Epidemiologie und Risikofaktoren der Frühgeburtlichkeit

A case control study, which was performed in 17 European countries, shown that social factors like education, occupation, and marital status are at least equally important risk factors for very early preterm deliveries (< 32 weeks) as for moderately early preterm deliveries (32–36 weeks). Additional maternal characteristics influencing the risk of prematurity are age, size, and body weight. The increase in risk related to maternal age, the socioeconomic status, and an unfavorable obstetrical history were higher for very early as compared to moderately early preterm deliveries. For multigravidae without an unfavorable history, the association of social status with the risk for a very early preterm delivery was stronger than for women with a second trimester abortion or a preterm delivery in previous pregnancies. In the second group, underlying medical disturbances seemed to dominate the risk for preterm delivery compared to social factors. For the high-risk group of very early preterm births, further research is needed for a better understanding of the association between different social factors and obstetrical history with very early preterm deliveries. It is hoped that a better understanding of these interactions will lead to new strategies for prevention.     

Induced abortion and risk of small-for-gestational-age birth

Objective  To investigate the possibility of an association between previous induced abortion and subsequent birth of a small-for-gestational-age (SGA) infant.
Design  Case–control study.
Setting  General and university hospitals.
Methods  Cases were 555 women who delivered SGA babies. Controls were 1966 women who gave birth at term (>37 weeks of gestation) to healthy infants of normal weight on randomly selected days at the hospital where cases had been identified. All women in the case and control categories were interviewed on the obstetric wards by one of a team of six interviewers. During the interviews, information was obtained regarding general socio-demographic factors, personal characteristics and habits, gynaecological and obstetric history, general anamnesis, family history of obstetric and gynaecological diseases, and the age of the father of the child. Further information on current pregnancy and delivery was also collected. We used conditional multiple logistic regression (with age as the matching variable), with maximum likelihood fitting, to obtain odds ratios and their corresponding 95% CIs. Included in the regression equations were terms for education, plus terms significantly associated in this data set with the risk of SGA birth (smoking in pregnancy, history of SGA, gestational hypertension and parity).
Population  Women admitted to a general and a university hospital.
Results  No significant increase in the risk of SGA birth was observed in women with a previous induced abortion [odds ratio (OR) 1.0; 95% CI 0.6–1.7]. The OR for SGA birth was 1.2 (95% CI 0.7–2.1) for preterm and 1.0 (95% CI 0.7–1.4) for term SGA births.
Conclusion  This study found no association between risk of SGA birth and induced abortion.     

Ischemic placental disease: epidemiology and risk factors

Objective

Preeclampsia, small for gestational age (SGA) and placental abruption - conditions that constitute the syndrome of “ischemic placental disease” (IPD) - may portend different clinical manifestations of a common underlying pathophysiology. We examined if (i) preeclampsia, SGA and abruption share similar risk profiles; and (ii) if there are any differences in these profiles between patients with IPD that delivered at term and preterm gestations.

Study design

We utilized data from the US Collaborative Perinatal Project, a multicenter, prospective cohort study (1959-1966), restricted to women that delivered singleton births at ≥20 weeks (n = 47,495.) We compared risk factors between women with and without IPD as well as preeclampsia, SGA and abruption.

Results

A strong overlap in risk factors for all 3 conditions was evident. Socio-economic class, income, age, parity, education, race, BMI, marital status, and history of preterm birth were different between preterm and term gestations in women with IPD. Although rates of preeclampsia only, SGA only and preeclampsia with SGA were similar between term and preterm birth, rates of other conditions were higher at preterm gestations, with abruption being the driving condition behind these associations.

Conclusions

The similar risk profiles for preeclampsia, SGA, and abruption provide compelling evidence to suggest that these conditions may share common pathophysiological mechanisms—ischemic placental disease. Greater homogeneity in risk profiles within preterm than term births suggests that IPD may be a syndrome that has strong underpinnings at preterm gestations.     

