Multiethnic variations in the pregnancy outcomes of military dependents.

OBJECTIVES. We examined the pregnancy outcomes of three ethnic groups: African-American Blacks, non-Hispanic Whites, and Filipinos. In an attempt to reduce ethnic dissimilarities in parental employment and access to health care, this investigation compared the single-live-birth outcomes of married, adult women who resided in the state of Hawaii and who indicated that their spouse was on active-duty status in the US military. METHODS. The data for this study were obtained from the 1979-1989 Hawaii vital-record file that provides linked live birth-infant death information. Multiple logistic regression was used to calculate odds ratios for the independent effects of maternal factors on low birthweight and neonatal mortality. RESULTS. Significant differences in maternal age, maternal education, paternal education, parity, hospital of delivery, and use of prenatal care were observed among the ethnic groups. The results of a logistic regression analysis of low birthweight indicated significantly higher risks for Filipinos and Blacks compared with Whites. For very low birthweight, only an increased risk for Blacks was observed. No ethnic differences in neonatal mortality were found. CONCLUSIONS. This investigation revealed more comparable infant mortality experiences among the ethnic groups in spite of persistent birthweight differences.     

Rates of preterm delivery among Black women and White women in the United States over two decades: an age-period-cohort analysis

The authors assessed the influence of age, period, and cohort effects on rates of preterm delivery in the United States. Rates of preterm delivery for singleton births (<37 weeks) in seven age groups (15-19, 20-24,., 45-49 years), five periods (1975, 1980, 1985, 1990, 1995), and 11 maternal birth cohorts (1926-1930, 1931-1935,., 1976-1980) were examined. Over the 20-year study interval, preterm delivery increased by 3.6% among Blacks (from 15.5% in 1975 to 16.0% in 1995) and by 22.3% among Whites (from 6.9% to 8.4%). Among Black primigravid women, rates of preterm delivery increased from 1975 to 1990 and began to decline thereafter; among Whites, the rates increased between 1975 and 1995. In Blacks, women aged 25-29 years had the lowest rates for the first and second births, and women aged 30-34 years had the lowest rate for subsequent births. In Whites, the age groups with the lowest preterm delivery rates were 20-24 years for first births and 25-29 years for subsequent births. Cohort-specific rates of preterm delivery remained fairly constant across age strata and periods for Whites, but a small trend was apparent for Blacks aged 30-44 years. The consistency of the observed age effects across periods and cohorts suggests that the age effect is partly due to biologic factors. The presence of period effects might be linked to the increased survival of premature infants or to increased viability among births occurring at lower lengths of gestation.     

Histologic chorioamnionitis and preterm delivery

Inconsistent findings linking placental histologic chorioamnionitis (HCA) and preterm delivery may result from variations in HCA definition, population studied, and exclusion criteria. This analysis from the 1998-2004 Pregnancy Outcomes and Community Health Study (five Michigan communities) includes the first 1,053 subcohort women (239 preterm, 814 term) with completed placental assessments. Multiple HCA definitions were constructed by 1) varying polymorphonuclear leukocytes/high-powered field thresholds and placenta components included and 2) using polymorphonuclear leukocyte characteristics to assign low/high maternal, fetal inflammation stage and grade. In African Americans, HCA was associated with preterm delivery before 35 weeks. The effect size was modest for polymorphonuclear leukocytes/high-powered field thresholds of greater than 10 and greater than 30 (odds ratios (ORs) = 0.8 and 2.0); larger for greater than 100 (OR = 3.2, 95% confidence interval (CI): 1.4, 7.1); strengthened after excluding medically indicated preterm deliveries (OR = 4.9, 95% CI: 2.0, 11.8); and strongest for high maternal/high fetal HCA (OR = 5.6, 95% CI: 1.4, 22.1). These latter HCA criteria also produced the largest effect size in Whites/others (OR = 2.7, 95% CI: 0.3, 26.9). Among preterm deliveries before 35 weeks excluding those medically indicated, 12% of Whites/others and 55% of African Americans had high maternal HCA. The authors conclude that HCA definition, exclusion criteria, and race/ethnicity influence the HCA-preterm delivery association and that HCA contributes to preterm delivery-related ethnic disparity.     

