Association between response to ovarian stimulation and miscarriage following IVF: an analysis of 124 351 IVF pregnancies

STUDY QUESTION

Is there a relationship between ovarian reserve, quantified as ovarian response to stimulation, and miscarriage rate following IVF treatment?

SUMMARY ANSWER

There is a strong association between the number of oocytes retrieved and miscarriage rate following IVF treatment, with the miscarriage rate decreasing with an increasing number of oocytes and then levelling off: poor responders have a higher miscarriage rate across all age groups.

WHAT IS ALREADY KNOWN

Poor ovarian response is a manifestation of a decline in the quantity of the primordial follicle pool. Whether poor ovarian response is associated with a decline in oocyte quality contributing to miscarriage is however debated.

STUDY DESIGN, SIZE, DURATION

Anonymous data were obtained from the Human Fertilization and Embryology Authority (HFEA), the statutory regulator of assisted reproduction treatment (ART) in the UK. The HFEA has collected data on all ART performed in the UK since 1991. Data from 1991 to June 2008 involving 402 185 stimulated fresh IVF cycles and 124 351 pregnancy outcomes were analysed.

PARTICIPANTS/ MATERIALS, SETTING, METHODS

Data on all women undergoing a stimulated fresh IVF treatment cycle with at least one oocyte retrieved during the period from 1991 to June 2008 were analysed for their early pregnancy outcomes.

MAIN RESULTS AND THE ROLE OF CHANCE

There was a strong association between the number of oocytes retrieved and the clinical miscarriage rate. The miscarriage rate fell from 20 to 13% with an increasing number of oocytes before levelling off. Stepwise logistic regression identified three cut-off points (4, 10 and 15 oocytes) at or beyond which the probability of clinical miscarriage fell. There was no increase in miscarriage rate with very high oocyte numbers (>20 oocytes). The lowest risk of miscarriage (9.9%) was for women under 38 years of age, with primary infertility without a female cause and producing more than three oocytes.

LIMITATIONS, REASONS FOR CAUTION

Although the analysis was performed only on stimulated IVF cycles (excluding unstimulated cycles), the data had the limitation that there was no information on the total gonadotrophin consumption. The model was adjusted for age and type of infertility, but the dataset contained no information on other confounders such as body mass index (BMI) of the women to allow adjustment.

WIDER IMPLICATIONS FOR THE FINDINGS

Analysis of this extensive dataset suggests that poor responders have a higher risk of clinical miscarriage, indicating that poor ovarian response is associated with a parallel decline in both oocyte quantity and quality. The miscarriage rate is also higher with advanced age, secondary infertility and a female cause of infertility compared with a younger age, male factor infertility and unexplained cause.

The effect of endometriosis on in vitro fertilisation outcome: a systematic review and meta-analysis

BACKGROUND

Endometriosis is found in 0.5-5% of fertile women and 25-40% of infertile women. It is known that endometriosis is associated with infertility, but there is uncertainty whether women with endometriosis have adverse pregnancy outcomes in in vitro fertilisation (IVF) treatment.

OBJECTIVES

To explore the association between endometriosis and IVF outcome.

SEARCH STRATEGY

Searches were conducted on MEDLINE, EMBASE, Cochrane Library and Web of Science (inception, December 2012) in all languages, together with reference lists of retrieved papers.

SELECTION CRITERIA

Studies comparing IVF outcome in women with endometriosis with women without endometriosis. Patients were classified by stage of endometriosis. The outcomes were fertilisation, implantation, clinical pregnancy and live birth rates. Study selection was conducted independently by two reviewers. The Newcastle-Ottawa Quality Assessment Scale was used for quality assessment.

DATA COLLECTION AND ANALYSIS

Data extraction was conducted independently by two reviewers. Relative risks from individual studies were meta-analysed.

MAIN RESULTS

Twenty-seven observational studies were included, comprising 8984 women. Meta-analysis of these studies showed that fertilisation rates were reduced in stage I/II of endometriosis (relative risk [RR] = 0.93, 95% confidence interval [95% CI] 0.87-0.99, P = 0.03). There was a decrease in the implantation rate (RR = 0.79, 95% CI 0.67-0.93, P = 0.006) and clinical pregnancy rate (RR = 0.79, 95% CI 0.69-0.91, P = 0.0008) in women with stage III/IV endometriosis undergoing IVF treatment.

