Previous Term Birth Research Articles

Association of interpregnancy interval and risk of adverse pregnancy outcomes in woman by different previous gestational ages.

With an increasing proportion of multiparas, proper interpregnancy intervals (IPIs) are urgently needed. However, the association between IPIs and adverse perinatal outcomes has always been debated. This study aimed to explore the association between IPIs and adverse outcomes in different fertility policy periods and for different previous gestational ages. We used individual data from China's National Maternal Near Miss Surveillance System between 2014 and 2019. Multivariable Poisson models with restricted cubic splines were used. Each adverse outcome was analyzed separately in the overall model and stratified models. The stratified models included different categories of fertility policy periods (2014-2015, 2016-2017, and 2018-2019) and infant gestational age in previous pregnancy (<28 weeks, 28-36 weeks, and ≥37 weeks). There were 781,731 pregnancies enrolled in this study. A short IPI (≤6 months) was associated with an increased risk of preterm birth (OR [95% CI]: 1.63 [1.55, 1.71] for vaginal delivery [VD] and 1.10 [1.03, 1.19] for cesarean section [CS]), low Apgar scores and small for gestational age (SGA), and a decreased risk of diabetes mellitus in pregnancy, preeclampsia or eclampsia, and gestational hypertension. A long IPI (≥60 months) was associated with an increased risk of preterm birth (OR [95% CI]: 1.18 [1.11, 1.26] for VD and 1.39 [1.32, 1.47] for CS), placenta previa, postpartum hemorrhage, diabetes mellitus in pregnancy, preeclampsia or eclampsia, and gestational hypertension. Fertility policy changes had little effect on the association of IPIs and adverse maternal and neonatal outcomes. The estimated risk of preterm birth, low Apgar scores, SGA, diabetes mellitus in pregnancy, and gestational hypertension was more profound among women with previous term births than among those with preterm births or pregnancy loss. For pregnant women with shorter or longer IPIs, more targeted health care measures during pregnancy should be formulated according to infant gestational age in previous pregnancy.

Degree of expression of inflammatory proteins in the amniotic cavity, but not prior obstetric history, is associated with the risk severity for spontaneous preterm birth after rescue cerclage for cervical insufficiency.

To examine whether the severity of spontaneous preterm birth (SPTB) risk after rescue cerclage for acute cervical insufficiency (CI) is linked tothe degree of inflammatory response in the amniotic fluid (AF) based on the concentrations of various inflammatory proteins and prior obstetric history. We conducted a retrospective cohort study of 65 singleton pregnantwomen (17-25weeks) who underwent rescue cerclage following the diagnosis of acute CI and were subjected to amniocentesis. EN-RAGE, IL-6, IL-8, and IP-10 as inflammatory mediators and kallistatin, MMP-2/8, and uPA as extracellular matrix remodeling-related molecules were assayed in the AF using ELISA. The level of each inflammatory mediator was divided into quartiles. Intra-amniotic inflammation (IAI; AF IL-6 level ≥2.6ng/mL) was independently associated with SPTB after cerclage placement. The odds of SPTB at<32weeks, even after adjusting for confounders, increased significantly with each increasing quartile of baseline AF levels for each inflammatory mediator (p for trend<.05). Kaplan-Meier survival curves showed that the cerclage-to-delivery intervals were significantly shorter as the quartiles of AF EN-RAGE and MMP-8 increased (log-rank test, p<.01 each). Neither previous term birth nor prior PTB was associated with SPTB risk or cerclage-to-delivery interval after rescue cerclage. Multiparous women who experience CI after term birth showed significantly elevated levels of MMP-8 and reduced kallistatin levels in the AF. In patients with CI, SPTB risk (especially risk severity) after rescue cerclage is associated with thedegree of the inflammatory response in AF as well as the presence of IAI but not with prior obstetric history.

