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Biomedical subjects

J Wadsworth

Publications and source records attributed to J Wadsworth.

At least 19 recordsLinked to original sources
PubMed2001

Maternal obesity and pregnancy outcome: a study of 287,213 pregnancies in London.

OBJECTIVE: To examine the maternal and foetal risks of adverse pregnancy outcome in relation to maternal obesity, expressed as body mass index (BMI, kg/m(2)) in a large unselected geographical population. DESIGN: Retrospective analysis of data from a validated maternity database system which includes all but one of the maternity units in the North West Thames Region. A comparison of pregnancy outcomes was made on the basis of maternal BMI at booking. SUBJECTS: A total of 287,213 completed singleton pregnancies were studied including 176,923 (61.6%) normal weight (BMI 20--24.9), 79 014 (27.5%) moderately obese (BMI 25--29.9) and 31,276 (10.9%) very obese (BMI> or =30) women. MEASUREMENTS: Ante-natal complications, intervention in labour, maternal morbidity and neonatal outcome were examined and data presented as raw frequencies and adjusted odds ratios with 99% confidence intervals following logistic regression analysis to account for confounding variables. RESULTS: Compared to women with normal BMI, the following outcomes were significantly more common in obese pregnant women (odds ratio (99% confidence interval) for BMI 25--30 and BMI> or =30 respectively): gestational diabetes mellitus (1.68 (1.53--1.84), 3.6 (3.25--3.98)); proteinuric pre-eclampsia (1.44 (1.28--1.62), 2.14 (1.85--2.47)); induction of labour (2.14 (1.85--2.47), 1.70 (1.64--1.76)); delivery by emergency caesarian section (1.30 (1.25--1.34), 1.83 (1.74--1.93)); postpartum haemorrhage (1.16 (1.12--1.21), 1.39 (1.32--1.46)); genital tract infection (1.24 (1.09--1.41), 1.30 (1.07--1.56)); urinary tract infection (1.17 (1.04-1.33), 1.39 (1.18--1.63)); wound infection (1.27 (1.09--1.48), 2.24 (1.91--2.64)); birthweight above the 90th centile (1.57 (1.50--1.64), 2.36 (2.23--2.50)), and intrauterine death (1.10 (0.94--1.28), 1.40 (1.14--1.71)). However, delivery before 32 weeks' gestation (0.73 (0.65--0.82), 0.81 (0.69--0.95)) and breastfeeding at discharge (0.86 (0.84--0.88), 0.58 (0.56--0.60)) were significantly less likely in the overweight groups. In all cases, increasing maternal BMI was associated with increased magnitude of risk. CONCLUSION: Maternal obesity carries significant risks for the mother and foetus. The risk increases with the degree of obesity and persists after accounting for other confounding demographic factors. The basis of many of the complications is likely to be related to the altered metabolic state associated with morbid obesity.

Adult↗
PubMed2000

Risk factors for community-acquired pneumonia diagnosed by general practitioners in the community.

The purpose of this study was to identify risk factors for pneumonia diagnosed in the community by general practitioners, using a case control study in 29 general practices in Nottingham, U.K. Patients with radiographically confirmed pneumonia were compared with adults randomly selected from electoral registers corresponding to the catchment areas of the general practices taking part in the study. Sixty-six cases and 489 controls participated. Significant risk factors in univariate analysis included age, chronic obstructive pulmonary disease, congestive heart failure and lifetime consumption of cigarettes. Multiple logistic regression analysis of these four variables showed that age [adjusted odds ratio = 2.69 (for 30 year increment), 95%CI = 1.66-4.35] and chronic obstructive pulmonary disease (adjusted odds ratio= 1.99, 95%CI = 1.15-3.45) were independent risk factors. Only age and chronic obstructive pulmonary disease were independent risk factors for pneumonia in this study. Since cigarette smoking is the major cause of chronic obstructive pulmonary disease, these data suggest that cigarette smoking is the main avoidable risk factor for community-acquired pneumonia in adults.

Adolescent↗
PubMed2000

Risk factors for community-acquired pneumonia diagnosed upon hospital admission. British Thoracic Society Pneumonia Study Group.