CONCLUSION

The presence of severe endometriosis (stage III/IV) is associated with poor implantation and clinical pregnancy rates in women undergoing IVF treatment.

A systematic review and thematic synthesis of qualitative studies on maternal emergency transport in low- and middle-income countries

BACKGROUND

Most maternal deaths are preventable with emergency obstetric care; therefore, ensuring access is essential. There is little focused information on emergency transport of pregnant women.

OBJECTIVES

The literature on emergency transport of pregnant women in low- and middle-income countries (LMICs) was systematically reviewed and synthesized to explore current practices, barriers, and facilitators for transport utilization.

SEARCH STRATEGY

MEDLINE, EMBASE, BNI, Cochrane Library, CINAHL, African Index Medicus, ASSIA, QUALIDATA, RHL, and Science Citation Index (inception to April 2012) were searched without language restriction.

SELECTION CRITERIA

Studies using qualitative methodology and reporting on emergency transportation in LMICs were included.

DATA COLLECTION AND ANALYSIS

Thematic framework and synthesis through examination and translation of common elements were used to analyze and synthesize the data.

MAIN RESULTS

Twenty-nine articles were included. Eight major themes were identified: time for transport; transport options; geography; local support; autonomy; culture; finance; and ergonomics. Key issues were transport availability; transport speed; terrain; meteorology; support; dependence for decision making; cultural issues; cost; and lack of safe, comfortable positioning during transport.

CONCLUSION

Themes should be appreciated within local contexts to illuminate barriers and facilitators. Potential solutions include motorcycle ambulance programs, collaboration with taxi services, community education, subsidies, and vehicle maintenance.

Women's groups practising participatory learning and action to improve maternal and newborn health in low-resource settings: a systematic review and meta-analysis

BACKGROUND

Maternal and neonatal mortality rates remain high in many low-income and middle-income countries. Different approaches for the improvement of birth outcomes have been used in community-based interventions, with heterogeneous effects on survival. We assessed the effects of women's groups practising participatory learning and action, compared with usual care, on birth outcomes in low-resource settings.

METHODS

We did a systematic review and meta-analysis of randomised controlled trials undertaken in Bangladesh, India, Malawi, and Nepal in which the effects of women's groups practising participatory learning and action were assessed to identify population-level predictors of effect on maternal mortality, neonatal mortality, and stillbirths. We also reviewed the cost-effectiveness of the women's group intervention and estimated its potential effect at scale in Countdown countries.

FINDINGS

Seven trials (119,428 births) met the inclusion criteria. Meta-analyses of all trials showed that exposure to women's groups was associated with a 37% reduction in maternal mortality (odds ratio 0.63, 95% CI 0.32-0.94), a 23% reduction in neonatal mortality (0.77, 0.65-0.90), and a 9% non-significant reduction in stillbirths (0.91, 0.79-1.03), with high heterogeneity for maternal (I(2)=58.8%, p=0.024) and neonatal results (I(2)=64.7%, p=0.009). In the meta-regression analyses, the proportion of pregnant women in groups was linearly associated with reduction in both maternal and neonatal mortality (p=0.026 and p=0.011, respectively). A subgroup analysis of the four studies in which at least 30% of pregnant women participated in groups showed a 55% reduction in maternal mortality (0.45, 0.17-0.73) and a 33% reduction in neonatal mortality (0.67, 0.59-0.74). The intervention was cost effective by WHO standards and could save an estimated 283,000 newborn infants and 41,100 mothers per year if implemented in rural areas of 74 Countdown countries.

INTERPRETATION

With the participation of at least a third of pregnant women and adequate population coverage, women's groups practising participatory learning and action are a cost-effective strategy to improve maternal and neonatal survival in low-resource settings.

FUNDING

Wellcome Trust, Ammalife, and National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care for Birmingham and the Black Country programme.

