Risk of ectopic pregnancy and previous induced abortion.

OBJECTIVES: This study investigated the role of prior history of induced abortion in subsequent ectopic pregnancies. METHODS: Data from two French case-control studies were used to examine the effect of induced abortion on ectopic pregnancy risk. Case patients (n = 570) were women admitted for ectopic pregnancy during the study period; controls (n = 1385) were women who delivered in the same center. RESULTS: The analysis among women with no previous ectopic pregnancy showed that, after control for the main ectopic pregnancy risk factors, prior induced abortion was associated with an increased risk of ectopic pregnancy (odds ratio [OR] = 1.5, 95% confidence interval [CI] = 1.0, 2.0); there was a significant trend between number of previous induced abortions and ectopic pregnancy risk (ORs = 1.4 for 1 previous induced abortion and 1.9 for 2 or more). CONCLUSIONS: This study suggests that induced abortion may be a risk factor for ectopic pregnancy for women with no previous ectopic pregnancy, particularly in the case of women who have had several induced abortions.     

母亲孕期被动吸烟烟及父亲饮酒与低出生体重儿关系研究

目的：为进一步探索低出生体重儿发生的相关危险因素。方法：我们对沈阳市妇婴等15家医院分娩的部分产妇进行了低出生体重儿的病例对照研究。结果：在控制孕妇患慢性疾病、生殖器官的畸形、严重妊娠反应、文化程度、巨细胞病毒等感染以及主动吸烟等混杂因素后,孕期被动吸烟分娩出低出生体重儿的危险性为非被动吸烟的2.95倍,95%可信区间OR95%CI为2.07-4.21;丈夫饮酒史、自然流产、人工流产史、家族低体重史、孕前的BMI、孕期服用解热镇痛药物以及职业接触有机物均可能是低出生体重儿的危险因素。     

Induced abortion: not an independent risk factor for pregnancy outcome, but a challenge for health counseling

PURPOSE: Low birth weight (LBW), preterm births, abnormal placentation, and miscarriages have been associated with prior induced abortions. An incidence-related effect has been suggested. The objective of this study is to assess the effects of prior induced abortions on obstetric risk factors and pregnancy outcome in conditions of free high-standard maternity care used by almost the entire pregnant population in Finland. METHODS: We analyzed a population-based database including 26,976 singleton pregnancies from 1989 to 2001, of which 2364 were among women with one prior induced abortion and 355 women had had at least two prior induced abortions. Data included maternal risk factors, pregnancy characteristics, and obstetric outcome measures and were based on results of a self-administered questionnaire at 20 weeks of pregnancy and clinical records. Odds ratios (ORs) concerning pregnancy outcomes were calculated in multiple logistic regression analysis. RESULTS: Induced abortions were associated with several known pregnancy risk factors; specifically, maternal age older than 35 years, unemployment, unmarried status, low educational level, smoking, alcohol consumption, overweight condition, and chronic illnesses. Preterm birth (OR, 1.19; 95% confidence interval, 1.01-1.41) in women with one prior abortion (7.3% versus 6.2%) and LBW (OR, 1.54; 95% confidence interval, 1.02-2.32) in women with two or more prior abortions (7.0% versus 4.7%) appeared to be more common, but after logistic regression analysis, we found no evidence of adverse pregnancy outcomes. CONCLUSIONS: Induced abortion is not an independent risk factor for adverse obstetric outcome. Marked health behavioral pregnancy risks are associated with prior induced abortions. Health counseling of these women is a challenge, but this objective has not yet been achieved.     

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.     

Abortion and its effect on risk of preeclampsia and transient hypertension

We examined the effect of abortion type, number, and gestational age on the risk of preeclampsia and transient hypertension among women who received prenatal care from 13 obstetric practices in southern Connecticut between April 1988 and December 1991 (N = 2,739). Subjects were interviewed before 16 weeks' gestation regarding reproductive history and pregnancy-related risk factors. We estimated the risk of preeclampsia (N = 44) and transient hypertension (N = 172) among nulliparous women who had had one or more abortions, with nulliparous women with no abortion as the referent group. Similar effects were seen for one spontaneous or induced abortion, when analyzed separately. A single prior abortion was associated with a decreased risk of preeclampsia [odds ratio (OR) = 0.35; 95% exact confidence interval (CI) = 0.09-1.01]. One abortion had only a small association with risk of transient hypertension (OR = 1.09, 95% exact CI = 0.68-1.72); however, a history of two or more abortions was associated with a decreased risk (OR = 0.42, 95% exact CI = 0.16-0.94). Among nulliparous women with a history of one abortion, a decreased risk of both hypertensive disorders was observed among women whose aborted pregnancy ended at > or =3 months gestation. These findings suggest that a history of abortion in nulliparous women is a protective factor against the risk of preeclampsia in the subsequent pregnancy.     