Ethnicity and birth outcome: New Zealand trends 1980-2001: Part 2. Pregnancy outcomes for Maori women

BACKGROUND: While traditionally Maori perinatal mortality has been similar to that of other ethnic groups, rates of preterm birth, small for gestational age (SGA) and teenage pregnancy have remained high. AIMS: To review current trends in preterm birth, SGA and teenage pregnancy for Maori during 1980-2001 and to highlight the major factors that have influenced Maori reproductive outcomes during this period. METHODS: De-identified birth registration data from 1 189 120 singleton live births and 5775 stillbirths were analysed for 1980-2001. Outcomes of interest included preterm birth, SGA and late fetal death while explanatory variables included maternal ethnicity, age and NZ Deprivation Index decile. Trend analysis was undertaken for 1980-1994 and multivariate logistic regression was used to explore risk factors for 1996-2001. RESULTS: During 1980-1994, Maori women had the highest preterm birth rates of any ethnic group in New Zealand, but in relative terms, inequalities declined as a consequence of a non-significant 7% fall in rates being offset by a statistically significant 30% increase for the European/other ethnic group. Rates of SGA were also higher amongst Maori women but declined by 25% during the 1980-1994 period. In addition, Maori women experienced significant socioeconomic gradients in SGA, with risk for Maori women in the most deprived NZDep areas being double that of Maori living affluent areas. Paradoxically, while Maori women had high rates of teenage pregnancy, this did not confer additional risk for preterm birth or SGA during the 1996-2001 period. CONCLUSIONS: While high rates of teenage pregnancy amongst Maori women appear not to confer additional risk for preterm birth or SGA, the social consequences of early childbearing may well be significant. The persistence of elevated rates of preterm birth and large socioeconomic gradients in SGA amongst Maori suggest that broader social and policy interventions are necessary if Maori are to achieve optimal birth outcomes in the coming decades.     

Maternal and neonatal epidemiological features in clinical subtypes of preterm birth

Objective: This study was designed to characterize and compare the maternal and newborn epidemiological characteristics through analysis of environmental factors, sociodemographic characteristics and clinical characteristics between the different clinical subtypes of preterm birth (PTB): Idiopathic (PTB-I), premature rupture of the membranes (PTB-PPROM) and medically indicated (PTB-M). The two subtypes PTB-I and PTB-PPROM grouped are called spontaneous preterm births (PTB-S).

Methods: A retrospective, observational study was conducted in 1.291 preterm nonmalformed singleton live-born children to nulliparous and multiparous mother’s in Tucumán-Argentina between 2005 and 2010. Over 50 maternal variables and 10 newborn variables were compared between the different clinical subtypes. The comparisons were done to identify heterogeneity between subtypes of preterm birth: (PTB-S) versus (PTB-M), and within spontaneous subtype: (PTB-I) versus (PTB-PPROM). In the same way, two conditional logistic multivariate regressions were used to compare the odds ratio (OR) between PTB-S and PTB-M, as well as PTB-I and PTB-PPROM. We matched for maternal age when comparing maternal variables and gestational age when comparing infant variables.

Results: The PTB-I subtype was characterized by younger mothers of lower socio-economic status, PTB-PPROM was characterized by environmental factors resulting from inflammatory processes, and PTB-M was characterized by increased maternal or fetal risk pregnancies.

Conclusions: The main risk factor for PTB-I and PTB-M was having had a prior preterm delivery; however, previous spontaneous abortion was not a risk factor, suggesting a reproductive selection mechanism.     

Preterm and term births of small for gestational age infants: a population-based study of risk factors among nulliparous women

Objective To study risk factors for small for gestational age (SGA) infants by gestational age among nulliparous women and to estimate mortality rates among SGA and appropriate-for-gestational-age (AGA) infants by gestational age.
Design A population-based study from the Swedish Medical Birth Register.
Setting Sweden 1992–1993.
Population Liveborn singleton infants to nulliparous women (   n = 96,662  ).
Main outcome measures Crude and adjusted odds ratios of risk factors for SGA by gestational age. Rates of neonatal and postneonatal mortality.
Results Older maternal age (≥ 30 years) was foremost associated with increased risks of very and moderately preterm SGA (≥ 32 weeks and 33–36 weeks, respectively), but also with term SGA (≥ 37 weeks). Risks of SGA increased with decreasing maternal height at all gestational ages. Smoking increased the risks of moderately preterm and term SGA. Short maternal education increased the risk of preterm SGA and low pre-pregnancy body mass index slightly increased the risk of term SGA. Pre-eclampsia and essential hypertension foremost increased the risk of very preterm SGA (OR = 40.5 and 32.4, respectively) and moderately preterm SGA (OR = 17.4 and 10.6, respectively), but also increased the risk of term SGA. Neonatal and postneonatal mortality rates of SGA infants were substantially influenced by gestational age, and mortality rates were consistently higher among preterm SGA infants compared with AGA infants.
Conclusions Risk factors for SGA and mortality rates among SGA infants vary by gestational age. A subdivision of risk factors by gestational age adds knowledge, particularly about risks of preterm SGA, where the highest rates of mortality were observed.     