Interventions to reduce or prevent obesity in pregnant women: a systematic review

BACKGROUND

Around 50% of women of childbearing age are either overweight [body mass index (BMI) 25-29.9 kg/m(2)] or obese (BMI ≥ 30 kg/m(2)). The antenatal period provides an opportunity to manage weight in pregnancy. This has the potential to reduce maternal and fetal complications associated with excess weight gain and obesity.

OBJECTIVES

To evaluate the effectiveness of dietary and lifestyle interventions in reducing or preventing obesity in pregnancy and to assess the beneficial and adverse effects of the interventions on obstetric, fetal and neonatal outcomes.

DATA SOURCES

Major electronic databases including MEDLINE, EMBASE, BIOSIS and Science Citation Index were searched (1950 until March 2011) to identify relevant citations. Language restrictions were not applied.

REVIEW METHODS

Systematic reviews of the effectiveness and harm of the interventions were carried out using a methodology in line with current recommendations. Studies that evaluated any dietary, physical activity or mixed approach intervention with the potential to influence weight change in pregnancy were included. The quality of the studies was assessed using accepted contemporary standards. Results were summarised as pooled relative risks (RRs) with 95% confidence intervals (CIs) for dichotomous data. Continuous data were summarised as mean difference (MD) with standard deviation. The quality of the overall evidence synthesised for each outcome was summarised using GRADE (Grading of Recommendations Assessment, Development, and Evaluation) methodology and reported graphically as a two-dimensional chart.

RESULTS

A total of 88 studies (40 randomised and 48 non-randomised and observational studies, involving 182,139 women) evaluated the effect of weight management interventions in pregnancy on maternal and fetal outcomes. Twenty-six studies involving 468,858 women reported the adverse effect of the interventions. Meta-analysis of 30 RCTs (4503 women) showed a reduction in weight gain in the intervention group of 0.97 kg compared with the control group (95% CI -1.60 kg to -0.34 kg; p = 0.003). Weight management interventions overall in pregnancy resulted in a significant reduction in the incidence of pre-eclampsia (RR 0.74, 95% CI 0.59 to 0.92; p = 0.008) and shoulder dystocia (RR 0.39, 95% CI 0.22 to 0.70; p = 0.02). Dietary interventions in pregnancy resulted in a significant decrease in the risk of pre-eclampsia (RR 0.67, 95% CI 0.53 to 0.85; p = 0.0009), gestational hypertension (RR 0.30, 95% CI 0.10 to 0.88; p = 0.03) and preterm birth (RR 0.68, 95% CI 0.48 to 0.96; p = 0.03) and showed a trend in reducing the incidence of gestational diabetes (RR 0.52, 95% CI 0.27 to 1.03). There were no differences in the incidence of small-for-gestational-age infants between the groups (RR 0.99, 95% CI 0.76 to 1.29). There were no significant maternal or fetal adverse effects observed for the interventions in the included trials. The overall strength of evidence for weight gain in pregnancy and birthweight was moderate for all interventions considered together. There was high-quality evidence for small-for-gestational-age infants as an outcome. The quality of evidence for all interventions on pregnancy outcomes was very low to moderate. The quality of evidence for all adverse outcomes was very low.

LIMITATIONS

The included studies varied in the reporting of population, intensity, type and frequency of intervention and patient complience, limiting the interpretation of the findings. There was significant heterogeneity for the beneficial effect of diet on gestational weight gain.

CONCLUSIONS

Interventions in pregnancy to manage weight result in a significant reduction in weight gain in pregnancy (evidence quality was moderate). Dietary interventions are the most effective type of intervention in pregnancy in reducing gestational weight gain and the risks of pre-eclampsia, gestational hypertension and shoulder dystocia. There is no evidence of harm as a result of the dietary and physical activity-based interventions in pregnancy. Individual patient data meta-analysis is needed to provide robust evidence on the differential effect of intervention in various groups based on BMI, age, parity, socioeconomic status and medical conditions in pregnancy.

Accuracy of single progesterone test to predict early pregnancy outcome in women with pain or bleeding: meta-analysis of cohort studies

OBJECTIVE

To determine the accuracy with which a single progesterone measurement in early pregnancy discriminates between viable and non-viable pregnancy.

DESIGN

Systematic review and meta-analysis of diagnostic accuracy studies.

