Obstetric and perinatal outcome of pregnancies following intracytoplasmic sperm mjection

The aim of this study was to describe the obstetric and perinataloutcome for births following intracytoplasmic sperm injection(ICSI). Of 210 infants born, 140 were singletons and 70 weretwins. There were no triplets or higher births. The multiplebirth frequency was 20%. Overall, 17% of deliveries were preterm,although for singleton pregnancies the incidence was reducedto 9%. The median birth weight of all live born infants was3168 g and of singletons 3470 g. Of all infants, 17% had a lowbirth weight (<2500 g) and 2% had a very low birth weight(<1500 g). Two major malformations occurred in two singletonchildren and four minor malformations occurred in four children.This was within the range of expected values in Sweden. Karyotypingwas performed in 58 pregnancies. All of them were normal. Theperinatal mortality was 0.5%. In conclusion, in this observationalstudy from Sweden of the first infants born after ICSI in ourprogramme, the incidence of multiple births, preterm births,low birth weight babies and congenital malformations was lowcompared with other series of in-vitro fertilization pregnanciesnot associated with ICSI.     

Neonatal sepsis in the neonatal intensive care unit: characteristics of early versus late onset.

Neonatal sepsis is a major cause of death in newborns despite sophisticated neonatal intensive care. This retrospective study reviewed the clinical characteristics of cases of culture-proven sepsis in a neonatal intensive care unit from January 1992 to December 2001. Patients were divided into those with onset of sepsis in the first 7 days of life (early-onset group) and those with onset after the seventh day of life (late-onset group). A total of 270 cases with 325 episodes of sepsis and 353 isolated pathogens were identified and included in the study. The male-to-female ratio was 1.4. The majority of cases of sepsis occurred in low birth weight (75.9%) and premature babies (76.7%). Late onset occurred in 71.9% of cases. Patients with late onset had a lower mortality rate than those with early onset (11.3% vs 28.9%). Coagulase-negative staphylococci (20.1%) was the most common organism isolated, but infection with Pseudomonas aeruginosa was associated with the highest morality rate (55.0%). Late-onset sepsis was significantly more common in very low birth weight and premature infants. The most frequently encountered pathogens in the early-onset group were group B streptococci (GBS) and Escherichia coli, while in the late-onset group, the organisms were coagulase-negative staphylococci and Enterobacteriaceae, including E. coli, Klebsiella pneumoniae, and Acinetobacter baumannii. GBS infection resulted in the highest mortality when the onset of sepsis was within the first 24 hours of life.     

Population-based study on association between birth weight and risk of asthma: A propensity score approach

BackgroundPrevious studies that assessed the role of birth weight in the risk of asthma have been limited because of selection bias and covariate imbalance.ObjectiveTo assess the association between birth weight and risk of asthma by applying a propensity score approach.MethodsThe study was designed as a retrospective cohort study based on a birth cohort of children born between January 1, 1976, and December 31, 1979, in Rochester, Minnesota. The propensity scores for birth weight were formulated using 16 covariates. We matched the propensity scores for children having low birth weight (<2,500 g) within a caliper of 0.2 SD of logit function of propensity scores. We calculated the cumulative incidence of asthma between low and normal birth weight groups using the Kaplan-Meier curve.ResultsThere were 3933 eligible children born between January 1, 1976, and December 31, 1979. Before matching, 13 of the 193 children (6.7%) born weighing 2,500 g developed asthma, whereas 201 of the 3,740 children (5.4%) born weighing 2,500 g and above developed asthma (P=.42). There were significant covariate imbalances between comparison groups. However, after propensity score matching, covariate imbalance was significantly reduced, and children born weighing less than 2,500 g had a similar risk to matched children born with normal birth weight (8.3% vs 7.3%, P=.75).ConclusionBirth weight is not associated with risk of asthma during the first 6 years of life. The propensity score may be a useful method for observational studies concerning asthma epidemiology.     

