Is conception delay a risk factor for reduced gestation or birthweight?

Previous studies have suggested an association between delays in conception and adverse perinatal outcomes, specifically, low birthweight and preterm birth. We investigated the relationship between conception delay (defined as >6 months to become pregnant) and three perinatal outcomes: low birthweight (LBW; <2500 g), preterm birth (PTB; <37 weeks), and small-for-gestational-age (SGA; <10th percentile weight for given gestational age) using data from the Collaborative Perinatal Project. The study cohort was limited to pregnancies with a known time-to-pregnancy (n = 8465; 15%). Generalised estimating equations were used to estimate odds ratios (OR) and 95% confidence intervals [CI] for risk of adverse perinatal outcomes accounting for the clustering of pregnancy outcomes for women with more than one pregnancy. After adjusting for confounders, all ORs were close to the null (LBW, OR = 1.01; 95% CI = 0.86, 1.20), (PTB, OR = 1.10; 95% CI = 0.95, 1.27), (SGA, OR = 1.06; 95% CI = 0.91, 1.25). Thus, we found no evidence to support an adverse relationship between conception delay and decrements in gestation or birthweight among this select sample of fertile women, even after varying the cut-point for defining conception delay.     

羊水过少的不同评估标准与围生儿结局的临床分析

目的:研究不同评估标准诊断的羊水过少指标在预测不同孕周不良围生儿结局临床意义。方法:回顾性收集2007～2011年本院住院分娩孕妇18262例临床资料,对羊水指数(AFI)<5cm、AFI<该胎龄第五位百分位数与正常AFI进行比较,评估新生儿转科人数、早产人数及出生儿体重等妊娠结局。结果:18262例孕妇中,AFI<5cm孕妇中有16.03%(145例)转新生儿科[相对风险度(RR)=2.2],AFI<该胎龄第五百分位的孕妇中有16.45%(235例)转新生儿科(RR=2.37)。敏感性和特异性AFI<5cm为10.9%(95%CI:9.3%～12.7%)和95.2%(95%CI:94.9%～95.5%),AFI<该胎龄的第五百分位数为17.6%(95%CI:15.6%～19.8%)和92.5%(95%CI:92.1%～92.9%)。在预测新生儿转科方面,AFI<该胎龄AFI的第五百分位数优于AFI<5cm(P<0.001)。AFI<5cm、<该胎龄AFI的第五百分位数孕妇与正常AFI孕妇比较,孕周、羊水指数、早产及胎儿出生体重等均存在统计学差异。结论:以AFI<该胎龄的第五位百分位数作为评估羊水过少,较AFI<5cm标准可能更能有效预测胎儿不良围生儿结局。     

The Association Between Rural-Urban Continuum, Maternal Education and Adverse Birth Outcomes in Québec, Canada

ABSTRACT:  Context: Rural relative to urban area and low socioeconomic status (SES) are associated with adverse birth outcomes. Whether a graded association of increasing magnitude is present across the urban-rural continuum, accounting for SES, is unclear. We examined the association between rural-urban continuum, SES and adverse birth outcomes. Methods: Singleton births from 1999 to 2003 (n = 356,147) were linked to Québec municipalities ranked on a continuum of 3 urban and 4 rural areas based on population and economic base. Maternal education was used to represent SES. Odds ratios (OR) were calculated for preterm birth (PTB), low birth weight (LBW), and small-for-gestational-age (SGA) birth, accounting for municipality and individual-level covariates. We used stratified analyses to examine interaction between SES and rural-urban continuum. Findings: Relative to metropolitan area residence, living in small urban or rural areas was associated with adverse birth outcomes. Living in rural areas was associated with SGA birth (OR 1.11, 95% CI 1.05-1.17) and LBW (OR 1.15, 95% CI 1.05-1.26), and living in small urban areas was associated with PTB (OR 1.14, 95% CI 1.08-1.20). Upon stratification by education, living in remote rural relative to metropolitan areas was associated with adverse birth outcomes among university educated mothers only, and living in small urban areas was associated with adverse birth outcomes among mothers with lesser but not higher education. An SES gradient was present in all rural-urban areas, particularly for SGA birth. Conclusion: Differences in perinatal health exist across the rural-urban continuum, and maternal education has a modifying influence.     

