Socioeconomic Risk Factors for Extreme Preterm Birth in Hawai'i.

ObjectiveTo determine whether the relationship between previous miscarriage and risk of preterm birth changed over the period 1980–2008, and to determine whether the pattern varied according to the cause of the preterm birth.DesignLinked birth databases.SettingAll Scottish NHS hospitals.PopulationA total of 732 719 nulliparous women with a first live birth between 1980 and 2008.MethodsRisk was estimated using logistic regression.Main outcome measuresPreterm birth, subdivided by cause (spontaneous, induced with a diagnosis of pre-eclampsia, or induced without a diagnosis of pre-eclampsia) and severity [extreme (24–28 weeks of gestation), moderate (29–32 weeks of gestation), and mild (33–36 weeks of gestation)].ResultsConsistent with previous studies, previous miscarriage was associated with an increased risk of all-cause preterm birth (adjusted odds ratio, aOR 1.26; 95% confidence interval, 95% CI 1.22–1.29). This arose from associations with all subtypes. The strongest association was found with extreme preterm birth (aOR 1.73; 95% CI 1.57–1.90). Risk increased with the number of miscarriages. Women with three or more miscarriages had the greatest risk of all-cause preterm birth (aOR 2.14; 95% CI 1.93–2.38), and the strongest association was with extreme preterm birth (aOR 3.87; 95% CI 2.85–5.26). The strength of the association between miscarriage and preterm birth decreased from 1980 to 2008. This was because of weakening associations with spontaneous preterm birth and induced preterm birth without a diagnosis of pre-eclampsia.ConclusionsThe association between a prior history of miscarriage and the risk of preterm birth declined in Scotland over the period 1980–2008. We speculate that changes in the methods of managing incomplete termination of pregnancy might explain the trend, through reduced cervical damage.

Vaginal progesterone or cerclage to prevent recurrent preterm birth?

Guideline No. 398: Progesterone for Prevention of Spontaneous Preterm Birth.

Preterm birth is the leading cause of neonatal mortality and morbidity. Women who have had a previous preterm birth are at increased risk for preterm birth in their subsequent pregnancies. Low-dose aspirin use reduces the risk for preterm birth among women at risk of developing preeclampsia, however, it is unclear whether low-dose aspirin may reduce the risk of recurrent preterm birth. This study aimed to investigate the association between low-dose aspirin use and preterm birth among women with a previous preterm birth. We conducted a Swedish register-based cohort study and included women who had a first and second pregnancy between 2006 and 2019, with the first pregnancy ending in preterm birth (medically indicated or with spontaneous onset <37 weeks of gestation). The association between low-dose aspirin use and preterm birth in the second pregnancy was estimated via logistic regression via standardization and expressed as marginal relative risks with the 95% confidence interval. Among the study cohort (N=22,127), 3057 women (14%) were prescribed low-dose aspirin during their second pregnancy and 3703 women (17%) gave birth prematurely. Low-dose aspirin use was associated with a reduced risk for preterm birth, (marginal relative risk, 0.87; 95% confidence interval, 0.77-0.99). There were no statistically significant associations between low-dose aspirin use and an altered risk for moderate preterm birth, defined as birth between 32 and 36 weeks' gestation (marginal relative risk, 0.90; 95% confidence interval, 0.78-1.03), or very preterm birth, defined as birth <32 weeks' gestation (marginal relative risk, 0.75; 95% confidence interval, 0.54-1.04). Regarding the onset of preterm birth, low-dose aspirin use was associated with a reduced risk for spontaneous preterm birth (marginal relative risk, 0.70; 95% confidence interval, 0.57-0.86) but no reduction in the risk for medically indicated preterm birth (marginal relative risk, 1.09; 95% confidence interval, 0.91-1.30) was observed. Among women with a previous preterm birth, low-dose aspirin use was associated with a reduced risk for preterm birth. When investigating preterm birth by onset in the second pregnancy, low-dose aspirin use was associated with a reduced risk for spontaneous preterm birth. Our results suggest that low-dose aspirin may be an effective prophylaxis for recurrent preterm birth.