Maternal selenium levels and whole genome screen in recurrent spontaneous preterm birth population: A nested case control study

ObjectiveTo establish if low maternal selenium (Se) was associated with sPTB in women with recurrent sPTB and identify genetic link with maternal Se levels. DesignNested case-control study. SettingTertiary Maternity Hospital. PopulationPlasma and whole blood from pregnant women with history of early sPTB/PPROM < 34+0 and European ancestry were obtained at 20 weeks (range 15–24 weeks). ‘Cases’ were recurrent PTB/PPROM < 34+0 weeks and term (≥37+0) deliveries were classified as ‘high-risk controls.’ Women with previous term births and index birth ≥ 39 weeks were ‘low-risk controls’. MethodsMaternal plasma Se measured by ICP-MS was used as a continuous phenotype in a GWAS analysis. Se was added to a logistic regression model using PTB predictor variables. Main outcome measuresMaternal Se concentration, recurrent early sPTB/PPROM. Results53/177 high-risk women had a recurrent sPTB/PPROM < 34+0weeks and were 2.7 times more likely to have a Se level < 83.3 ppm at 20weeks of pregnancy compared with low-risk term controls (n = 179), (RR 2.7, 95%CI 1.5–4.8; p = .001). One SNP from a non-coding region (FOXN3 intron variant, rs55793422) reached genome-wide significance level (p = 3.73E−08). Targeted analysis of Se gene variant did not show difference between preterm and term births. (χ2 test, OR = 0.95; 95%CI = 0.59–1.56; p = 0.82). When Se levels were added to a clinical prediction model, only an additional 5% of cases (n = 3) and 0.6% (n = 1) of controls were correctly identified. ConclusionsLow plasma Se is associated with sPTB risk but is not sufficiently predictive at individual patient level. We did not find a genetic association between maternal Se levels and Se-related genes.

Plasma long-chain omega-3 fatty acid status and risk of recurrent early spontaneous preterm birth: a prospective observational study.

A 2018 Cochrane review found that omega-3 supplementation in pregnancy was associated with a risk reduction of early preterm birth of 0.58; prompting calls for universal supplementation. Recent analysis suggests the benefit may be confined to women with a low baseline omega-3 fatty acid status. However, the contemporary omega-3 fatty acid status of pregnant women in the UK is largely unknown. This is particularly pertinent for women with a previous preterm birth, in whom a small relative risk reduction would have a larger reduction of absolute risk. This study aimed to assess the omega-3 fatty acid status of a UK pregnant population and determine the association between the long-chain omega-3 fatty acids and recurrent spontaneous early preterm birth. A total of 283 high-risk women with previous early preterm birth were recruited to the prospective observational study in Liverpool, UK. Additionally, 96 pregnant women with previous term births and birth ≥39+0 weeks in the index pregnancy provided a low-risk population sample. Within the high-risk group we assessed the odds ratio of recurrent early preterm birth compared with birth at ≥37+0 weeks of gestation according to plasma eicosapentaenoic acid plus docosahexaenoic acid (EPA+DHA) at 15-22weeks of gestation. Our participants had low EPA+DHA; 62% (143/229) of women with previous preterm birth and 69% (68/96) of the population sample had levels within the lowest two quintiles of a previously published pregnancy cohort. We found no association between long-chain omega-3 status and recurrent early preterm birth (n=51). The crude odds ratio of a recurrent event was 0.91 (95% CI 0.38-2.15, p=0.83) for women in the lowest, compared with the highest three quintiles of EPA+DHA. In the majority of our participants, levels of long-chain omega-3 were low; within the range that may benefit from supplementation. However, levels showed no association with risk of recurrent early spontaneous preterm birth. This could be because our population levels were too low to show benefit in being omega-3 "replete"; or else omega-3 levels may be of lesser importance in recurrent early preterm birth.

Associations between interpregnancy interval and preterm birth by previous preterm birth status in four high-income countries: a cohort study.

To investigate the effect of interpregnancy interval (IPI) on preterm birth (PTB) according to whether the previous birth was preterm or term. Cohort study. USA (California), Australia, Finland, Norway (1980-2017). Women who gave birth to first and second (n=3213855) singleton livebirths. Odds ratios (ORs) for PTB according to IPIs were modelled using logistic regression with prognostic score stratification for potential confounders. Within-site ORs were pooled by random effects meta-analysis. PTB (gestational age<37weeks). Absolute risk of PTB for each IPI was 3-6% after a previous term birth and 17-22% after previous PTB. ORs for PTB differed between previous term and preterm births in all countries (P-for-interaction≤0.001). For women with a previous term birth, pooled ORs were increased for IPI<6months (OR 1.50, 95% CI 1.43-1.58); 6-11months (OR 1.10, 95% CI 1.04-1.16); 24-59months (OR 1.16, 95% CI 1.13-1.18); and≥60months (OR 1.72, 95%CI 1.60-1.86), compared with 18-23months. For previous PTB, ORs were increased for<6months (OR 1.30, 95% CI 1.18-1.42) and≥60months (OR 1.29, 95% CI 1.17-1.42), but were less than ORs among women with a previous term birth (P<0.05). Associations between IPI and PTB are modified by whether or not the previous pregnancy was preterm. ORs for short and long IPIs were higher among women with a previous term birth than a previous PTB, which for short IPI is consistent with the maternal depletion hypothesis. Given the high risk of recurrence and assuming a causal association between IPI and PTB, IPI remains a potentially modifiable risk factor for women with previous PTB. Short versus long interpregnancy intervals associated with higher ORs for preterm birth (PTB) after a previous PTB.