Determinants of Small for Gestational Age Birth at Term

Background: Being born small for gestational age (SGA) is an indicator of intrauterine growth restriction (IUGR) and later health risks. This study investigated determinants of severe and moderate SGA (respectively, birthweight <3rd percentile and 3rd to <10th percentile for gestational age and sex). Methods: A total of 2195 term pregnancies from a prospective cohort were studied. Prenatal data arose from maternal interview at 10–22 weeks of gestation and perinatal data were collected from hospital charts. Severe and moderate SGA were classified by Canadian population standards. Risk factors for SGA were identified from fitting multivariable logistic regression models. Results: Multivariable associations with severe SGA were: maternal age ≥ 35 [odds ratio (OR) 3.2 [95% confidence interval (CI) 1.4, 6.9]], maternal smoking during pregnancy (OR 5.3 [95% CI 2.4, 11.7]), preeclampsia (OR 4.6 [95% CI 1.6, 13.2]) and threatened preterm labour (OR 3.9 [95% CI 1.3, 11.4]). Primiparity was associated with both severe and moderate SGA with OR 2.4 [95% CI 1.1, 5.1] and OR 1.9 [95% CI 1.3, 2.9] respectively. Underweight pre‐pregnancy body mass index was associated with moderate SGA (OR 2.4 [95% CI 1.2, 5.0]). Inclusion of placental weight, in the final model attenuated the associations. Conclusions: This study demonstrated different determinants for severe and moderate SGA. We speculate that the majority of severe SGA infants are IUGR while moderate SGA infants may be a mixture of IUGR and constitutionally small newborns. This study has also contributed evidence linking preterm labour and SGA as two, potentially related, outcomes of overlapping causal mechanisms reflective of ischaemic placental disease.     

Maternal coffee drinking in pregnancy and risk of small for gestational age birth

OBJECTIVE: We have analysed the association between coffee drinking before and during the three trimesters of pregnancy and risk of small for gestational age (SGA) birth. METHODS: Cases were 555 women who delivered SGA births (ie <10th percentile according Italian standard). The controls included 1966 women who gave birth at term (>/=37 weeks of gestation) to healthy infants of normal weight. RESULTS: In comparison with nondrinkers, the ORs for SGA birth were 1.3 (95% confidence interval, CI, 0.9-1.9) for consumption of four or more cups of coffee/day before pregnancy, and 1.2 (95% CI 0.8-1.8), 1.2 (95% CI 0.8-1.8) and 0.9 (95% CI 0.6-1.4) for consumption of three or more cups of coffee/day during the first, second and third trimester of pregnancy, respectively. CONCLUSION: These findings were consistent in women who delivered preterm and at term births and were not affected by potential confounding such as smoking.     

Adverse perinatal and neonatal outcomes and their determinants in rural Vietnam 1999-2005

Population-based estimations of perinatal and neonatal outcomes are sparse in Vietnam. There are no previously published data on small for gestational age (SGA) infants. A rural population in northern Vietnam was investigated from 1999 to 2005 (n=5521). Based on the birthweight distributions within the population under study, reference curves for intrauterine growth for Vietnamese infants were constructed and the prevalence and distribution of SGA was calculated for each sex. Neonatal mortality was estimated as 11.6 per 1000 live births and the perinatal mortality as 25.0 per 1000 births during the study period. The mean birthweight was 3112 g and the prevalence of low birthweight was 5.0%. The overall prevalence of SGA was 6.4%. SGA increased with gestational age and was 2.2%, 4.5% and 27.1% for preterm, term and post-term infants, respectively. Risk factors for SGA were post-term birth: adjusted odds ratio (AOR) 7.75 [95% CI 6.02, 9.98], mothers in farming occupations AOR 1.72 [95% CI 1.21, 2.45] and female infant AOR 1.61 [95% CI 1.27, 2.03]. There was a pronounced decrease in neonatal mortality after 33 weeks of gestation. Suggested interventions are improved prenatal identification of SGA infants by ultrasound investigation for fetal growth among infants who do not follow their expected clinical growth curve at the antenatal clinic. Other suggestions include allocating a higher proportion of preterm deliveries to health facilities with surgical capacity and neonatal care.     