A case-control study of risk factors for community-acquired pneumonia in adults admitted to hospital is reported. Cases were surviving patients (n = 178) admitted to 14 hospitals in England. Controls were individuals (n = 385) randomly selected from the electoral registers of the areas served by the hospitals. The two groups were compared with regard to risk factors for pneumonia using a standardized postal questionnaire. Independent risk factors associated with cases in log-linear regression analysis were age, heart disease (as indicated by congestive heart failure and/or digitalis treatment), lifetime smoking history, chronic airway disease (chronic bronchitis and/or asthma), occupational dust exposure, pneumonia as a child, single marital status and unemployment. Corticosteroid and bronchodilator therapy were also independent risk factors in the log-linear regression analysis, but may reflect the severity of underlying lung disease for which these drugs were prescribed. These data suggest that cigarette smoking is the major avoidable risk factor for acute pneumonia in adults.

Adolescent↗
PubMed2000

Vocal control of acoustic information for sonar discriminations by the echolocating bat, Eptesicus fuscus.

This study aimed to determine whether bats using frequency modulated (FM) echolocation signals adapt the features of their vocalizations to the perceptual demands of a particular sonar task. Quantitative measures were obtained from the vocal signals produced by echolocating bats (Eptesicus fuscus) that were trained to perform in two distinct perceptual tasks, echo delay and Doppler-shift discriminations. In both perceptual tasks, the bats learned to discriminate electronically manipulated playback signals of their own echolocation sounds, which simulated echoes from sonar targets. Both tasks utilized a single-channel electronic target simulator and tested the bat's in a two-alternative forced choice procedure. The results of this study demonstrate changes in the features of the FM bats' sonar sounds with echolocation task demands, lending support to the notion that this animal actively controls the echo information that guides its behavior.

Animals↗
PubMed1999

Teenage fertility and life chances.

Teenage mothers and their children face poorer prospects in life than do women who delay motherhood until later in life. Moreover, patterns of early childbearing tend to be repeated in subsequent generations. Therefore, an understanding of the factors associated with early fertility is important for the prevention of adverse consequences. This paper uses data from the National Survey of Sexual Attitudes and Lifestyles to explore these associations. Early sexual intercourse is an important predictor of early fertility, as is poor educational attainment, although it is not clear to what extent pregnancy acts to thwart academic ambitions, or to what extent poor educational performance leads to a need to seek personal fulfilment in other than academic goals. Thus, interventions designed to influence age at first intercourse and to improve educational performance both have potential in terms of impacting on teenage pregnancy rates. Family background also exerts a powerful influence on teenage fertility. Young people for whom one or both parents are absent are more likely to become parents early in life. However, the most important factor of family life determining the chances of teenage motherhood appear to be the quality of communication about sexual matters with the home. In terms of outcomes, teenage mothers are more likely to live in social housing, are less likely to be in paid employment and have larger than average sized families. Certain areas of the country, notably the older, run-down industrial areas, have higher rates of teenage motherhood than the newer, more prosperous areas. Because most of these effects are independent of one another, there is potential merit in intervening to prevent unintended conception at several points in a young woman's life. Primary preventive efforts are needed to reduce the rates at which teenage pregnancy occurs in this country. Yet, if the cycle of deprivation that means the children of young mothers themselves enter parenthood early is to be broken, then efforts must also be made to mitigate the effects of teenage fertility for both mother and child.

Adolescent↗
PubMed1998

Private sexual behavior, public opinion, and public health policy related to sexually transmitted diseases: a US-British comparison.

OBJECTIVES: The purpose of this study was to characterize sexual behavior and opinions about sex in the United States and Britain; implications are discussed for effective public health policy regarding sexually transmitted diseases (STDs) in the United States. METHODS: Large-scale national probability surveys conducted in the 2 countries detailed sexual behavior, opinions, and the prevalence of STDs. RESULTS: In comparison with that of Britain, the US population has greater variability in sexual behavior, less tolerant opinions about sexual behavior, and a higher STD prevalence and lower condom usage among men. CONCLUSIONS: The survey data show compelling evidence from both countries of a strong association between number of sex partners and STD risk. In the United States relative to Britain, there is both greater dispersion in sexual behavior and a greater incidence of unconditional opposition to certain sexual practices. The former implies a need for strong public health policy to address the risks of STDs, but the latter implies strong opposition to that policy. This disjuncture between public health need and feasibility may contribute to the high US rate of STDs.

Adolescent↗
PubMed1997

Fluorescence in situ hybridization assessment of the telomeric regions of jumping translocations in a case of aggressive B-cell non-Hodgkin lymphoma.

