Treatment with vaginal progesterone reduces the risk of miscarriage and preterm birth in selected high-risk women. The hypothesis that vaginal progesterone can reduce the risk of hypertensive disorders of pregnancy (HDP) is unexplored. To summarise the evidence on the effectiveness of vaginal progesterone to reduce the risk of HDP.
Search Strategy: We searched Embase (OVID), MEDLINE (OVID), PubMed, CENTRAL and clinicaltrials.gov from inception until 20 June 2023.
Selection Criteria: We included placebo-controlled randomised trials (RCTs) of vaginal progesterone for the prevention or treatment of any pregnancy complications.
Data Collection and Analysis: We extracted absolute event numbers for HDP and pre-eclampsia in women receiving vaginal progesterone or placebo, and meta-analysed the data with a random effects model. We appraised the certainty of the evidence using GRADE methodology. MAIN The quantitative synthesis included 11 RCTs, of which three initiated vaginal progesterone in the first trimester, and eight in the second or third trimesters. Vaginal progesterone started in the first trimester of pregnancy lowered the risk of any HDP (risk ratio [RR] 0.71, 95% confidence interval [CI] 0.53-0.93, 2 RCTs, n = 4431 women, I(2) = 0%; moderate-certainty evidence) and pre-eclampsia (RR 0.61, 95% CI 0.41-0.92, 3 RCTs, n = 5267 women, I(2) = 0%; moderate-certainty evidence) when compared with placebo. Vaginal progesterone started in the second or third trimesters was not associated with a reduction in HDP (RR 1.19, 95% CI 0.67-2.12, 3 RCTs, n = 1602 women, I(2) = 9%; low-certainty evidence) or pre-eclampsia (RR 0.97, 95% CI 0.71-1.31, 5 RCTs, n = 4274 women, I(2) = 0%; low-certainty evidence). Our systematic review found first-trimester initiated vaginal micronised progesterone may reduce the risk of HDP and pre-eclampsia.
The evidence on the association between diet and miscarriage risk is scant and conflicting. To summarize the evidence on the association between periconceptual diet and miscarriage risk in healthy women of reproductive age. Data Sources: Electronic databases were searched from inception to August 2022 without restriction of regions, publication types, or languages. Experimental or observational studies were considered for inclusion. The population was healthy women of reproductive age. Exposure was periconception diet. Study quality was assessed using the modified Newcastle-Ottawa Scale. Summary effect sizes (odds ratio [OR] with 95% confidence interval [CI]) were calculated for each food category. Outcomes: Miscarriage rate (as defined by primary studies). We included 20 studies (11 cohort and 9 case-control), of which 6 presented data suitable for meta-analysis (2 cohort and 4 case-control, n = 13,183 women). Our primary analyses suggest a reduction in miscarriage odds with high intake of the following food groups: fruit (OR, 0.39; 95% CI, 0.33-0.46), vegetables (OR, 0.59; 95% CI, 0.46-0.76), fruit and vegetables (OR, 0.63; 95% CI, 0.50-0.81), seafood (OR, 0.81; 95% CI, 0.71-0.92), dairy products (OR, 0.63; 95% CI, 0.54-0.73), eggs (OR, 0.81; 95% CI, 0.72-0.90), and cereal (grains) (OR, 0.67; 95% CI, 0.52-0.87). The evidence was uncertain for meat, red meat, white meat, fat and oil, and sugar substitutes. We did not find evidence of an association between adherence to predefined dietary patterns and miscarriage risk. However, a whole diet containing healthy foods as perceived by the trialists, or with a high Dietary Antioxidant Index score (OR, 0.43; 95% CI, 0.20-0.91) may be associated with a reduction in miscarriage risk. In contrast, a diet rich in processed food was demonstrated to be associated with increased miscarriage risk (OR, 1.97; 95% CI, 1.36-3.34). A diet abundant in fruit, vegetables, seafood, dairy, eggs, and grain may be associated with lower miscarriage odds. Further interventional studies are required to accurately assess the effectiveness of periconception dietary modifications on miscarriage risk. PROSPERO Registration: CRD42020218133.
