Sinéad M. O'Neill

Research review: Birth by caesarean section and development of autism spectrum disorder and attention-deficit/hyperactivity disorder: a systematic review and meta-analysis.

BACKGROUND Given the growing prevalence of birth by Caesarean section (CS) worldwide, it is important to understand any long-term effects CS delivery may have on a childs development. We assessed the impact of mode of delivery on autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD). METHODS We conducted a systematic review of the literature in PubMed, Embase, CINAHL, PsycINFO and Web of Science up to 28 February 2014. No publication date, language, location or age restrictions were employed. RESULTS Thirteen studies reported an adjusted estimate for CS-ASD, producing a pooled odds ratio (OR) of 1.23 (95% CI: 1.07, 1.40). Two studies reported an adjusted estimate for CS-ADHD, producing a pooled OR of 1.07 (95% CI: 0.86, 1.33). CONCLUSIONS Delivery by CS is associated with a modest increased odds of ASD, and possibly ADHD, when compared to vaginal delivery. Although the effect may be due to residual confounding, the current and accelerating rate of CS implies that even a small increase in the odds of disorders, such as ASD or ADHD, may have a large impact on the society as a whole. This warrants further investigation.

Caesarean Delivery and Subsequent Stillbirth or Miscarriage: Systematic Review and Meta-Analysis

Objective To compare the risk of stillbirth and miscarriage in a subsequent pregnancy in women with a previous Caesarean or vaginal delivery. Design Systematic review of the published literature including seven databases: CINAHL; the Cochrane library; Embase; Medline; PubMed; SCOPUS and Web of Knowledge from 1945 until November 11th 2011, using a detailed search-strategy and cross-checking of reference lists. Study Selection Cohort, case-control and cross-sectional studies examining the association between previous Caesarean section and subsequent stillbirth or miscarriage risk. Two assessors screened titles to identify eligible studies, using a standardised data abstraction form and assessed study quality. Data synthesis 11 articles were included for stillbirth, totalling 1,961,829 pregnancies and 7,308 events. Eight eligible articles were included for miscarriage, totalling 147,017 pregnancies and 12,682 events. Pooled estimates across the stillbirth studies were obtained using random-effect models. Among women with a previous Caesarean an increase in odds of 1.23 [95% CI 1.08, 1.40] for stillbirth was yielded. Subgroup analyses including unexplained stillbirths yielded an OR of 1.47 [95% CI 1.20, 1.80], an OR of 2.11 [95% CI 1.16, 3.84] for explained stillbirths and an OR of 1.27 [95% CI 0.95, 1.70] for antepartum stillbirths. Only one study reported adjusted estimates in the miscarriage review, therefore results are presented individually. Conclusions Given the recent revision of the National Institute for Health and Clinical Excellence guidelines (NICE), providing women the right to request a Caesarean, it is essential to establish whether mode of delivery has an association with subsequent risk of stillbirth or miscarriage. Overall, compared to vaginal delivery, the pooled estimates suggest that Caesarean delivery may increase the risk of stillbirth by 23%. Results for the miscarriage review were inconsistent and lack of adjustment for confounding was a major limitation. Higher methodological quality research is required to reliably assess the risk of miscarriage in subsequent pregnancies.

Worldwide prevalence of tocophobia in pregnant women: systematic review and meta-analysis

Tocophobia is defined as a severe fear of pregnancy and childbirth. There is increasing evidence that tocophobia may have short‐term and long‐term adverse effects on mother and baby. We performed a systematic review and meta‐analysis to determine the global prevalence of tocophobia in pregnancy.

Caesarean section and subsequent ectopic pregnancy: a systematic review and meta-analysis

Caesarean section rates are increasing worldwide, and the long‐term effects are unknown.

Does a Caesarean section increase the time to a second live birth? A register-based cohort study

STUDY QUESTION Does a primary Caesarean section influence the rate of, and time to, subsequent live birth compared with vaginal delivery? SUMMARY ANSWER Caesarean section was associated with a reduction in the rate of subsequent live birth, particularly among elective and maternal-requested Caesareans indicating maternal choice plays a role. WHAT IS KNOWN ALREADY Several studies have examined the relationship between Caesarean section and subsequent birth rate with conflicting results primarily due to poor epidemiological methods. STUDY DESIGN, SIZE, DURATION This Danish population register-based cohort study covered the period from 1982 to 2010 (N = 832 996). PARTICIPANTS/MATERIALS, SETTING, METHODS All women with index live births were followed until their subsequent live birth or censored (maternal death, emigration or study end) using Cox regression models. MAIN RESULTS AND THE ROLE OF CHANCE In all 577 830 (69%) women had a subsequent live birth. Women with any type of Caesarean had a reduced rate of subsequent live birth (hazard ratio [HR] 0.86, 95% confidence intervals [CI] 0.85, 0.87) compared with spontaneous vaginal delivery. This effect was consistent when analyses were stratified by type of Caesarean: emergency (HR 0.87, 95% CI 0.86, 0.88), elective (HR 0.83, 95% CI 0.82, 0.84) and maternal-requested (HR 0.61, 95% CI 0.57, 0.66) and in the extensive sub-analyses performed. LIMITATIONS, REASONS FOR CAUTION Lack of biological data to measure a womans fertility is a major limitation of the current study. Unmeasured confounding and limited availability of data (maternal BMI, smoking, access to fertility services and maternal-requested Caesarean section) as well as changes in maternity care over time may also influence the findings. WIDER IMPLICATIONS OF THE FINDINGS This is the largest study to date and shows that Caesarean section is most likely not causally related to a reduction in fertility. Maternal choice to delay or avoid childbirth is the most plausible explanation. Our findings are generalizable to other middle- to high-income countries; however, cross country variations in Caesarean section rates and social or cultural differences are acknowledged. STUDY FUNDING/COMPETING INTERESTS Funding was provided by the National Perinatal Epidemiology Centre, Cork, Ireland and conducted as part of the Health Research Board PhD Scholars programme in Health Services Research (Grant No. PHD/2007/16). L.C.K. is a Science Foundation Ireland Principal Investigator (08/IN.1/B2083) and the Director of the SFI funded Centre, INFANT (12/RC/2272). The authors have no competing interests to declare.

