Couples' prepregnancy body mass index and time to pregnancy among those attempting to conceive their first pregnancy.

OBJECTIVE: To explore the relationship between couples' prepregnancy body mass index (BMI) and time to pregnancy (TTP) among those with no prior gravidity. DESIGN: Retrospective cohort study. SETTING: Local maternal/child health care or family-planning service institutions. PATIENT(S): A total of 2,301,782 eligible couples participating in the National Free Preconception Check-up Projects from January 1, 2015 to December 31, 2017. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Time to pregnancy. RESULT(S): Underweight, overweight, or obese status in women and underweight status in men were associated with couples' prolonged TTP. The optimal BMI levels were 20.61-23.06 kg/m2 and 22.69-27.74 kg/m2 for women and men, respectively. Compared with couples in whom both partners had a normal BMI, the pregnancy rates were reduced by 10% (fecundability odds ratio [FOR] 0.90; 95% confidence interval [CI], 0.88-0.92) and 19% (FOR 0.81; 95% CI, 0.78-0.84) for couples in whom both partners were underweight or obese, respectively. The combination of women with a normal BMI and overweight men had the greatest fertility (FOR 1.03; 95% CI, 1.02-1.03), and the combination of obese women and underweight men had the lowest fertility (FOR 0.70; 95% CI, 0.65-0.76). CONCLUSION(S): Abnormal prepregnancy BMIs in either women or men were associated with prolonged TTP among couples with no prior gravidity. Scientific management of couples' prepregnancy BMI could improve their fertility.

Pre-pregnancy maternal fasting plasma glucose levels in relation to time to pregnancy among the couples attempting first pregnancy.

STUDY QUESTION: What is the relationship between pre-pregnancy maternal glucose levels and fecundability in Chinese couples? SUMMARY ANSWER: Elevated pre-pregnancy maternal glucose levels were associated with fecundability, as reflected by prolonged time to pregnancy (TTP) among the couples with no prior gravidity. STUDY DESIGN, SIZE, DURATION: Based on the National Free Pre-conception Check-up Projects supported by the Chinese government, 2 226 048 eligible couples attempting first pregnancy and participating in the project from 2015 to 2016 were included. They were followed-up for 1 year or until they reported pregnancy. PARTICIPANTS/MATERIALS, SETTINGS, METHODS: The Kaplan-Meier method was used to estimate the cumulative pregnancy rate in each menstrual cycle, and the discrete-time analogue of the Cox models was used to estimate the fecundability odds ratios (FORs) and 95% CIs by different pre-pregnancy maternal glucose levels (impaired fasting glucose (IFG) or diabetes as compared to normal). MAIN RESULTS AND THE ROLE OF CHANCE: The cumulative pregnancy rate for 12 cycles of the normal fasting plasma glucose (FPG) level group was 42.29%, significantly higher than that of the IFG (35.52%) and diabetes groups (31.52%). After adjusting for confounding factors, the FORs were 0.82 (95% CI: 0.81-0.83) and 0.74 (95% CI: 0.72-0.76) for the IFG and diabetes groups, respectively, as compared to the normal group. The association between pre-pregnancy maternal FPG levels and the FORs was non-linear, and the optimal FPG level for greatest fecundability (shortest TTP) was 3.90-4.89 mmol/L. LIMITATIONS, REASONS FOR CAUTION: The findings from this register-based cohort study require cautious interpretation given that information bias would be inevitable for single FPG measurements and for TTP calculations that were based on telephone follow-up information. Additionally, because couples who achieved pregnancy during their first menstrual cycle in the study were excluded, the pregnancy rates reported were low and possibly biased. WIDER IMPLICATIONS OF THE FINDINGS: The current report suggests that elevated pre-pregnancy maternal glucose levels were associated with prolonged TTP. Early evaluation and preventive treatment for female partners with IFG or diabetes in a pre-pregnancy examination are necessary. STUDY FUNDING/COMPETING INTEREST(S): Funding was provided by the National Key Research and Development Program of China (grants No. 2016YFC1000300 and 2016YFC1000307), the National Natural Science Foundation of China (grant No. 81872634), the CAMS Innovation Fund for Medical Sciences (grant No. 2018-I2M-1-004), the National Human Genetic Resources Sharing Service Platform (grant No. 2005DKA21300) and the National Population and Reproductive Health Science Data Center (grant No. 2005DKA32408), People's Republic of China. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Preconception blood pressure and time to pregnancy among couples attempting to conceive their first pregnancy.