Tamblyn JA et al., 2022·Fertility and sterility·
Open Access
To investigate whether a significant association between vitamin D status and the risk of miscarriage or recurrent miscarriage (RM) exists. Systematic review and meta-analysis. Not applicable. PATIENT(S): Women with miscarriage and RM. INTERVENTION(S): We searched the Ovid MEDLINE, Embase, the Cumulative Index to Nursing and Allied Health Literature, and Cochrane Central Register of Controlled Trials from database inception to May 2021. Randomized and observational studies investigating the association between maternal vitamin D status and miscarriage and/or vitamin D treatment and miscarriage were included. MAIN OUTCOME MEASURE(S): The primary outcome was miscarriage or RM, with vitamin D status used as the predictor of risk. Whether vitamin D treatment reduces the risk of miscarriage and RM was also assessed. RESULT(S): Of 902 studies identified, 10 (n = 7,663 women) were included: 4 randomized controlled trials (n = 666 women) and 6 observational studies (n = 6,997 women). Women diagnosed with vitamin D deficiency (<50 nmol/L) had an increased risk of miscarriage compared with women who were vitamin D replete (>75 nmol/L) (odds ratio, 1.94; 95% confidence interval, 1.25-3.02; 4 studies; n = 3,674; I2 = 18%). Combined analysis, including women who were vitamin D insufficient (50-75 nmol/L) and deficient (<50 nmol/L) compared with women who were replete (>75 nmol/L), found an association with miscarriage (odds ratio, 1.60; 95% confidence interval, 1.11-2.30; 6 studies; n = 6,338; I2 = 35%). Although 4 randomized controlled trials assessed the effect of vitamin D treatment on miscarriage, study heterogeneity, data quality, and reporting bias precluded direct comparison and meta-analysis. The overall study quality was "low" or "very low" using the Grading of Recommendations, Assessment, Development and Evaluations approach. CONCLUSION(S): Vitamin D deficiency and insufficiency are associated with miscarriage. Whether preconception treatment of vitamin D deficiency protects against pregnancy loss in women at risk of miscarriage remains unknown. CRD42021259899.
Coomarasamy A et al., 2020·Am J Obstet Gynecol·
Open Access
Progesterone is essential for the maintenance of pregnancy. Several small trials have suggested that progesterone supplementation may reduce the risk of miscarriage in women with recurrent or threatened miscarriage. Cochrane Reviews summarized the evidence and found that the trials were small with substantial methodologic weaknesses. Since then, the effects of first-trimester use of vaginal micronized progesterone have been evaluated in 2 large, high-quality, multicenter placebo-controlled trials, one targeting women with unexplained recurrent miscarriages (the PROMISE [PROgesterone in recurrent MIScarriagE] trial) and the other targeting women with early pregnancy bleeding (the PRISM [PRogesterone In Spontaneous Miscarriage] trial). The PROMISE trial studied 836 women from 45 hospitals in the United Kingdom and the Netherlands and found a 3% greater live birth rate with progesterone but with substantial statistical uncertainty. The PRISM trial studied 4153 women from 48 hospitals in the United Kingdom and found a 3% greater live birth rate with progesterone, but with a P value of .08. A key finding, first observed in the PROMISE trial, and then replicated in the PRISM trial, was that treatment with vaginal micronized progesterone 400 mg twice daily was associated with increasing live birth rates according to the number of previous miscarriages. Prespecified PRISM trial subgroup analysis in women with the dual risk factors of previous miscarriage(s) and current pregnancy bleeding fulfilled all 11 conditions for credible subgroup analysis. For the subgroup of women with a history of 1 or more miscarriage(s) and current pregnancy bleeding, the live birth rate was 75% (689/914) with progesterone vs 70% (619/886) with placebo (rate difference 5%; risk ratio, 1.09, 95% confidence interval, 1.03-1.15; P=.003). The benefit was greater for the subgroup of women with 3 or more previous miscarriages and current pregnancy bleeding; live birth rate was 72% (98/137) with progesterone vs 57% (85/148) with placebo (rate difference 15%; risk ratio, 1.28, 95% confidence interval, 1.08-1.51; P=.004). No short-term safety concerns were identified from the PROMISE and PRISM trials. Therefore, women with a history of miscarriage who present with bleeding in early pregnancy may benefit from the use of vaginal micronized progesterone 400 mg twice daily. Women and their care providers should use the findings for shared decision-making.
