Low birth weight in relation to multiple induced abortions.

BACKGROUND. Most studies report that a single induced abortion does not increase risk for delivering a low birth weight infant in a subsequent pregnancy. However, the effect of multiple abortions has not been adequately evaluated. METHODS. This relationship was studied in 6541 White women who delivered their first child between 1984 and 1987. We compared the frequencies of low birth weight (less than 2500 g) among infants born to 1999 women without prior induced abortion and 1999 women with one abortion with the frequencies of low birth weight among infants born to women with two (n = 1850), three (n = 520), and four or more (n = 173) prior induced abortions. RESULTS. After adjustment for confounding variables, we found no linear relationship in risk of low birth weight among women with one (relative risk [RR] = 1.2, 95% confidence interval [CI] = 0.9-1.5), two (RR = 1.5, 95% CI = 1.1-2.0), three (RR = 1.3, 95% CI = 0.8-1.9), or four or more (RR = 1.6, 95% CI = 0.9-2.9) prior induced abortions. CONCLUSIONS. These findings confirm earlier reports of little or no evidence of harmful effects on birth weight by one or by two or more induced abortions. We further report that risk is not significantly elevated even in women with three, four, or more prior terminations of pregnancy when compared with women with one or two abortions.     

Delayed childbearing: no evidence for increased risk of low birth weight and preterm delivery

Prior studies of the effect of increased maternal age on reproductive outcome in primiparous women have often ignored the possible influence on this relation of more frequent histories of spontaneous abortion and infertility in older women. When these histories are taken into account, the present study of 1,382 white primiparous women who had live singleton deliveries at Yale-New Haven Hospital finds no evidence for an increased risk of low birth weight (relative risk (RR) = 1.06, 95% confidence interval (CI) = 0.38-2.94) or preterm delivery (RR = 1.07, 95% CI = 0.50-2.24) in women delivering at age 30 years or more compared with younger women. Mean birth weight (beta = -19 g, p = 0.57) and gestational age (beta = -0.16 weeks, p = 0.34) were also not significantly affected by older maternal primiparity. Women aged 35 years or more had twice the rate of preterm births compared with women under age 30, although this result was not statistically significant in this data set (RR = 2.07, 95% CI = 0.67-6.35). Other confounding variables were taken into account.     

Association of low birth weight with passive smoke exposure in pregnancy

In a prospective study of 3,891 antenatal patients at Yale-New Haven Hospital between 1980 and 1982, one fourth (23.6%) had not smoked cigarettes during pregnancy but had been exposed to sidestream smoke for at least two hours per day. Among the nonsmokers, passive smoke exposure was significantly related to delivering a low birth weight (less than 2,500 g) newborn. This relation only occurred in term (greater than or equal to 37 weeks) deliveries. Compared with unexposed women, the relative risk of low birth weight after adjustment for confounding factors was 2.17 (95% confidence interval (CI) = 1.05-4.50). Those exposed to passive smoke delivered infants 24 g lighter on average. There was no additive effect of passive smoking on smokers themselves. Repeating the analysis on all women with term deliveries, therefore, resulted in a slightly diminished risk of low birth weight due to passive smoking of 1.52 (95% CI = 0.90-2.56). The risk of low birth weight at term due to direct cigarette smoking was 3.54 (95% CI = 1.62-7.71). Gestational age was unrelated to passive smoking, which appears to exert its effect primarily through growth retardation in term newborns.     

Job stress and adverse outcome of pregnancy: a causal link or recall bias?