Increased incidence of hypertensive disorders of pregnancy in women with a history of spontaneous preterm birth: A longitudinal linked national cohort study.

Determine the risk of hypertensive disorders of pregnancy (HD) in women with a history of spontaneous preterm birth (SPTB). Longitudinal linked national cohort study within the Dutch Perinatal Registry (1999-2009) on linked data among 349,291 women with a first and second singleton pregnancy in the Netherlands. The incidence of HD, small for gestational age (SGA) and placental abruption in the second pregnancy. Out of 349,291 women with a singleton first pregnancy, 19,991 (5.7%) had a SPTB. The incidence of HD in the second pregnancy was 8.1% in women with a previous SPTB, as compared to 5.6% in women with a previous term birth (aOR 1.49 (CI 1.41-1.57)). Also after excluding HD, SGA and/or placental abruption in the first pregnancy, women with a history of SPTB had a higher risk of HD in their second pregnancy compared to women with a previous term birth (4.6% versus 2.7%, aOR 1.77 (CI 1.64-191)). Similarly, the incidence of SGA and placental abruption was higher in the second pregnancy in women with a history of SPTB compared to term birth in the first pregnancy. Women with a history of SPTB are at elevated risk of HD in the subsequent pregnancy. These results support shared pathophysiology between SPTB and HD.

Previous Adverse Outcome of Term Pregnancy and Risk of Preterm Birth in Subsequent Pregnancy.

Objective Evaluate risk of preterm birth (PTB, < 37 completed weeks' gestation) among a population of women in their second pregnancy with previous full term birth but other adverse pregnancy outcome. Methods The sample included singleton live born infants between 2007 and 2012 in a birth cohort file maintained by the California Office of Statewide Health Planning and Development. The sample was restricted to women with two pregnancies resulting in live born infants and first birth between 39 and 42weeks' gestation. Logistic regression was used to calculate the risk of PTB in the second birth for women with previous adverse pregnancy outcome including: small for gestational age (SGA) infant, preeclampsia, placental abruption, or neonatal death (≤ 28 days). Risks were adjusted for maternal factors recorded for second birth. Results The sample included 133,622 women. Of the women with any previous adverse outcome, 4.7% had a PTB while just 3.0% of the women without a previous adverse outcome delivered early (relative risk adjusted for maternal factors known at delivery 1.4, 95% CI 1.3-1.5). History of an SGA infant, placental abruption, or neonatal death increased the adjusted risk of PTB in their second birth by 1.5-3.7-fold. History of preeclampsia did not elevate the risk of a preterm birth in the subsequent birth. Conclusions for Practice The findings indicate that women with previous SGA infant, placental abruption, or neonatal death, despite a term delivery, may be at increased risk of PTB in the subsequent birth. These women may be appropriate participates for future interventions aimed at reduction in PTB.

705: Previous adverse outcome of pregnancy and risk of preterm birth in subsequent birth