BACKGROUND: The association of abnormal blood pressure levels (including hypertension and prehypertension) with reduced fecundability among young childbearing-age couples is not yet elucidated completely. OBJECTIVE: The purpose of this study was to investigate the association between abnormal preconception blood pressure level and time to pregnancy among couples who are attempting to conceive their first pregnancy. STUDY DESIGN: A total of 2,234,350 eligible couples (with no previous gravidity and whose female partners were 20-49 years old) participated in the National Free Preconception Check-up Projects from January 1, 2015, to December 31, 2016. Each couples' preconception blood pressure levels were measured, and time to pregnancy was recorded. Cox models for discrete survival time were used to estimate fecundability odds ratios and their corresponding 95% confidence intervals after adjustment for age, ethnicity, educational level, occupation, household registration, region, tobacco exposure, alcohol intake, body mass index, duration of marriage of the couples, and fasting plasma glucose levels of the female partner. RESULTS: Compared with normotensive women, those women with hypertension (systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg) had a 21% lower pregnancy rate (fecundability odds ratio, 0.79; 95% confidence interval, 0.78-0.81). A similar finding was found among men (fecundability odds ratio, 0.89; 95% confidence interval, 0.88-0.90). Prehypertension (systolic blood pressure between 120 and 139 mm Hg, and/or a diastolic blood pressure between 80 and 89 mm Hg) in both male and female partners was associated slightly with reduced fecundability odds ratios. Compared with couples in which both partners were normotensive, the pregnancy rate was reduced by 27% (fecundability odds ratio, 0.73; 95% confidence interval, 0.69-0.77) among couples in which both partners had hypertension. CONCLUSION: Abnormal preconception blood pressure levels were associated with prolonged time to pregnancy among couples who were attempting to conceive their first pregnancy; the mechanism is worth further investigation.

The association between low glucose-6-phosphate dehydrogenase activity level and hepatitis B virus infection among pre-pregnant reproductive-age Chinese females.

The relationship between females with low glucose-6-phosphate dehydrogenase activity level (LG6PD) and HBV infection is unclear. We conducted a cross sectional study of 124 406 reproductive-age Chinese females who participated in the National Free Pre-conception Check-up Projects to investigate the risk of HBV infection among females with LG6PD and its effect on liver enzyme. Based on HBV serological test results, the participants were divided into the susceptible, immunized, and HBV infected groups. The multivariable-adjusted odds ratios (ORs) for HBV infection in LG6PD participants were 1.71 (95% confidence interval (CI): 1.45-2.01) and 1.41 (95% CI: 1.23-1.62), respectively with the susceptible and immunized participants as references, compared to those without LG6PD. Participants with HBV infection only and combined with HBV infection and LG6PD had 184% and 249% significantly higher risks of elevated alanine transaminase (ALT) (susceptible participants as reference). If the immunized participants were used as reference, significant higher odds of elevated ALT occurred (3.48 (95% CI: 3.18-3.80), 4.28 (95% CI: 2.92-6.28)). Thus, reproductive-age females with LG6PD had a higher prevalence of HBV infection, and LG6PD might exacerbate ALT elevation in HBV infected females. Our findings underscore the need to explore collaborative management approaches for these two diseases among reproductive-age females for maternal and child health.

MicroRNA biogenesis pathway genes polymorphisms and cancer risk: a systematic review and meta-analysis.

MicroRNAs (miRNAs) may promote the development and progression of human cancers. Therefore, components of the miRNA biogenesis pathway may play critical roles in human cancer. Single nucleotide polymorphisms (SNPs) or mutations in genes involved in the miRNA biogenesis pathway may alter levels of gene expression, affecting disease susceptibility. Results of previous studies on genetic variants in the miRNA biogenesis pathway and cancer risk were inconsistent. Therefore, a meta-analysis is needed to assess the associations of these genetic variants with human cancer risk. We searched for relevant articles from PubMed, Web of Science, CNKI, and CBM through Jun 21, 2016. In total, 21 case-control articles met all of the inclusion criteria for the study. Significant associations were observed between cancer risk and the DGCR8polymorphism rs417309 G >A (OR 1.22, 95% CI [1.04-1.42]), as well as the DICER1 polymorphism rs1057035 TT (OR 1.13, 95% CI [1.05-1.22]). These SNPs exhibit high potential as novel diagnostic markers. Future studies with larger sample sizes and more refined analyses are needed to shed more light on these findings.

Genetic variants in the MicroRNA biosynthetic pathway Gemin3 and Gemin4 are associated with a risk of cancer: a meta-analysis.

The effects of the microRNA (miRNA) processing genes Gemin3 and Gemin4 on cellular signaling pathways could have a major impact on the risk of cancer. Several studies concerning the association between the Gemin3 rs197412, Gemin4 rs7813 and Gemin4 rs2740348 polymorphisms with cancer susceptibility have been published. The present meta-analysis summarized this evidence and evaluated the precision of these relationships. Relevant studies (published prior to December 16th, 2015) without language restriction were identified using the PubMed, Web of Science and China National Knowledge Infrastructure (CNKI) on-line databases. The data were extracted from the eligible studies and were processed using Stata 12.0 software. Seven studies (2,588 cases and 2,549 controls) indicated that the rs7813 polymorphism was significantly associated with increased cancer risk (TT vs TC + CC, OR = 1.18 95% CI [1.05-1.32]). Six studies (1,314 cases and 1,244 controls) indicated that rs2740348 was associated with an increased cancer risk (GG vs. GC + CC, OR = 1.41 95% CI [1.00-1.83]). However the rs197412 polymorphism was not associated with an increased cancer risk (OR = 0.97 95% CI [0.80-1.19]). Our results suggest that the Gemin4 rs7813 T > C and rs2740348 G > C polymorphisms are associated with cancer susceptibility.