新生儿破伤风并发症对预后影响的危险因素分析

目的探讨各种危险因素对新生儿破伤风预后的影响。方法对1998年6月至2006年3月收治的新生儿破伤风104例进行回顾性分析。结果治愈68例（65.4%）,死亡36例（34.6%）。单因素分析结果显示,死亡组发病时间〈7d、窒息、吸入性肺炎、呼吸衰竭、心力衰竭、败血症、脑水肿、硬肿症、酸碱失衡、低体重儿和弥散性血管内凝血的比例明显增多,差异具有统计学意义（P〈0.05）。多因素Logistic回归分析表明,发病时间〈7d、窒息、吸入性肺炎、呼吸衰竭、败血症和低体重儿是影响新生儿破伤风预后的危险因素。结论发病时间〈7d、窒息、吸入性肺炎、呼吸衰竭、败血症和低体重儿是影响新生儿破伤风预后的危险因素,积极防治新生儿破伤风并发症各种危险因素可改善新生儿破伤风的预后,提高抢救治疗成功率。     

Group B streptococcal bacteremia in non-pregnant adults.

BACKGROUND AND PURPOSE: An increasing incidence of group B streptococcus (GBS) infection in non-pregnant adults has been noted in recent years. To understand the incidence, clinical characteristics, and outcome of GBS bacteremia in non-pregnant adults, we conducted a retrospective study at a tertiary teaching hospital in Taiwan. METHODS: This retrospective analysis included 94 non-pregnant adults (age >/=18 years) with GBS bacteremia hospitalized between January 2001 and December 2003. RESULTS: The incidence of GBS bacteremia increased from 0.16 cases/1000 admissions in 2001 to 0.30 cases/1000 admissions in 2003 (p=0.017, chi-squared test for trend). The mean age of patients was 64.7 +/- 1.39 years. At least 1 underlying systemic disease was found in 81% of patients, with the most frequent being malignancy (43.6%), diabetes mellitus (42.6%), and liver cirrhosis (16%). The 2 major clinical syndromes were primary bacteremia (34%) and soft tissue infection (31.9%). The overall mortality rate was 20.2%. Staphylococcus aureus and Klebsiella pneumoniae were the 2 most common concurrently isolated bloodstream pathogens. Polymicrobial bacteremia, thrombocytopenia, and shock were independent risk factors for mortality in GBS bacteremia. CONCLUSIONS: The increasing incidence of GBS bacteremia is noteworthy, especially among patients with invasive infections. These infections are also responsible for substantial mortality in elderly patients with underlying diseases. Susceptibility testing indicated that penicillin G remains the drug of choice for GBS bacteremia.     

Impact of maternal age and maternal somatic characteristics on newborn size

Pregnancies during early adolescence were commonly thought to represent special risks, such as preterm delivery or low‐weight newborns, resulting in increased mortality and morbidity of mother and child. An important biopsychosocial interaction can be assumed. In the present study the impact of maternal age and maternal somatic characteristics such as prepregnancy weight, stature, or pregnancy weight gain on newborn somatometric features (birth weight, birth length, head circumference, and arcomial circumference) using a dataset of 8,011 single term births were analyzed. The offspring of 215 extremely young mothers ages 12–16 years were significantly (P < 0.0001) lighter and smaller in all body dimensions than the offspring of older adolescent mothers, ages 17–19 years, and the offspring of adult gravida, ages 20–29 years, although no increased incidence of low‐weight newborns (<2,500g) could be observed. As expected, the youngest mothers were also significantly smaller and lighter than their older, biologically more mature counterparts, although the relative weight gain during pregnancy was highest in the youngest age group (23.4% vs. 22.9 and 22.1%, respectively). In general, age but also pregnancy weight gain and prepregnancy weight status were significantly associated with pregnancy outcome. Within term births taking place under sufficient psychosocial support, maternal somatic features had an important impact on newborn size. Am. J. Hum. Biol. 15:220–228, 2003. ©2003 Wiley‐Liss, Inc.     

Increased frequency of high serum IgM among mothers of infants with neonatal group-B streptococcal septicemia

Total serum IgM levels were studied in 84 mothers of infants with group-B streptococcal (GBS) septicemia/meningitis and compared to IgM concentrations in 91 parturients who were urogenital carriers of GBS but nevertheless gave birth to healthy infants. In all, 22 (27%) in the study group showed IgM levels above the arbitrarily selected limit of 2.40 g/l, in contrast to 12 (13%) of 91 controls (p = 0.02). Among the study group members whose infants were infected with GBS type III, 8 of 34 (24%) were high in serum IgM, compared to only 2 of 34 (6%) of the corresponding controls (p = 0.04). The total serum IgG levels did not differ between the two groups.     