STUDY QUESTIONIs polycystic ovary syndrome (PCOS) associated with higher risks of extreme birth size and/or preterm birth in mothers with different hypertension types?SUMMARY ANSWERPCOS was associated with additional risks of preterm birth in mothers with chronic hypertension and in singleton pregnancies of mothers with pre-eclampsia, and with higher risks of offspring born large for gestational age (LGA) in mothers with gestational hypertension.WHAT IS KNOWN ALREADYWomen with PCOS are more likely to develop gestational hypertension, pre-eclampsia, and chronic hypertension. Although adverse birth outcomes have been frequently reported in mothers with PCOS, such associations in the setting of a hypertensive disorder remain unknown.STUDY DESIGN, SIZE, DURATIONThis is a population-based cohort study including all live births 2004–2014 in Finland (n = 652 732). To ensure diagnosis specificity, mothers with diagnoses that could cause signs and symptoms resembling PCOS were excluded.PARTICIPANTS/MATERIALS, SETTING, METHODSMaternal diagnoses of PCOS, gestational hypertension, chronic hypertension, and pre-eclampsia were identified from the Finnish national registries. Generalized estimating equation and multivariable logistic regression were used to assess the adjusted odds ratio (aOR) and 95% CIs of preterm birth, very preterm birth, and offspring being small for gestational age (SGA) or LGA in hypertensive mothers with or without PCOS, using normotensive mothers without PCOS as reference.MAIN RESULTS AND THE ROLE OF CHANCEOf 43 902 (6.7%) mothers with hypertensive disorders, 1709 (3.9%) had PCOS. Significant interactions were detected for PCOS with hypertension on preterm birth, very preterm birth, offspring born SGA and LGA (Fpreterm = 504.1, Pinteraction < 0.001; Fvery preterm = 124.2, Pinteraction < 0.001; FSGA = 99.5, Pinteraction < 0.001; FLGA = 2.7, Pinteraction = 0.012, respectively). Using mothers with no hypertensive disorder and no PCOS as reference, the risks of preterm and very preterm birth were overrepresented in non-PCOS mothers with chronic hypertension or pre-eclampsia. PCOS was associated with higher risks of preterm birth (aORPCOS 4.02, 3.14–5.15 vs aORnon-PCOS 2.51, 2.32–2.71) in mothers with chronic hypertension, with significant interaction between the exposures (F = 32.7, Pinteraction < 0.001). PCOS was also associated with a higher risk of preterm birth in singleton pregnancies of mothers with pre-eclampsia (aORPCOS 7.33, 5.92–9.06 vs aORnon-PCOS 5.72, 5.43–6.03; F = 50.0, Pinteraction < 0.001). Furthermore, the associations of PCOS comorbid with chronic hypertension or pre-eclampsia was detected also for spontaneous births. Moreover, the risk of offspring LGA was higher in mothers with PCOS and gestational hypertension although lower in those with gestational hypertension alone (aORPCOS 2.04, 1.48–2.80 vs aORnon-PCOS 0.80, 0.72–0.89; F = 9.7, Pinteraction = 0.002), whereas for offspring SGA, the risks were comparable between hypertensive mothers with and those without PCOS.LIMITATIONS, REASONS FOR CAUTIONInformation on medication treatment, gestational weeks of onset for pre-eclampsia and gestational hypertension, weight gain during pregnancy, and PCOS phenotypes were not available. All diagnoses were retrieved from registries, representing only those seeking medical care for their symptoms. The ICD-9 codes used to identify PCOS before year 1996 are known to underestimate the prevalence of PCOS, while the inclusion of anovulatory infertility as PCOS might introduce an overrepresentation bias, although PCOS constitutes 80% of anovulatory infertility. The risk of very preterm birth in relation to maternal PCOS and hypertensive disorders should be interpreted with caution owing to limited sample sizes. Multifetal pregnancies among maternal PCOS were too few for a subgroup analysis. Moreover, ART included IVF/ICSI only. Potential effects of other treatments, such as ovulation induction, were not examined.WIDER IMPLICATIONS OF THE FINDINGSPCOS was associated with additional risks of preterm birth or offspring being LGA in hypertensive mothers, which varied between hypertension types. The exacerbated risks highlight consideration of PCOS in pregnancy counseling and management for women with hypertensive disorders.STUDY FUNDING/COMPETING INTEREST(S)This study was supported by Shandong Provincial Natural Science Foundation, China [ZR2020MH064 to X.C.], the joint research funding of Shandong University and Karolinska Institute [SDU-KI-2019-08 to X.C. and C.L.], the Finnish Institute for Health and Welfare: Drug and pregnancy project [M.G.], the Swedish Research Council [2022-01188 to C.L.], the regional agreement on medical training and clinical research (ALF) between Stockholm County Council and Karolinska Institute Stockholm County Council [RS2021-0855 to C.L.], the Swedish Brain Foundation [FO2021-0412 to C.L.]. The funders had no role in study design, data collection, analysis, and interpretation, writing of the report or decision to submit for publication. The authors report no conflicts of interest.TRIAL REGISTRATION NUMBERN/A.

