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PubMed1991

Biphasic reduction and concanavalin A binding properties of serum alpha-fetoprotein in preterm and term infants.

Reference values for postnatal serum alpha-fetoprotein (AFP) and concanavalin A (ConA) binding subfractions of AFP in preterm and term infants are presented. Preterm infants had 10-fold higher serum concentrations of AFP than did term infants at birth. The reduction of serum values of AFP was biphasic in both groups and differed significantly between the two groups. The first declining phase continued for approximately 4 months in preterm and for 2 months in term infants, and was related to the degree of prematurity. The AFP values reached adult levels by 12 months in preterm and by 9 months in term infants. The developmental pattern of the carbohydrate moiety of AFP was determined by ConA fractioning. The proportion of the ConA nonreactive subfraction of AFP in preterm and term infants at birth was 6% and 13%, respectively; it increased more rapidly in term than in preterm infants but reached 85% to 95% by the age of 6 months in both infant groups. Our results indicate that the postnatal maturation of AFP synthesis is dependent on gestational age. Malignant recurrences of neonatal sacrococcygeal teratomas were associated with an increase in serum concentration of AFP and a decrease in the proportion of the ConA nonreactive subfraction of AFP.

Concanavalin A↗

PubMed1985

Response of preterm infants to diphtheria-tetanus-pertussis immunizations.

To establish guidelines for the routine use of diphtheria, tetanus, and pertussis (DTP) vaccine in preterm infants, we quantitated antibody responses of preterm infants to DTP and determined the nature and extent of side effects. Twenty-five preterm infants were immunized with 0.5 ml DTP vaccine at routine intervals. Term infants served as controls. Immediately before each immunization and 2 months after the third, DTP-specific antibodies were quantitated. Clinical side effects were determined by parental report. After the second immunization, 100% of preterm infants had evidence of specific antibody production against diphtheria, tetanus, and pertussis. The incidence of side effects was low, but irritability was significantly more common in preterm infants after the second immunization. These observations suggest that the initiation of primary immunization with DTP in preterm infants need not be delayed beyond 2 months of age.

Diphtheria Toxoid↗

PubMed1987

Energetics and mechanics of nutritive sucking in the preterm and term neonate.

Energetics and mechanics of sucking in preterm and term neonates were determined by simultaneous records of intraoral pressure, flow, volume, and work of individual sucks. Nine term infants (mean postconceptional age: 38.6 +/- 0.7 SD weeks; mean postnatal age: 18.4 +/- 6.1 SD days) and nine preterm infants (mean postconceptional age: 35.2 +/- 0.7 SD weeks; mean postnatal age: 21.9 +/- 5.4 SD days) were studied under identical feeding conditions. Preterm infants generated significantly lower peak pressure (mean values of 48.5 cm H2O compared with 65.5 cm H2O in term infants; P less than 0.01), and the volume ingested per such was generally less than or equal to 0.5 mL. Term infants demonstrated a higher frequency of sucking, a well-defined suck-pause pattern, and a higher minute consumption of formula. Energy and caloric expenditure estimations revealed significantly lower work performed by preterm infants for isovolumic feeds (1190 g/cm/dL in preterm infants compared with 2030 g.cm/dL formula ingested in term infants; P less than 0.01). Furthermore, work performed by term infants was disproportionately higher for volumes greater than or equal to 0.5 mL ingested. This study indicates that preterm infants expend less energy than term infants to suck the same volume of feed and also describes an objective technique to evaluate nutritive sucking during growth and development.

Biomechanical Phenomena↗

PubMed1988

The electroretinogram in preterm infants.

With the hope that the electroretinogram (ERG) in preterm infants could help clarify their vitamin A requirements, a technique for recording the full-field ERG in the neonate is described. One hundred seventy-seven ERGs were performed in 59 preterm and 52 term infants. An ERG was recorded as soon as 7 hours after birth and as early as 30 weeks after conception. In preterm infants the a-wave latency was longer and the amplitude less than in term infants of the same age. The amplitude of the ERG in preterm infants increased with the duration of light exposure. Longitudinal data on 15 preterm infants showed a reduction in a-wave latency. None of the ERG findings correlated with postconceptional age, which suggests that the duration of light exposure is a major determinant of the ERG pattern in preterm infants. Despite low circulating levels of retinol, no correlations with any of the ERG values were found.