Maternal age and parity-associated risks of preterm birth: differences by race/ethnicity

There is a well-known interaction between maternal age and parity in the risk of adverse perinatal outcomes, including preterm birth (PTB), such that young multiparae and older primiparae have greater risks. Yet it is not known whether this interaction varies by race/ethnicity. US birth records for singleton births from 2000 to 2002 were used to examine the incidence of PTB by maternal age and parity within non-Hispanic White, non-Hispanic Black and Hispanic subgroups. PTB was categorised as moderately (32-36 weeks), very (28-31 weeks), or extremely (<28 weeks) preterm. Odds ratios of PTB according to age and parity were calculated in racial/ethnic specific multinomial logistic regression models. Within each race/ethnicity, comparisons were made relative to 25- to 29-year-old primiparae. Young teenagers (<18), particularly multiparae, generally had a higher risk of each degree of PTB among all three racial/ethnic groups. However, Black teenagers did not have a higher risk of extremely PTB. For very and extremely PTB, teenagers had considerably higher risk among Whites than Blacks or Hispanics. Within each racial/ethnic group, older (35+ years) primiparae had similarly higher risk of each category of PTB relative to 25- to 29-year-old primiparae. Older multiparae had higher risk of moderately and very PTB among Black and Hispanic women only. Adjustment for education did not alter these findings. Teenagers and older primiparae are already widely regarded as having greater perinatal risks. This study suggests that, among Black and Hispanic women, older multiparae may also have a higher risk of moderately and very PTB.     

Racial/ethnic disparities in mortality by stroke subtype in the United States, 1995-1998.

Healthy People 2010 objectives for improving health include a goal to eliminate racial disparities in stroke mortality. Age-specific death rates by stroke subtype are not well documented among racial/ethnic minority populations in the United States. This report examines mortality rates by race/ethnicity for three stroke subtypes during 1995-1998. National Vital Statistics' death certificate data were used to calculate death rates for ischemic stroke (n = 507,256), intracerebral hemorrhage (n = 97,709), and subarachnoid hemorrhage (n = 27,334) among Hispanics, Blacks, American Indians/Alaska Natives, Asians/Pacific Islanders, and Whites by age and sex. Comparisons with Whites as the referent were made using age-standardized risk ratios and age-specific risk ratios. Age-standardized mortality rates for the three stroke subtypes were higher among Blacks than Whites. Death rates from intracerebral hemorrhage were also higher among Asians/Pacific Islanders than Whites. All minority populations had higher death rates from subarachnoid hemorrhage than did Whites. Among adults aged 25-44 years, Blacks and American Indians/Alaska Natives had higher risk ratios than did Whites for all three stroke subtypes. Increased public health attention is needed to reduce incidence and mortality for stroke, the third leading cause of death. Particular attention should be given to increasing awareness of stroke symptoms among young minority groups.     

The influence of maternal age on very preterm birth of twins: differential effects by parity

For singleton births, parity can modify the effect of maternal age on birth outcomes such as low birthweight and preterm birth; however, it is unknown whether this relationship exists for twin births. As the rate of twin births increases among older women, it is important to understand how parity may influence the relationship between maternal age and adverse birth outcomes. The NCHS Matched Multiple Birth Data Set, which contains all twin births in the USA from 1995 to 1998, was analysed. Parity was grouped into two levels (primiparous--no prior live births, and multiparous--at least one prior live birth), and maternal age was divided into the following groups: 20-24, 25-29, 30-34, 35-39, and 40 years or more. Very preterm birth was defined as births occurring before 33 weeks. Logistic regression was used to obtain odds ratios (OR) to estimate the risk of very preterm birth, and to determine the relationships between parity, maternal age, and very preterm birth. Among primiparae, women 40 years and older had a reduced risk of very preterm birth compared with women of 25-29 years (OR 0.74 [95% CI=0.66, 0.84]). Among multiparae, women 40 years and older had the same risk of very preterm birth compared with women of 25-29 years (OR 1.00 [95% CI=0.90, 1.12]). However, stratification by education revealed that the age gradient was limited to women with >12 years education among primiparae. The effect of maternal age on very preterm birth of twins differs according to parity. To some extent, that effect is further modified by education. Therefore, future analyses of maternal age and twin birth outcomes should account for measures of obstetric history and other factors, which may influence these results.     

