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Objective: Evidence for the association between subclinical thyroid dysfunction before conception and its pregnancy outcomes is inconsistent. Thus, we evaluated the relationship between preconception thyroid-stimulating hormone (TSH) levels and adverse pregnancy outcomes., Design: Retrospective cohort study., Methods: A total of 50,217 women without prior thyroid disease who became pregnant within 1 year after undertaking a routine TSH test in the Chongqing Municipality of China (2010-2016) were studied. Restricted cubic spline regression and logistic regression were used to estimate the association between preconception TSH levels and pregnancy outcomes. The main outcomes were individual and composite adverse pregnancy outcomes (CAPOs) comprising pregnancy loss, small for gestational age, large for gestational age, and preterm birth., Results: Incidence of CAPO was 24.19%. Increased preconception TSH level was positively associated with CAPO (odds ratio [OR]/SD: 1.04, 95% confidence interval [CI]: 1.01-1.07) when TSH was ≥2.1 mIU/L, positively associated with pregnancy loss (OR/SD: 1.06, 95% CI: 1.01-1.12) when TSH was <2.1 mIU/L, negatively and positively associated with preterm delivery when TSH levels were <1.3 mIU/L (OR/SD: 0.90, 95% CI: 0.83-0.97) and >3.0 mIU/L (OR/SD: 1.08, 95% CI: 1.00-1.17), respectively. Women with subclinical hypothyroidism before conception were at a higher risk for CAPO (adjusted odds ratio [aOR]: 1.12, 95% CI: 1.04-1.22), while those with subclinical hyperthyroidism had a higher risk of preterm delivery (aOR: 1.31, 95% CI: 1.01-1.70)., Conclusions: Nonlinear associations were indicated between preconception TSH levels and pregnancy outcomes. Subclinical thyroid dysfunction before conception was associated with an increased risk of adverse pregnancy outcomes., (© 2021 John Wiley & Sons Ltd.)

Background: Reproductive tract infections can cause serious adverse outcomes for pregnant women such as spontaneous abortion and preterm birth. However, it is unclear whether maternal reproductive tract infection before pregnancy would also be related to any adverse pregnancy outcomes. This study aims to investigate the association of maternal preconception reproductive tract infections with subsequent adverse pregnancy outcomes., Methods: A retrospective cohort study was conducted in the Chongqing Municipality of China between April 2010 and December 2016. A total of 57,586 women (57,708 pregnancies) from all 39 counties of Chongqing who participated in the National Free Preconception Health Examination Project were included. They all took preconception examinations for gonorrhea, chlamydia, trichomoniasis, syphilis, bacterial vaginosis and candidiasis before pregnancy within one year. Primary outcomes included spontaneous abortion (< 28 weeks gestation), preterm birth (< 37 weeks gestation), macrosomia and low birthweight., Results: Of the 57,708 pregnancies, 2438 (4.22%) had at least one type of reproductive tract infections. Compared with women who were not infected with any reproductive tract infection before pregnancy, women with reproductive tract infections had a higher rate of spontaneous abortion (7.88% vs. 5.62%, p < 0.001). After analyzing by each infection, there were few significant associations between pre-pregnancy infections and adverse outcomes. Preconception syphilis infection was significantly associated with increased odds of spontaneous abortion (aOR = 2.07, 95%CI 1.50-2.85), induced abortion/labour due to medical reasons (aOR = 1.60, 95%CI 1.01-2.54) and preterm birth (aOR = 1.60, 95%CI 1.12-2.30) after adjusting for potential confounders. Preconception trichomoniasis was intended to relate to a higher risk of spontaneous abortion (aOR = 1.65, 95%CI 1.01-2.71), but its impact seemed to be attributed to its co-infection with other RTIs. Women who were chlamydia or bacterial vaginosis positive before pregnancy showed higher odds of macrosomia (aOR = 2.00, 95% CI 1.07-3.74 for chlamydia; aOR = 1.58, 95% CI 1.06-2.34 for bacterial vaginosis). Preconception bacterial vaginosis might also be associated with higher risks of very preterm birth (aOR = 2.16, 95%CI 1.23-3.78) and large for gestational age (aOR = 1.36, 95%CI 1.02-1.81)., Conclusions: Women with infections of the genital tract before pregnancy might also have increased risks of subsequent adverse outcomes including spontaneous abortion, preterm birth and macrosomia., (© 2022. The Author(s).)