Neighbourhood Income and Risk of Having an Infant With Concomitant Preterm Birth and Severe Small for Gestational Age Birth Weight

ObjectiveSocioeconomic position gradients have been individually demonstrated for preterm birth (PTB) at <37 weeks gestation and severe small for gestational age birth weight at <5th percentile (SGA). It is not known how neighbourhood income is related to the combination of PTB and severe SGA, a state reflective of greater placental dysfunction and higher risk of neonatal morbidity and mortality than PTB or severe SGA alone.MethodsThis population-based study comprised all 1 367 656 singleton live births in Ontario from 2002 to 2011. Multinomial logistic regression was used to estimate the odds of PTB with severe SGA, PTB without severe SGA, and severe SGA without PTB, compared with neither PTB nor severe SGA, in relation to neighbourhood income quintile (Q). The highest income quintile, Q5, served as the exposure referent. Adjusted odds ratios (aORs) were adjusted for maternal age at delivery, parity, marital status, and world region of birth (Canadian Task Force Classification II-2).ResultsRelative to women residing in Q5 (2.3 per 1000), the rate of PTB with severe SGA was highest among those in Q1 (3.6 per 1000), with an aOR of 1.34 (95% confidence interval [CI] 1.20–1.50). The corresponding aORs were 1.23 (95% CI 1.09–1.37) for Q2, 1.14 (95% CI 1.02–1.28) for Q3, and 1.06 (95% CI 0.95–1.20) for Q4. Less pronounced aORs were seen for each individual outcome of PTB and severe SGA.ConclusionWomen residing in the lowest-income areas are at highest risk of having a fetus born too small and too soon. Future research should focus on identifying those women most predisposed to combined PTB and severe SGA.     

First trimester chorionic villus sampling versus mid-trimester genetic amniocentesis--preliminary results of a controlled prospective trial

This controlled prospective study assesses the relative risks of first trimester chorionic villus sampling (CVS) versus mid-trimester gentic amniocentesis (GA). CVS subjects and amniocentesis controls were comparable with regard to several confounding variables which might influence the risk of pregnancy loss including maternal age, smoking, alcohol consumption, gestational age at study entry, and history of vaginal bleeding or poor prior reproductive outcome. The most common indication for prenatal diagnosis was advanced maternal age (n = 511). In this subgroup, spontaneous abortion (less than 24 weeks) occurred in 2.9 per cent of CVS subjects versus 4.3 per cent of amniocentesis controls. The sum of spontaneous and therapeutic abortions (less than 24 weeks) was identical (5.3 per cent) in both groups. Therefore, intervention in the CVS group (i.e., therapeutic abortion for cytogenetic abnormalities) did not influence the observed risk of pregnancy loss. Overall perinatal mortality rates were also similar in both groups. No significant differences were identified for a number of pregnancy outcome parameters including 5 min Apgar score, birth weight, body length, head circumference, gestational age at delivery, preterm delivery, fetal growth retardation, congenital malformations, and neonatal complications. Preliminary results of this controlled prospective study suggest that chorionic villus sampling carries a low and acceptable risk.     