We report a jumping translocation involving a donor chromosome 1 long arm in a case of aggressive B-cell non-Hodgkin lymphoma (NHL). Conventional cytogenetic banding studies demonstrated a breakpoint distal to the heterochromatic region of the donor 1q chromosome. Characterization by fluorescence in situ hybridization (FISH) of the jumping translocation demonstrated an apparent telomeric sequence loss of the recipient chromosomes. Additional cytogenetic aberrations, including the t(18;22) translocation associated with non-Hodgkin lymphoma, were also observed in this case. Cytogenetically similar cases of jumping translocations reported in the literature have implicated a preferential involvement of the donor chromosomes' heterochromatic regions and the telomeric regions of the recipient chromosomes. Jumping translocations are still considered rare and their appearance is associated with a poor prognosis. The presence of these specific findings for this case are discussed and compared with those previously reported in other hematologic disorders.

Chromosome Banding↗
PubMed1997

Assessing participation bias in a sexual behaviour survey: implications for measuring HIV risk.

OBJECTIVES: To assess the likelihood of participation bias in a large population-based sex survey, and its possible effect on estimates of HIV risk behaviours. DESIGN: Construction of general hypotheses about non-participants through comparisons of willing and unwilling participants. METHODS: British adults aged 16-59 years were surveyed in 1990-1991. Interviews consisted of a face-to-face section combined with a self-completion booklet (n = 18876). Interviewers recorded interviewee embarrassment. Homosexual experience and number of lifetime heterosexual partners (grouped 0, 1, 2 or more) were recorded prior to booklet offer. Logistic regression was performed, with embarrassment and booklet refusal as outcome variables, assessing their association with sexual behaviour after controlling for demographic variables. Assuming that, in sexual behaviour, non-participants are closer to the embarrased and the booklet refusers ('unwilling' participants) than to others, these analyses provide an indication of the nature of participation bias. RESULTS: Higher refusal an embarrassment rates were associated with both reporting no homosexual experience and fewer heterosexual partners. CONCLUSIONS: Under our untestable assumption, these results are consistent with non-participants being generally at lower risk of HIV infection. Methods need to be developed both to reduce participation bias in sex surveys, and to incorporate it in analysis.

Adolescent↗
PubMed1997

An evaluation of 'rapid review' as a method of quality control of cervical smears using the AxioHOME microscope.

One method of quality control which has recently been recommended by professional bodies in the UK is the 'rapid review' method. This involves the microscopic 30 s review of all negative cervical smears with the intention of flagging potential missed abnormalities. Although it has been suggested that rapid review is better than 10% random rescreening of negative smears, the efficiency and efficacy of this method of quality control have not been thoroughly evaluated. We have used the AxioHOME system, which can record the area of a slide covered and the screening time, to investigate slide coverage during rapid review quality control, as performed by 15 cytoscreeners and MLSOs reviewing a test set of 22 slides each. The test set comprised 18 negative slides, three positive slides, and one unsatisfactory slide. We have recorded two distinct methods of rapid review in use amongst cytotechnologists, the step method and the whole slide method. The data show that rapid review takes longer on average than the recommended 30 s, the mean screening times being 76 s and 82 s for the step and whole slide methods, respectively. Abnormal smears were missed on three of 15 occasions by the step method (sensitivity 80%, positive predictive value 85%), and on seven of 30 occasions by the whole slide method (sensitivity 76.6%, positive predictive value 45%). However, the 95% confidence intervals were wide (57.7-90.7% for the step method, and 51.9-95.7% for the whole slide method). Analysis of scanning tracks and screening rates shows significant flaws in the methodology of rapid review. Abnormal cells were not identified, although dyskaryotic cells were included in the scanning track on nine occasions, seven using the whole slide method and two using the step method. On one occasion (using the step method) abnormal cells were not identified because they were not included in the scanning track. Further research is in progress to determine optimal methods of rapid review, and whether the rapid review technique is as effective as automated screening systems for quality assurance in cytology.

False Negative Reactions↗
PubMed1996

Behavioural risk factors for HIV infection amongst blood donors in London.