Induced abortion and low birthweight in the following pregnancy

BACKGROUND: To examine whether induced abortion increases the risk of low birthweight in subsequent singleton live births. METHODS: Cohort study using the Danish Medical Birth Registry (MBR), the Hospital Discharge Registry (HDR), and the Induced Abortion Registry (IAR). All women who had their first pregnancy during 1980-1982 were identified in the MBR, the HDR, and the IAR. We included all 15,727 women whose pregnancy was terminated by a first trimester induced abortion in the induced abortion cohort and 46,026 women whose pregnancy was not terminated by an induced abortion were selected for the control cohort. All subsequent pregnancies until 1994 were identified by register record linkage. RESULTS: Low birthweight (<2500 g) in singleton term live births occurred more frequently in women with one, two, three or more previous induced abortions, compared with women without any previous induced abortion of similar gravidity, 2.2% versus 1.5%, 2.4% versus 1.7%, and 1.8% versus 1.6%, respectively. Adjusting for maternal age and residence at time of pregnancy, interpregnancy interval, gender of newborn, number of previous spontaneous abortions and number of previous low birthweight infants (control cohort only), the odds ratios (OR) of low birthweight in singleton term live births in women with one, two or more previous first trimester induced abortions were 1.9 (95% CI: 1.6, 2.3), and 1.9 (95% CI: 1.3, 2.7), respectively, compared with the control cohort of similar gravidity. High risks were mainly seen in women with an interpregnancy interval of more than 6 months. CONCLUSIONS: The findings suggest a positive association between one or more first trimester induced abortions and the risk of low birthweight in subsequent singleton term live births when the interpregnancy interval is longer than 6 months. This result was unexpected and confounding cannot be ruled out.     

南方女性复发性流产环境因素分析

目的:探讨南方女性不明原因复发性流产(undentifiedrecurrentspontaneousabortion,URSA)流行病学因素。方法:对326例URSA及400例正常对照育龄妇女进行健康问卷调查,用Logistic回归模型,纳入体重指数(BMI)、自然流产家族史、吸烟史、被动吸烟史、饮酒史、饮咖啡史,找出有独立意义的环境危险因素,并对自然流产次数3次及≥4次者进行分层分析。结果:吸烟史、饮酒史和饮咖啡史不是URSA的危险因素,短时间被动吸烟(1h/天)及长时间被动吸烟(≥1h/天)是URSA的危险因素,OR及95%CI分别是2.30,1.50～3.52及4.76,3.24～6.99。家族史及BMI≥24.0kg/m2是URSA危险因素,OR及95%CI分别是2.12,1.28～3.49及1.55,1.12～2.14。结论:被动吸烟史、BMI≥24.0kg/m2、自然流产家族史是中国南方女性URSA独立危险因素。     

昆山市2001～2009年低出生体重儿流行病学分析

目的:描述昆山市2001～2009年9年间低出生体重(LBW)发生率,分析产妇及胎儿特征对低出生体重的影响。方法:利用昆山市《围产保健监测系统》研究33 631对产妇与胎儿,使用单因素与多因素无序多分类Logistic回归分析来估计各因素对出生体重的影响。结果:LBW发生率为1.86%。产妇超重肥胖、有人工流产史、男性胎儿可减小LBW发生风险。产妇体质指数偏低、初产妇、习惯性流产史可增加LBW发生风险。按照体质指数(BMI)分层,相对于LBW,BMI偏低组,高水平的孕期体重变化均可减小LBW胎儿发生风险。BMI正常组,高水平的孕期体重变化可减小LBW胎儿发生风险。没有发现在超重与肥胖组产妇孕期体重变化与分娩LBW胎儿之间存在统计学关联。结论:LBW发生率为1.86%,产妇与胎儿特征综合影响LBW。体重偏低与正常人群中,高水平的孕期体重变化可减小LBW发生风险。     