Neighborhood deprivation and preterm birth among non-Hispanic Black and White women in eight geographic areas in the United States

Disparities in preterm birth by race and ethnic group have been demonstrated in the United States. Recent research has focused on the impact of neighborhood context on racial disparities in pregnancy outcomes. The authors utilized vital-record birth certificate data and US Census data from eight geographic areas in four states (Maryland, Michigan, North Carolina, and Pennsylvania) to examine the relation between neighborhood deprivation and preterm birth among non-Hispanic White and Black women. The years covered by the data varied by site and ranged from 1995 to 2001. Results were adjusted for maternal age and education, and specific attention was paid to racial and geographic differences in the relation between neighborhood deprivation and preterm birth. Preterm birth rates were higher for non-Hispanic Blacks (10.42-15.97%) than for non-Hispanic Whites (5.77-9.13%), and neighborhood deprivation index values varied substantially across the eight areas. A significant association was found between neighborhood deprivation and risk of preterm birth; for the first quintile of the deprivation index versus the fifth, the adjusted summary odds ratio was 1.57 (95% confidence interval: 1.41, 1.74) for non-Hispanic Whites and 1.15 (95% confidence interval: 1.08, 1.23) for non-Hispanic Blacks. In this study, deprivation at the neighborhood level was significantly associated with increased risk of preterm birth among both non-Hispanic White women and non-Hispanic Black women.     

Does gestation vary by ethnic group? A London-based study of over 122,000 pregnancies with spontaneous onset of labour

BACKGROUND: Evidence exists that normal gestational length varies with ethnicity. This UK-based study compares gestational length amongst a cohort of white European, Black and Asian women. METHODS: The cohort comprised 122 415 nulliparous women with singleton live fetuses at the time of spontaneous labour, giving birth in the former North West Thames Health Region, London, UK. RESULTS: The median gestational age at delivery was 39 weeks in Blacks and Asians and 40 weeks in white Europeans. Black women with normal body mass index (BMI) (18.5-24.9 kg/m(2)) had increased odds of preterm delivery (odds ratio [OR] = 1.33, 95% CI: 1.15, 1.56, adjusted for deprivation and BMI) compared with white Europeans. The OR of preterm delivery was also increased in Asians compared with white Europeans (OR = 1.45, 95% CI: 1.33, 1.56, adjusted for single unsupported status and smoking). Meconium stained amniotic fluid, which is a sign of fetal maturity, was statistically significantly more frequent in preterm Black and Asian infants and term Black infants compared with white European infants. CONCLUSIONS: This research suggests that normal gestational length is shorter in Black and Asian women compared with white European women and that fetal maturation may occur earlier.     

Mexican-Americans' use of prenatal care and its relationship to maternal risk factors and pregnancy outcome.

We evaluate the adequacy of prenatal care use and the association of use to a series of maternal risk factors and pregnancy outcomes, such as low birthweight, preterm delivery, and macrosomia in both Mexican-Americans and non-Hispanic whites in Arizona. The data came from all live-birth certificates from 1986 and 1987 for a total of 101,202 (26,826 Mexican-Americans). We evaluated the adequacy of prenatal care using a redesigned index that accounts for three factors: the month when prenatal care began, the number of prenatal care visits, and the duration of pregnancy. From this index we identified six prenatal care groups: intensive, adequate, intermediate, inadequate, no-care, and missing/unknown. Overall, we observed ethnic differences in patterns of prenatal care use, social profiles, and medical risk factors. Non-Hispanic whites, compared to Mexican-Americans, showed a greater risk for low birthweight and preterm delivery in those groups receiving poor prenatal care versus those who received adequate care. Within Mexican-Americans the risk of low birthweight was not the same for all subgroups. A higher overall prevalence of preterm delivery and macrosomia in comparison to low birthweight occurred in Mexican-Americans. We discuss the implications of the results for the identification, interpretation, evaluation, and public health significance of perinatal health problems of Mexican-Americans.     

Paternal age and preterm birth

BACKGROUND: There is growing evidence that advanced paternal age can be a reproductive hazard. METHODS: We studied couples and their first children using nationwide registers in Denmark between 1980 and 1996. We restricted the analysis to mother's age 20-29 years. We estimated odds ratios (ORs) of preterm (< 37 weeks gestation) and very preterm birth (< 32 weeks) as a function of paternal age using logistic regression to adjust for potential confounding variables. RESULTS: The risk of preterm birth increased with paternal age, almost entirely resulting from an association for very preterm birth. Compared with fathers age 20-24 years, ORs for very preterm birth were 1.3 (age 25-29), 1.4 (age 35-39), 1.7 (age 40-44), 1.6 (age 45-49), and 2.1 (age 50+) (test for trend: P = 0.01). CONCLUSIONS: Risk of very preterm birth increases among older fathers, perhaps as a result of a paternal placental effect.     