A randomized, controlled trial of very early prophylactic ligation of the ductus arteriosus in babies who weighed 1000 g or less at birth

We speculated that prophylactic ligation of the ductus arteriosus would reduce mortality and morbidity in very-low-birth-weight infants. To test this hypothesis, we randomly assigned 84 babies who weighed 1000 g or less at birth and required supplemental oxygen either to receive standard treatment (n = 44) or to undergo prophylactic surgical ligation of the ductus arteriosus on the day of birth (n = 40). The ductus was ligated in babies in the control group only if the shunt was hemodynamically important. All the babies were followed for one year. The incidence of necrotizing enterocolitis was reduced in the group that underwent prophylactic ligation (3 of 40 [8 percent]) as compared with the control group (13 of 44 [30 percent]; P = 0.002). The frequency of death, bronchopulmonary dysplasia, retinopathy of prematurity, and intraventricular hemorrhage was similar in both groups. Because early enteral feeding may have increased the incidence of necrotizing enterocolitis, we analyzed separately the babies who were fed early. Among the infants who were fed within 14 days of birth, those who underwent prophylactic ligation had a lower incidence of necrotizing enterocolitis (1 of 11 [9 percent]) than those who did not (13 of 24 [54 percent]; P = 0.001). Within the control group, the infants who were fed within 14 days of birth and whose ductus was ligated for medical reasons within 5 days of birth had a lower incidence of necrotizing enterocolitis (2 of 10 [20 percent]) than those whose ductus was ligated later or not at all (11 of 14 [79 percent]; P = 0.004). We conclude that early surgical closure of the ductus arteriosus reduces the risk of necrotizing enterocolitis in infants of very low birth weight who require supplemental oxygen.     

Risk factors for nosocomial infection in the neonatal intensive care unit by the Japanese Nosocomial Infection Surveillance (JANIS)

We evaluated the infection risks in the neonatal intensive care unit (NICU) using data of NICU infection surveillance data. The subjects were 871 NICU babies, consisting of 465 boys and 406 girls, who were cared for between June 2002 and January 2003 in 7 medical institutions that employed NICU infection surveillance. Infections were defined according to the National Nosocomial Infection Surveillance (NNIS) System. Of the 58 babies with nosocomial infections, 15 had methicillin-resistant Staphylococcus aureus (MRSA) infection. Multiple logistic regression analysis demonstrated that the odds ratio for nosocomial infections was significantly related to gender, birth weight and the insertion of a central venous catheter (CVC). When the birth weight group of more than 1, 500 g was regarded as the reference, the odds ratio was 2.35 in the birth weight group of 1,000-1,499 g and 8.82 in the birth weight group of less than 1,000g. The odds ratio of the CVC (+) for nosocomial infection was 2.27. However, other devices including artificial ventilation, umbilical artery catheter, umbilical venous catheter, and urinary catheter were not significant risk factors. The incidence of MRSA infection rapidly increased from 0.3% in the birth weight group of more than 1,500 g to 2.1% in the birth weight group of 1,000-1,499 g, and to 11.1% in the birth weight group of less than 1,000g. When the birth weight group of more than 1,500 g was regarded as the reference, multiple logistic regression analysis demonstrated that the odds ratio was 7.25 in the birth weight group of 1,000-1,499 g and 42.88 in the birth weight group of less than 1,000g. These odds ratios were significantly higher than that in the reference group. However, the application of devices did not cause any significant differences in the odds ratio for MRSA infection.     

A population-based study of birth defects in Malaysia

Birth defects are one of the leading causes of paediatric disability and mortality in developed and developing countries. Data on birth defects from population-based studies originating from developing countries are lacking. One of the objectives of this study was to determine the epidemiology of major birth defects in births during the perinatal period in Kinta district, Perak, Malaysia over a 14-month period, using a population-based birth defect register. There were 253 babies with major birth defects in 17,720 births, giving an incidence of 14.3/1000 births, a birth prevalence of 1 in 70. There were 80 babies with multiple birth defects and 173 with isolated birth defects. The exact syndromic diagnosis of the babies with multiple birth defects could not be identified in 18 (22.5%) babies. The main organ systems involved in the isolated birth defects were cardiovascular (13.8%), cleft lip and palate (11.9%), clubfeet (9.1%), central nervous system (CNS) (including neural tube defects) (7.9%), musculoskeletal (5.5%) and gastrointestinal systems (4.7%), and hydrops fetalis (4.3%). The babies with major birth defects were associated with lower birth weights, premature deliveries, higher Caesarean section rates, prolonged hospitalization and increased specialist care. Among the cohort of babies with major birth defects, the mortality rate was 25.2% during the perinatal period. Mothers with affected babies were associated with advanced maternal age, birth defects themselves or their relatives but not in their other offspring, and significantly higher rates of previous abortions. The consanguinity rate of 2.4% was twice that of the control population. It is concluded that a birth defects register is needed to monitor these developments and future interventional trials are needed to reduce birth defects in Malaysia.     