An antenatal prediction model for adverse birth outcomes in an urban population: The contribution of medical and non-medical risks

Objectivesin the Netherlands the perinatal mortality rate is high compared to other European countries. Around eighty percent of perinatal mortality cases is preceded by being small for gestational age (SGA), preterm birth and/or having a low Apgar-score at 5 minutes after birth. Current risk detection in pregnancy focusses primarily on medical risks. However, non-medical risk factors may be relevant too. Both non-medical and medical risk factors are incorporated in the Rotterdam Reproductive Risk Reduction (R4U) scorecard.We investigated the associations between R4U risk factors and preterm birth, SGA and a low Apgar score.Designa prospective cohort study under routine practice conditions.Settingsix midwifery practices and two hospitals in Rotterdam, the Netherlands.Participants836 pregnant women.Interventionsthe R4U scorecard was filled out at the booking visit.Measurementsafter birth, the follow-up data on pregnancy outcomes were collected. Multivariate logistic regression was used to fit models for the prediction of any adverse outcome (preterm birth, SGA and/or a low Apgar score), stratified for ethnicity and socio-economic status (SES).Findingsfactors predicting any adverse outcome for Western women were smoking during the first trimester and over-the-counter medication. For non-Western women risk factors were teenage pregnancy, advanced maternal age and an obstetric history of SGA. Risk factors for high SES women were low family income, no daily intake of vegetables and a history of preterm birth. For low SES women risk factors appeared to be low family income, non-Western ethnicity, smoking during the first trimester and a history of SGA.Key conclusionsthe presence of both medical and non-medical risk factors early in pregnancy predict the occurrence of adverse outcomes at birth. Furthermore the risk profiles for adverse outcomes differed according to SES and ethnicity.Implications for practiceto optimise effective risk selection, both medical and non-medical risk factors should be taken into account in midwifery and obstetric care at the booking visit.     

The epidemiology of preterm labor

There are many factors that are associated with preterm labor and delivery. These include maternal conditions such as medical illness, anemia and uterine malformation. They may be related to past events such as prior obstetric complication, previous preterm labor, cervical surgery or induced abortion. They may be intrinsic to the current pregnancy, such as reproductive tract infection, multifetal gestation, maternal age, short interpregnancy interval or prolonged menstrual conception interval. Maternal behaviors such as smoking and substance abuse can be risk factors for a short gestation. Demographic variables such as race, employment and socioeconomic status can also be associated with preterm labor. This article briefly reviews these subjects.     

Previous induced abortions and the risk of very preterm delivery: results of the EPIPAGE study

OBJECTIVES: To evaluate the risk of very preterm birth (22-32 weeks of gestation) associated with previous induced abortion according to the complications leading to very preterm delivery in singletons. DESIGN: Multicentre, case-control study (the French EPIPAGE study). SETTING: Regionally defined population of births in France. SAMPLE: The sample consisted of 1943 very preterm live-born singletons (< 33 weeks of gestation), 276 moderate preterm live-born singletons (33-34 weeks) and 618 unmatched full-term controls (39-40 weeks). METHODS: Data from the EPIPAGE study were analysed using polytomous logistic regression models to control for social and demographic characteristics, lifestyle habits during pregnancy and obstetric history. The main mechanisms of preterm delivery were classified as gestational hypertension, antepartum haemorrhage, fetal growth restriction, premature rupture of membranes, idiopathic preterm labor and other causes. MAIN OUTCOME MEASURES: Odds ratios for very preterm birth by gestational age and by pregnancy complications leading to preterm delivery associated with a history of induced abortion. RESULTS: Women with a history of induced abortion were at higher risk of very preterm delivery than those with no such history (OR + 1.5, 95% CI 1.1-2.0); the risk was even higher for extremely preterm deliveries (< 28 weeks). The association between previous induced abortion and very preterm delivery varied according to the main complications leading to very preterm delivery. A history of induced abortion was associated with an increased risk of premature rupture of the membranes, antepartum haemorrhage (not in association with hypertension) and idiopathic spontaneous preterm labour that occur at very small gestational ages (< 28 weeks). Conversely, no association was found between induced abortion and very preterm delivery due to hypertension. CONCLUSION: Previous induced abortion was associated with an increased risk of very preterm delivery. The strength of the association increased with decreasing gestational age.     

A comparison of customized and population-based birth-weight standards: The influence of gestational age

Objectives

We examined how customized birth-weight standards compare to population birth-weight references at term (≥37 weeks), nearly term (34–36 weeks), moderately preterm (32–33 weeks) and for the very preterm births (28–31 weeks), with respect to perinatal mortality.