DATA SOURCES

Medline, Embase, CINAHL, Web of Science, ProQuest, Conference Proceedings Citation Index, and the Cochrane Library from inception until April 2012, plus reference lists of relevant studies.

STUDY SELECTION

Studies were selected on the basis of participants (women with spontaneous pregnancy of less than 14 weeks of gestation); test (single serum progesterone measurement); outcome (viable intrauterine pregnancy, miscarriage, or ectopic pregnancy) diagnosed on the basis of combinations of pregnancy test, ultrasound scan, laparoscopy, and histological examination; design (cohort studies of test accuracy); and sufficient data being reported.

RESULTS

26 cohort studies, including 9436 pregnant women, were included, consisting of 7 studies in women with symptoms and inconclusive ultrasound assessment and 19 studies in women with symptoms alone. Among women with symptoms and inconclusive ultrasound assessments, the progesterone test (5 studies with 1998 participants and cut-off values from 3.2 to 6 ng/mL) predicted a non-viable pregnancy with pooled sensitivity of 74.6% (95% confidence interval 50.6% to 89.4%), specificity of 98.4% (90.9% to 99.7%), positive likelihood ratio of 45 (7.1 to 289), and negative likelihood ratio of 0.26 (0.12 to 0.57). The median prevalence of a non-viable pregnancy was 73.2%, and the probability of a non-viable pregnancy was raised to 99.2% if the progesterone was low. For women with symptoms alone, the progesterone test had a higher specificity when a threshold of 10 ng/mL was used (9 studies with 4689 participants) and predicted a non-viable pregnancy with pooled sensitivity of 66.5% (53.6% to 77.4%), specificity of 96.3% (91.1% to 98.5%), positive likelihood ratio of 18 (7.2 to 45), and negative likelihood ratio of 0.35 (0.24 to 0.50). The probability of a non-viable pregnancy was raised from 62.9% to 96.8%.

CONCLUSION

A single progesterone measurement for women in early pregnancy presenting with bleeding or pain and inconclusive ultrasound assessments can rule out a viable pregnancy.

The effect of sperm DNA fragmentation on miscarriage rates: a systematic review and meta-analysis

STUDY QUESTION

Is there an association between high levels of sperm DNA damage and miscarriage?

SUMMARY ANSWER

Miscarriage rates are positively correlated with sperm DNA damage levels.

WHAT IS KNOWN ALREADY

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, DURATION

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, METHODS

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 RESULTS AND THE ROLE OF CHANCE

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, REASONS FOR CAUTION

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.

WIDER IMPLICATIONS OF THE FINDINGS

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.

Effects of interventions in pregnancy on maternal weight and obstetric outcomes: meta-analysis of randomised evidence

OBJECTIVE

To evaluate the effects of dietary and lifestyle interventions in pregnancy on maternal and fetal weight and to quantify the effects of these interventions on obstetric outcomes.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Major databases from inception to January 2012 without language restrictions.

STUDY SELECTION

Randomised controlled trials that evaluated any dietary or lifestyle interventions with potential to influence maternal weight during pregnancy and outcomes of pregnancy.

DATA SYNTHESIS

Results summarised as relative risks for dichotomous data and mean differences for continuous data.

RESULTS

We identified 44 relevant randomised controlled trials (7278 women) evaluating three categories of interventions: diet, physical activity, and a mixed approach. Overall, there was 1.42 kg reduction (95% confidence interval 0.95 to 1.89 kg) in gestational weight gain with any intervention compared with control. With all interventions combined, there were no significant differences in birth weight (mean difference -50 g, -100 to 0 g) and the incidence of large for gestational age (relative risk 0.85, 0.66 to 1.09) or small for gestational age (1.00, 0.78 to 1.28) babies between the groups, though by itself physical activity was associated with reduced birth weight (mean difference -60 g, -120 to -10 g). Interventions were associated with a reduced the risk of pre-eclampsia (0.74, 0.60 to 0.92) and shoulder dystocia (0.39, 0.22 to 0.70), with no significant effect on other critically important outcomes. Dietary intervention resulted in the largest reduction in maternal gestational weight gain (3.84 kg, 2.45 to 5.22 kg), with improved pregnancy outcomes compared with other interventions. The overall evidence rating was low to very low for important outcomes such as pre-eclampsia, gestational diabetes, gestational hypertension, and preterm delivery.