Metabolic and Endocrine Agents · Thyroid Replacement
Dhillon-Smith RK et al., 2019·Efficacy Mech Eval·
Open Access
Thyroid autoantibodies, specifically thyroid peroxidase antibodies, have been associated with miscarriage and pre-term birth in women with a normal thyroid function. Small randomised controlled trials have found that treatment with levothyroxine may reduce such adverse outcomes in pregnancy. The Thyroid AntiBodies and LEvoThyroxine (TABLET) trial was conducted to explore the effects of levothyroxine in euthyroid women with thyroid peroxidase antibodies. This was a randomised, double-blind, placebo-controlled, multicentre study conducted in 49 hospitals across the UK between 2011 and 2016. Euthyroid women who tested positive for thyroid peroxidase antibodies, were aged between 16 and 41 years and were trying to conceive either naturally or through assisted conception were eligible. Participants were randomised to levothyroxine at a dose of 50 mcg daily or placebo. The primary outcome was live birth at >= 34 completed weeks of gestation. Of the 19,556 women screened, 1420 were eligible and 952 were randomised. The live birth rate was 37% in the levothyroxine group and 38% in the placebo group (relative risk 0.97, 95% CI 0.83 to 1.14; p = 0.74). Levothyroxine therapy in a dose of 50 mcg per day does not improve live birth rate in euthyroid women with thyroid peroxidase antibodies.
Coomarasamy A et al., 2019·N Engl J Med·
Open Access
Bleeding in early pregnancy is strongly associated with pregnancy loss. Progesterone is essential for the maintenance of pregnancy. Several small trials have suggested that progesterone therapy may improve pregnancy outcomes in women who have bleeding in early pregnancy. We conducted a multicenter, randomized, double-blind, placebo-controlled trial to evaluate progesterone, as compared with placebo, in women with vaginal bleeding in early pregnancy. Women were randomly assigned to receive vaginal suppositories containing either 400 mg of progesterone or matching placebo twice daily, from the time at which they presented with bleeding through 16 weeks of gestation. The primary outcome was the birth of a live-born baby after at least 34 weeks of gestation. The primary analysis was performed in all participants for whom data on the primary outcome were available. A sensitivity analysis of the primary outcome that included all the participants was performed with the use of multiple imputation to account for missing data. A total of 4153 women, recruited at 48 hospitals in the United Kingdom, were randomly assigned to receive progesterone (2079 women) or placebo (2074 women). The percentage of women with available data for the primary outcome was 97% (4038 of 4153 women). The incidence of live births after at least 34 weeks of gestation was 75% (1513 of 2025 women) in the progesterone group and 72% (1459 of 2013 women) in the placebo group (relative rate, 1.03; 95% confidence interval [CI], 1.00 to 1.07; P = 0.08). The sensitivity analysis, in which missing primary outcome data were imputed, resulted in a similar finding (relative rate, 1.03; 95% CI, 1.00 to 1.07; P = 0.08). The incidence of adverse events did not differ significantly between the groups. Among women with bleeding in early pregnancy, progesterone therapy administered during the first trimester did not result in a significantly higher incidence of live births than placebo. (Funded by the United Kingdom National Institute for Health Research Health Technology Assessment program; PRISM Current Controlled Trials number, ISRCTN14163439.).