湖南省2011-2017年孕产妇HIV感染者早产、低出生体重和小于胎龄儿发生率及其影响因素分析

目的 了解湖南省孕产妇HIV感染者早产、低出生体重（LBW）和小于胎龄儿（SGA）的发生状况并探讨其影响因素。方法 以2011年1月至2017年12月湖南省预防艾滋病母婴传播管理信息系统报告的已分娩的孕产妇HIV感染者为研究对象,对其人口学特征、妊娠情况、抗病毒治疗（ART）、丈夫/性伴情况和妊娠结局等因素进行分析,分别计算早产、LBW和SGA发生率,采用多因素logistic回归分析其相关影响因素。结果 共纳入780例孕产妇HIV感染者,其早产率为7.9%（62/780）,LBW发生率为9.9%（77/780）,SGA发生率为21.3%（166/780）。孕产妇HIV感染者早产的危险因素包括妊娠期中重度贫血、妊娠期高血压疾病、<14孕周开始ART（与孕期未进行ART相比）和丈夫/性伴年龄>35岁（与26~30岁相比）,其aOR值分别为4.59（95% CI：1.51~13.95）、4.90（95% CI：1.56~15.46）、2.40（95% CI：1.26~4.56）和2.29（95% CI：1.21~4.36）。妊娠期中重度贫血、妊娠合并HBV感染和<14孕周开始ART（与孕期未进行ART相比）是LBW的危险因素,其aOR值分别为3.28（95% CI：1.13~9.54）、4.37（95% CI：1.42~13.44）和2.68（95% CI：1.51~4.76）。妊娠合并HBV感染和<14孕周开始ART（与孕期未进行ART相比）是SGA的危险因素,其aOR值分别为4.41（95% CI：1.43~13.63）和2.67（95% CI：1.51~4.73）。结论 早产、LBW和SGA是湖南省孕产妇HIV感染者常见的不良妊娠结局,受妊娠合并症、ART和丈夫/性伴的年龄等因素影响。     

Mifepristone-induced abortion and vaginal bleeding in subsequent pregnancy

BackgroundThe aim of this study is to explore the effect of first-trimester mifepristone-induced abortion on vaginal bleeding in subsequent pregnancy.Study DesignThis observational cohort study was conducted during 1998–2001 at antenatal clinics in Beijing, Chengdu, and Shanghai, China. The study enrolled 4,931 women with one previous mifepristone-induced abortion, 4,925 women with no history of induced abortion, and 4,800 women with one previous surgical abortion and followed them through pregnancy and childbirth.ResultsThe rates of vaginal bleeding in pregnant women with a history of medical abortion, no abortion, and surgical abortion were 16.5%, 13.9%, and 17.3%, respectively. The women with medical abortion had a higher risk (adjusted relative risk (aRR)=1.17, 95% confidence interval (CI): 1.07, 1.29) of vaginal bleeding compared with those with no abortion but similar risk to prior surgical abortion. When the correlation between medical abortion and vaginal bleeding was examined by period, increased risk was observed only in the early period (<16 gestational weeks) (aRR=1.25, 95% CI: 1.12, 1.39). The comparison between subgroups of medical abortion and no abortion showed that the observed risks increased particularly in those with abortion at gestational age ≤7 weeks (aRR=1.33, 95% CI: 1.18, 1.49), those followed by a postabortion curettage (aRR=1.58, 95% CI: 1.37, 1.84) or complications (aRR=1.99, 95% CI: 1.67, 2.37). There was no difference between women with medical abortion and women with surgical abortion in the occurrence of vaginal bleeding for either period.ConclusionsOne previous mifepristone-induced abortion increased the risk of vaginal bleeding in early gestation period of subsequent pregnancy compared with no abortion, especially if abortion occurred before 7 weeks of gestation and was followed by a curettage or complications.     

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.     