Study design

Data from the national Swedish Medical Births Register for the years 1992–2001, consisting of a total of 783,303 singletons born at or after 28 completed gestational weeks. Infants were classified as small for gestational age (SGA, <10th centile) according to a conventional population based birth-weight reference and a customized standard. Risk ratios (RR) for still birth and neonatal death were compared between standards by prematurity of the birth. Diagnostic performance measures of specificity, sensitivity and positive and negative predictive values were also evaluated.

Results

More than half, 59% (209), of the 355 infants still-born between 28 and 31 weeks gestation were classified as SGA by the customized standard, but only 23% (80), were so classified as SGA by the population reference. However, only 14% (95%CI 13–16) of the 1461 very preterm infants classified as SGA by the customized standard were still-born, compared to 23% (95%CI 19–28) of the 348 infants classified as SGA by the population reference. Therefore, the relative risk of still birth for those classified as SGA by the customized standard is lower, 2.02 (95%CI: 1.65, 2.46), than for the population reference 2.64 (95%CI: 2.11, 3.30). Similar results were observed for the risk of neonatal death. For term weeks, customized standards showed stronger relationships than population references (RR: 4.30 (95%CI 3.82, 4.84) vs. 4.00 (95%CI 3.55, 4.51) for still births).

Conclusions

Customized standards categorize a higher absolute number of preterm infants who are still-born as SGA. However, infants classified as SGA by population references are at higher risk of perinatal mortality than infants classified as SGA by customized standards.     

Smoking, maternal age, fetal growth, and gestational age at delivery

The relationship between smoking and maternal age and their combined effects on birth weight, intrauterine growth retardation, and preterm delivery were studied. Smoking lowers birth weight both by decreasing fetal growth and by lowering gestational age at delivery. However, the effect of smoking on both fetal growth and gestational age is significantly greater as maternal age advances. In a multiple logistic regression model adjusting for race, parity, marital status, maternal weight, weight gain, and alcohol use, smoking was associated with a fivefold increased risk of growth retardation in women older than 35 but less than a twofold increased risk in women younger than 17. Smoking reduced birth weight by 134 gm in young women but 301 gm in women older than 35. Smoking in older women also was associated with more instances of preterm delivery and a lower mean gestational age when compared to women 25 or younger.     

Outcome of pregnancies subsequent to placental abruption: a risk assessment

OBJECTIVE: To assess the risk of small for gestational age (SGA), preterm birth, pregnancy induced hypertension (PIH), and perinatal death in the pregnancy immediate subsequent to a placental abruption (PA) in the same mother. DESIGN: A cohort study based on the Medical Birth Registry of Norway. RESULTS: Odds ratios of SGA in subsequent PA- and non-PA deliveries were 2.8 (absolute risk = 18.5%) and 2.0 (13.9%), respectively, compared with non-PA deliveries without a history of previous PA among siblings (7.5%) after exclusion of cases with SGA in the immediate previous birth. After exclusion of cases with spontaneous preterm birth in the immediate previous delivery, odds ratios of spontaneous preterm birth in subsequent PA- and non-PA deliveries were 17.0 (36.3%) and 2.1 (6.6%), compared with non-PA deliveries without a history of previous PA among siblings (3.2%). After exclusion of cases with PIH in the immediate previous pregnancy, odds ratios of PIH in subsequent PA- and non-PA pregnancies were 2.9 (6.3%) and 1.6 (3.4%), compared with non-PA deliveries without a history of previous PA among siblings (2.3%). After adjustment for demographic variables and obstetrical complications, the increased risks persisted. CONCLUSION: A pregnancy following a PA must be considered a high risk pregnancy, not only in terms of excess risk of recurrence, but also due to excess risk of SGA, preterm birth, and PIH irrespective of recurrence of PA. Consequently, all pregnancies following a pregnancy with PA should be offered close antenatal surveillance and care.     