A case-base study in a population of 214,108 commercial and clerical female workers in Denmark during the period 1983-1985 investigated whether increasing job stress, defined as increasing job demands and decreasing job control, increased the risk of an adverse outcome of pregnancy. Information on the cohort, the outcome of 24,362 pregnancies, was obtained by linkage with nationwide health registers. Six case groups were selected: 1) 2,248 spontaneous abortions, 2) 209 stillbirths or deaths within the first year of life, 3) 661 infants with congenital malformations, 3) 593 preterm deliveries, 4) 587 infants with term low birth weights, 5) 988 infants with light-for-date birth weights, and 6) a random sample of 2,252 pregnancies that constituted the reference group. Information on exposure was obtained by mailed questionnaire. When dichotomized scales on data concerning job demand and control were used, there was an increased relative risk of spontaneous abortion (odds ratio = 1.28, 95% confidence interval (CI) 1.05-1.57) and term low birth weight (odds ratio = 1.46, 95% CI 1.05-2.04) for women experiencing high job stress. For the other case groups, the odds ratios were as follows: congenital malformation, 1.23 (95% CI 0.93-1.63); preterm delivery, 1.03 (95% CI 0.77-1.39); light-for-date birth weight, 1.08 (95% CI 0.83-1.40); and stillbirth/death within the first year of life, 1.42 (95% CI 0.90-2.24). No substantial response bias was found. When occupational titles were used as an exposure matrix, no increased risk was found, except for term low birth weight. Recall bias is one possible explanation. Thus, the results must be interpreted with caution.     

Weight loss during pregnancy is associated with adverse pregnancy outcomes among HIV-1 infected women

In a prospective study of 1002 pregnant, HIV-1 infected Tanzanian women, we examined the incidence of fetal death, preterm delivery, low birth weight (LBW), and small for gestational age (SGA) births in relation to maternal anthropometry at the first prenatal visit, weight loss, and low weight gain during pregnancy. Anthropometric measurements were obtained monthly during the 2nd and 3rd trimesters. Low maternal height and weight at the first visit were significantly related to lower mean birth weight and increased risk of SGA, but not to preterm delivery. Maternal stature < 150 cm was significantly related to fetal death. Weight loss during pregnancy, defined as a negative slope of the regression of weight measurements on the week of gestation, occurred in 10% of the women. It was related to increased relative risk (RR) of fetal death (RR = 1.83, 95% CI = 0.93, 3.57), preterm delivery (RR = 1.85, 95% CI = 1.40, 2.44), and LBW (RR = 2.85, 95% CI = 1.69, 4.79) after adjusting for multivitamin supplementation, height, primiparity, baseline weight, malaria, CD4 cell count, HIV disease stage, and intestinal parasitoses. The significant association with fetal death was stronger for weight loss during the 2nd trimester, whereas increased risks of preterm delivery and LBW were higher for weight loss during the 3rd. Similar but weaker associations were found with low weight gain during pregnancy (slope < 25th percentile). We conclude that poor anthropometric status at the first prenatal visit and weight loss during pregnancy among HIV-1 infected women are strong risk factors for adverse pregnancy outcomes.     

Gestational vaginal bleeding and pregnancy outcome

The relation between vaginal bleeding and pregnancy outcome was examined in a prospective study of 3,531 women seeking prenatal care in New York City from 1975 through 1985. Women were interviewed in the second trimester or later and were followed up at delivery. The frequency of vaginal bleeding during pregnancy was 22%. Few maternal characteristics or exposures were predictive of bleeding, and those that were associated with an increased risk of bleeding were only marginally so. Risk factors included advanced maternal age, previous spontaneous or induced abortion, working during pregnancy, and certain gynecologic conditions (fibroids, cervical inflammation, and ovarian cysts). Severity of bleeding was examined in relation to birth weight and length of gestation at delivery. Light bleeding during pregnancy was not associated with decreased birth weight or with shortened gestation at delivery. Heavy bleeding was associated with a decrease in mean birth weight of about 100 g (p less than 0.05) but was not significantly associated with the risk of low birth weight (odds ratio (OR) = 1.7, 95% confidence interval (CI) 0.9-3.3). Heavy bleeding was associated with preterm delivery among private patients (OR = 6.4, 95% Cl 1.7-23.5) but not public patients (OR = 0.3, 95% Cl 0.1-1.4). First trimester bleeding of any severity was marginally associated with congenital malformations in the offspring (OR = 1.7, 95% Cl 1.0-2.9); the effect was the same for major and minor abnormalities. There was no association between first trimester bleeding and placental complications of pregnancy or the delivery of a stillborn infant.     