Low birth weight in pregnancies following induced abortion: no evidence for an association

Compared with women delivering a first pregnancy, those delivering a second pregnancy after aborting the first have similar rates of low (less than 2,500 g) birth weight newborns (relative risk (RR) G2A1/G1 = 0.86, 95% confidence interval (CI) = 0.49-1.51) and mean birth weight (delta = 16.3 g, p = 0.63). Abortion of the first pregnancy prevents the reduction in low birth weight and increase in mean birth weight in the second pregnancy which delivery of the first pregnancy normally bestows (RR G2P1/G2A1 = 0.48, 95% CI = 0.25-0.90; delta = 135.3 g, p less than 0.0001). Two prior induced abortions do not significantly increase risk for low birth weight (RR G3A2/G1 = 1.14, 95% CI = 0.37-3.56) or decrease mean birth weight (delta = 29.0 g), compared with women delivering their first pregnancy. The second of two deliveries has a reduced risk of low birth weight irrespective of whether both deliveries follow an aborted first pregnancy. Adjustment for confounding factors did not materially change these results. Low birth weight rates were higher after abortions performed in hospital compared with elsewhere (p = 0.03), but mean birth weight was not affected. Gestation at abortion, vacuum aspiration or dilatation and curettage, and abortion complications were unrelated to birth weight of subsequent pregnancies. Pregnancies conceived within six months of a prior abortion or delivery had lower birth weight than if the antecedent pregnancy ended more than six months previously.     

Relations of gestational length and timing and type of incomplete pregnancy to ovarian cancer risk

While the protective nature of parity with respect to ovarian cancer has been well documented, whether a history of incomplete pregnancy affects ovarian cancer risk is uncertain. Data collected from 739 epithelial ovarian cancer cases and 1,313 community controls in the Delaware Valley from 1994 to 1998 were used to evaluate the relation between gestational length and timing of first induced or spontaneous abortion and ovarian cancer risk. Incomplete pregnancy was not associated with ovarian cancer among nulliparous women or among ever-pregnant women either before or after adjustment for relevant confounders (for nulliparous women, odds ratio (OR) = 1.12, 95% confidence interval (CI): 0.66, 1.89; for ever-pregnant women, OR = 0.95, 95% CI: 0.76, 1.18). Among unigravid women, one full-term pregnancy was more protective than an incomplete pregnancy (adjusted OR = 0.29, 95% CI: 0.15, 0.57). These results were independent of the type of pregnancy loss. Among ever-pregnant women, a spontaneous abortion before a first birth provided significant protection (adjusted OR = 0.47, 95% CI: 0.30, 0.75), while no significant effect was found for an induced abortion prior to a first birth (adjusted OR = 0.80, 95% CI: 0.44, 1.47). These data do not support an independent association between incomplete pregnancies, either spontaneous or induced, and ovarian cancer risk.     

Mifepristone-induced abortion and vaginal bleeding in subsequent pregnancy

Background

The aim of this study is to explore the effect of first-trimester mifepristone-induced abortion on vaginal bleeding in subsequent pregnancy.

Study Design

This observational cohort study was conducted during 1998–2001 at antenatal clinics in Beijing, Chengdu, and Shanghai, China. The study enrolled 4,931 women with one previous mifepristone-induced abortion, 4,925 women with no history of induced abortion, and 4,800 women with one previous surgical abortion and followed them through pregnancy and childbirth.

Results

The rates of vaginal bleeding in pregnant women with a history of medical abortion, no abortion, and surgical abortion were 16.5%, 13.9%, and 17.3%, respectively. The women with medical abortion had a higher risk (adjusted relative risk (aRR)=1.17, 95% confidence interval (CI): 1.07, 1.29) of vaginal bleeding compared with those with no abortion but similar risk to prior surgical abortion. When the correlation between medical abortion and vaginal bleeding was examined by period, increased risk was observed only in the early period (<16 gestational weeks) (aRR=1.25, 95% CI: 1.12, 1.39). The comparison between subgroups of medical abortion and no abortion showed that the observed risks increased particularly in those with abortion at gestational age ≤7 weeks (aRR=1.33, 95% CI: 1.18, 1.49), those followed by a postabortion curettage (aRR=1.58, 95% CI: 1.37, 1.84) or complications (aRR=1.99, 95% CI: 1.67, 2.37). There was no difference between women with medical abortion and women with surgical abortion in the occurrence of vaginal bleeding for either period.

