = 1.32), whose last pregnancy interval was shorter than 6 months (RR = 1.48), whose nonpregnant weight was less than 40 kg (RR = 1.3), whose height was less than 145 cm (RR = 1.51), whose hemoglobin was less than 9 g/dl (RR = 1.53), who bled during the third trimester (RR = 1.87), and who delivered the infant prematurely (i.e., 32 weeks) (RR = 3.84). Mothers with 8-10 years of formal schooling were less likely to have an LBW infant than illiterate mothers (RR = 0.78). Boys were less likely to be LBW infants than girls (RR = 0.78). The multivariate logistic regression analysis revealed that the adjusted odds ratio for LBW fell as gestational age (0.207), nonpregnant weight (0.711), parity (0.835), and maternal educational status (0.869) increased. The attributable risk percentages for risk factors were 73.9% for premature birth, 46.6% for third trimester bleeding, 41.4% for very low socioeconomic status, 34.5% for hemoglobin less than 9 g/dl, 32.5% for last pregnancy interval shorter than 6 months, 29.5% for height less than 145 cm, 24.4% for primiparity, 22.9% for nonpregnant weight less than 40 kg, 21.3% for adolescent mother, and 21.5% (preventive fraction) for high maternal educational status. These findings suggest that health professionals should target limited resources to improving maternal education and nutrition status (i.e., reducing anemia), to providing wider availability of contraception to delay age at first pregnancy and to increase intervals between births, and to making sure that mothers at greatest risk of delivering a LBW infant receive appropriate care.

Low birth weight incidence in Lundu, Sarawak.

The overall mean birth weight of the total deliveries (1986-1988) in Lundu Hospital was 2.96 kg. The mean birth weight for the male babies was 2.94 kg. The Chinese babies had a significantly higher mean birth weight (3.12 kg) than the other ethnic groups (p < 0.05). The overall incidence of low birth weight (LBW) in this study was 11.84 per cent. The Chinese again had a lower incidence of LBW of 6.73 per cent compared to Ibans who had the highest incidence of LBW, 13.59 per cent, with the Bidayuhs 12.97 per cent and Malays, 12.45 per cent. It was also noticed that of the 14.9 per cent preterm deliveries, 37.5 per cent were LBW. The very young mothers (15-19 years) and older mothers (> 40 years) seem to have a higher incidence of LBW. Mothers who had medical conditions like anaemia, hypertension, pre-eclampsia also had a higher incidence of LBW when compared to mothers who did not have a medical condition. Special emphasis should be given to mothers who have medical conditions, and to very young and very old mothers during antenatal care, to prevent incidence of LBW.

PIP: An analysis of all deliveries in Lundu Hospital during 1986-1988 (1088) in western Sarawak, Malaysia, was conducted to examine and compare the incidence of low birth weight (LBW) of the various ethnic groups. Hospital deliveries comprised 58.1% of all deliveries in Lundu district. 40.9%, 33.1%, 16.4%, and 9.5% of deliveries were Bidayuhs, Malays, Chinese, and Ibans, respectively. 11.8% of all hospital deliveries were LBW infants. Only 1.64% of infants weighed less than 2 kg. The incidence of LBW for the Ibans and Bidayuhs was significantly higher than that of the Chinese (13.6%, 12.9%, and 6.7%, respectively; p 0.05). The Chinese had the highest mean birth weight, while the Ibans had the lowest mean birth weight (3.13 vs. 2.89 kg; p 0.05). The overall mean birth weight was 2.96 kg. The incidence of LBW was highest among 15-19 year old mothers (17.5%) and mothers 40 years old and older (15.2-50%). This pattern was the same for all ethnic groups, except for the Ibans. The highest incidence of LBW among Ibans occurred in 25-29 year olds (14.8% vs. 2.5-14.2%). 14.9% of all deliveries were premature deliveries. Premature infants were more likely to have a LBW than term infants (37.5% vs. 8.7%; p 0.05). The 58 mothers who had medical conditions during pregnancy (i.e., preeclampsia, anemia, hypertension, and prepartum hemorrhage) were more likely to have a LBW infant than those who had no such conditions (44.8% vs. 10%; p 0.05). These findings show that prenatal care services should be emphasized among the very young and older mothers who have a medical condition, particularly if they are Iban or Bidayuh. Increased emphasis on these high-risk groups coupled with health education will lower the incidence of LBW in Lundu.

Maternal influences on low birth weight.