Familial aggregation of fetal growth restriction in a French cohort of 7,822 term births between 1971 and 1985

An association between fetal growth restriction and increased rates of metabolic and cardiovascular diseases in adulthood has been reported. This study evaluated familial aggregation of fetal growth restriction in term births. The population consisted of 3,505 sibships comprised of 7,822 full-term singleton infants born between 1971 and 1985 in Haguenau, France, and selected from a regional register of births. Sib-sib odds ratios were estimated for being born small for gestational age (SGA), defined as having a birth weight below the 10th percentile of the sex-specific curve of birth weight by week of gestation. SGA births were further stratified according to ponderal index (birth weight/length(3)). After adjustment for maternal factors, the sib-sib odds ratios were 4.8 (95% confidence interval (CI): 3.7, 6.3) for all SGA births, 7.7 (95% CI: 4.1, 14.7) for SGA births with a low ponderal index (<10th percentile), and 4.4 (95% CI: 2.3, 8.2) for SGA births with a normal ponderal index (25th-75th percentile). None of the maternal factors investigated significantly influenced the magnitude of these odds ratios. This strong residual sib-sib aggregation suggests a role for genetic and/or shared environmental factors in the etiology of fetal growth restriction, especially when associated with a low ponderal index.     

The predictive ability of conditional fetal growth percentiles

Hutcheon JA, Egeland GM, Morin L, Meltzer SJ, Jacobsen G, Platt RW. The predictive ability of conditional fetal growth percentiles. Paediatric and Perinatal Epidemiology 2010; 24: 131–139. Conditional fetal growth percentiles are percentiles that are calculated taking into account (conditional on) an infant's weight earlier in pregnancy. Although they have been proposed in the statistical literature as a more methodologically appropriate method of measuring fetal growth, their ability to predict adverse perinatal outcomes due to fetal growth restriction is unknown. Using a large, unselected clinical ultrasound database at the Royal Victoria Hospital in Montreal, Canada, we calculated conditional growth percentiles for infants' weight at birth, given their weight at the time of a routine 32‐ or 33‐week ultrasound. The risk of adverse perinatal outcome (perinatal mortality, low Apgar, acidaemia, or seizures/organ failure due to asphyxia) among small‐for‐gestational‐age infants (SGA) as established by conditional growth percentiles was calculated as well as the risk among infants classified as SGA by conventional weight‐for‐gestational‐age percentiles. Regardless of the threshold used to define SGA (fifth, 10th, 15th, 20th), conditional percentiles did not appear to improve the identification of adverse perinatal outcomes compared with conventional weight‐for‐gestational‐age charts. Further work is needed to confirm our results as well as to explore potential reasons for the lack of benefits from using a measure of growth instead of size to identify fetal growth restriction.     

小于胎龄儿产科危险因素的病例对照研究

目的探讨产科因素及孕母文化程度与小于胎龄儿（SGA）之间的关系。方法采用病例对照方法，选取于2000年1月至2004年10月在第三医院出生的单胎活产SGA，全部病例共834例（男443例，女391例）作为病例组。以胎儿性别及出生胎龄进行频数匹配，按1：3的比例，采用完全随机抽样方法选取性别及胎龄别出生体重在10％～90％分位的适于胎龄儿2502名（男1329名，女1173名）为对照组，比较了病例组及对照组新生儿母亲年龄、文化程度及主要产科危险因素的比例。结果多因素logistic回归分析显示，SGA病例组母亲妊娠合并妊娠高血压综合征（妊高征）、羊水过少、有既往异常妊娠史和病毒性肝炎与对照组比较，OR值（95％Cj）分别为4．00（2．81～5．71）、2．95（2．27～3-83）、5．95（3．05～10．64）和0．50（0．30～0．84）；SGA母亲为初中及以下文化程度者与大专或以上文化程度者比较OR=3．46（95％CI：2．75～4．24）。其他因素与SGA无统计学意义的关联。结论孕母文化程度低、孕期合并妊高征、羊水过少、不良妊娠史可显著增加SGA发生的危险性。     