What is the chance of clinical pregnancy when fallopian tube catheterization is used for proximal tubal obstruction? The pooled clinical pregnancy rate of tubal catheterization after proximal tubal obstruction is 27% (95% CI 25-30%). Restoring fallopian tube patency by performing tubal catheterization has fallen out of favour since the increased availability of IVF. Our study is the first systematic review and meta-analysis to investigate reproductive outcomes following tubal catheterization for proximal tubal obstruction. STUDY DESIGN, SIZE, We undertook a systematic review and meta-analysis of 27 observational studies consisting of 1720 patients undergoing tubal catheterization for proximal tubal obstruction, who attempted to conceive naturally after the procedure. PARTICIPANTS/MATERIALS, SETTING, Systematic literature searches were performed in MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials. A total of 2195 titles and abstracts were reviewed. Only studies that reported outcomes when tubal catheterization was performed with no other tubal surgery were included. Twenty-seven cohort studies matched the inclusion criteria for the meta-analysis. MAIN The meta-analysis showed a pooled clinical pregnancy rate of 27% (95% CI 25-30%) after the use of tubal catheterization for unilateral or bilateral proximal tubal obstruction (27 studies, 1556 patients). In women with bilateral obstruction (14 studies, 617 patients), the clinical pregnancy rate was 27% (95% CI 23-32%). Our meta-analysis demonstrated that the pooled cumulative clinical pregnancy rates were 22.3% (95% CI 17.8-27.8%) at 6 months, 25.8% (95% CI 21.1-31.5%) at 9 months, 26.4% (95% CI 23.0-30.2%) at 12 months, 26.0% (95% CI 22.8-29.7%) at 18 months, 27.0% (95% CI 24.0-30.5%) at 24 months, 27.9% (95% CI 24.9-31.3%) at 36 months and 28.5% (95% CI 25.5-31.8%) at 48 months. The pooled live birth rate (14 studies, 551 patients) was 22% (95% CI 18-26%). The pooled ectopic pregnancy rate (27 studies, 1556 patients) was 4% (95% CI 3-5%). The included studies scored satisfactorily on the Newcastle-Ottawa quality assessment scale. LIMITATIONS, The pooled clinical pregnancy rate after tubal catheterization was found to be almost comparable to that after IVF. However, included studies were small, non-comparative series with significant clinical heterogeneity in population characteristics, follow-up and surgical equipment, technique and experience. These findings suggest fallopian tube catheterization as an alternative strategy to IVF in patients presenting with proximal tubal obstruction. Further research should focus on comparing different surgical techniques of fallopian tube catheterization with IVF and provide cumulative reproductive outcomes over long-term follow-up. STUDY FUNDING/COMPETING INTEREST(S): No funding was required and the authors have no competing interests to declare. N/A.
Progesterone is essential for the maintenance of pregnancy. However, whether progesterone supplementation in the first trimester of pregnancy would increase the rate of live births among women with a history of unexplained recurrent miscarriages is uncertain. We conducted a multicenter, double-blind, placebo-controlled, randomized trial to investigate whether treatment with progesterone would increase the rates of live births and newborn survival among women with unexplained recurrent miscarriage. We randomly assigned women with recurrent miscarriages to receive twice-daily vaginal suppositories containing either 400 mg of micronized progesterone or matched placebo from a time soon after a positive urinary pregnancy test (and no later than 6 weeks of gestation) through 12 weeks of gestation. The primary outcome was live birth after 24 weeks of gestation. A total of 1568 women were assessed for eligibility, and 836 of these women who conceived naturally within 1 year and remained willing to participate in the trial were randomly assigned to receive either progesterone (404 women) or placebo (432 women). The follow-up rate for the primary outcome was 98.8% (826 of 836 women). In an intention-to-treat analysis, the rate of live births was 65.8% (262 of 398 women) in the progesterone group and 63.3% (271 of 428 women) in the placebo group (relative rate, 1.04; 95% confidence interval [CI], 0.94 to 1.15; rate difference, 2.5 percentage points; 95% CI, -4.0 to 9.0). There were no significant between-group differences in the rate of adverse events. Progesterone therapy in the first trimester of pregnancy did not result in a significantly higher rate of live births among women with a history of unexplained recurrent miscarriages. (Funded by the United Kingdom National Institute of Health Research; PROMISE Current Controlled Trials number, ISRCTN92644181.).