Risks of preterm delivery and small-for-gestational age infants following abortion: a population study

Summary. We examined hospital discharge records in 1980–81 for singleton third trimester deliveries in Scotland. We compared 3000 women who had previously experienced induced termination of pregnancy, and 4000 who had experienced spontaneous abortion with primigravidae and with women in their second pregnancy, their first having resulted in a litebirth. Two aspects of low birthweight were examined: delivery before the 37th completed week of gestation, and low hirth weight for gestational age. Our comparisons were further controlled for maternal height, age, sex of infant, marital status and social class. Women with previous spontaneous abortions experienced significantly increased risk of preterm delivery but not of low birthweight for gestational age. Women with a history of induced abortion also experienced increased risk of preterm delivery, but for women aged 18–24 years, risk of low birth weight for gestational a ge was significantly reduced compared with primigravidae.     

Very Low Birth-Weight (< 1,500 g) and Previous Induced Abortion: Victoria 1982–1972

In Victoria, previous termination of pregnancy is a risk factor for giving birth to a very low birth-weight infant (less than 1,500 g)--the risk of giving birth to an infant less than 1,000 g is increased more than 2.5-fold by a prior induced abortion and more than 3.5-fold by 2 or more prior abortions. However, more than 97% of women with a prior termination gave birth to infants weighing more than 1,500 g. Subsequent very preterm delivery appears to be a real but rare complication of induced abortion, responsible for about 9% of very low birth-weight infants in 1982-1983.     

Adverse obstetrical outcomes after treatment of precancerous cervical lesions: a Belgian multicentre study

Please cite this paper as: Simoens C, Goffin F, Simon P, Barlow P, Antoine J, Foidart J, Arbyn M. Adverse obstetrical outcomes after treatment of precancerous cervical lesions: a Belgian multicentre study. BJOG 2012;119:1247-1255. Objective To assess the impact of cervical intraepithelial neoplasia (CIN) treatment on the risk of (spontaneous) preterm delivery (PD) and small for gestational age (SGA) at birth. Design A multicentre cohort study. Setting Maternity wards of four academic hospitals in Belgium. Population Ninety-seven exposed pregnant women (with a CIN treatment history) and 194 nonexposed pregnant women (without a history of CIN treatment). Methods A questionnaire and check of obstetrical files included socio-demographic characteristics, risk factors for PD, obstetrical history for all women and characteristics of the CIN treatment for exposed women. Pregnancy outcomes were recorded after delivery. The influence of previous treatment of CIN on pregnancy outcomes, adjusted for confounding variables, was assessed by Cox regression and lifetables (for the outcome gestational age at birth) and by logistic regression (for the outcomes PD and SGA at birth). Main outcome measures Occurrence of PD and SGA at birth. Results Seventy-nine per cent of the women in the database were multiparous; 16.3% of women with a previous excisional treatment spontaneously delivered preterm, compared with 8.1% of unexposed women [odds ratio (OR), 2.19; 95% confidence interval (CI), 0.97-4.99]. When adjusting for confounding factors (ethnicity, HIV status, education, age, smoking and parity), the OR for PD was 2.33 (95% CI, 0.99-5.49). Excisional treatment did not have an impact on SGA at birth (OR, 0.94; 95% CI,0.41-2.15). The depth of the cone was >10?mm in 63.5% of the documented cases. Large cones, more than 10?mm deep, were associated with a significantly increased risk of PD (adjusted OR, 4.55; 95% CI, 1.32-15.65) compared with untreated women, whereas smaller cones (≤10?mm) were not significantly associated with PD (OR, 2.77; 95% CI, 0.28-27.59). The associations seen for PD with respect to the cone size did not hold for SGA at birth. Conclusions There was an increased risk of (spontaneous) PD after excision of CIN, in particular when the cone depth exceeded 10?mm.     

Mode of Delivery and Neonatal Outcomes in Preterm, Small-for-Gestational-Age Newborns

OBJECTIVE:: To compare neonatal outcomes by method of delivery in preterm (34 weeks of gestation or prior), small-for-gestational-age (SGA) newborns in a large diverse cohort. METHODS:: Birth data for 1995-2003 from New York City were linked to hospital discharge data. Data were limited to singleton, liveborn, vertex neonates delivered between 25 and 34 weeks of gestation. Births complicated by known congenital anomalies and birth weight less than 500 g were excluded. Small for gestational age was used as a surrogate for intrauterine growth restriction. Associations between method of delivery and neonatal morbidities were estimated using logistic regression. RESULTS:: Two thousand eight hundred eighty-five SGA neonates meeting study criteria were identified; 42.1% were delivered vaginally, and 57.9% were delivered by cesarean. There was no significant difference in intraventricular hemorrhage, subdural hemorrhage, seizure, or sepsis between the cesarean delivery and vaginal delivery groups. Cesarean delivery compared with vaginal delivery was associated with increased odds of respiratory distress syndrome. The increased odds persisted after controlling for maternal age, parity, ethnicity, education, primary payer, prepregnancy weight, gestational age at delivery, diabetes, and hypertension. CONCLUSION:: Cesarean delivery was not associated with improved neonatal outcomes in preterm SGA newborns and was associated with an increased risk of respiratory distress syndrome. LEVEL OF EVIDENCE:: II.     