Cocaine use during pregnancy: perinatal outcomes

The relation between maternal cocaine use and perinatal outcomes was investigated among 17,466 non-Asian singleton deliveries in 1988 from the University of Illinois Perinatal Network data base in the metropolitan Chicago area. Elevated adjusted relative risks (RR) of low birth weight (RR = 2.8, 95% confidence interval (CI) 2.2-3.7), prematurity (RR = 2.4, 95% CI 1.9-3.1), abruptio placentae (RR = 4.5, 95% CI 2.4-8.5), and perinatal death (RR = 2.1, 95% CI 1.1-4.0) were observed for "any" cocaine users (n = 408) compared with women who did not use cocaine or any other drugs or alcohol (n = 17,058). There was an increased (although unstable) risk of intrapartum placenta previa not previously reported (RR = 2.3, 95% CI 1.0-5.1). The relative risk of small-for-gestational-age births for cocaine users who did not smoke (RR = 3.4, 95% CI 1.8-6.5) was greater than that for cocaine users who did (RR = 2.1, 95% CI 1.1-4.1). Irrespective of smoking status, cocaine use during pregnancy increased the risk of small-for-gestational-age births.     

Tobacco smoke exposure and pregnancy outcome among working women. A prospective study at prenatal care centers in Orebro County, Sweden

Among 4,687 women undergoing prenatal care in Orebro County, Sweden, from October 1980 to June 1983, 678 nonsmokers reported passive exposure to tobacco smoke. Of these women, 267 had been passively exposed at work, and the risk ratio (RR) for intrauterine death (spontaneous abortion or stillbirth) among these pregnancies was increased to 1.53 (95% confidence interval (CI) 0.98-2.38) compared with pregnancies of unexposed working women. This could not be explained by age, previous spontaneous abortion, educational level, planning of pregnancy, or alcohol use. The effect was confined to first-trimester fetal loss (adjusted RR = 2.16, 95% CI 1.23-3.81), while active smoking was associated with intrauterine death after the first trimester. Passive exposure in the workplace was weakly associated with preterm birth (less than 37 weeks) but not with low birth weight (less than 2,500 g) among full-term livebirths. Active smoking clearly increased the risk of both of these outcomes. However, passive exposure in the home only did not seem to affect pregnancy outcome. The lack of quantitative exposure data points to the need for more research before passive exposure to tobacco smoke can be regarded as an established hazard to fetal development and survival.     

The association between low birth weight and caffeine consumption during pregnancy

In a prospective study of 3,891 antenatal patients at Yale-New Haven Hospital between 1980 and 1982, 76.7% consumed caffeine from coffee, tea, colas, and drugs. A dose response of caffeine intake to increased risk for delivering low birth weight (less than 2,500 g) singleton newborns was observed. This relation was observed in deliveries after 36 weeks gestational age. When comparison was made with women who had no caffeine exposure, the relative risks of low birth weight after adjustment for confounding factors were 1.4 (95% confidence interval (CI) 0.7-3.0) for 1-150 mg of caffeine daily; 2.3 (95% CI 1.1-5.2) for 151-300 mg; and 4.6 (95% CI 2.0-10.5) for over 300 mg. Decreases in mean birth weight were 6, 31, and 105 g, respectively. Gestational age did not appear to be related to caffeine consumption in the crude or adjusted analysis. Maternal caffeine intake seems to exert an effect on birth weight through growth retardation in term newborns.     