Use of prenatal health care and risk of infants born small-for-gestational-age. Preliminary results of a case-control study in the Lódź voivodeship

It is well documented that small-for-gestational age (SGA) infants are at an increased risk of perinatal mortality and morbidity. In order to identify the major modifiable risk factors of SGA birth, a case-control study was launched in the area of Lód? voivodeship, Poland. The project was focused on the evaluation of the role of perinatal health services and avoidance of exposure to tobacco smoke in the prevention of SGA births. The study population consisted of mothers of 153 SGA infants (cases) and 93 mothers of control infants. SGA infants were identified as infants with body weight below 10th percentile for gestational age, using Ballarda scale. The controls were non-SGA infants delivered after 37 week of gestation. The infants from both groups were delivered in 26 maternity wards in the Lód? voivodeship within the period of June 1-November 1, 2003. One month after delivery, each mother of SGA and control infants was visited by an interviewer who collected information about her profile of use of perinatal health care and on active and passive exposure to tobacco smoke in pregnancy. Odds ratios and 95% confidence units (CU) were calculated using EpiInfo software developed by CDC, Atlanta, Georgia, US. Late booking for perinatal care (after 12 week of gestation) and less than 5 visits during pregnancy was found to be related to an increased risk of SGA, however, the OR values included unity. About 1/3 of mothers of SGA infants and "of the controls were served mainly by the private health sector. The use of private care was related to a lower risk of SGA: OR= 0.55 95% CI (0.31-0.96). This protective pattern was observed in the population of women aged 19-25 living in rural areas years and with only primary education. The preconception visits to obstetricians and contacts with health educators during pregnancy were also found to have some protective effect, however, the ORs were not statistically significant. The adverse effect of smoking during pregnancy was clearly confirmed in the study population, OR= 2.69 95%CI (1.37-5.33), while the role of passive smoking was difficult to assess due to the small number of nonsmoking women exposed to ETS. There are some indications that the poor use of perinatal health services may account for the elevated risk of SGA births in the Lód? voivodeship. The use of the private health sector is growing and seems to be related to a lower risk of SGA births. More effective tools to prevent maternal smoking have to be developed and implemented in routine perinatal care.     

Maternal occupation and adverse pregnancy outcomes: a Finnish population-based study

BACKGROUND: There is accumulating evidence that the type of work and environmental exposures in the working environment may have adverse effects on foetal development. AIM: To compare the risk of low birth weight (LBW), small-for-gestational age (SGA) and pre-term delivery (PD) in broad categories of maternal occupation including farming and forestry; factory, mining and construction; office, non-manual and service work and housewives. METHODS: The study population consisted of 2568 singleton newborns of women who participated in The Finnish Prenatal Environment and Health Study after the delivery (response rate 94%). Information on maternal occupation and work during pregnancy was collected after the delivery. The health outcomes were LBW (<2500 g), SGA and PD (<37 weeks). RESULTS: In newborns of women working in factories, mining and construction, the risk of LBW (adjusted odds ratio [OR] 3.66, 95% confidence interval [CI] 1.15-11.62), SGA (adjusted OR 1.53, 95% CI 0.73-3.21), but not the risk of PD (adjusted OR 0.64, 95% CI 0.19-2.22), was higher compared with newborns of housewives. In newborns of farmers and forestry workers, the risks of PD (adjusted OR 2.38, 95% CI 1.01-5.65), LBW (adjusted OR 2.86, 95% CI 0.78-11.58) and SGA (adjusted OR 1.51, 95% CI 0.62-3.65) were all elevated. In office, non-manual and service workers, the corresponding estimates were lower (LBW: 1.62, 0.67-3.95; SGA: 1.45, 0.92-2.28; PD: 1.18, 0.69-2.01). CONCLUSIONS: There were substantial differences in the risk of adverse pregnancy outcomes between the main branches of industry.     