Impact of body mass index on incident hypertension and diabetes in Chinese Asians, American Whites, and American Blacks: the People's Republic of China Study and the Atherosclerosis Risk in Communities Study

Researchers have hypothesized that the impact of body mass index on chronic disease may be greater in Asians than in Whites; however, most studies are cross-sectional and have no White comparison group. The authors compared the associations with body mass index in Chinese Asians (n = 5,980), American Whites (n = 10,776), and American Blacks (n = 3,582) using prospective data from the People's Republic of China Study (1983-1994) and the Atherosclerosis Risk in Communities Study (1987-1998). Slopes of risk differences over body mass index levels were compared among the three ethnic groups in adjusted analyses. The authors found larger associations with body mass index in Chinese Asians compared with American Whites and Blacks for hypertension (p < 0.05). The increase in the incidence of hypertension associated with a one-unit increase in body mass index over approximately 8 years of follow-up was 2.5, 1.7, and 1.8 percentage points for Chinese Asians, American Whites, and American Blacks, respectively. For diabetes, the estimates were 1.7, 1.1, and 1.6 percentage points for the same groups- higher in Chinese Asians than in American Whites (p < 0.05) but similar between Chinese Asians and American Blacks. Given the ethnic differences in associations, the results support advocacy of public health and medical actions toward obesity prevention and treatment in China.     

Maternal second-trimester serum ferritin concentrations and subsequent risk of preterm delivery

We studied the relationship between maternal second-trimester serum ferritin concentrations and preterm delivery. The 312 preterm delivery cases, studied in aggregate and in subgroups [spontaneous preterm labour, preterm premature rupture of membranes, medically induced preterm delivery, moderate preterm delivery (gestational age at delivery 34-36 weeks) and very preterm delivery (gestational age at delivery <34 weeks)] were compared with 424 randomly selected women who delivered at term. Maternal ferritin concentrations, measured in serum collected at 17 weeks gestation on average, was determined using a two-site chemiluminometric immunoassay. Using multiple logistic regression, we derived maximum likelihood estimates of adjusted odds ratios (OR) and 95% confidence intervals [CI]. Elevation in maternal second-trimester ferritin was weakly associated with the risk of preterm delivery overall. After adjusting for possible confounding by maternal age, race/ethnicity, parity, Medicaid payment status and smoking during the index pregnancy, the OR for extreme quartiles (>64.5 vs. <26.0 ng/mL) of ferritin was 1.3 [95% CI 0.8, 2.1]. Stratified analyses indicated that elevated maternal serum ferritin was associated with an increased risk of preterm premature rupture of membranes (OR = 2.1; 95% CI 1.1, 4.1), but not with spontaneous preterm labour (OR = 0.9; 95% CI 0.4, 1.7) or medically induced preterm delivery (OR = 1.1; 95% CI 0.6, 2.0). The relationship between elevated maternal second-trimester serum ferritin concentrations and preterm delivery was strongest for spontaneous very preterm deliveries (<34 weeks gestation). Women with ferritin concentrations in the highest decile (>96 ng/mL) experienced a 2.7-fold increased risk of delivering before 34 completed weeks, compared with women with concentrations <26.0 ng/mL. These results are consistent with some previous reports, and further underline the potential for heterogeneity in the aetiology of preterm delivery.     

Characteristics of preterm delivery and low birthweight among 113,994 infants in Alberta: 1994-1996

This study examined the impact of infant and maternal factors on preterm delivery and low birthweight (LBW) in Alberta between January 1, 1994 and December 31, 1996. Data on 113,994 births were collected from vital statistics registration birth data. Logistic regression models for preterm and LBW delivery suggested the key risk factors were multiple and still birth (odds ratios > 22.0). Other characteristics included female gender, birth defects, nulliparous women, maternal age 35 and greater, unmarried, history of abortion, maternal smoking, maternal street drug use, and having less than 4 prenatal visits (odds ratios 0.86-2.54). Interactions between smoking and alcohol, and smoking and parity were noted. Efforts to improve the currently low rates (8.2%) of smoking cessation during pregnancy are required. Social, economic and medical factors associated with delayed childbearing and birth outcomes should be investigated.     