Time to subsequent live birth according to mode of delivery in the first birth

To estimate the rate and time to next live birth by mode of delivery.

Incidence of surgical site infection following caesarean section: a systematic review and meta-analysis protocol

Introduction Caesarean section (CS) rates have increased globally during the past three decades. Surgical site infection (SSI) following CS is a common cause of morbidity with reported rates of 3–15%. SSI represents a substantial burden to the health system including increased length of hospitalisation and costs of postdischarge care. The definition of SSI varies with the postoperative follow-up period among different health systems, resulting in differences in the reporting of SSI incidence. We propose to conduct the first systematic review and meta-analysis to determine the pooled estimate for the overall incidence of SSI following CS. Methods and analysis We will perform a comprehensive search to identify all potentially relevant published studies on the incidence of SSI following CS reported from 1992 in the English language. Electronic databases including PubMed, CINAHL, EMBASE and Scopus will be searched using a detailed search strategy. Following study selection, full-text paper retrieval, data extraction and synthesis, we will appraise study quality and risk of bias and assess heterogeneity. Incidence data will be combined where feasible in a meta-analysis using Stata software and fixed-effects or random-effects models as appropriate. This systematic review will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Ethics and dissemination Ethical approval is not required as this review will use published data. The review will evaluate the overall incidence of SSI following CS and will provide the first quantitative estimate of the magnitude of SSI. It will serve as a benchmark for future studies, identify research gaps and remaining challenges, and emphasise the need for appropriate prevention and control measures for SSI post-CS. A manuscript reporting the results of the systematic review and meta-analysis will be submitted to a peer-reviewed journal and presented at scientific conferences. Trial registration number CRD42015024426.

Thin-for-gestational age infants are at increased risk of neurodevelopmental delay at 2 years

Background Infants born small-for-gestational age (SGA) are at increased risk of developmental difficulties. Identifying those most at risk is challenging. We examined the effect of neonatal body composition and customised birthweight centiles on neurocognitive and behavioural outcomes at age 2. Study design Prospective cohort study of term infants from the Cork BASELINE Birth Cohort Study classified into the following exposure groups: a birth weight <10th customised centile (SGA, n=51); body fat percentage at birth <10th centile (thin-for-gestational age (TGA, n=51)) or both SGA and TGA infants (small- and thin-for-gestational age (STGA), n=13). The SGA, TGA and STGA groups were compared with a reference (unexposed) group of appropriate-for-gestational age (AGA, n=189) infants. Outcome was assessed at 24 months using the Bayley Scales of Infant Development Version III and the Child Behaviour Checklist. Results Outcomes in the SGA infants did not differ significantly from the AGA group. TGA infants had significantly lower scores across all three domains, with a 0.35, 0.38 and 0.41 SD reduction in language, cognitive and motor scale scores, respectively. STGA infants had poorer cognitive outcome with a median cognitive scale score of 90 (IQR 85–95) compared with 95 (IQR 90–100) in the AGA reference group, p=0.005. The adjusted OR of developmental delay at 2 years was 5.00 (95% CI 1.46 to 17.13, p=0.010) in the STGA group. Conclusion TGA infants, in particular those born STGA, are at increased risk of developmental delay at 2 years compared with the AGA infants.

The terrorist attacks and the human live birth sex ratio: a systematic review and meta-analysis

AIM The live birth sex ratio is defined as male/total births (M/F). Terrorist attacks have been associated with a transient decline in M/F 3-5 months later with an excess of male losses in ongoing pregnancies. The early 21st century is replete with religious/politically instigated attacks. This study estimated the pooled effect size between exposure to attacks and M/F. Registration number CRD42016041220. METHODS PubMed and Scopus were searched for ecological studies that evaluated the relationship between terrorist attacks from 1/1/2000 to 16/6/2016 and M/F. An overall pooled odds ratio (OR) for the main outcome was generated using the generic inverse variance method. RESULTS Five studies were included: 2011 Norway attacks; 2012 Sandy Hook Elementary School shooting; 2001 September 11 attacks; 2004 Madrid and 2005 London bombings. OR at 0.97 95% CI (0.94-1.00) (I2 = 63%) showed a small statistically significant 3% decline in the odds (p = 0.03) of having a male live birth 3-5 months later. For lone wolf attacks there was a 10% reduction, OR 0.90 95% CI (0.86-0.95) (p = 0.0001). CONCLUSION Terrorist (especially lone wolf) attacks were significantly associated with reduced odds of having a live male birth. Pregnancy loss remains an important Public Health challenge. Systematic reviews and meta-analyses considering other calamities are warranted.