Evidence on the relationship between maternal Hb concentration and spontaneous abortion (SA) risk is limited and conflicting. The purpose of the study was to evaluate whether maternal preconception anaemia or high Hb concentration is associated with risk of SA.

A population-based cohort study established between 2013 and 2017.

Local maternal and child care service centres in each county.

In total, 3 971 428 women aged 20–49 years, who participated in National Free Pre-Pregnancy Checkups Project from 2013 to 2016 and successfully got pregnant before 2017 in rural China.

A total of 101 700 (2·56 %) women were recorded having SA, with highest SA rate in women with severe anaemia (4·58 %). Compared with women with Hb of 110–149 g/l, the multivariable-adjusted OR for SA was 1·52 (95 % CI: 1·25, 1·86) for women with Hb < 70 g/l, 0·92 (0·84, 1·01) for 70–99 g/l, 0·80 (0·77, 0·83) for 100–109 g/l, 1·11 (1·08, 1·15) for 150–159 g/l, 1·12 (1·04, 1·20) for 160–169 g/l and 1·02 (0·93, 1·12) for ≥ 170 g/l, respectively. An approximate U-shaped curve for the risk of SA with Hb concentrations was observed when Hb concentrations less than 145 g/l, above which the association plateaued (Pnon-linear < 0·001).

Severe anaemia and high Hb concentration before pregnancy were associated with an increased risk of SA. Women with mild anaemia prior to pregnancy had lower risk of SA. Underlying mechanisms need to be further studied.

To assess the association between maternal caffeine intake and risk of pregnancy loss using a systematic review and meta-analysis.

Categorical and dose–response meta-analysis of prospective studies.

Relevant articles were identified by searching MEDLINE and SCOPUS databases through 30 January 2015. Two authors independently extracted information from eligible studies. Random-effects models were used to derive the summary relative risks (RR) and corresponding 95 % CI for specific categories of caffeine consumption and for a continuous association using generalized least-squares trend estimation.

A total of 130 456 participants and 3429 cases in fourteen included studies.

Compared with the reference category with no or very low caffeine intake, the RR (95 % CI) of pregnancy loss was 1·02 (0·85, 1·24; I2=28·3 %) for low intake (50–149 mg/d), 1·16 (0·94, 1·41; I2=49·6 %) for moderate intake (150–349 mg/d), 1·40 (1·16, 1·68; I2=18·6 %) for high intake (350–699 mg/d) and 1·72 (1·40, 2·13; I2=0·0 %) for very high intake (≥700 mg/d). In the dose–response analysis, each 100 mg/d increment in maternal caffeine intake (~1 cup of coffee) was associated with 7 % (95 % CI 3 %, 12 %) higher risk of pregnancy loss. Our results may have been affected by publication bias, but the association remained significant for the subset of larger studies. Furthermore, adjustment for smoking and pregnancy symptoms may have been incomplete, potentially resulting in residual confounding.

Albeit inconclusive, higher maternal caffeine intake was associated with a higher risk of pregnancy loss and adherence to guidelines to avoid high caffeine intake during pregnancy appears prudent.

Emergency department targeted ultrasonography (EDTU) offers the possibility of rapid exclusion of ectopic pregnancy in patients with first-trimester pelvic pain or bleeding. We sought to systematically review the evidence describing the diagnostic accuracy and clinical utility of EDTU in the first trimester of pregnancy, and to generate a pooled estimate of the sensitivity and specificity of EDTU for the detection of intrauterine pregnancy (IUP).

The literature search, abstract review and study selection were performed using predefined criteria. We abstracted the sensitivity and specificity of EDTU for IUP from included studies, and evaluated and summarized the evidence assessing the effect of EDTU use on time to diagnosis, time to treatment of ectopic pregnancy, emergency department (ED) length of stay and health care costs.

The specificity of EDTU for IUP in most studies exceeds 98%. The sensitivity in most studies exceeds 90%. Pooled estimates were not calculated because of statistical heterogeneity between studies. Published evidence indicates that EDTU use reduces the frequency of missed ectopic pregnancies, decreases time to surgery for ectopic pregnancy, shortens the length of stay for patients with normal pregnancies and may be more cost-effective than diagnostic strategies requiring formal ultrasonography.

EDTU is highly specific for the identification of IUP. Patients who have an IUP identified with EDTU may be safely discharged from the ED with outpatient follow-up. The specificity of EDTU for IUP, along with the potential improvements in patient care that EDTU affords, justifies its adoption as routine ED care in evaluating first-trimester pain or bleeding.