Maternal obesity and diabetes as risk factors for adverse pregnancy outcomes: differences among 4 racial/ethnic groups

OBJECTIVES: We examined associations between obesity, diabetes, and 3 adverse pregnancy outcomes--primary cesarean delivery, preterm birth, and low birth-weight (LBW)--by racial/ethnic group. Our goal was to better understand how these associations differentially impact birth outcomes by group in order to develop more focused interventions. METHODS: Data were collected from the 1999, 2000, and 2001 New York City birth files for 329,988 singleton births containing information on prepregnancy weight and prenatal weight gain. Separate logistic regressions for 4 racial/ethnic groups predicted the adverse pregnancy outcomes associated with diabetes. Other variables in the regressions included obesity, excess weight gain, hypertension, preeclampsia, and substance use during pregnancy (e.g., smoking). RESULTS: Chronic and gestational diabetes were significant risks for a primary cesarean and for preterm birth in all women. Diabetes as a risk for LBW varied by group. For example, whereas chronic diabetes increased the risk for LBW among Asians, Hispanics, and Whites (adjusted odds ratios=2.28, 1.69, and 1.59), respectively, it was not a significant predictor of LBW among Blacks. CONCLUSIONS: In this large, population-based study, obesity and diabetes were independently associated with adverse pregnancy outcomes, highlighting the need for women to undergo lifestyle changes to help them control their weight during the childbearing years and beyond.     

Perceived Spousal Religiosity and Marital Quality Across Racial and Ethnic Groups

The relationship between the perceived religiosity of one's spouse and marital quality varies across racial and ethnic groups (i.e., Asians, Blacks, Hispanics, and non‐Hispanic Whites) in the United States. In this study, data were drawn from a nationally representative sample of married Americans (N = 1,162). Although perceived spousal religiosity predicted higher marital quality across all racial and ethnic groups, this effect was stronger for Asians, Blacks, and Hispanics than for Whites. Compared to Whites, the 3 racial and ethnic minority groups experienced a larger boost in frequency of expressive forms of love as perceived spousal religiosity increased. This effect was also found regarding marital satisfaction for Asians and Blacks relative to Whites, but not for Hispanics. Moreover, although racial and ethnic minorities tended to report lower marital quality than Whites at low levels of perceived spousal religiosity, their marital quality tended to be higher than Whites at high levels of perceived spousal religiosity. Three‐way interactions indicated that these trends hold regardless of gender.     

Occurrence of low birthweight and preterm delivery among California infants before and after compulsory food fortification with folic acid

OBJECTIVES: Studies suggest that folic acid intake influences the occurrence of low birthweight and preterm delivery. Since 1998, there has been compulsory fortification of flour and other grains with folic acid in the U.S. The objective of this study was to investigate the frequencies of low birthweight and preterm delivery after mandatory folic acid fortification among approximately six million California births. METHODS: The authors investigated prevalences of low birthweight and preterm delivery before and after compulsory fortification among 5,916,630 singleton California live births that occurred from January 1990 through December 2000. RESULTS: The unadjusted prevalences of very low birthweight, low birthweight, and preterm delivery did not substantially vary across birth years. That is, substantial decreased prevalences during the fortification period relative to the period preceding it were not observed. However, analyses that simultaneously adjusted for maternal age, parity, race/ethnicity, education, year of birth, and fortification period revealed the following relative risk ratios (RR) and 95% confidence intervals (CI): RR = 0.91, CI 0.88, 0.94 for very low birthweight, RR = 0.94; 95% CI 0.93, 0.96 for low birthweight, and RR = 0.96; 95% CI 0.94, 0.97 for preterm delivery. CONCLUSION: Findings indicate small reductions in prevalences of these outcomes associated with the timing of fortification of the U.S. food supply.     

Trends in preterm birth and neonatal mortality among blacks and whites in the United States from 1989 to 1997

Preterm birth, a major determinant of infant mortality, has been increasing in recent years. The authors examined trends in preterm birth and its determinants by using the US birth and infant death files for 1989-1997. The impact of trends in preterm birth rates on neonatal and infant mortality was also evaluated. Among Whites, preterm births (<37 completed weeks of gestation) increased from 8.8% of livebirths in 1989 to 10.2% in 1997, a relative increase of 15.6%. On the other hand, preterm births among Blacks decreased by 7.6% (from 19.0% to 17.5%) during the same period. An increase in obstetric interventions contributed to increases in preterm births for both races but was outweighed by other unidentified favorable influences for Blacks. Neonatal mortality among preterm Whites dropped 34% during the 8 years of the study, while the decrease was only 24% among Blacks. This large disparity countered the changes in preterm birth rates so that the percentage decline in neonatal mortality was similar in the two racial groups (18-20%). In conclusion, the anticipated mortality benefit from a lower preterm birth rate for Blacks has been blunted by suboptimal improvement in mortality among the remaining preterm infants. The widening race gap in mortality among preterm infants merits attention.     