Fasting during Ramadan Increases Risk of Very Preterm Birth among Arabic-Speaking Women

Trophectoderm biopsy is associated with lower risks of moderate to extreme prematurity and low birthweights: a national registry cohort study of singleton livebirths from frozen-thawed blastocyst transfers

Impact of subgroup analysis on estimates of infertility

BackgroundPost-term births and preterm births (PTBs) are associated with increased risks for both mother and baby, and have resource implications for NHS maternity services. Increased body mass index (BMI) is...

Background: The relationship between maternal copper and zinc intake and the risk of preterm birth is unclear Objectives: This study was designed to investigate the effects of daily copper and zinc intake before and during pregnancy on the risk of preterm birth and to assess whether there is an interaction between copper and zinc intake and the risk of preterm birth Methods: A nested case - control study was conducted in Lanzhou, involving 880 cases and 8017 controls. Eligible participants were interviewed about their diet and characteristics during pregnancy. Unconditional logistic regression was used to determine the association between dietary copper and zinc intake and the risk of preterm birth, including its clinical subtypes. A multivariate adjusted restricted cubic spline (RCS) model was used to investigate the nonlinear relationship between dietary copper and zinc intake and the risk of preterm birth. Results: The study revealed that compared to pregnant women with the highest dietary copper intake before and during pregnancy, those with copper intake in the lower three quartiles (quartiles 1, 2, and 3) had increased risks of preterm birth, with adjusted odds ratios (ORs) of 1.05 (0.96 - 1.14), 1.05 (0.93 - 1.18), and 1.04 (0.82 - 1.32), respectively. The trend test yielded significant results (P = 0.013), particularly in late pregnancy, indicating an association between lower copper intake and increased risks of preterm and spontaneous preterm birth. Maternal dietary zinc intake during pregnancy was positively associated with the risk of preterm birth. The adjusted ORs for quartile 2 compared to quartile 4 were 1.29 (1.09 - 1.52), 1.55 (1.13 - 2.12), and 1.20 (1.00 - 1.46) throughout pregnancy, indicating significantly increased risks in the mid to late stages of pregnancy. No significant association was found between zinc intake and medically induced preterm birth. Zinc intake below the nutritional reference value in late pregnancy was significantly associated with an increased risk of preterm birth (P &lt; 0.05). A nonlinear relationship was observed between copper/zinc intake and the risk of preterm birth (P Nonlinear &lt; 0.05). A synergistic effect of low copper and zinc intake on the risk of preterm birth was found (OR: 2.23, 95% CI: 1.64 - 3.04, P &lt; 0.001). Conclusions: Efforts to promote adequate copper and zinc intake before and during pregnancy need to be intensified to reduce the incidence of preterm birth.