隐睾发生的危险因素研究

目的：研究隐睾发生的危险因素。方法：采用以医院为基础的1：2配比的病例对照研究方法，按统一的调查方法对99例隐睾及198例对照组面对面问卷调查。应用SAS6。12软件对所调查因素进行单因素及多因素logistic回归分析，结果：胎儿隐睾与母亲孕早期感冒伴发热（OR＝9．37，95％CI：2．25－39．09），孕期发生先兆流产（OR＝4．66，95％CI，2．02＝10．74），孕期发生先兆子痫（OR＝16．33，95％CI：1．40－191．20），父亲职业性接触农药（OR＝12．79％CI；2．90－56．43），低出生体重（OR＝5．77，95％CI：1．39－23．98），母亲怀孕年龄＜24（OR＝2．89，95％CI：1．29－4．06）呈正相关。结论：母亲孕早期感冒伴发热，孕期发生先兆流产及先兆子痫，父亲职业性接触农药，低出体重，母亲怀孕年龄＜24岁是隐睾发病的主要危险因素。     

Risk factors for ectopic pregnancy: a comprehensive analysis based on a large case-control,population-based study in France

This case-control study was associated with a regional register of ectopic pregnancy between 1993 and 2000 in France. It included 803 cases of ectopic pregnancy and 1,683 deliveries and was powerful enough to investigate all ectopic pregnancy risk factors. The main risk factors were infectious history (adjusted attributable risk = 0.33; adjusted odds ratio for previous pelvic infectious disease = 3.4, 95% percent confidence interval (CI): 2.4, 5.0) and smoking (adjusted attributable risk = 0.35; adjusted odds ratio = 3.9, 95% CI: 2.6, 5.9 for >20 cigarettes/day vs. women who had never smoked). The other risk factors were age (associated per se with a risk of ectopic pregnancy), prior spontaneous abortions, history of infertility, and previous use of an intrauterine device. Prior medical induced abortion was associated with a risk of ectopic pregnancy (adjusted odds ratio = 2.8, 95% CI: 1.1, 7.2); no such association was observed for surgical abortion (adjusted odds ratio = 1.1, 95% CI: 0.8, 1.6). The total attributable risk of all the factors investigated was 0.76. As close associations were found between ectopic pregnancy and infertility and between ectopic pregnancy and spontaneous abortion, further research into ectopic pregnancy should focus on risk factors common to these conditions. In terms of public health, increasing awareness of the effects of smoking may be useful for ectopic pregnancy prevention.     

Pregnancy complications and subsequent maternal cerebrovascular events: a retrospective cohort study of 119,668 births

Low birth weight infants are at increased risk of cerebrovascular disease in adulthood. This has been attributed to physiologic programming following inadequate intrauterine nutrition. The authors sought to determine whether mothers who deliver low birth weight infants or who suffer related pregnancy complications are also at increased risk. They used routine data to identify all first singleton livebirths in Scotland (1981-1985) and found that 342 of the 119,668 mothers suffered cerebrovascular events over 14-19 years' follow-up. Compared with women who delivered babies of > or = 3,500 g, women who delivered low birth weight (<2,500 g) infants were at increased risk of cerebrovascular disease (adjusted hazards ratio (HR) = 2.51, 95% confidence interval (CI): 1.71, 3.70) with a consistent trend across birth weight categories. The lowest birth weight quintile (adjusted HR = 1.29, 95% CI: 1.01, 1.65), preterm delivery (adjusted HR = 1.91, 95% CI: 1.35, 2.70), and previous spontaneous abortion (adjusted HR = 1.49, 95% CI: 1.09, 2.03) were all predictive of subsequent maternal cerebrovascular events. The effects were additive. Women who experienced all three complications had a sevenfold risk (adjusted HR = 7.03, 95% CI: 2.24, 22.06). The association with low birth weight in mothers, as well as offspring, is unlikely to be explained by intrauterine programming and suggests that cerebrovascular disease and low birth weight may share common genetic or lifestyle risk factors.     

The effect of high doses of folic acid and iron supplementation in early-to-mid pregnancy on prematurity and fetal growth retardation: the mother–child cohort study in Crete, Greece (Rhea study)

Purpose

We examined whether high doses of folic acid and iron supplementation in early-to-mid pregnancy affect the risk of preterm birth, low birth weight, and small for gestational age neonates, in the mother–child cohort in Crete, Greece (Rhea study).

Methods

We included 1,279 women with singleton pregnancies with complete data on supplements use in early-to-mid pregnancy and birth outcomes. Anthropometric measurements at birth were obtained from medical records. Red blood cell folate concentrations in cord blood were measured in a subsample of the study population (n = 58).