A population-based study of birth defects in Malaysia

Birth defects are one of the leading causes of paediatric disability and mortality in developed and developing countries. Data on birth defects from population-based studies originating from developing countries are lacking. One of the objectives of this study was to determine the epidemiology of major birth defects in births during the perinatal period in Kinta district, Perak, Malaysia over a 14-month period, using a population-based birth defect register. There were 253 babies with major birth defects in 17?720 births, giving an incidence of 14.3/1000 births, a birth prevalence of 1 in 70. There were 80 babies with multiple birth defects and 173 with isolated birth defects. The exact syndromic diagnosis of the babies with multiple birth defects could not be identified in 18 (22.5%) babies. The main organ systems involved in the isolated birth defects were cardiovascular (13.8%), cleft lip and palate (11.9%), clubfeet (9.1%), central nervous system (CNS) (including neural tube defects) (7.9%), musculoskeletal (5.5%) and gastrointestinal systems (4.7%), and hydrops fetalis (4.3%). The babies with major birth defects were associated with lower birth weights, premature deliveries, higher Caesarean section rates, prolonged hospitalization and increased specialist care. Among the cohort of babies with major birth defects, the mortality rate was 25.2% during the perinatal period. Mothers with affected babies were associated with advanced maternal age, birth defects themselves or their relatives but not in their other offspring, and significantly higher rates of previous abortions. The consanguinity rate of 2.4% was twice that of the control population. It is concluded that a birth defects register is needed to monitor these developments and future interventional trials are needed to reduce birth defects in Malaysia.     

Neonatal and maternal anthropometric characteristics in a high altitude population of the western Himalaya

A study of neonatal anthropometric characteristics was undertaken in Ladakh, India, a region comprising the western portion of the trans-Himalayan plateau. The object was to better understand the dynamics of high altitude adaptation in the Himalaya. In a largely native sample of 168 women and their newborns, mean birth weight was 2,764 g, mean length was 48.02 cm, and mean Ponderal Index (PI) was 2.49. Female newborns were significantly lighter and shorter than males. Overall, 27% of newborns fell into the standard category of infants at increased risk of mortality ( < 2,500 g); 37% of females and 17% of males were so classified. In multivariate regression analysis, maternal weight and the sex and gestational age of the newborn were the only significant predictors of birth weight, but explained a small (18%) part of the variance. Compared to Andean and Tibetan samples, Ladakhi newborns were between 300 and 550 g lighter. This variation is explained, in part, by maternal characteristics, such as lower average parity, age, and weight. Reproductive capacity appears to be compromised in this population because of inadequate nutrition in the face of high energy demands of agricultural work, which may further compromise maternal adaptation to hypoxic conditions. The population of Ladakh has a relatively recent ancestry in this high altitude region and is likely a genetically heterogeneous population from an extensive history of immigration. Thus it is possible that the low average birth weight in Ladakh may also be influenced by inadequate genetic adaptation to hypoxia. © 1994 Wiley-Liss, Inc.     

Ochrobactrum anthropi: An unusual pathogen: Are we missing them?

With increasing incidence of immunocompromised patients, many unusual organisms are emerging as pathogens in these patients. Ochrobactrum anthropi is an emerging opportunistic pathogen in immunocompromised patients. Here, we report two cases of neonates who presented with septicemia due to O. anthropi. Both were preterm and low birth weight babies admitted in the Neonatal Intensive Care Unit of our Hospital. One baby manifested with respiratory distress and eventually died. The second baby responded well to treatment and was discharged. The clinical presentation of infections along with microbiological characteristics and clinical significance of the organism are described.     