Electroretinography↗

PubMed1989

Gestational evolution of small intestine motility in preterm and term infants.

Continuous perfusion manometry was performed in 31 preterm and term infants to assess the influence of gestational age on small intestinal motility. Gestational ages ranged from 27 to 42 weeks. All 8 term infants had interdigestive cycles that included all three phases. Only 4 of 23 preterm infants had complete interdigestive cycles. The remaining 19 preterm infants had only periods of motor quiescence and nonpropagating contractions. In term infants the interdigestive cycle was significantly shorter and the amplitude of phase 3 activity was significantly greater (p less than 0.01); velocity and duration of phase 3 activity were similar in both groups of infants. Rhythmic nonpropagating activity, or clusters, made up more than 60% of the phase 2 activity in both term and preterm infants. Although clusters did not propagate across three or more leads, approximately 25% of cluster activity was propagated across two leads. The duration of total cluster activity was similar for all gestational ages, but the frequency of clusters decreased and the mean duration of individual clusters increased with gestational age (both p less than 0.01). The amplitude of individual pressure peaks in clusters and phase 3 increased significantly with gestational age (p less than 0.03 and p less than 0.01, respectively). The motility index also increased with gestational age (p less than 0.02). We conclude that small intestinal motility is more immature in preterm infants than in term infants. Furthermore, cluster activity, which increases in duration and amplitude with gestational age, may be an immature form of phase 3 activity. These data and techniques will provide neonatologists with a direct way of tracking preterm intestinal motor function to provide more appropriate enteral nutrition.

Enteral Nutrition↗

PubMed1995

Plasma mineral concentrations in preterm infants fed a nutrient-enriched formula after hospital discharge.

OBJECTIVE: To determine whether prolonged feeding of preterm infant formula to preterm infants can accelerate recovery to normal plasma zinc levels without affecting plasma mineral homeostasis. DESIGN: Part of concurrent prospective feeding trials in a university hospital-based population. SUBJECTS AND INTERVENTION: Preterm infants (n = 33; birth weight, 1037 +/- 157 gm) were fed a preterm infant formula with higher concentrations of zinc, copper, calcium, magnesium, and potassium until 2 months past expected term, then a term infant formula. Term infants (n = 38; birth weight, 3318 +/- 401 gm) fed this term infant formula from birth were a reference group for comparison with study infants and with published values. Plasma mineral levels were analyzed by inductively coupled plasma atomic emission spectroscopy. RESULTS: Preterm infants fed a preterm infant formula after discharge from the hospital appeared to achieve normal plasma zinc concentrations by at least 2 months past term without adverse effects on mineral homeostasis.

Adolescent↗

PubMed1996

Recurrent respiratory distress syndrome in successive preterm pregnancies.

BACKGROUND: Earlier studies suggesting an increased recurrence risk of respiratory distress syndrome (RDS) among the subsequent infants of women with a previously affected infant were based on low birth weight inclusion criteria that did not differentiate between preterm and growth-retarded infants. METHODS: We therefore carried out two cohort studies of women who delivered two singleton preterm (gestational age < 37 completed weeks) infants: 1978 to 1989 at the Royal Victoria Hospital (RVH) in Montreal and 1959 to 1966 in the United States Collaborative Perinatal Project (CPP). We compared the relative risk (RR) of the development of RDS in the second infant according to the RDS status of the first. The diagnosis of RDS was based on respiratory distress of more than 24 hours' duration and a reticulogranular pattern on a chest radiograph. RESULTS: The RVH study sample comprised 284 infants born to 142 women, and the CPP sample 642 infants born to 321 mothers. In the RVH cohort the crude RR of RDS in the second sibling was 3.3 (95% confidence interval = 1.0 to 15.1) in women whose first preterm infant had RDS versus those whose first preterm infant did not have RDS. In the CPP cohort the corresponding RR was 2.5 (95% confidence interval = 0.8 to 7.9). These elevated risks were not altered substantially when multiple logistic regression was used to control for potentially confounding factors known to influence the risk of RDS (gestational age, sex, route of delivery, antenatal corticosteroids, and respiratory depression of birth). CONCLUSIONS: We conclude that preterm infants born to women with a previous preterm infant affected by RDS are at an increased risk of RDS, which suggests an important genetic (or other familial) tendency in its origin.

Cohort Studies↗

PubMed1997

Apnea after immunization of preterm infants.