Robinson L et al., 2012·Human reproduction (Oxford, England)
Is there an association between high levels of sperm DNA damage and miscarriage? Miscarriage rates are positively correlated with sperm DNA damage levels. Most ejaculates contain a subpopulation of sperm with DNA damage, also referred to as DNA fragmentation, in the form of double or single-strand breaks which have been induced in the DNA prior to or following ejaculation. This DNA damage may be particularly elevated in some subfertile men, hence several studies have examined the link between sperm DNA damage levels and conception and miscarriage rates. STUDY DESIGN, SIZE, A systematic review and meta-analysis of studies which examined the effect of sperm DNA damage on miscarriage rates was performed. Searches were conducted on MEDLINE, EMBASE and the Cochrane Library without any language restrictions from database inception to January 2012. PARTICIPANTS/MATERIALS, SETTING, We used the terms 'DNA damage' or 'DNA fragmentation' combined with 'miscarriage', 'abortion' or 'pregnancy' to generate a set of relevant citations. Data extraction was performed by two reviewers. Study quality was assessed using the Newcastle-Ottawa Scale. Meta-analysis of relative risks of miscarriage was performed with a random effects model. Subgroup analyses were performed by the type of DNA damage test, whether the sperm examined were prepared or from raw semen and for pregnancies resulting from IVF or ICSI treatment. MAIN We identified 16 cohort studies (2969 couples), 14 of which were prospective. Eight studies used acridine orange-based assays, six the TUNEL assay and two the COMET assay. Meta-analysis showed a significant increase in miscarriage in patients with high DNA damage compared with those with low DNA damage [risk ratio (RR) = 2.16 (1.54, 3.03), P < 0.00001)]. A subgroup analysis showed that the miscarriage association is strongest for the TUNEL assay (RR = 3.94 (2.45, 6.32), P < 0.00001). LIMITATIONS, There is some variation in study characteristics, including the use of different assays and different thresholds for DNA damage and the definition of pregnancy loss. The use of methods which select sperm without DNA damage for use in assisted conception treatment may reduce the risk of miscarriage. This finding indicates that assays detecting DNA damage could be considered in those suffering from recurrent pregnancy loss. Further research is necessary to study the mechanisms of DNA damage and the potential therapeutic effects of antioxidant therapy. STUDY FUNDING/COMPETING INTEREST(S): None.
Ross C et al., 2010·Reproductive biomedicine online
The use of antioxidants in treatment of infertile men has been suggested, although the evidence base for this practice is unclear. A systematic review of randomized studies was conducted to evaluate the effects of oral antioxidants (vitamins C and E, zinc, selenium, folate, carnitine and carotenoids) on sperm quality and pregnancy rate in infertile men. MEDLINE, EMBASE, Cochrane Library and CINAHL were searched for relevant trials published from respective database inception dates to May 2009. Study selection, quality appraisal and data extraction were performed independently and in duplicate. Seventeen randomized trials, including a total of 1665 men, were identified, which differed in the populations studied and type, dosage and duration of antioxidants used. Only two-thirds of the studies (11/17) reported using allocation concealment and three studies (18%) used intention-to-treat analysis. Despite the methodological and clinical heterogeneity, 14 of the 17 (82%) trials showed an improvement in either sperm quality or pregnancy rate after antioxidant therapy. Ten trials examined pregnancy rate and six showed a significant improvement after antioxidant therapy. The use of oral antioxidants in infertile men could improve sperm quality and pregnancy rates. Adequately powered robust trials of individual and combinations of antioxidants are needed to guide clinical practice.