Narcotic addiction: the expectant mother and her baby

In a retrospective study of the period 1982-1985, the records of 29 narcotic-addicted mothers and their 42 babies were reviewed. All mothers were from socially deprived backgrounds, had a poor record of ante-natal attendance and had frequent admissions to hospital. Thirteen mothers had a past history of hepatitis B and four were HBsAg positive. The babies had significantly lower mean gestational age and mean birth weight than the control group. Features of withdrawal were recorded in 84% of babies where a history was available. A high incidence of twins (10.5%) was also observed. Testing for HIV antibody in more recent cases has revealed positive results in seven mothers and three babies; one infant has since died from acquired immune deficiency syndrome.     

Neonatal septicemia in Stockholm

In a prospective study to determine the incidence and etiology of neonatal septicemia at Karolinska Hospital, Stockholm, all cases of neonatal septicemia in infants born at the hospital from 1981 to 1985 were reviewed. There were 4.0 cases of neonatal septicemia per 1000 live births during the study period. During the five year period the incidence of septicemia tended to increase, mainly due to the increasing incidence of septicemia in infants with a birth weight below 1500 grams. The single most common causative organism was group B streptococci with an incidence of 1.4 per 1000 live births,Staphylococcus aureus accounting for 1.1 cases,Staphylococcus epidermidis for 0.7 cases, and gram-negative rods for only 0.4 cases per 1000 live births. In a retrospective study of the incidence of neonatal septicemia in a non-selected patient population, all cases in the Stockholm area in 1983 were reviewed. In that year there were 17,586 live births in the area and the incidence of neonatal septicemia was 2.6 per 1000 live births. Group B streptococci,Staphylococcus aureus, Staphylococcus epidermidis and gram-negative rods were equally common as causative agents.     

Tibetan protection from intrauterine growth restriction (IUGR) and reproductive loss at high altitude

Chronic hypoxia at high altitude restricts fetal growth, reducing birth weight and increasing infant mortality. We asked whether Tibetans, a long‐resident high‐altitude population, exhibit less altitude‐associated intrauterine growth restriction (IUGR) and prenatal or postnatal reproductive loss than Han (ethnic Chinese), a group that has lived there for a shorter period of time. A population sample was obtained, comprising 485 deliveries to Tibetan or Han women over an 18‐month period at 8 general hospitals or clinics located at 2,700–4,700 m in the Tibet Autonomous Region, China. Birth weight, gestational age, and other information were recorded for each delivery. Prenatal and postnatal mortality were calculated using information obtained from all pregnancies or babies born to study participants. Tibetan babies weighed more than the Han, averaging 310 g heavier at altitudes 2,700–3,000 m (95% CI = 126, 494 g; P < 0.01) and 530 g heavier at 3,000–3,800 m (210, 750 g; P < 0.01). More Han than Tibetan babies were born prematurely. Prenatal and postnatal mortality rose with increasing elevation and were 3‐fold higher across all altitudes in the Han than the Tibetans (P < 0.05). Tibetans experience less altitude‐associated IUGR than Han and have lower levels of prenatal and postnatal mortality. When the relationships between birth weight and altitude are compared among these and other high‐altitude populations, those living at high altitude the longest have the least altitude‐associated IUGR. This may suggest the occurrence of an evolutionary adaptation. Am. J. Hum. Biol. 13:635–644, 2001. © 2001 Wiley‐Liss, Inc.     

Late Neuropsychological Outcomes in Preterm Infants of Normal IQ: Selective Vulnerability of the Visual System

Evaluated neuropsychological outcomes in 635 children, ages7 to 10 years, in relation to birth weight group: 1,000 g;1,001–1,500 g; 1,501–2,500 g, and > 2,500 g.The prevalence of low IQ (<85) was related to birth weight.Among children with IQ > 84 (N = 475): (a) Birth weight wasunrelated to Verbal IQ, Performance IQ, Full-scale IQ, or readingachievement; (b) extremely low birth weight (ELBW) childrenachieved more poorly in mathematics than did other birth weightgroups (p < .05); (c) ELBW and very low birth weight childrenperformed more poorly on the Rey-Osterrieth Complex Figure,a complex visual processing task, than did heavier birth weightchildren (p < .05), but performance on the Beery Test ofVisuomotor Integration was not related to birth weight. Resultsare consistent with heightened neurobehavioral vulnerabilityof visual processing to preterm birth.     