OBJECTIVE: To determine the frequency of adverse reactions, particularly the occurrence of apnea, among preterm infants after immunization with diphtheria and tetanus toxoids and whole cell pertussis vaccine adsorbed (DTP) and Haemophilus influenzae type b conjugate (HibC) vaccine in the neonatal intensive care unit. STUDY DESIGN: After the occurrence of apnea in two preterm infants following immunization with DTP and HibC, a prospective surveillance of 97 preterm infants younger than 37 weeks of gestation who were immunized with DTP (94 also received HibC at the same time) in the neonatal intensive care unit was performed to assess the frequency of adverse reactions and in particular, the occurrence of apnea. For each infant, data were recorded for a 3-day period before and after receipt of the immunization. RESULTS: The majority of preterm infants tolerated immunizations with DTP and HibC without ill effects. However, 12 (12%) infants experienced a recurrence of apnea, and 11 (11%) had at least a 50% increase in the number of apneic and bradycardic episodes in the 72 hours after immunization. This occurred primarily among smaller preterm infants who were immunized at a lower weight (p = 0.01), had experienced more severe apnea of prematurity (p = 0.01), and had chronic lung disease (p = 0.03). CONCLUSION: The temporal association observed between immunization of preterm infants and a transient increase or recurrence of apnea after vaccination merits further study. Cardiorespiratory monitoring of these infants after immunization may be advisable.

Apnea↗

PubMed1998

An epidemiologic longitudinal study of sleeping problems and feeding experience of preterm and term children in southern Finland: comparison with a southern German population sample.

OBJECTIVE: To determine the influence of breast-feeding on the prevalence and persistence of sleeping problems in southern Finland (SF) and southern Germany (SG). DESIGN: Prospective binational population study of infants admitted to special care units (SCUs) in geographically defined areas in SF and SG. SUBJECTS: In SF, the number of SCU infants was 1057 (very preterm, 47; preterm, 258; term, 752); 485 term infants were control subjects. In SG, the number of SCU infants was 4427 (very preterm, 284; preterm, 1419; term, 2724). MAIN OUTCOME MEASURE: Parent reports of child sleeping problems at 5, 20, and 56 months of age. RESULTS: Night waking at 5 months of age was less frequent for SCU very preterm (25.5%), preterm (40.6%), and term infants (48%) than for term control subjects (56.7% to 59.9%) in SF. No differences in sleeping behavior according to gestation were found at 20 and 56 months. Sleeping problems were greater in SF infants (25.5% to 48%) than in SG infants (15.1% to 19.1%) at 5 months of age and were explained by a higher rate of breast-feeding in SF. Breast-feeding had no long-term effects on night waking or on co-sleeping in SF. In contrast, breast-fed infants continued to wake more often in SG. CONCLUSIONS: Breast-feeding rather than gestational age is strongly related to night waking. More support for dealing with night waking might prevent early termination of breast-feeding.

Breast Feeding↗

PubMed2000

Prepregnancy body mass index and pregnancy weight gain: associations with preterm delivery. The NMIHS Collaborative Study Group.

OBJECTIVE: To examine associations between rate of pregnancy weight gain and preterm delivery among women of varying prepregnancy body mass indices (BMI). METHODS: Subjects were 3511 mother-infant pairs from the 1988 National Maternal and Infant Health Survey. Prenatal weight measured between 14 and 28 weeks' gestation was used to calculate rate of pregnancy weight gain for each woman. Weight gain (lb/week) was categorized as low (under 0.5), average (0.5-1.5), or high (above 1.5). Prepregnancy BMI was calculated as weight divided by height in (kg/m(2)) and categorized as low (under 19.8), average (19.8-26.0), and high (above 26). Delivery before 37 weeks' gestation was considered preterm. Associations between BMI, weight gain, and preterm delivery were examined before and after exclusion of medically indicated preterm deliveries and pregnancies complicated by maternal medical conditions potentially related to weight gain or fetal growth restriction. Associations were expressed as odds ratios (OR) adjusted for several potential confounding factors. RESULTS: Women with low pregnancy weight gain were at increased risk of preterm delivery. The magnitude of risk varied according to a woman's prepregnancy BMI. After all exclusions and adjustments for confounders, ORs, and 95% confidence intervals (CI) for low pregnancy weight gain were 6.7 (1.1, 40.6) for underweight women, 3.6 (1.6, 8.0) for average-weight women, and 1.6 (0.7, 3.5) for overweight women compared with average-weight women with average pregnancy weight gain. CONCLUSIONS: Low weight gain in pregnancy was associated with increased risk of preterm delivery, particularly if women were underweight or of average weight before pregnancy.