Results

Sixty-six percent of the study participants reported high doses of supplemental folic acid use (5 mg/day), while 21 % reported excessive doses of folic acid use (>5 mg/day) in early-to-mid pregnancy. Daily intake of 5-mg supplemental folic acid was associated with a 31 % decrease in the risk of preterm birth (RR, 0.69; 95 % CI, 0.44, 0.99), 60 % decrease in the risk of delivering a low birth weight neonate (RR, 0.40; 95 % CI, 0.21, 0.76), and 66 % decrease in the risk of delivering a small for gestational age (SGA) neonate (RR, 0.34; 95 % CI, 0.16, 0.73). Daily doses of iron supplementation more than 100 mg were associated with a twofold increased risk for SGA neonates (RR, 2.14; 95 % CI, 0.99, 5.97).

Conclusion

These findings suggest that high daily doses of supplementary folic acid in early-to-mid pregnancy may be protective for preterm birth, low birth weight, and small for gestational age neonates, while high daily doses of supplementary iron may be harmful for fetal growth.     

舟山市2002-2015年出生体重变化与不良出生结局及影响因素分析

目的 描述舟山市2002-2015年新生儿出生体重变化,分析不良出生结局的发生率及影响因素。方法 利用舟山市电子医疗数据库,收集孕产妇及新生儿的相关信息,描述新生儿出生体重和不良出生结局发生率的变化趋势,采用多元Logistic回归分析其影响因素。结果 37 141例新生儿的平均出生体重为（3 388±462） g,低出生体重儿、巨大儿、早产的发生率分别为2.34%,9.42%和3.61%;高危妊娠（OR=1.80,95%CI:1.42~2.28）是低出生体重儿的危险因素;出生季节为夏季、秋季、母亲年龄<25岁、孕前消瘦等是巨大儿的保护因素。母亲孕前超重和肥胖是巨大儿的危险因素;母亲年龄<25岁是早产发生的保护因素。母亲年龄>30岁（OR=1.38,95%CI:1.19~1.60）、冬季出生（OR=1.24,95%CI:1.06~1.45）、母亲孕前超重和肥胖、高危妊娠（OR=1.95,95%CI:1.66~2.29）等是早产的危险因素。结论 舟山市2002-2015年新生儿出生体重呈下降趋势,低出生体重儿和早产儿发生率呈上升趋势。新生儿性别、出生季节,母亲年龄、孕前体质指数（body mass index,BMI）、高危妊娠等因素影响低出生体重儿、巨大儿或早产儿的发生。     

Effects of calcium supplementation during pregnancy on maternal, fetal and birth outcomes

Gestational hypertensive disorders are the second leading cause of maternal death worldwide. Epidemiological and clinical studies have shown that an inverse relationship exists between calcium intake and development of hypertension in pregnancy. The purpose of this review was to evaluate preventive effect of calcium supplementation during pregnancy on gestational hypertensive disorders and related maternal and neonatal morbidity and mortality. A literature search was carried out on PubMed, WHOLIS, PAHO and Cochrane Library. Only randomised trials were included in the review. Data were extracted into a standardised Excel sheet. Primary outcomes were pre-eclampsia, preterm birth and birthweight. Other neonatal outcomes such as neonatal mortality, small-for-gestational age and low birthweight were also evaluated. A total of 15 randomised controlled trials were included in this review. Pooled analysis showed that calcium supplementation during pregnancy reduced risk of pre-eclampsia by 52% [relative risk (RR) 0.48; 95% confidence interval (CI) 0.34, 0.67] and that of severe pre-eclampsia by 25% (RR 0.75 [95% CI 0.57, 0.98]). There was no effect on incidence of eclampsia (RR 0.73 [95% CI 0.41, 1.27]). There was a significant reduction for risk of maternal mortality/severe morbidity (RR 0.80 [95% CI 0.65, 0.97]). Calcium supplementation during pregnancy was also associated with a significant reduction in risk of pre-term birth (RR 0.76 [95% CI 0.60, 0.97]). There was an extra gain of 85 g in the intervention group compared with control (mean difference 85 g [95% CI 37, 133]). There was no effect of calcium supplementation on perinatal mortality (RR 0.90 [95% CI 0.74, 1.09]). There was a statistically non-significant increased risk of urolithiasis in the intervention group compared with control (RR 1.52 [95% CI 0.06, 40.67]). In conclusion, calcium supplementation during pregnancy is associated with a reduction in risk of gestational hypertensive disorders and pre-term birth and an increase in birthweight. There is no increased risk of kidney stones.     