CONCLUSIONS

Dietary and lifestyle interventions in pregnancy can reduce maternal gestational weight gain and improve outcomes for both mother and baby. Among the interventions, those based on diet are the most effective and are associated with reductions in maternal gestational weight gain and improved obstetric outcomes.

Should androgen supplementation be used for poor ovarian response in IVF?

Poor ovarian response is reported in 9-24% of IVF cycles. Several interventions have been proposed to improve the outcome, although evidence to support these has been scant. There has been interest in the use of adjuvant androgens in this context and a recent worldwide survey showed that nearly a quarter of IVF clinicians used dehydroepiandrosterone (DHEA) in poor responders. We examine the rationale for the use of adjuvant androgens and suggest that the current clinical uncertainty should be addressed by a randomized controlled trial of DHEA in poor responders.

Effectiveness of strategies incorporating training and support of traditional birth attendants on perinatal and maternal mortality: meta-analysis

OBJECTIVE

To assess the effectiveness of strategies incorporating training and support of traditional birth attendants on the outcomes of perinatal, neonatal, and maternal death in developing countries.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

Medline, Embase, the Allied and Complementary Medicine database, British Nursing Index, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, BioMed Central, PsycINFO, Latin American and Caribbean Health Sciences Literature database, African Index Medicus, Web of Science, Reproductive Health Library, and Science Citation Index (from inception to April 2011), without language restrictions. Search terms were "birth attend*", "traditional midwife", "lay birth attendant", "dais", and "comadronas". Review methods We selected randomised and non-randomised controlled studies with outcomes of perinatal, neonatal, and maternal mortality. Two independent reviewers undertook data extraction. We pooled relative risks separately for the randomised and non-randomised controlled studies, using a random effects model.

RESULTS

We identified six cluster randomised controlled trials (n=138 549) and seven non-randomised controlled studies (n=72 225) that investigated strategies incorporating training and support of traditional birth attendants. All six randomised controlled trials found a reduction in adverse perinatal outcomes; our meta-analysis showed significant reductions in perinatal death (relative risk 0.76, 95% confidence interval 0.64 to 0.88, P<0.001; number needed to treat 35, 24 to 70) and neonatal death (0.79, 0.69 to 0.88, P<0.001; 98, 66 to 170). Meta-analysis of the non-randomised studies also showed a significant reduction in perinatal mortality (0.70, 0.57 to 0.84, p<0.001; 48, 32 to 96) and neonatal mortality (0.61, 0.48 to 0.75, P<0.001; 96, 65 to 168). Six studies reported on maternal mortality and our meta-analysis showed a non-significant reduction (three randomised trials, relative risk 0.79, 0.53 to 1.05, P=0.12; three non-randomised studies, 0.80, 0.44 to 1.15, P=0.26).

CONCLUSION

Perinatal and neonatal deaths are significantly reduced with strategies incorporating training and support of traditional birth attendants.

Reproductive outcomes in women with congenital uterine anomalies: a systematic review

OBJECTIVE

Congenital uterine anomalies are common but their effect on reproductive outcome is unclear. We conducted a systematic review to evaluate the association between different types of congenital uterine anomaly and various reproductive outcomes.

METHODS

Searches were performed using MEDLINE, EMBASE, the Cochrane Library and Web of Science. The Newcastle-Ottawa Quality Assessment Scale was used for quality assessment. Uterine defects were grouped into arcuate uteri, canalization defects (septate and subseptate uteri) and unification defects (unicornuate, bicornuate and didelphys uteri). Pooled risk ratios (RR) with 95% confidence intervals (CI) were computed using random effects models.