PIP: To identify the maternal risk factors associated with low birth weight in Malaysia, the records of the 2613 infants delivered at North Okkalapa General Hospital from January to September 1990 were reviewed. The incidence of low birth weight during the 9-month study period was 21.1%; 18.1% of these cases were attributable to intrauterine growth retardation and 3% were associated with preterm births. Univariate analysis identified the following risk factors as significant: age under 20 years (.001), parity 1 (.001), maternal height of 145 cm or under (.01), maternal cigarette smoking (.01), maternal education of 8 years or less (.001), parity 5 or above (.05), and maternal age of 35 years and above (.05). A last birth interval of 1 year or less and more than 3 years was associated with an odds ratio exceeding 1, but the correlation with low birth weight was not significant. These risk factors should be used to design maternal health programs aimed at reducing the incidence of low birth weight.^ieng

Past obstetric history of the mother and its association with low birthweight of a subsequent child: a population based study.

A total population sample of 7286 multigravidae from the Greek National Perinatal Survey (April 1983) was used to determine the association between maternal obstetric history and low birthweight of the subsequent singleton delivery. Significant associations were found with previous early and late fetal losses (miscarriages, induced abortions, stillbirths) and history of haemorrhage during a prior pregnancy. It was found that mothers who had experienced miscarriage(s), induced abortion(s) or stillbirth(s) had relative risks (RRs) of 1.65, 1.81 and 3.59 respectively compared with mothers without any fetal loss. The risk increased substantially with the increasing number of losses and reached 8.83 for the small group of mothers who had experienced all three kinds of fetal loss. For mothers with a history of bleeding in a previous pregnancy the risk was double that of mothers without such a history. The results above were changed only slightly when the significant socio-economic characteristics of the family were taken into account.

Birth weight: a community perspective.

PIP: A social revolution may be required in India before the levels of low birth weight (LBW) infants can be reduced. India currently has one of the highest 5 years mortality rates, above 140, which is comprised of a high infant mortality rate that is affected by the high incidence of LBW. About 30% of all births in India are LBW. The task of increasing child survival is made difficult when 80% of infants are not even weighted at birth. Even in educated families, the concept of birth weight as an important measure of health is missing. Health personnel in the field must be surrogate measures, such as specially marked tapes for determining mid arm or thigh circumference, which are correlated with birth weight. Intervention after the fact may never be effective when risk factors are maternal age 20 years or 40 years, high parity or primiparity, and short height. Prevention would be a better strategy for reducing LBW, through increasing the age at conception, increasing the birth interval to 24 months, and improving maternal nutrition, particularly addressing anemia. Nutritional improvement must begin before pregnancy, when fetal demands on maternal resources are greatest. A healthy and well nourished girl is at lower risk of negative birth outcomes. The question always remains in the background about the relationship between LBW and socioeconomic status. In Japan, the gross national product (GNP) per capita is $23,810, and incidence of LBW is only 5%, while the India the GNP/capita is $340. If socioeconomic status were the only significant factor, then there could be no explanation for why Jamaica, with a GNP/capita of $1260, has only 8% LBW. There are many social changes required in India in order to increase child survival and reduce LBW.^ieng

A study of the consequences of malarial infection in pregnant women and their infants.

An outline is given of a field research study to be undertaken in Malawi to investigate the pattern and consequences of malaria in pregnancy and infants. The central question to be investigated is whether babies born to anaemic mothers in malarious areas are at increased risk of developing anaemia or altered risk for morbidity from malaria or develop anaemia in the first year of life. The framework for the case control and cohort study to be undertaken is outlined.

PIP: Outlined is the protocol for field research in Malawi aimed at ascertaining whether infants born to anemic mothers in areas where malaria is prevalent are at increased risk of morbidity. Specifically, the research seeks to: 1) quantify the prevalence and pattern of anemia in infants living in areas where malaria is endemic; 2) investigate whether birth hemoglobin is associated with clinical risk in infancy; 3) measure the associations between fetal anemia, maternal iron status, and malaria in pregnancy; and 4) quantify the contribution of maternal anemia and iron status to fetal growth retardation. Anemia incidence and malaria prevalence will be assessed through a larger cohort study of infants enrolled at birth and followed for up to 18 months. Also planned is a case-control study that will compare infants born with and without fetal anemia. Odds ratios for maternal anemia, iron deficiency, and parasitemia will be computed for cases and controls to determine the relative contribution of each to fetal hemoglobin status. Finally, the risk of maternal parasitemia, iron deficiency, and anemia will be measured in low-birth-weight, growth-retarded infants and those with normal birth weights. The findings will be used to develop a strategy for anemia control among high risk mothers and infants. This is of particular concern in developing countries, where blood transfusions for anemia can lead to human immunodeficiency virus infection.