Women with a preterm birth (PTB) are at risk of PTB in subsequent pregnancies. However, less is known about women with previous term birth but other adverse pregnancy outcomes. Here, we evaluate risk of PTB among a population of women with previous term birth but other adverse pregnancy outcome. The sample was drawn from 2005-2012 singleton live born infants included in a birth cohort file maintained by the California Office of Statewide Health Planning and Development. The sample was restricted to women with two live births and previous delivery between 39-42 weeks. Women with fetal anomalies in either birth were excluded. Logistic regression was used to calculate the risk of PTB in the second birth for women with previous fetal demise/termination, placenta previa, placental abruption, preeclampsia, small for gestational age (SGA) infant, or infant death. The file did not differentiate between fetal demise and termination. Risks were adjusted for race/ethnicity, age, education, body mass index, insurance coverage, smoking status, hypertension, preeclampsia, diabetes, infection, drug/alcohol use, mental illness, anemia, interpregnancy interval, placenta previa, placental abruption, and SGA (all recorded for second birth). 282,196 women were included. Of the women with any previous poor outcome, 4.2% had a PTB (Figure). A history of an adverse pregnancy outcome conferred a 1.2-fold increased risk of PTB and a 1.4-fold increased risk of PTB <32 weeks. Women with a fetal demise/termination between their two live births, and women with a previous infant who died were at highest risk of PTB in their second delivery (aRRs 1.8). Previous placental abruption or a SGA infant also increased the risk of the second birth occurring preterm (aRRs 1.5-1.8) (Table). Previous placental abruption, SGA infant, and infant death increased the risk of PTB in the subsequent live birth among a population of women with no prior PTB. Previous fetal demise/termination also a risk for PTB in subsequent pregnancies, however indication for termination was unavailable in the dataset.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

A universal mid-trimester transvaginal cervical length screening program and its associated reduced preterm birth rate

Mid-trimester transvaginal cervical length assessment can identify women who are at risk of preterm birth and afford opportunities for preterm birth prevention. However, the incidence of a short cervix is low, and some physicians have questioned whether a universal screening program among women without a previous preterm birth would be beneficial. The purpose of this study was to examine whether the introduction of a universal transvaginal cervical length screening program is associated with a reduction in the preterm birth rate. This is a cohort study of women with singleton gestations and without any previous preterm births who underwent an obstetric sonogram at 18-24 weeks of gestation and who had their delivery at a single tertiary institution from January 2007 to January 2014. In July 2011, a program was implemented in which all pregnant women who had a sonogram at 18-24 weeks of gestation were to receive a transvaginal cervical length measurement. The preterm birth rates were compared before and after the implementation of the universal cervical length screening program. Multivariable analysis was used to identify whether the universal cervical length screening program was associated independently with the frequency of preterm birth. The Breslow-Day test for homogeneity was used to assess whether any interaction existed in the association based on parity. Of 64,207 eligible women, 46,598 underwent their mid-trimester sonogram before the universal cervical length screening program, and 17,609 underwent a sonogram after implementation of the program. Of the 17,590 women (99.9%) who agreed to cervical length measurement, 157 (0.89%) had a measurement of ≤25 mm. The introduction of the cervical length program was associated with a significant decrease in the frequency of preterm birth at <37 weeks of gestation (6.7% vs 6.0%; adjusted odds ratio, 0.82 [95% confidence interval, 0.76-0.88]), <34 weeks of gestation (1.9% vs 1.7%; adjusted odds ratio, 0.74 [95% confidence interval, 0.64-0.85]), and <32 weeks of gestation (1.1% vs 1.0%; adjusted odds ratio, 0.74 (95% confidence interval, 0.62-0.90]). This reduction in frequency of preterm birth primarily was due to a change in spontaneous (and not medically indicated) preterm births. The effect size for the reduction in preterm birth was similar in nulliparous and multiparous women with previous term births. The introduction of a universal transvaginal cervical length screening program in women without a history of preterm birth is associated with a reduction in the frequency of preterm birth.

Incidence and risk factors for recurrent spontaneous preterm birth: A retrospective cohort study in Japan.

The aim of this study was to assess the incidence and risk factors for recurrent spontaneous preterm birth (PTB) in Japan. A retrospective cohort study was conducted at five tertiary perinatal centers in Osaka, Japan from 2008 through 2012. Perinatal data were collected from medical records of women with a singleton gestation and a previous spontaneous PTB. Exclusion criteria were first-trimester spontaneous abortion, first antenatal visit beyond 14 weeks of gestation, and previous PTB with medical indications, placenta previa, abruptio placenta, multiple pregnancy, fetal anomaly, and antepartum fetal demise. The associations between recurrent spontaneous PTB and perinatal factors were evaluated by logistic regression analysis. Of 547 women with a previous spontaneous PTB, 89 (16.3%) suffered a recurrent spontaneous PTB. The risk factors for recurrence included multiple previous spontaneous PTB (adjusted odds ratio [aOR]: 2.26; 95% confidence interval [CI]: 1.19-4.30; P = 0.013), no previous term birth (aOR: 2.08; 95%CI: 1.24-3.49; P = 0.005), and interpregnancy interval < 12 months (aOR: 2.13; 95%CI: 1.17-3.85; P = 0.013). Approximately one in six women with a previous spontaneous PTB suffered a recurrent spontaneous PTB. Multiple previous spontaneous PTB, no previous term birth, and short interpregnancy interval were independent risk factors for recurrence.