Risk of Extreme, Moderate, and Late Preterm Birth by Maternal Race, Ethnicity, and Nativity

BackgroundPreterm (< 37 weeks gestation) and post–term birth (≥42 weeks gestation) are associated with increased morbidity and mortality for mother and infant. Obesity (body mass index (BMI) ≥30 kg/m2) is increasing in women of reproductive age. Maternal obesity has been associated with adverse pregnancy outcomes including preterm and post–term birth. However, the effect sizes vary according to the subgroups of both maternal BMI and gestational age considered. The aim of this retrospective analysis was to determine the association between maternal obesity classes and gestational age at delivery.MethodsA secondary data analysis of 13 maternity units in England with information on 479,864 singleton live births between 1990 and 2007. BMI categories were: underweight (< 18.5 kg/m2), recommended weight (18.5–24.9 kg/m2), overweight (25.0–29.9 kg/m2) and obesity classes I (30.0–34.9 kg/m2), II (35.0–39.9 kg/m2), IIIa (40–49.9 kg/m2) and IIIb (≥50 kg/m2). Gestational age at delivery categories were: Gestational age at delivery (weeks): extreme preterm (20–27), very preterm (28–31), moderately preterm (32–36), early term (37, 38), full term (39–40), late term (41) and post–term (≥42). The adjusted odds of births in each gestational age category (compared to full-term birth), according to maternal BMI categories were estimated using multinomial logistic regression. Missing data were estimated using multiple imputation with chained equations.ResultsThere was a J-shaped association between the absolute risk of extreme, very and moderate preterm birth and BMI category, with the greatest effect size for extreme preterm. The absolute risk of post-term birth increased monotonically as BMI category increased. The largest effect sizes were observed for class IIIb obesity and extreme preterm birth (adjusted OR 2.80, 95% CI 1.31–5.98).ConclusionWomen with class IIIb obesity have the greatest risks for inadequate gestational age. Combining obesity classes does not accurately represent risks for many women as it overestimates the risk of all preterm and post-term categories for women with class I obesity, and underestimates the risk for women in all other obesity classes.

Breast cancer mortality is higher for Black and younger women. This study evaluated 2 possible contributors to disparities-time to treatment and treatment duration-by race and age. Among 2841 participants with stage I-III disease in the Carolina Breast Cancer Study, we identified groups of women with similar patterns of socioeconomic status (SES), access to care, and tumor characteristics using latent class analysis. We then evaluated latent classes in association with treatment delay (initiation >60 days after diagnosis) and treatment duration (in quartiles by treatment modality). Thirty-two percent of younger Black women were in the highest quartile of treatment duration (versus 22% of younger White women). Black women experienced a higher frequency of delayed treatment (adjusted relative frequency difference [RFD], 5.5% [95% CI, 3.2%-7.8%]) and prolonged treatment duration (RFD, 8.8% [95% CI, 5.7%-12.0%]). Low SES was significantly associated with treatment delay among White women (RFD, 3.5% [95% CI, 1.1%-5.9%]), but treatment delay was high at all levels of SES in Black women (eg, 11.7% in high SES Black women compared with 10.6% and 6.7% among low and high SES White women, respectively). Neither SES nor access to care classes were significantly associated with delayed initiation among Black women, but both low SES and more barriers were associated with treatment duration across both groups. Factors that influence treatment timeliness persist throughout the care continuum, with prolonged treatment duration being a sensitive indicator of differences by race, SES, and care barriers.

Relationship of trimester-specific smoking patterns and risk of preterm birth

Effects of race/ethnicity and BMI on the association between height and risk for spontaneous preterm birth