Does participation in a nurse visitation programme reduce the frequency of adverse perinatal outcomes in first-time mothers?

Children First (C1), a nurse home visitation programme for first-time mothers, was implemented statewide in Oklahoma in mid-1997. The objective of this study was to compare the risks of low (< 2500 g) and very low birthweight (< 1500 g), preterm (< 37 weeks) and very preterm (< 30 weeks) deliveries and infant mortality between mothers participating and not participating in C1. All 239,466 Oklahoma birth certificates were reviewed. The C1 and birth certificate databases were matched to identify C1 participants. Mother's age at delivery, education level, race, marital status, prior pregnancy loss or pregnancy risk factors, birthweight and gestational age at delivery were measured from the birth certificates. Death certificates were matched to the birth certificates to identify infant deaths. A Bayesian multivariable logistic regression was used to analyse the data. Among single mothers without pregnancy risk factors, the risks of all study outcomes were lower for participants in C1: adjusted odds ratio (aOR) 0.89, [95% Bayesian Credible Interval (BCI) 0.79, 1.00] for preterm delivery; aOR 0.71, [95% BCI 0.50, 0.98] for very preterm delivery; aOR 0.86, [95% BCI 0.75, 0.98] for low birthweight; aOR 0.77, [95% BCI 0.56, 1.02] for very low birthweight and aOR 0.36, [95% BCI 0.17, 0.63] for infant mortality. These risk reductions were not observed among married mothers. In both single and married mothers, the presence of pregnancy risk factors reduced the impact of C1 on lowering the risk of low birthweight and preterm deliveries. The C1 programme targets young, pregnant women of low socio-economic level. We found that among single mothers, the risks of perinatal adverse outcomes are reduced or similar to those found in non-participating mothers. A reduced effect of C1 in the presence of pregnancy risk factors may be because mothers with pregnancy risk factors who did not participate in C1 received better prenatal care, or that C1 interventions do not impact these particular factors. C1 shows promise in reducing infant mortality in single mothers. Lower incidence of preterm and very preterm deliveries is especially interesting and future analyses should focus on isolating programme components specifically associated with influencing these outcomes.     

Influence of inter-pregnancy interval on preterm delivery

The influence of pregnancy spacing on preterm delivery (<37 weeks gestation) was examined in a group of mothers attending three Maternal and Child Health centres in three different districts in the city of Alexandria, Egypt between October 2001 and July 2002. All pregnant mothers attending the centres were interviewed or had their medical records reviewed. They were followed up until delivery and were questioned about current and past obstetric history and their medical history; their haemoglobin level was measured. The inter-pregnancy interval was calculated as the number of months between the delivery date of the women's last previous live infant and the date of the last menstrual period before the current pregnancy. There were 1202 pregnant women eligible for inclusion. The inter-pregnancy intervals were divided into five categories: <12, 12-36, 37-48, 49-60 and >60 months. We calculated the rates of preterm deliveries for each inter-pregnancy interval. Unadjusted odds ratios were estimated and stepwise logistic regression analysis was then used to adjust for all confounding factors. The rate of preterm delivery was 9.4%, and the lowest risk occurred in women who had an inter-pregnancy interval >60 months; 7.3% of those women gave birth to preterm infants. The rate of preterm delivery increased with increasing inter-pregnancy interval until 49-60 months; however, the association between inter-pregnancy interval and preterm delivery was not statistically significant whether using the crude or adjusted odds ratios.     

Association between low gynaecological age and preterm birth

Low gynaecological age, defined as conception within 2 completed years of menarche, was examined for its association with preterm birth, using data from a geographically based cohort of over 1700 young primigravidae aged 18 or younger at start of prenatal care. After stratifying by chronological age and controlling for confounding variables, low gynaecological age was associated with almost double the risk of preterm delivery whether estimated from the mother's last menstrual period (adjusted odds ratio (AOR) = 1.77, 95% CI 1.19-2.64) or using the obstetric estimate of gestation (AOR = 2.10, 95% CI 1.36-3.25). Low gynaecological age was also associated with an increase in risk of low birthweight (LBW) (AOR = 1.70, 95% CI 1.01-2.88), but not of small-for-gestational-age babies (AOR = 0.94, 95% CI 0.49-1.81). Thus low gynaecological age may be an important addition to assessment systems to detect women at risk of preterm labour and delivery.