Down syndrome birth weight in England and Wales: Implications for clinical practice

The aim of this study was to determine if syndrome‐specific birth weight charts were beneficial for babies with Down syndrome in England and Wales. Birth weights of 8,825 babies with Down syndrome born in England and Wales in 1989–2010 were obtained from the National Down Syndrome Cytogenetic Register. Birth weight centiles for 30–42 weeks gestation by sex were fitted using the LMS method and were compared to those for unaffected babies from the UK‐WHO growth charts. For babies born with Down syndrome the median birth weight from 37 to 42 weeks was 2,970 g (10th–90th centile: 2,115–3,680) for boys and 2930 g (2,100–3,629) for girls, and the modal age of gestation was 38 weeks, 2 weeks earlier than for unaffected babies. At 38 weeks gestation they were only slightly lighter than unaffected babies (159 g for boys and 86 g for girls). However at 40 weeks gestation the shortfall was much greater (304 g and 239 g, respectively). In neonates with Down syndrome there is little evidence of growth restriction before 38 weeks gestation, so up to this age it is appropriate to use the UK‐WHO birth weight charts. Thereafter birth weight is below that of unaffected babies and it should be plotted on the UK Down syndrome growth charts. © 2015 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.     

Perinatal outcome and congenital malformations in in-vitro fertilization babies from the Bourn-Hallam group.

The perinatal outcome and congenital malformations in children born between 1978 and 1987 in Great Britain after in-vitro fertilization (IVF) at Bourn Hall Clinic and the Hallam Medical Centre are presented. The average maternal age was 34.2 years. Multiple births were frequent, constituting 23% of all deliveries; 19% were twins and 4% triplets. There were no quadruplet or higher order multiple births during that period. Twenty-five per cent of all deliveries were preterm. The mean birth weight was 2793 g and was strongly related to multiplicity of pregnancy and gestational age. Overall, 32% of babies had a low birthweight (less than 2500 g) with 6% having a very low birthweight (less than 1500 g). The overall stillbirth and infant mortality rates were two to three times higher than those of infants born after natural conception in England and Wales; this is attributed to the high incidence of multiple births. The stillbirth rates were 5.07, 20.8 and 24.7 per thousand total births in singletons, twins and triplets respectively. The corresponding figures for perinatal mortality were 13.5, 38.2 and 37 per thousand. Overall, 2.5% of the babies had one or more major congenital malformations diagnosed within one week of life. This was within the range of expected values in the United Kingdom and there was no significant increase in any specific malformation.     

Group B streptococcus colonization of Greek pregnant women and neonates: prevalence, risk factors and serotypes

Objective  To evaluate the prevalence and risk factors of group B streptococcus (GBS) colonization among pregnant women and their neonates in Greece, and to examine the serotype distribution of the GBS strains isolated and their susceptibility to antibiotics.
Methods  A vaginal and a rectal swab were obtained from 1014 pregnant or parturient women followed at public and private hospitals in Athens and in a city of northern Greece. Cultures were also taken 24 h after birth from 428 neonates born to these women.
Results  The overall maternal and neonatal colonization rates were 6.6% and 2.4%, respectively. The vertical transmission rate was 22.5%. By logistic regression analysis, multiparity (≥III) was associated with a lower colonization rate (odds ratio 4.4, 95% confidence interval 1.08–18.63). In contrast with other studies, middle-class women followed privately were more frequently colonized (10%) than those followed at the public hospital (3.9%) (odds ratio 3.1, 95% confidence interval 1.83–5.42). A higher number of prenatal visits was also associated with a higher colonization rate (change in true odds ratio when visits increased by one, 1.3; 95% confidence interval 1.14–1.60). No association was found between colonization and maternal age, previous obstetric history, marital status, nationality, prematurity, Caesarean section, or infant birth weight. The most common serotypes were II (26.9%), III (22.4%), Ia (19%), Ib (12%), and V (9%). A considerable proportion of the isolated strains was resistant to erythromycin (4.5%), clindamycin (6%), or both (6%).
Conclusion  The rate and risk factors of maternal and neonatal GBS colonization may vary in different communities. These rates, as well as the incidence of neonatal disease, need to be thoroughly evaluated in each country to allow the most appropriate preventive strategy to be selected.