Human chorionic gonadotropin (hCG) concentrations during the late first trimester are associated with fetal growth in a fetal sex-specific manner

Human chorionic gonadotropin (hCG) is a pregnancy-specific hormone that regulates placental development. hCG concentrations vary widely throughout gestation and differ based on fetal sex. Abnormal hCG concentrations are associated with adverse pregnancy outcomes including fetal growth restriction. We studied the association of hCG concentrations with fetal growth and birth weight. In addition, we investigated effect modification by gestational age of hCG measurement and fetal sex. Total serum hCG (median 14.4 weeks, 95 % range 10.1–26.2), estimated fetal weight (measured by ultrasound during 18–25th weeks and >25th weeks) and birth weight were measured in 7987 mother–child pairs from the Generation R cohort and used to establish fetal growth. Small for gestational age (SGA) was defined as a standardized birth weight lower than the 10th percentile of the study population. There was a non-linear association of hCG with birth weight (P = 0.009). However, only low hCG concentrations measured during the late first trimester (11th and 12th week) were associated with birth weight and SGA. Low hCG concentrations measured in the late first trimester were also associated with decreased fetal growth (P = 0.0002). This was the case for both male and female fetuses. In contrast, high hCG concentrations during the late first trimester were associated with increased fetal growth amongst female, but not male fetuses. Low hCG in the late first trimester is associated with lower birth weight due to a decrease in fetal growth. Fetal sex differences exist in the association of hCG concentrations with fetal growth.     

Association of periconceptional multivitamin use and risk of preterm or small-for-gestational-age births

The authors' objective was to determine the relation between periconceptional multivitamin use and the risk of small-for-gestational-age (SGA: <5th percentile; 5th-<10th percentiles) or preterm (<34 weeks; 34-<37 weeks) births. Women in the Pregnancy Exposures and Preeclampsia Prevention Study (1997-2001) reported at enrollment their regular multivitamin use in the past 6 months (n=1,823). Women were classified as users or nonusers in multinomial logistic models. After adjustment for race, age, education, enrollment gestational age, and household density, periconceptional multivitamin use was associated with a reduced risk of preterm births (<34 weeks) (odds ratio (OR)=0.29, 95% confidence interval (CI): 0.13, 0.64) and spontaneous preterm births (<34 weeks) (OR=0.40, 95% CI: 0.16, 0.99). Risk of SGA (<5th percentile) was marginally lower (OR=0.64, 95% CI: 0.40, 1.03) after adjustment for smoking, education, parity, enrollment gestational age, and body mass index. Prepregnancy body mass index modified this relation. Nonobese users had a reduction (OR=0.54, 95% CI: 0.32, 0.91) in risk of SGA (<5th percentile); there was no effect among obese women. There was no effect of multivitamin use on risk of preterm births (34-<37 weeks) or SGA (5th-<10th percentiles). Sensitivity analysis for unmeasured confounding by folate intake supported these findings. Study results indicate lower rates of severe preterm births and extreme SGA in women who report periconceptional vitamin use, although these should be considered cautiously until replicated.     

Preconception homocysteine and B vitamin status and birth outcomes in Chinese women

BACKGROUND: The associations between homocysteine, B vitamin status, and pregnancy outcomes have not been examined prospectively. OBJECTIVE: We assessed the associations of preconception homocysteine and B vitamin status with preterm birth and birth of low-birth-weight (LBW) and small-for-gestational-age (SGA) infants in Chinese women. DESIGN: This was a case-control study of women aged 21-34 y. Preterm cases (n = 29) delivered living infants at <37 wk gestation; term controls (n = 405) delivered infants at > or =37 wk. LBW cases (n = 33) had infants weighing <2500 g; normal-birth-weight controls (n = 390) had infants weighing > or =2500 g. SGA cases (n = 65) had infants below the 10th percentile of weight-for-gestational-age; appropriate-for-gestational-age controls (n = 358) had infants above this cutoff. Nonfasting plasma concentrations of homocysteine, folate, and vitamins B-6 and B-12 were measured before conception. RESULTS: Elevated homocysteine (> or =12.4 micro mol/L) was associated with a nearly 4-fold higher risk of preterm birth (OR: 3.6; 95% CI: 1.3, 10.0; P < 0.05). The risk of preterm birth was 60% lower among women with vitamin B-12 > or =258 pmol/L than among vitamin B-12-deficient women (OR: 0.4; 95% CI: 0.2, 0.9; P < 0.05) and was 50% lower among women with vitamin B-6 > or =30 nmol/L than among vitamin B-6-deficient women (OR: 0.5; 95% CI: 0.2, 1.2; NS). Folate status was not associated with preterm birth, and homocysteine and B vitamin status were not associated with LBW or SGA status. CONCLUSIONS: Elevated homocysteine and suboptimal vitamin B-12 and B-6 status may increase the risk of preterm birth. These results need to be confirmed in larger prospective studies.     