Adolescent↗

PubMed2000

Serial salivary estriol to detect an increased risk of preterm birth.

OBJECTIVE: To evaluate serial measurements of salivary estriol (E3) to detect increased risk of spontaneous preterm labor and preterm birth. METHODS: A masked, prospective, multicenter trial of 956 women with singleton pregnancies was completed at eight United States medical centers. Saliva was collected weekly, beginning at the 22nd week of gestation until birth, and tested for unconjugated E3 by enzyme-linked immunosorbent assay. Women were separated into high-risk and low-risk groups using the Creasy scoring system. RESULTS: A single, positive (at or above 2.1 ng/mL) salivary E3 test predicted an increased risk of spontaneous preterm labor and delivery in the total population (relative risk [RR] 4.0, P <.005), in the low-risk population (RR 4.0, P < or =.05), and in the high-risk population (RR 3.4, P =.05). Two consecutive positive tests significantly increased the RR in all study groups, with a dramatic improvement in test specificity and positive predictive value but only a modest decrease in sensitivity. In women who presented with symptomatic preterm labor, salivary E3 identified 61% of those who delivered within 2 weeks, using a threshold of 1.4 ng/mL. CONCLUSION: Elevated salivary E3 is associated with increased risk of preterm birth in asymptomatic women and symptomatic women who present for evaluation of preterm labor.

Adult↗

PubMed2000

Cervical length at 16-22 weeks' gestation and risk for preterm delivery.

OBJECTIVE: To determine whether cervical length, as measured by transvaginal sonogram in asymptomatic gravidas at 16-22 weeks, is associated with risk of spontaneous preterm delivery. METHODS: In a prospective observational study in an unselected urban tertiary care population, cervical length was measured by transvaginal ultrasound during routine anatomic surveys in 760 gravidas at 16 0/7 to 22 6/7 weeks. The predictor variable was cervical length and the outcome variable was gestational age at delivery. Care providers were not masked to the results. Spontaneous preterm delivery was analyzed as before 37, 35, and 32 weeks. Shortened cervical length was defined by the tenth, fifth, and two and a half percentiles for our population. Yates-corrected chi(2) was used to evaluate the significance on univariate analysis of the relative risk (RR) and 95% confidence intervals (CI). Multiple logistic regression analysis was used to control for background variables in evaluating the probability of preterm delivery at less than 35 weeks. Sensitivity, specificity, positive and negative predictive values also were calculated. RESULTS: Cervical lengths were normally distributed (mean 38.5 +/- 8.0 mm at 19.9 +/- 1.5 weeks) independent of gestational age at measurement, and the tenth, fifth, and two and a half percentiles were 30, 27, and 22 mm, respectively. Eighty-five women delivered before 37 weeks, 51 before 35 weeks, and 27 before 32 weeks. Relative risks (95% CI) for spontaneous preterm delivery before 37 weeks were 3.8 (2.6, 5.6), 5.4 (3.3, 9.0), and 6.3 (3.0, 13.0) for the tenth, fifth, and two and a half percentiles, respectively; RRs for before 35 weeks were 4.5 (2.9, 6.9), 7.5 (4.5, 12.5), and 7.8 (3.6, 16.7); and for before 32 weeks were 5.2 (3.3, 8.3), 9.7 (5.8, 16.1), and 8.4 (3.6, 19.9), respectively. Multiple logistic regression analysis confirmed that cervical length was a significant predictor of preterm birth before 35 weeks, and that paras had a 43% greater risk compared with nulliparas. Sensitivity ranged from 13-44%, specificity 90-99%, positive predictive value 15-47%, and negative predictive value 80-98%. CONCLUSION: Transvaginal measurement of cervical length during routine ultrasound at 16-22 weeks' gestation in asymptomatic gravidas might help identify women at risk for spontaneous preterm delivery.

Adult↗

PubMed2002

Psychiatric and substance use disorders as risk factors for low birth weight and preterm delivery.