This paper compares the prevalence of risk factors for sexual acquisition of human immunodeficiency virus infection (HIV-1) among blood donors with the risk in the general population. Sexual behaviour data collected as part of a cross-sectional survey of central London blood donors were compared, after indirect standardization for age and sex, with those collected among Greater London participants of the National Survey of Sexual Attitudes and Lifestyles (NATSSAL). Overall, male blood donors had lower risk sexual lifestyles than age-matched NATSSAL participants in that they had had fewer lifetime female sexual partners, were more likely to have had first sexual intercourse after 16 years and were less likely to have had a homosexual partner. Men who have had sex with men since 1977 were asked not to donate blood. Despite this, 3.6% of male donors had had some sexual experience with another man and 1.9% had had sexual intercourse with at least one male partner. In contrast, female donors had had more sexual partners, were more likely to have had first sexual intercourse before 16 years and had probable higher rates of sexually transmitted disease (STD) clinic attendance than NATSSAL participants, explained by the much higher proportion of single rather than married female blood donors at each age. In conclusion, male donors had lower risk sexual lifestyles than age-matched NATSSAL participants, although even low levels of homosexual contact give some cause for concern. Female donors appeared to have higher risk sexual lifestyles than the general population because a much higher proportion of the female blood donors were single. The results provide important insights for those defining blood donor referral criteria.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Community service needs of people with HIV infection in London.

The objectives of this study were to describe the expressed needs for community services of HIV-infected individuals by disease stage, gender and transmission category and the barriers which prevent the receipt of such services. Structured interviewer-administered questionnaires concerning a 6-month retrospective period were used to obtain information on need for community services and problems which prevented the receipt of services. The study sample included 70 homosexual men with asymptomatic HIV disease, 42 homosexual men with symptomatic non-AIDS, 53 homosexual men with AIDS, 23 heterosexual men, 29 heterosexual women, 9 male and 9 female injecting drug users. The main outcome measures were the extent to which needs for community services were met and person/service combinations for which problems or barriers prevented the receipt of community services. On average, subjects expressed a need for 10 categories of community services over the 6-month period: homosexuals expressed a mean of 10, heterosexuals 10, injecting drug users 11, subjects with asymptomatic HIV infection 9, subjects with symptomatic non-AIDS 11, subjects with AIDS 13, men 9 and women 14. A total of 58% of community service needs were always met, 6% were rarely not met, 16% were sometimes not met, 6% were often not met and 14% were not met at all. The extent to which subjects felt that their needs were met was similar for the different study groups, but the needs of women were met somewhat less frequently than those of men. Similarly, people with AIDS felt that their needs were met slightly less often. Reported levels of unmet need were high for a wide range of services. The most common reason subjects gave for not having received a community service for which they expressed a need was ignorance of where or how to obtain the service. This was mentioned in one-third of all such cases. Anxieties over the competence with which a service would be rendered was mentioned in 13% of cases and long waiting times in 11%. The frequencies of unmet need for many community services were high and often seemed to arise either from a lack of awareness on the part of subjects on how and where services could be obtained or from doubts about the relevance of services offered. Both of these barriers should be surmountable through the provision of better information to patients, extending user involvement in service development and the better co-ordination of service delivery through care management approaches.

Adult↗
PubMed1996

The use and cost of hospital services by London AIDS patients with different AIDS defining conditions.

BACKGROUND: Contracting for HIV service provision is now an established part of the National Health Service commissioning process. AIDS is a heterogeneous condition, comprising various opportunistic illnesses which require different services and which have different resource implications. This study describes the use of hospital services and associated costs for the management of different AIDS defining conditions. METHOD: A retrospective case-notes analysis was performed, of 335 AIDS patients treated at St Mary's Hospital, London, between 1 January 1983 and 30 September 1989, as well as a costing exercise of 37 clinical departments to calculate HIV-related costs. RESULTS: Mean age at time of AIDS diagnosis for these predominantly homosexual men was 38 years. Use of services varied, as did associated costs-from 8163 pounds per patient-year for patients with Constitutional Disease to 42,124 pounds for those with Cytomegalovirus Disease Most diagnostic categories showed a shift over the study period from an in-patient- to an out-patient-based service. Patients diagnosed after 1987 had overall lower costs per patient-year compared with those diagnosed before 1987: whereas out-patient costs for most groups had increased, in-patient expenditure decreased. For most categories, in-patient care costs and out-patient drugs prescribed provided the greatest proportion of total costs. Average costs per in-patient day ranged from 334 pounds to 433 pounds, and average costs per out-patient visit ranged from 99 pounds to 411 pounds for different AIDS defining conditions. CONCLUSIONS: Different opportunistic illnesses of symptomatic HIV disease have different treatment and resource implications. Casemix will need to be taken into consideration when contracting for HIV services, including extra-contractual referrals.