Neighbourhood deprivation and small-for-gestational-age term births in the United States

Residential context has received increased attention as a possible contributing factor to race/ethnic and socio-economic disparities in birth outcomes in the United States. Utilising vital statistics birth record data, this study examined the association between neighbourhood deprivation and the risk of a term small-for-gestational-age (SGA) birth among non-Hispanic whites and non-Hispanic blacks in eight geographical areas. An SGA birth was defined as a newborn weighing <10th percentile of the sex- and parity-specific birthweight distribution for a given gestational week. Multi-level random intercept logistic regression models were employed and statistical tests were performed to examine whether the association between neighbourhood deprivation and SGA varied by race/ethnicity and study site.
The risk of term SGA was higher among non-Hispanic blacks (range 10.8–17.5%) than non-Hispanic whites (range 5.1–9.2%) in all areas and it was higher in cities than in suburban locations. In all areas, non-Hispanic blacks lived in more deprived neighbourhoods than non-Hispanic whites. However, the adjusted associations between neighbourhood deprivation and term SGA did not vary significantly by race/ethnicity or study site. The summary fully adjusted pooled odds ratios, indicating the effect of one standard deviation increase in the deprivation score, were 1.15 [95% CI 1.08, 1.22] for non-Hispanic whites and 1.09 [95% CI 1.05, 1.14] for non-Hispanic blacks. Thus, neighbourhood deprivation was weakly associated with term SGA among both non-Hispanic whites and non-Hispanic blacks.     

Cocaine and cigarettes: a comparison of risks

Summary. In order to provide additional data and perspective to current clinical, policy, and legal debates surrounding the prenatal use of cocaine in the USA, a retrospective cohort study was conducted to examine effects of cocaine on selected perinatal outcomes, and to compare the relative risks of adverse perinatal outcomes among users of cocaine and users of cigarettes. Using data from a large urban perinatal registry, relative risks of selected perinatal outcomes were determined for maternal cocaine users who were non-smokers of cigarettes, and used no marijuana, heroin, amphetamines, or alcohol (n = 64), and for cigarette smokers who do not use illicit drugs or alcohol during pregnancy (n = 3209). When compared with women with no recorded prenatal exposure to drugs or cigarettes (n = 13043), cocaine users had higher risks than smokers for the following adverse outcomes: low birthweight [Relative Risk (RR) 5.3, 95% Confidence Interval (CI) 3.0–9.3], small-for-ges-tational age (SGA) [RR4.2, 95% CI 2.4–7.3], prematurity [RR4.0, 95% CI 2.3–7.0], abruptio placentae [RR = 10.0,95% CI 3.5–29.0], placenta prae-via [RR = 2.4, 95% CI 0.3–17.8] and perinatal death [RR = 5.3, 95% CI 1.9–15.2]. Smokers who did not use any drugs experienced most of the same adverse perinatal outcomes as cocaine users, but the magnitude of risk was greater in cocaine users than in smokers for all outcomes. However, given the greater numbers of cigarette smokers than cocaine users in the population the numbers of infants in the population suffering these adverse outcomes is likely to be greater among offspring of cigarette smokers. The data support current concern about the risk of cocaine, and current efforts to provide treatment to pregnant cocaine users. The data also underline the continued substantial risks of cigarette smoking to large numbers of pregnant women.     

The associations of birth intervals with small-for-gestational-age,preterm, and neonatal and infant mortality: a meta-analysis

Background

Short and long birth intervals have previously been linked to adverse neonatal outcomes. However, much of the existing literature uses cross-sectional studies, from which deriving causal inference is complex. We examine the association between short/long birth intervals and adverse neonatal outcomes by calculating and meta-analyzing associations using original data from cohort studies conducted in low-and middle-income countries (LMIC).