Intrauterine growth retardation and preterm delivery: prenatal risk factors in an indigent population

Prenatally ascertained risk factors for low birth weight were evaluated in a population of 17,000 indigent women for their specific effect on intrauterine growth retardation and on the rate of preterm delivery. In a univariate analysis, intrauterine growth retardation occurred more frequently in women who were black, single, primiparous, less than 17 or greater than 30 years old, short, thin, had a previous preterm delivery, consumed alcohol, took drugs, or gained limited weight. Preterm delivery occurred significantly more frequently in women who were black, single, thin, less than 17 or greater than 30 years old, had less than a twelfth grade education, or gained limited weight. In logistic regression analyses, race, parity, maternal age, a history of preterm delivery, smoking, short stature, low weight, and low weight gain remained significant risk factors of intrauterine growth retardation. Of these factors, smoking, short stature, low weight, and low weight gain showed the greatest correlation. Factors significantly related to preterm delivery included black race, single marital status, younger or older ages, previous preterm delivery, smoking, low weight, and very low or high weight gain. A previous preterm delivery and very low maternal weight had the greatest correlation. Identification of specific risk factors of both intrauterine growth retardation and preterm delivery should aid in the development of strategies to reduce the prevalence of these conditions.     

The Effect of Maternal Age on Adverse Birth Outcomes: Does Parity Matter?

ObjectivesTo examine the effect of parity on the association between older maternal age and adverse birth outcomes, specifically stillbirth, neonatal death, preterm birth, small for gestational age, and neonatal intensive care unit admission.MethodsWe conducted a retrospective cohort study of singleton births in British Columbia between 1999 and 2004. In the cohort, 69 023 women were aged 20 to 29, 25 058 were aged 35 to 39, and 4816 were aged 40 and over. Perinatal risk factors, obstetric history, and birth outcomes were abstracted from the British Columbia Perinatal Database Registry. Logistic regression was used to calculate adjusted odds ratios (aOR) and 95% confidence intervals for adverse outcomes in the two older age groups compared with the young control subjects.ResultsCompared with younger control subjects, women aged 35 to 39 years had an aOR of stillbirth of 1.5 (95% CI 1.2 to 1.9) and women aged ≥ 40 years also had an aOR of 1.5 (95% CI 1.0 to 2.4). The aOR for NICU admission was 1.2 (95% CI 1.0 to 1.3) in women aged 35 to 39 years and 1.4 (95% CI 1.1 to 17) in women aged ≥ 40 years compared with younger control subjects. The risk of preterm birth and SGA differed by parity. The aOR for preterm birth compared with younger primiparas was 1.5 (95% CI 1.4 to 1.7) for women aged 35 to 39 years and 1.6 (95% CI 1.3 to 2.0) for women aged ≥ 40 years. In multiparas the aOR for preterm birth was 1.1 (95% CI 1.1 to 1.2) in women aged 35 to 39 and 1.3 (95% CI 1.1 to 1.5) in women > 40 years. The aOR for SGA in primiparas was 1.2 (95% CI 1.1 to 1.4) for women aged 35 to 39 and 1.4 (95% CI 1.1 to 1.7) for women aged ≥ 40 years. The risk of neonatal death was not significantly different between groups.ConclusionOlder women were at elevated risk of stillbirth, preterm birth, and NICU admission regardless of parity. Parity modified the effect of maternal age on preterm birth and SGA. Older primiparas were at elevated risk for SGA, but no association between age and SGA was found in multiparas. Older primiparas were at higher risk of preterm birth than older multiparas compared with younger women.