Conclusions

One previous mifepristone-induced abortion increased the risk of vaginal bleeding in early gestation period of subsequent pregnancy compared with no abortion, especially if abortion occurred before 7 weeks of gestation and was followed by a curettage or complications.     

Breast cancer in relation to the occurrence and time of induced and spontaneous abortion

The authors evaluated whether an induced or spontaneous abortion during the first six months of gestation, particularly if it occurs before the first term pregnancy, increases the risk of breast cancer. Data from a case-control study of women under 70 years of age were used: 3,200 cases of breast cancer were compared with 4,844 controls with nonmalignant nongynecologic conditions. Among both nulliparous and parous women, the risk of breast cancer was not related to the number of induced or spontaneous abortions. After allowance for all identified potential confounding factors, the estimated relative risk for nulliparous women with an induced abortion relative to those who had never been pregnant was 1.3 (95% confidence interval (CI) 0.8-2.2), and for spontaneous abortion, the corresponding estimate was 0.9 (95% CI 0.5-1.5). Among parous women, the estimated relative risks were 1.2 (95% CI 0.9-1.6) for an induced abortion and 0.9 (95% CI 0.8-1.0) for a spontaneous abortion, relative to never having had an abortion of any type. The time of the abortion had little effect: The relative risk estimates were 0.9 (95% CI 0.5-1.4) for induced abortion before the first term birth, 1.4 (95% CI 1.0-1.9) for induced abortion first occurring after the first term birth, 0.9 (95% CI 0.7-1.2) for spontaneous abortion before the first term birth, and 0.9 (95% CI 0.7-1.0) for spontaneous abortion first occurring after the first term birth. Similar results were evident for women under age 40, among whom the frequency of induced abortion was relatively high. These data suggest that the risk of breast cancer is not materially affected by abortion, regardless of whether it occurs before or after the first term birth.     

Analysis of factors associated with the occurrence of low birth weight infants

The relationship between low birth weight infants (LBW) and 3 perinatal factors; pre-pregnant maternal Body Mass Index (BMI: Quetelet's index), maternal height and parity was investigated by the log-linear analysis, using the birth records of an obstetric facility at Naha city. In this facility there were 4,894 deliveries from Jan. 1978 to Dec. 1987. Of the 4,894 infants, 4,142 were live singletons with available data for the analysis. The odds ratio of each risk factor was calculated by the log-linear model. Women with lower pre-pregnant BMI (less than 20) had an increased LBW risk by 1.80 (95% CI: 1.32-2.43) compared to women with higher pre-pregnant BMI (20 less than). Lower maternal height (150 cm greater than) was associated with significant LBW risk (1.47; 95% CI: 1.03-2.12). Primiparae had higher LBW risk than multiparae (1.68; 95% CI: 1.25-2.28). In this analysis we evaluated the interaction effects on LBW occurrence of the three factors and found no interaction effects among them.     

Maternal Hypertension as a Risk Factor for Low Birth Weight Infants: Comparison of Haitian and African-American Women

Background: The rate of low birth weight (LBW) of Black women is more than twice that of White women. This study explores if the rate of LBW differs between Haitian and African-American women with chronic hypertension. Methods: A retrospective cohort study of all Black women self-identified as African-American (n = 12,258) or Haitian (n = 4320) delivering a singleton infant in Massachusetts between 1996 and 2000. Results: Haitian women were more likely than African-American women to have chronic hypertension (2.7% vs. 2.1%, p = 0.006), but had similar rates of preeclampsia (3.1% vs. 3.3%, p = 0.27). The LBW rate was 10% among African-American women and 8.2% among Haitian women. After adjustment for sociodemographic, medical, and prenatal care characteristics, the greatest risks for delivering a LBW infant for Haitian women were chronic hypertension (OR = 6.8; 95% CI, 4.3, 10.6) and preeclampsia (OR = 3.2; 95% CI, 2.0, 5.1). For African-American women, the greatest risks for LBW infants were a history of delivering a LBW infant (OR = 3.9; 95% CI, 2.8, 5.4) and chronic hypertension (OR = 2.9; 95% CI, 2.1, 4.0). In a combined logistic regression model including interaction terms, chronic hypertension and preeclampsia continued to be associated with the greatest risk of LBW among all women. Conclusions: Differences in maternal risk factors and rates of LBW (8.2% vs. 10%) exist between Haitian and African-American women delivering infants in Massachusetts. While chronic hypertension and preeclampsia are strong risk factors for LBW for both Haitian and African-American women, unknown factors make these disorders much more potent for Haitian women.     