Women's intentions to breastfeed: a population‐based cohort study

Given that intention to breastfeed is a strong predictor of breastfeeding initiation and duration, the objectives of this study were to estimate the population-based prevalence and the factors associated with the intention to breastfeed. Retrospective population-based cohort study. All hospitals in Ontario, Canada (1 April 2009-31 March 2010). Women who gave birth to live, term, singletons/twins. Patient, healthcare provider, and hospital factors that may be associated with intention to breastfeed were analysed using univariable and multivariable regression. Population-based prevalence of intention to breastfeed and its associated factors. The study included 92,364 women, of whom 78,806 (85.3%) intended to breastfeed. The odds of intending to breastfeed were higher amongst older women with no health problems and women who were cared for exclusively by midwives (adjusted OR 3.64, 95% CI 3.13-4.23). Being pregnant with twins (adjusted OR 0.73, 95% CI 0.57-0.94), not attending antenatal classes (adjusted OR 0.58, 95% CI 0.54-0.62), having previous term or preterm births (adjusted OR 0.79, 95% CI 0.78-0.81, and adjusted OR 0.87, 95% CI 0.82-0.93, respectively), and delivering in a level-1 hospital (adjusted OR 0.85, 95% CI 0.77-0.93) were associated with a lower intention to breastfeed. In this population-based study ~85% of women intended to breastfeed their babies. Key factors that are associated with the intention to breastfeed were identified, which can now be targeted for intervention programmes aimed at increasing the prevalence of breastfeeding and improving overall child and maternal health.

Recurrence of preterm birth and perinatal mortality in northern Tanzania: registry-based cohort study.

ObjectivesTo estimate the recurrence risk of preterm delivery and estimate the perinatal mortality in repeated preterm deliveries.MethodsProspective study in Tanzania of 18 176 women who delivered a singleton between 2000 and 2008 at KCMC hospital. The women were followed up to 2010 for consecutive births. A total of 3359 women were identified with a total of 3867 subsequent deliveries in the follow-up period. Recurrence risk of preterm birth and perinatal mortality was estimated using log-binomial regression and adjusted for potential confounders.ResultsFor women with a previous preterm birth, the risk of preterm birth in a subsequent pregnancy was 17%. This recurrence risk was estimated to be 2.7-fold (95% CI: 2.1–3.4) of the risk of women with a previous term birth. The perinatal mortality of babies in a second preterm birth of the same woman was 15%. Babies born at term who had an older sibling that was born preterm had a perinatal mortality of 10%. Babies born at term who had an older sibling who was also born at term had a perinatal mortality of 1.7%.ConclusionPrevious delivery of a preterm infant is a strong predictor of future preterm births in Tanzania. Previous or repeated preterm births increase the risk of perinatal death substantially in the subsequent pregnancy.

PP.13 Previous Caesarean Delivery and the Risk of Unexplained Stillbirth: Analysis of 128,585 Second Pregnancies in Scotland, 1999–2008

BackgroundA previous study (Lancet 2003; 362:1779–84) reported an increased risk of unexplained stillbirth in women with previous caesarean delivery among women having second births in Scotland, 1992–1998. Subsequent studies have...

Primiparity: An ‘intermediate’ risk group for spontaneous and medically indicated preterm birth