Folic acid supplements modify the adverse effects of maternal smoking on fetal growth and neonatal complications

Maternal smoking during pregnancy leads to increased risks of neonatal complications. The use of folic acid supplements might reduce the adverse effects of smoking. We examined whether folic acid supplement use modifies the associations of maternal smoking with first trimester plasma homocysteine concentrations, fetal growth characteristics, and risks of neonatal complications. The associations were studied in 6294 mothers participating in a prospective population-based cohort study in The Netherlands. Main outcomes measurements were first trimester plasma homocysteine concentrations, fetal growth characteristics, and neonatal complications, including preterm birth, low birth weight, and small-size-for-gestational-age. Continued maternal smoking was associated with higher first trimester plasma homocysteine concentrations [difference 0.52 μmol/L (95% range = 0.20, 2.14)], lower third trimester fetal weight (difference -44 g (95% CI = -57, -31)], and birth weight [difference -148 g (95% CI = -179, -118)]. There were significant interactions between maternal smoking and folic acid supplements on all outcome measures (all P-interaction < 0.040). Among mothers who continued smoking during pregnancy, those who did not use folic acid supplements had the highest risk of delivering a child with low birth weight [OR = 3.45 (95% CI = 1.25, 9.54)] compared to those who did use periconceptional folic acid supplements. No significant effects were observed for the risks of preterm birth and small-size-for-gestational-age at birth. Our results suggest that some adverse effects of maternal smoking on fetal growth and neonatal outcomes might be reduced by the use of folic acid supplements. The observed interaction seems to be mainly driven by smoking in the first trimester only.     

Comparison of midwifery-led and consultant-led maternity care for low risk deliveries in Nepal

OBJECTIVE: To evaluate Nepal's first independent midwifery unit, the Patan Hospital Birthing Centre (BC), as a model for training and service provision for low risk deliveries. Specifically, to compare its efficacy with that of an adjacent Consultant-led Maternity Unit (CMU). METHODS: Unpaired comparison of delivery procedures and outcomes at the Patan Hospital, Lalitpur. The sample was 988 women (550 at BC, 438 at CMU). Women judged to be at low risk of complications were enrolled at delivery at each facility. Information was collected by standardized interviews and record review. Main outcome measures were incidence of complications of labour, technical procedures and access to postnatal care and family planning services. RESULTS: Artificial rupture of membranes was more likely to be performed at the BC (RR 1.26, 95% CI 1.10-1.44). Augmentation of labour with oxytocin was less likely to be performed (RR 0.26, 95% CI 0.20-0.33), as was episiotomy (RR 0.64, 95% CI 0.57-0.72). The incidence of oxytocic augmentation was high at the CMU (205/438: 46.9%). The incidence of moderately or thickly meconium-stained liquor was lower at the BC than at the CMU (RR 0.62, 95% CI 0.43-0.91), a finding that was associated with oxytocic augmentation of labour. No significant differences were found for duration or complications of labour, mode of delivery, birth weight, neonatal Apgar score or admission to the special care baby unit. Women delivering at the BC were more likely to attend both postnatal (RR 1.33, 95% CI 1.18-1.51) and family planning clinics (RR 1.85, 95% CI 1.44-2.38). CONCLUSIONS: After appropriate screening, intrapartum care for low risk deliveries is effectively provided by midwives. The Birthing Centre model should be considered throughout the developing world, particularly as a site for training of skilled attendants.     