Physician assistants as providers of surgically induced abortion services

OBJECTIVES: We compared complication rates after surgical abortions performed by physician assistants with rates after abortions performed by physicians. METHODS: A 2-year prospective cohort study of women undergoing surgically induced abortion was conducted. Ninety-one percent of eligible women (1363) were enrolled. RESULTS: Total complication rates were 22.0 per 1000 procedures (95% confidence interval [CI] = 11.9, 39.2) performed by physician assistants and 23.3 per 1000 procedures (95% CI = 14.5, 36.8) performed by physicians (P =.88). The most common complication that occurred during physician assistant-performed procedures was incomplete abortion; during physician-performed procedures the most common complication was infection not requiring hospitalization. A history of pelvic inflammatory disease was associated with an increased risk of total complications (odds ratio = 2.1; 95% CI = 1.1, 4.1). CONCLUSIONS: Surgical abortion services provided by experienced physician assistants were comparable in safety and efficacy to those provided by physicians.     

孕前体质指数及孕期增重对新生儿出生体重影响的前瞻性队列研究

  目的   分析孕妇孕前体质指数(body mass index, BMI)及孕期增重(gestational weight gain, GWG)与新生儿出生体重的关联性, 并探究孕妇孕前及孕中体重动态变化对新生儿低出生体重(low birth weight, LBW)及巨大儿的影响。   方法   收集中国孕产妇队列·协和纳入的孕早期孕妇孕前体重, 并随访至分娩后, 收集分娩前体重及新生儿出生结局。将孕妇孕前BMI分为低体重组、正常体重组及超重/肥胖组, 将GWG分为适宜、不足及过多组。采用多因素多分类(多项)Logistic回归分析模型探讨孕前BMI及GWG与新生儿出生体重的关系。   结果   孕前BMI及GWG与子代出生体重相关(均有P < 0.05)。孕前超重/肥胖(OR=2.339, 95% CI:1.674~2.282, P < 0.001)、GWG过多(OR=1.398, 95% CI:1.188~1.978, P=0.048)显示为巨大儿的危险因素, GWG不足(OR=1.479, 95% CI:1.461~1.679, P=0.035)显示为LBW的危险因素, GWG过多会降低LBW的发生风险(OR=0.428, 95% CI:0.225~0.817, P=0.010)。低BMI-GWG不足(OR=1.335, 95% CI:1.048~2.319, P=0.048)是LBW的危险因素; 正常BMI-GWG过多(OR=1.088, 95% CI:1.016~1.675, P=0.038)和超重/肥胖-GWG过多(OR=1.498, 95% CI:1.244~2.017, P=0.046)是巨大儿的危险因素。   结论   孕前BMI及GWG是影响新生儿出生体重的重要因素, 提示女性应合理控制孕前及孕中体重变化。     

Risk of low birthweight and prematurity among foreign-born mothers.

Data collected during postnatal visits were used to study the risk of low birthweight (LBW) and prematurity among foreign-born mothers and mothers born in Canada. 2,913 singleton live births were included in the analysis. Odds ratios (OR) and 95% confidence intervals (CI) for LBW and prematurity were estimated using a logistic regression model. Foreign-born mothers did not have a higher risk of LBW or prematurity as compared to native-born mothers (OR = 1.1, 95% CI = 0.8-1.5; OR = 1.0, 95% CI = 0.7-1.4, respectively). For both LBW and prematurity, women in the intermediate category of length of stay (1-3 years) had a somewhat lower risk and women with the shortest length of stay (less than one year) had a slightly higher risk than women with the longest length of stay (more than 3 years). However, none of these results was statistically significant. Results of this study suggest that foreign-born mothers do not have a higher risk than Canadian-born mothers of bearing a LBW or premature infant. This finding differs from the widespread perception that immigrant mothers are at high risk for adverse birth outcomes.