AIDS-Related Opportunistic Infections↗
PubMed1996

Geographic variation in sexual behaviour in Britain: implications for sexually transmitted disease epidemiology and sexual health promotion.

OBJECTIVES: To explore geographical variation in sexual behaviour in Great Britain with reference to the prevalence of HIV infection. DESIGN: The National Survey of Sexual Attitudes and Lifestyles comprises a randomly selected, representative sample of almost 19,000 men and women aged 16-59 years living in Great Britain. METHODS: The survey was carried out using a combination of face-to-face interview and self-completion questionnaires and a wide range of data was collected. In this study, data on numbers and sex of sexual partners, condom use, injecting drug use, perception of risk of AIDS and lifestyle change were analysed, and comparisons were made between the different geographical areas in Great Britain. RESULTS: In the last 5 years, men living in Inner London were more likely to have a male partner [odds ratio (OR), 5.6; 95% confidence interval (CI), 3.1-10.0] or to have had 10 or more female partners (OR, 2.4; 95% CI, 1.6-3.6) than men living in other parts of the country. Similar results were observed for women living in Inner London: OR for a female partner in the last 5 years was 4.1 (95% CI, 1.6-10.2) and for five or more male partners in the last 5 years was 2.1 (95% CI, 1.5-2.8). More complex, but less striking patterns of behaviour were seen in different parts of the country. Both men and women living in Inner London were more likely to recognize that they were at some risk of acquiring HIV and were also more likely to report a change in sexual lifestyle. CONCLUSIONS: These analyses highlight the difficulties inherent in extrapolating from sexual behaviour data gathered using purposive samples to the population as a whole. The results are consistent with the known epidemiology of HIV and sexually transmitted diseases in Britain. The data suggest that cases of HIV will continue to be concentrated in Inner London, but Londoners are particularly aware of their risk. Reported behaviour change in response to perception of risk of AIDS underlines the importance of effective health promotion.

Adolescent↗
PubMed1996

Who goes to sexually transmitted disease clinics? Results from a national population survey.

OBJECTIVES: To examine the pattern of attendance at sexually transmitted disease (STD) clinics in Britain. To compare the demographic characteristics, behaviours and attitudes of STD clinic attenders with those of non-attenders, and to assess the extent to which STD clinics are used by those with high-risk sexual lifestyles. DESIGN: Random sample general population survey of sexual attitudes and lifestyle. SUBJECTS: 18,876 randomly selected men and women resident in Britain aged 16-59 years. MAIN OUTCOME MEASURES: Demographic characteristics, pattern of homosexual partnerships, heterosexual partnerships, payment for sex, abortion, drug injection in the last five years, and attitudes to sexual behaviours amongst 512 respondents who had attended STD clinic in the last five years compared with those who had not. RESULTS: 8.3% of men and 5.6% of women had attended a clinic in their lifetime and 3.4% and 2.6% respectively in the last five years. Attendance rates varied substantially with area of residence. 11% of Inner London residents had attended in the last five years. In multivariate analysis, STD clinic attendance for men was most strongly associated with increased numbers of heterosexual partners, (OR = 6.01 (4.44-8.15) and homosexual partnerships (OR = 9.59 (5.83-15.8)) and more weakly associated with payment for sex, non-manual social class, age 25-44, unmarried status and smoking. Clinic attendance for women was most strongly associated with numbers of heterosexual partners (OR = 3.74 (2.76-5.08) and injecting drug use (OR = 4.39 (1.73-11.1)). A weaker independent association was found with a history of abortion, anal sex, non-manual social class, non-married status and age 16-24. From the total population, 1 in 6 men and 1 in 7 women in the top 5% of the distribution for numbers of heterosexual partners and 1 in 5 men paying for sex and 1 in 4 of those with a homosexual partner had attended a clinic in the last five years. The probability of attendance increased with multiple risk behaviours. Of women 64.2% and of men 69.7% attending clinics reported major risk markers for STD transmission. CONCLUSIONS: STD clinics in Britain are used by a wide demographic spectrum of the population. The behaviours, but not the attitudes, of attenders differed markedly from those of non-attenders. Clinics are relatively efficient in attracting only those with high-risk lifestyles, but, at a population level, the minority of those reporting risk-markers for STD transmission attend clinics. These findings suggest that STD clinics are an important focus for sexual health promotion, but that community programmes are also important for reaching non-attenders.

Adolescent↗
PubMed1996

The economic costs of caring for people with HIV infection and AIDS in England and Wales.