Objective: To investigate the association between maternal pregestational blood glucose level and adverse pregnancy outcomes., Design: Retrospective cohort study., Setting: This study was conducted in the Chongqing Municipality of China between April 2010 and December 2016., Participants: A total of 60 222 women (60 360 pregnancies) from all 39 counties of Chongqing who participated in the National Free Preconception Health Examination Project and had pregnancy outcomes were included., Primary Outcome Measures: Adverse pregnancy outcomes included spontaneous abortion, induced abortion or labour due to medical reasons, stillbirth, preterm birth (PTB), macrosomia, large for gestational age, low birth weight (LBW) and small for gestational age., Results: Of the 60 360 pregnancies, rates of hypoglycaemic, normoglycaemia, impaired fasting glycaemia (IFG) and diabetic hyperglycaemic before conception were 5.06%, 89.30%, 4.59% and 1.05%, respectively. Compared with women with normoglycaemia, women with pregestational glucose at the diabetic level (≥7.0 mmol/L) might have a higher rate of macrosomia (6.18% vs 4.16%), whereas pregestational IFG seemed to be associated with reduced risks of many adverse outcomes, including spontaneous abortion, induced abortion due to medical reasons, PTB and LBW. After adjusting for potential confounders, pregestational diabetic hyperglycaemic was remained to be significantly associated with an increased risk of macrosomia (adjusted risk ratio 1.49, 95% CI 1.07 to 2.09). Abnormal maternal glucose levels before pregnancy (either hypoglycaemic or hyperglycaemic) seemed to have no significant negative effect on spontaneous abortion or induced abortion due to medical reasons., Conclusion: Although without overt diabetes mellitus, women with once diabetic fasting glucose level during their preconception examinations could be associated with an increased risk for macrosomia. Uniform guidelines are needed for maternal blood glucose management during pre-pregnancy care to improve pregnancy outcomes., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Intervention studies have shown that long-chain (LC) n-3 PUFA intake can prolong gestation but the dose-time-effect relations remain unresolved., Objectives: We examined the effect on gestation duration of 2 doses of supplemental LC n-3 PUFAs., Methods: We undertook a 3-group parallel randomized controlled trial in areas of China with low (median: 2.1 g/d) and higher (14.3 g/d) fish intake. Unselected women (median: age, 26.2 y; BMI, 20. kg/m2) were randomly assigned at midgestation to take four 0.72-g identical gelatin capsules per day until the last day of the preterm period (<259 days of gestation), when they were asked to stop. Capsules contained fish oil [high fish oil (HFO) group (60% w/w LC n-3 PUFAs)], a 1:3 mixture of fish oil to olive oil [low fish oil (LFO) group (20%)], or olive oil [control (CON) group (0%)], providing 2.0, 0.5, and 0 g/d of LC n-3 PUFAs, respectively. Habitual fish intake was recorded at baseline. Hazard rate ratios (HRRs) for spontaneous delivery <259 days of gestation and <273 days of gestation across groups were estimated by Cox regression., Results: Among 5531 women randomly assigned, 92.5% were included in analyses (1706/1825, 1695/1851, and 1717/1855, respectively). The groups were similar with respect to hazard rates <259 days of gestation [HRR: 1.04 (95% CI: 0.70, 1.53) for LFO compared with CON and 0.90 (95% CI: 0.60, 1.35) for HFO compared with CON], hazard rates <273 days of gestation [HRR: 1.00 (95% CI: 0.86, 1.18) and 0.91 (95% CI: 0.77, 1.07), respectively], and mean gestation durations [differences: 0.2 d (95% CI: -0.5, 0.8) and 0.6 d (95% CI: -0.06, 1.2), respectively]. Inspection of pregnancy survival curves suggested that LC n-3 PUFAs delayed delivery in low fish consumers by 5-10 d and that this effect ceased rapidly after stopping taking the capsules., Conclusion: This trial could not substantiate that fish oil prevents preterm birth in Chinese women, possibly because statistical power was too low. This trial was registered at clinicaltrials.gov as NCT02770456., (Copyright © American Society for Nutrition 2019.)