OBJECTIVE: We examined the associations between psychiatric and substance use diagnoses and low birth weight (LBW), very low birth weight (VLBW), and preterm delivery among all women delivering in California hospitals during 1995. METHODS: This population-based retrospective cohort analysis used linked hospital discharge and birth certificate data for 521,490 deliveries. Logistic regression analyses were conducted to assess the associations between maternal psychiatric and substance use hospital discharge diagnoses and LBW, VLBW, and preterm delivery while controlling for maternal demographic and medical characteristics. RESULTS: Women with psychiatric diagnoses had a significantly higher risk of LBW (adjusted odds ratio [OR] 2.0; 95% confidence interval [CI] 1.7, 2.3), VLBW (OR 2.9; 95% CI 2.1, 3.9), and preterm delivery (OR 1.6; 95% CI 1.4, 1.9) compared with women without those diagnoses. Substance use diagnoses were also associated with higher risk of LBW (OR 3.7; 95% CI 3.4, 4.0), VLBW (OR 2.8; 95% CI 2.3, 3.3), and preterm delivery (OR 2.4; 95% CI 2.3, 2.6). CONCLUSION: Maternal psychiatric and substance use diagnoses were independently associated with low birth weight and preterm delivery in the population of women delivering in California in 1995. Identifying pregnant women with current psychiatric disorders and increased monitoring for preterm and low birth weight delivery among this population may be indicated.

Adolescent↗

PubMed2003

Randomized clinical trial of metronidazole plus erythromycin to prevent spontaneous preterm delivery in fetal fibronectin-positive women.

OBJECTIVE: To estimate whether antibiotic treatment of asymptomatic women with a positive cervical or vaginal fetal fibronectin test in the second trimester would reduce the risk of spontaneous preterm delivery. METHODS: Women were screened between 21 weeks 0 days and 25 weeks 6 days of gestation with cervical or vaginal swabs for fetal fibronectin. Women with a positive test (50 ng/mL or more) were randomized to receive metronidazole (250 mg orally three times per day) and erythromycin (250 mg orally four times per day) or identical placebo pills for 10 days. The primary outcome was spontaneous delivery before 37 weeks' gestation after preterm labor or premature membrane rupture. RESULTS: A total of 16,317 women were screened for fetal fibronectin, and 6.6% had a positive test; 715 fetal fibronectin test-positive women consented to randomization. Outcome data were available for 703 women: 347 in the antibiotic group and 356 in the placebo group. The antibiotic and placebo groups were not significantly different for maternal age (P =.051), ethnicity (P =.849), marital status (P =.127), education (P =.244), and bacterial vaginosis (P =.236). No difference was observed in spontaneous preterm birth before 37 weeks' (odds ratio [OR] 1.17, 95% confidence interval [CI] 0.80, 1.70), less than 35 weeks' (OR 0.92, 95% CI 0.54, 1.56), or less than 32 weeks' (OR 1.94, 95% CI 0.83, 4.52) gestation in antibiotic- compared with placebo-treated women. Among women with a prior spontaneous preterm delivery, the rate of repeat spontaneous preterm delivery at less than 37 weeks' gestation was significantly higher in the active drug compared with the placebo group (46.7% versus 23.9%, P =.039). CONCLUSION: Treatment with metronidazole plus erythromycin of asymptomatic women with a positive cervical or vaginal fetal fibronectin test in the late second trimester does not decrease the incidence of spontaneous preterm delivery.

Adult↗

PubMed1997

A critical review of the relationship between gestational weight gain and preterm delivery.

OBJECTIVE: To review the relationship between gestational weight gain and preterm delivery. DATA SOURCES: We identified published studies through Medline searches (for the period 1980-1996), and we reviewed bibliographies from published articles. METHODS OF STUDY SELECTION: We excluded non-English-language articles and articles that used total weight gain, unadjusted for gestational age. Thirteen articles were identified for review. TABULATION, INTEGRATION AND RESULTS: Eleven of the 13 studies reported a significant association between maternal weight gain and risk of preterm delivery, and most reported that inadequate rate of maternal weight gain was associated with an increased risk (approximately 50-100%) of preterm delivery. Studies examining pattern of gain noted that a low rate of gain during the latter part of pregnancy (but not early pregnancy) was associated with an increased risk of preterm delivery (also approximately 50-100%). The studies' findings were relatively consistent, despite the use of diverse samples, study designs, and analytic strategies. CONCLUSION: The evidence suggests that a lower rate of weight gain during pregnancy is associated with an increased risk of preterm delivery, and that a slow rate of gain during the latter part of pregnancy may be particularly important. To improve our understanding of the mechanisms of these relationships, future studies should examine pattern of gain; they should stratify analyses on the different subtypes of preterm delivery and provide more detailed descriptions of methods for assessing gestational duration.