The objectives of this study were firstly to estimate total lifetime care costs for an individual with HIV/AIDS, and secondly to estimate the total costs of caring people with HIV infection and AIDS in England and Wales between 1992 and 1997 inclusive. Questionnaires and monthly diaries were used to collate data on healthcare utilisation from patients with HIV infection over a 6-month period. These data were then used to estimate the annual total direct costs of care (stratified by disease stage), total lifetime costs of care, and present and future total national care costs for England and Wales. Costing data were obtained from providers of services throughout Greater London. In total, 235 patients with HIV infection were recruited from 2 clinics in Greater London. All costs were calculated in 1992-93 pounds sterling (pound; 1 pound = $US1.58, December 1995). Annual care costs were estimated at 4515 pounds ($US7134) for a person with asymptomatic HIV disease, 8836 pounds ($US13,961) for a person with symptomatic non-AIDS and 15 268 pounds ($US24,123) for a person with AIDS. Lifetime care costs were estimated at 84,522 pounds ($US133,545) per patient. The total costs of care for England and Wales were forecast to increase from 116,627,400 pounds ($US184,271,300) in 1992 to 162,638,100 pounds ($US256,968,200) in 1997. In conclusion, our study further emphasises the continued shift in hospital services from the inpatient sector to the outpatient sector. The importance of community care and informal care, in terms of the associated direct economic costs, is also highlighted. This emphasises the need for close collaboration between different agencies and strategic coordination of services. Finally, the study forecasts an increase in care costs in England and Wales during the 1990s.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Provision of sex education and early sexual experience: the relation examined.

OBJECTIVES: To explore the relation between receipt of sex education and experience of first intercourse. SUBJECTS AND DESIGN: The national survey of sexual attitudes and lifestyles is based on a sample of 18,876 respondents aged 16-59, randomly selected from the Post Office's small-user postcode address file. Data were collected between May 1990 and November 1991 by personal interviews combining a self administered questionnaire with a face to face interview. MAIN OUTCOME MEASURES: Age at first intercourse, use of contraception at first intercourse, actual and preferred source of sex education (including school based lessons). RESULTS: Median age at first intercourse fell by four years for women and three years for men over the past four decades, to 17 for both men and women aged 16-19 at the time of interview. Of those respondents for whom school was the main source of information about sexual matters, men were less likely, and women no more likely, to have had intercourse before the age of 16 than were those citing other main sources, such as friends and the media. Both men and women were more likely to have used some method of contraception. In multivariate analysis, these effects remained after controlling for the effect of current age, educational attainment, and religious affiliation. CONCLUSIONS: These data provide no evidence to support the concern that provision of school sex education might hasten the onset of sexual experience. These findings have important implications for the provision of sexual health education and highlight the need to carry out prospective and randomised studies of the impact of sex education.

Adolescent↗
PubMed1995

Relation between maternal haemoglobin concentration and birth weight in different ethnic groups.

OBJECTIVE: To assess the relation of the lowest haemoglobin concentration in pregnancy with birth weight and the rates of low birth weight and preterm delivery in different ethnic groups. DESIGN: Retrospective analysis of 153,602 pregnancies with ethnic group and birth weight recorded on a regional pregnancy database during 1988-91. The haemoglobin measurement used was the lowest recorded during pregnancy. SETTING: North West Thames region. SUBJECTS: 115,262 white women, 22,206 Indo-Pakistanis, 4570 Afro-Caribbeans, 2642 mediterraneans, 3905 black Africans, 2351 orientals, and 2666 others. MAIN OUTCOME MEASURES: Birth weight and rates of low birth weight (< 2500 g) and preterm delivery (< 37 completed weeks). RESULTS: Maximum mean birth weight in white women was achieved with a lowest haemoglobin concentration in pregnancy of 85-95 g/l; the lowest incidence of low birth weight and preterm labour occurred with a lowest haemoglobin of 95-105 g/l. A similar pattern occurred in all ethnic groups. CONCLUSIONS: The magnitude of the fall in haemoglobin concentration in pregnancy is related to birth weight; failure of the haemoglobin concentration to fall below 105 g/l indicates an increased risk of low birth weight and preterm delivery. This phenomenon is seen in all ethnic groups. Some ethnic groups have higher rates of low birth weight and preterm delivery than white women, and they also have higher rates of low haemoglobin concentrations. This increased rate of "anaemia," however, does not account for their higher rates of low birth weight, which occurs at all haemoglobin concentrations.

Africa↗