RESULTS

We identified nine studies comprising 3805 women. Meta-analysis showed that arcuate uteri were associated with increased rates of second-trimester miscarriage (RR, 2.39; 95% CI, 1.33-4.27, P = 0.003) and fetal malpresentation at delivery (RR, 2.53; 95% CI, 1.54-4.18; P < 0.001). Canalization defects were associated with reduced clinical pregnancy rates (RR, 0.86; 95% CI, 0.77-0.96; P = 0.009) and increased rates of first-trimester miscarriage (RR, 2.89; 95% CI; 2.02-4.14; P < 0.001), preterm birth (RR, 2.14; 95% CI, 1.48-3.11; P < 0.001) and fetal malpresentation (RR, 6.24; 95% CI, 4.05-9.62; P < 0.001). Unification defects were associated with increased rates of preterm birth (RR, 2.97; 95% CI, 2.08-4.23; P < 0.001) and fetal malpresentation (RR, 3.87; 95% CI, 2.42-6.18; P < 0.001).

CONCLUSIONS

Canalization defects reduce fertility and increase rates of miscarriage and preterm delivery. None of the unification defects reduces fertility but some are associated with miscarriage and preterm delivery. Arcuate uteri are specifically associated with second-trimester miscarriage. All uterine anomalies increase the chance of fetal malpresentation at delivery.

The prevalence of congenital uterine anomalies in unselected and high-risk populations: a systematic review

BACKGROUND

The prevalence of congenital uterine anomalies in high-risk women is unclear, as several different diagnostic approaches have been applied to different groups of patients. This review aims to evaluate the prevalence of such anomalies in unselected populations and in women with infertility, including those undergoing IVF treatment, women with a history of miscarriage, women with infertility and recurrent miscarriage combined, and women with a history of preterm delivery.

METHODS

Searches of MEDLINE, EMBASE, Web of Science and the Cochrane register were performed. Study selection and data extraction were conducted independently by two reviewers. Studies were grouped into those that used ‘optimal’ and ‘suboptimal’ tests for uterine anomalies. Meta-analyses were performed to establish the prevalence of uterine anomalies and their subtypes within the various populations.

RESULTS

We identified 94 observational studies comprising 89 861 women. The prevalence of uterine anomalies diagnosed by optimal tests was 5.5% [95% confidence interval (CI), 3.5–8.5] in the unselected population, 8.0% (95% CI, 5.3–12) in infertile women, 13.3% (95% CI, 8.9–20.0) in those with a history of miscarriage and 24.5% (95% CI, 18.3–32.8) in those with miscarriage and infertility. Arcuate uterus is most common in the unselected population (3.9%; 95% CI, 2.1–7.1), and its prevalence is not increased in high-risk groups. In contrast, septate uterus is the most common anomaly in high-risk populations.

CONCLUSIONS

Women with a history of miscarriage or miscarriage and infertility have higher prevalence of congenital uterine anomalies compared with the unselected population.

A comparison of clinical officers with medical doctors on outcomes of caesarean section in the developing world: meta-analysis of controlled studies

OBJECTIVE

To review the effectiveness and safety of clinical officers (healthcare providers trained to perform tasks usually undertaken by doctors) carrying out caesarean section in developing countries compared with doctors.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

Medline, Embase, Cochrane Central Register of Controlled Trials, CINAHL, BioMed Central, the Reproductive Health Library, and the Science Citation Index (inception-2010) without language restriction.

STUDY SELECTION

Controlled studies.

DATA EXTRACTION

Information was extracted from each selected article on study characteristics, quality, and outcome data. Two independent reviewers extracted data.

RESULTS

Six non-randomised controlled studies (16,018 women) evaluated the effectiveness of clinical officers carrying out caesarean section. Meta-analysis found no significant differences between the clinical officers and doctors for maternal death (odds ratio 1.46, 95% confidence interval 0.78 to 2.75; P=0.24) or for perinatal death (1.31, 0.87 to 1.95; P=0.19). The results were heterogeneous, with some studies reporting a higher incidence of both outcomes with clinical officers. Clinical officers were associated with a higher incidence of wound infection (1.58, 1.01 to 2.47; P=0.05) and wound dehiscence (1.89, 1.21 to 2.95; P=0.005). Two studies accounted for confounding factors.

CONCLUSION

Clinical officers and doctors did not differ significantly in key outcomes for caesarean section, but the conclusions are tentative owing to the non-randomised nature of the studies. The increase in wound infection and dehiscence may highlight a particular training need for clinical officers.