Methods

We identified five cohort studies. Adjusted odds ratios (aOR) were calculated for each study, with birth interval as the exposure and small-for-gestational-age (SGA) and/or preterm birth, and neonatal and infant mortality as outcomes. The associations were controlled for potential confounders and meta-analyzed.

Results

Birth interval of shorter than 18 months had statistically significant increased odds of SGA (pooled aOR: 1.51, 95% CI: 1.31-1.75), preterm (pooled aOR: 1.58, 95% CI: 1.19-2.10) and infant mortality (pooled aOR: 1.83, 95% CI: 1.19-2.81) after controlling for potential confounding factors (reference 36-<60 months). It was also significantly associated with term-SGA, preterm-appropriate-for-gestational-age, and preterm-SGA. Birth interval over 60 months had increased risk of SGA (pooled aOR: 1.22, 95% CI: 1.07-1.39) and term-SGA (pooled aOR: 1.14, 95% CI: 1.03-1.27), but was not associated with other outcomes.

Conclusions

Birth intervals shorter than 18 months are significantly associated with SGA, preterm birth and death in the first year of life. Lack of access to family planning interventions thus contributes to the burden of adverse birth outcomes and infant mortality in LMICs. Programs and policies must assess ways to provide equitable access to reproductive health interventions to mothers before or soon after delivering a child, but also address underlying socioeconomic factors that may modify and worsen the effect of short intervals.

     

The impact of maternal education on intrauterine growth: a comparison of former West and East Germany

BACKGROUND: Objective of this re-analysis of datasets from former East and West Germany was to examine the influence of maternal education on intrauterine growth in two different political and social systems. METHODS: Information on socio-demographic or lifestyle factors and pregnancy outcome was available for 3374 liveborn singletons from West Germany (1987/88) and 3070 from East Germany (1990/91). Multiple logistic regression was used to estimate the association between maternal education and the risk of delivering a small-for-gestational-age (SGA) newborn below the 10th percentile of birthweight. RESULTS: Women with the lowest education had a significantly elevated risk of SGA newborns compared to women with the highest education in West (odds ratio [OR] = 2.58, 95% CI : 1.17-5.67) and East Germany (OR = 2.77, 95% CI : 1.54- 5.00). The distribution of factors known to influence intrauterine growth varied with education in both states. After adjusting for these factors, women with the lowest educational level still had a higher risk of SGA birth: OR (West) = 2.02, 95% CI : 0.87-4.72; OR (East) = 1.95, 95% CI : 1.02-3.74. CONCLUSIONS: Our findings support the assumption that in former socialist countries health inequalities as a result of social inequalities existed.     

Low levels of ambient air pollution during pregnancy and fetal growth among term neonates in Brisbane, Australia

There is mounting evidence that maternal exposure to ambient air pollution during pregnancy is associated with adverse birth outcomes. We examined birth weight and small for gestational age (SGA <10th percentile for age and gender) among 26,617 singleton full-term births in Brisbane, Australia (July 2000-June 2003), in relation to ambient pollution during pregnancy. We also examined head circumference (HC) and crown-heel length (CHL) among a sub-sample (n=21,432) of the term neonates. Maternal exposure to PM(10), visibility reducing particles (bsp), O(3) and NO(2) was assessed by calculating average exposure estimates over months and trimesters of pregnancy based on a citywide average of the pollutants. Linear and logistic regression models were employed to examine the effect of these pollutants on the birth outcomes after adjusting for potential confounders and season of birth. The regression coefficients were based on an inter-quartile range (IQR) increase in exposure as well as quartiles of exposure with the lowest used as a reference category. Trimester- and monthly specific exposures to all pollutants were not significantly associated with a reduction in either birth weight or HC, or an increased risk of SGA. An IQR increase in NO(2) during the third trimester was associated with a reduction in CHL (beta=-0.15cm, 95% CI -0.25 to -0.05cm) and this was concentrated around exposure during month nine. No other pollutants were associated with a reduction in CHL. In conclusion, there was no strong evidence suggesting that ambient air pollution during pregnancy is associated with sub-optimal fetal growth in Brisbane.