Delivery, Obstetric↗

PubMed1998

High third-trimester ferritin concentration: associations with very preterm delivery, infection, and maternal nutritional status.

OBJECTIVE: To determine whether a high concentration of serum ferritin during the third trimester is a marker of subclinical maternal infection and very preterm delivery and is associated with maternal nutritional status. METHODS: A total of 1162 gravidas was followed prospectively from entry to prenatal care (15.0 +/- 4.9 completed weeks' gestation) in Camden, New Jersey, between 1985 and 1995. Multiple logistic regression and analysis of covariance were used to examine the influence of serum ferritin on the outcomes of interest. RESULTS: High concentrations of serum ferritin (at or above the 90th percentile) at week 28, but not at entry to prenatal care, increased risk of preterm and very preterm delivery, but the risk changed if the concentration of ferritin declined from entry. If the concentration declined as expected, high ferritin concentration had no influence on outcome. If the concentration increased, then high ferritin concentration at week 28 was associated with very preterm delivery (adjusted odds ratio [AOR] 8.77; 95% confidence interval [CI] 3.90, 19.72), preterm delivery (AOR 3.81; 95% CI 1.93, 7.52), low birth weight (AOR 5.15; 95% CI 2.47, 10.72), clinical chorioamnionitis (AOR 2.56; 95% CI 1.01, 6.52), and symptoms of "flu" as an index of unmeasured infection (AOR 6.02; 95% CI 1.16, 31.17). Factors associated with failure of the ferritin concentration to decline included iron deficiency anemia earlier in pregnancy (AOR 3.98; 95% CI 1.17, 8.98) and lower levels of serum and red cell folate. CONCLUSION: High serum ferritin concentration in the third trimester, resulting from a failure of ferritin to decline, is associated with very preterm delivery and markers of maternal infection. Iron deficiency anemia and other indicators reflecting poor maternal nutritional status earlier in pregnancy underlie this relationship.

Adolescent↗

PubMedDate not supplied

Preterm labor in the triage setting.

Preterm birth is one of the most devastating problems facing obstetrics today. Despite all of the available sophisticated research and therapeutic technology, the preterm birth rate has remained the same for the last 40 years. One birth in 10 occurs prematurely. Preterm labor manifests itself in a variety of ways. It is essential to promptly differentiate true preterm labor from preterm contractions or other conditions that present with similar symptoms. True preterm labor requires prompt clinical intervention in the obstetric triage setting.

Adolescent↗

PubMed2001

Association between maternal serum concentration of the DDT metabolite DDE and preterm and small-for-gestational-age babies at birth.

BACKGROUND: DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) is highly effective against most malaria-transmitting mosquitoes and is being widely used in malaria-endemic areas. The metabolite, DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene), has been linked to preterm birth in small studies, but these findings are inconclusive. Our aim was to investigate the association between DDE exposure and preterm birth. METHODS: Our study was based on the US Collaborative Perinatal Project (CPP). From this study we selected a subset of more than 44000 eligible children born between 1959 and 1966 and measured the DDE concentration in their mothers' serum samples stored during pregnancy. Complete data were available for 2380 children, of whom 361 were born preterm and 221 were small-for-gestational age. FINDINGS: The median maternal DDE concentration was 25 mg/L (range 3-178)-several fold higher than current US concentrations. The adjusted odds ratios (OR) of preterm birth increased steadily with increasing concentrations of serum DDE (ORs=1, 1.5, 1.6, 2.5, 3.1; trend p<0.0001). Adjusted odds of small-for-gestational-age also increased, but less consistently (ORs=1, 1.9, 1.7, 1.6, 2.6; trend p=0.04). After excluding preterm births, the association of DDE with small-for-gestational-age remained. INTERPRETATION: The findings strongly suggest that DDT use increases preterm births, which is a major contributor to infant mortality. If this association is causal, it should be included in any assessment of the costs and benefits of vector control with DDT.

Adolescent↗