Objective. Most women in their first pregnancy are at ‘unknown’ risk for preterm birth. We hypothesized that such women may be at an increased risk for preterm birth in comparison to those with a prior term birth.Methods. We used Missouri's maternally-linked data (1989–97), comprised of women delivering their first singleton live birth (N = 259 431) and women delivering their first two consecutive singleton live births (N = 154 810). We compared preterm birth (<37 weeks) rates among women with a previous term birth, women with no reproductive history (primiparous women), and in those with a previous preterm birth. Risks of spontaneous and medically indicated preterm birth were also examined after adjustments for confounders through multivariate log-binomial regression models.Results. Preterm birth rates were 8.1%, 9.6%, and 23.3% among women with a previous term birth, among primiparous women, and among those with a previous preterm birth, respectively. In comparison to women with a prior term birth, risks of spontaneous preterm birth among primiparous women and among women with a prior preterm birth were 1.1-fold (95% confidence interval (CI) 1.0, 1.2) and 2.5-fold (95% CI 2.4, 2.6) higher, respectively. These risks were higher for medically indicated preterm birth among both primiparous women (RR 1.3, 95% CI 1.2, 1.4) and those with a prior preterm birth (RR 3.2, 95% CI 3.0, 3.5) than for spontaneous preterm births.Conclusions. Primiparous women are at increased risk of both medically indicated and spontaneous preterm birth. The findings suggest that studies on preterm birth should consider a risk assignment to include three groups: low-risk (prior term birth), intermediate risk (primiparity), and high-risk (prior preterm birth). This strategy will be informative for the identification of women with impending risk of delivering preterm, and complications associated with prematurity.

Risk factors for cervical insufficiency after term delivery

Cervical insufficiency can be unexpected in a woman with a previous term birth. Our objective was to determine what risk factors, if any, place women with a term delivery at risk for cervical insufficiency in a subsequent pregnancy. Demographic characteristics were collected for a cohort of women with at least 1 previous term birth followed by cervical insufficiency (subject group) and for uncomplicated multiparous women (control group). Multiparous women with cervical insufficiency (subjects; n = 49) were compared with multiparous women who were experiencing repeat term birth with no history of cervical insufficiency (control group; n = 49). Patients with cervical insufficiency were similar to control subjects demographically. No difference was noted in previous cervical procedures or spontaneous preterm deliveries. Multivariate logistic regression analysis identified a history of curettage (odds ratio, 4.6; 95% CI, 1.7-12.5), precipitous delivery (odds ratio, 6.8; 95% CI, 1.6-29.6), and prolonged second stage of labor (odds ratio, 24.9; 95% CI, 2.4-253) as independent predictors of cervical insufficiency. Multiparous women who experience cervical insufficiency after a term birth are more likely to have had a previous precipitous delivery, a prolonged second stage of labor, or a previous curettage compared with multiparous women who experience a repeat term birth with no cervical insufficiency.

The Alabama Preterm Birth Project: Placental histology in recurrent spontaneous and indicated preterm birth

For unknown reasons, a previous preterm birth (PTB) is a major risk factor for PTB in the current pregnancy. Our goal is to evaluate placental histology for clues related to the recurrent nature of PTB. Four hundred fifty-seven mother/infant dyads delivering between 23 and 32 weeks were first classified as having a spontaneous (S) or indicated (I) PTB, and then sorted into the following mutually exclusive categories by pregnancy history: 1) nulliparous; 2) having no previous PTB; 3) having any previous IPTB; or 4) having a previous SPTB. The placentas were evaluated for acute inflammation in the free membranes, umbilical cord, and chorionic plate, chronic inflammation in the membranes and decidua basalis, thrombosis in the chorionic plate and umbilical cord, and diffuse decidual leukocytoclastic necrosis (DDLN), a lesion associated with decreased placental perfusion. Women who had a SPTB were far more likely (85.5 vs 14.4 P < .0001) to have a SPTB in the previous pregnancy, while women with an IPTB were significantly more likely to have had a previous IPTB (89.7 vs 10.3 P < .0001). Nulliparas and women with previous term births each had about 64% SPTB and 36% IPTB. Acute inflammation at any site was present in 73.9% of SPTB versus 8.0% of IPTB (P < .0001). Chorionic plate thrombosis was also more common in SPTB than IPTB (16.2 vs 7.6, P = .01). Chronic inflammation at any site was more common in IPTB than SPTB (21.0 vs 12.7%, P = .02), as was DDLN (46.5 vs 16.1, P < .0001). When classified by SPTB and IPTB in the current pregnancy, the histologic results were not further influenced by the previous pregnancy history. SPTB and IPTB are strongly repetitive. Women with SPTB are significantly more likely to have acute inflammation in the free membranes, chorionic plate, and cord, and chorionic plate thrombosis, while women with an IPTB are significantly more likely to have chronic inflammation and especially DDLN. Past obstetric history does not further influence the placental histology.