Association between the number of eggs and live birth in IVF treatment: an analysis of 400 135 treatment cycles

BACKGROUND

While live birth is the principal clinical outcome following in vitro fertilization (IVF) treatment, the number of eggs retrieved following ovarian stimulation is often used as a surrogate outcome in clinical practice and research. The aim of this study was to explore the association between egg number and live birth following IVF treatment and identify the number of eggs that would optimize the IVF outcome.

METHODS

Anonymized data on all IVF cycles performed in the UK from April 1991 to June 2008 were obtained from the Human Fertilization and Embryology Authority (HFEA). We analysed data from 400 135 IVF cycles. A logistic model was fitted to predict live birth using fractional polynomials to handle the number of eggs as a continuous independent variable. The prediction model, which was validated on a separate HFEA data set, allowed the estimation of the probability of live birth for a given number of eggs, stratified by age group. We produced a nomogram to predict the live birth rate (LBR) following IVF based on the number of eggs and the age of the female.

RESULTS

The median number of eggs retrieved per cycle was 9 [inter-quartile range (IQR) 6-13]. The overall LBR was 21.3% per fresh IVF cycle. There was a strong association between the number of eggs and LBR; LBR rose with an increasing number of eggs up to ∼15, plateaued between 15 and 20 eggs and steadily declined beyond 20 eggs. During 2006-2007, the predicted LBR for women with 15 eggs retrieved in age groups 18-34, 35-37, 38-39 and 40 years and over was 40, 36, 27 and 16%, respectively. There was a steady increase in the LBR per egg retrieved over time since 1991.

CONCLUSION

The relationship between the number of eggs and live birth, across all female age groups, suggests that the number of eggs in IVF is a robust surrogate outcome for clinical success. The results showed a non-linear relationship between the number of eggs and LBR following IVF treatment. The number of eggs to maximize the LBR is ∼15.

Association between thyroid autoantibodies and miscarriage and preterm birth: meta-analysis of evidence

OBJECTIVES

To evaluate the association between thyroid autoantibodies and miscarriage and preterm birth in women with normal thyroid function. To assess the effect of treatment with levothyroxine on pregnancy outcomes in this group of women.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, Cochrane Library, and SCISEARCH (inception-2011) without any language restrictions. We used a combination of key words to generate two subsets of citations, one indexing thyroid autoantibodies and the other indexing the outcomes of miscarriage and preterm birth.

STUDY SELECTION

Studies that evaluated the association between thyroid autoantibodies and pregnancy outcomes were selected in a two stage process. Two reviewers selected studies that met the predefined and explicit criteria regarding population, tests, and outcomes.

DATA SYNTHESIS

Odds ratios from individual studies were pooled separately for cohort and case-control studies with the random effects model.

RESULTS

30 articles with 31 studies (19 cohort and 12 case-control) involving 12,126 women assessed the association between thyroid autoantibodies and miscarriage. Five studies with 12,566 women evaluated the association with preterm birth. Of the 31 studies evaluating miscarriage, 28 showed a positive association between thyroid autoantibodies and miscarriage. Meta-analysis of the cohort studies showed more than tripling in the odds of miscarriage with the presence of thyroid autoantibodies (odds ratio 3.90, 95% confidence interval 2.48 to 6.12; P < 0.001). For case-control studies the odds ratio for miscarriage was 1.80, 1.25 to 2.60; P = 0.002). There was a significant doubling in the odds of preterm birth with the presence of thyroid autoantibodies (2.07, 1.17 to 3.68; P = 0.01). Two randomised studies evaluated the effect of treatment with levothyroxine on miscarriage. Both showed a fall in miscarriage rates, and meta-analysis showed a significant 52% relative risk reduction in miscarriages with levothyroxine (relative risk 0.48, 0.25 to 0.92; P=0.03). One study reported on the effect of levothyroxine on the rate of preterm birth, and noted a 69% relative risk reduction (0.31, 0.11 to 0.90).

CONCLUSION

The presence of maternal thyroid autoantibodies is strongly associated with miscarriage and preterm delivery. There is evidence that treatment with levothyroxine can attenuate the risks.