Association of maternal caffeine consumption with decrements in fetal growth

Whether caffeine consumption during pregnancy represents a fetal hazard remains uncertain. The authors report on a large prospective study designed to examine this question. In 1996-2000, 2,291 mothers with singleton livebirths in Connecticut and Massachusetts were evaluated after their first prenatal visit and were questioned about caffeine consumption and important confounding factors. Urine samples were provided to analyze urinary caffeine, cotinine, and creatinine levels. Mothers were followed throughout pregnancy to monitor changes in consumption. Pregnancy outcomes were obtained from medical records. Self-reports of caffeine consumption in the first and third trimesters were not associated with intrauterine growth retardation, low birth weight, or preterm delivery. For every 1 mg/g creatinine increase in urinary caffeine, risk of intrauterine growth retardation was essentially unchanged (odds ratio (OR) = 0.96, 95% confidence interval (CI): 0.85, 1.08). In contrast, a 0.005 mg/g creatinine increase in urinary cotinine significantly increased risk (OR = 1.003, 95% CI: 1.001, 1.005). Mean birth weight was reduced by reported caffeine consumption (-28 g per 100 mg of caffeine consumed daily, 95% CI: -0.10, -0.46, p = 0.001) but not mean gestational age. Decaffeinated coffee did not increase risk for any perinatal outcome. This small decrease in birth weight, observed for maternal caffeine consumption, is unlikely to be clinically important except for women consuming >/=600 mg of caffeine daily (approximately six 10-ounce (1 ounce = 28.3 g) cups of coffee).     

Previous abortion and the risk of low birth weight and preterm births

OBJECTIVE: To investigate the association between previous abortion and low birth weight (LBW) and preterm birth (PB). METHOD: The study examined live, singleton births using data from the United States Collaborative Perinatal Project. Logistic regression was used to control for obstetric and medical history, and lifestyle and demographic factors. RESULT: Compared with women with no history of abortion, women who had one, two and three or more previous abortions were 2.8 (95% CI 2.48 to 3.07), 4.6 (95% CI 3.94 to 5.46) and 9.5 (95% CI 7.72 to 11.67) times more likely to have LBW, respectively. The risk for PB was also 1.7 (95% CI 1.52 to 1.83), 2.0 (95% CI 1.73 to 2.37) and 3.0 (95% CI 2.47 to 3.70) times higher for women with a history of one, two and three or more previous abortions, respectively. CONCLUSION: Previous abortion is a significant risk factor for LBW and PB, and the risk increases with the increasing number of previous abortions. Practitioners should consider previous abortion as a risk factor for LBW and PB.     

Adverse reproductive outcomes among female veterinarians

Because female veterinarians are exposed to several known reproductive hazards, the authors conducted a reproductive survey of all female graduates of a US veterinary school (n = 537) and law school (comparison group, n = 794). Analysis was confined to pregnancies completed after the second year of professional school and from 1966 to 1986. Based on one randomly chosen eligible pregnancy per woman (veterinarians, n = 176; lawyers, n = 229), spontaneous abortion rates, adjusted for elective abortions, were 13.3% for the veterinarians and 15.1% for the lawyers; these did not differ significantly. A Cox life table regression model controlling for age, smoking, alcohol use, and prior spontaneous abortion also showed no significant difference in spontaneous abortion rates between the two populations. Using all pregnancies, veterinarians who reported performing five or more radiographic examinations per week had a marginally elevated risk of spontaneous abortion, but the statistical significance disappeared when analysis was limited to one random pregnancy per woman. For one random eligible birth per woman, the mean birth weight did not differ significantly between the veterinarians and lawyers, even after controlling for possible confounders in regression analyses. A higher rate of reportable birth defects was observed among the veterinarians than among the lawyers (relative risk = 4.2, 95% confidence interval 1.2-15.1), but this unexpected result must be considered hypothesis-generating. The authors did not find an overall increased risk for spontaneous abortion or low birth weight infants among veterinarians compared with lawyers, but veterinarians who reported performing five or more radiographic examinations per week may have been at increased risk for spontaneous abortion.