Fetal interleukin-1 receptor antagonist gene polymorphism, intra-amniotic interleukin-1β levels, and history of spontaneous abortion

The purpose of this study was to determine whether fetal carriage of specific alleles of the polymorphic interleukin-1 receptor antagonist gene is associated with variations in intra-amniotic cytokine levels and previous pregnancy outcomes. Fetal cells in midtrimester amniotic fluid from 189 women were tested for interleukin-1 receptor antagonist intron 2 length polymorphisms. Concentrations of cytokines in amniotic fluid were tested by enzyme-linked immunosorbent assay. Pregnancy history data were obtained subsequently. Homozygosity for interleukin-1 receptor antagonist allele 1 was detected in 13 of 17 fetuses (76.5%) from women whose previous pregnancies all ended in spontaneous abortions, as compared with 33 of 74 fetuses (44.6%) from women with at least 1 previous term birth ( P = .02). Fetal carriage of interleukin-1 receptor antagonist allele 2 was associated with only 1 (5.9%) previous spontaneous abortion, as opposed to 31 pregnancies (41.9%) that were associated with a previous term delivery ( P = .004). A similar relationship between interleukin-1 receptor antagonist allele 1 and spontaneous abortions was observed when pregnancies of white women only were analyzed. Median mid trimester amniotic fluid interleukin-1beta concentrations were higher in women whose previous pregnancies ended in term deliveries (15.7 pg/mL), as opposed to women with 1 to 2 (6.4 pg/mL; P = .04) or > or =3 (4.1 pg/mL; P = .007) previous spontaneous abortions. Fetal carriage of interleukin-1 receptor antagonist allele 2 was associated with elevated intra-amniotic interleukin-1beta levels (16.2 pg/mL), as compared with interleukin-1 receptor antagonist allele 1 homozygotes (10.8 pg/mL; P = .03). Fetal carriage of interleukin-1 receptor antagonist allele 1 is associated with reduced intra-amniotic interleukin-1beta concentrations and an increased occurrence of spontaneous abortions in previous pregnancies.

Recurrence Risk of Preterm Birth due to Preeclampsia

There may be an increased risk of preterm birth due to preeclampsia among women whose previous pregnancies ended in preterm birth due to preeclampsia. We studied 1,130 women who delivered 2 successive singleton infants in our hospital, excluding women who delivered an abnormally formed infant during the study period. We reviewed the gestational week at delivery in these 2,260 pregnancies and found a total of 182 preterm deliveries (8.1%) by 156 women. The causes of preterm birth were reviewed. Failed tocolysis, including premature rupture of membranes and clinical chorioamnionitis, and preeclampsia accounted for 135 (74.2%) and 30 (16.5%) of the 182 preterm deliveries, respectively. Women whose 1st delivery was preterm had a 3.26 times (95% CI 2.21–4.79) higher risk of a subsequent preterm delivery than women whose 1st delivery was term (26/96 vs. 60/1,034). The risk of preeclampsia-related preterm delivery was 54.4 times (17.2 to 172.5) higher in women with a previous preeclampsia-related preterm delivery than in women with a previous term delivery (5/19 vs. 5/1034). Women who had a history of preeclampsia-related preterm birth had a greater risk of preeclampsia-related preterm birth in a subsequent pregnancy as compared with women with a previous term birth.

Suboptimal pregnancy outcome among women with prior abortions and premature births

Data from 25,958 consecutive UCLA deliveries were analyzed to determine the effect of prior abortions and premature births on current pregnancy outcome. Perinatal death rate, combining stillbirths and neonatal deaths, in reased more than threefold among women with at least one prior premature birth and at least one prior abortion and approached 18 per cent of current deliveries when there were three or more prior premature births. Abnormal live births, defined as infants with either birth weight under 2,501 grams, gestational age less than 37 weeks, or congenital anomalies, significantly increased as the number of prior abortions and premature births increased, each in a range of 0 through 3 or more. For example, among women with at least three prior premature births, there were greater than 50 per cent abnormal live births. The risk was mostly that of low birth weight and low gestational age, although there was a slight increase in congenital anomalies. The risk was reduced considerably when there were previous term births and was influenced variably by race, clinic classification, maternal illness, and prior pregnancy complications. This empirical data on pregnancy outcome should be useful in reproductive counseling among women with pregnancy losses and premature births.