A population-based cohort study of the effect of Caesarean section on subsequent fertility.

STUDY QUESTION: Is there an association between Caesarean section and subsequent fertility? SUMMARY ANSWER: There is no or only a slight effect of Caesarean section on future fertility. WHAT IS KNOWN ALREADY: Previous studies have reported that delivery by a Caesarean section is associated with fewer subsequent pregnancies and longer inter-pregnancy intervals. The interpretation of these findings is difficult because of significant weaknesses in study designs and analytical methods, notably the potential effect of the indication for Caesarean section on subsequent delivery. STUDY DESIGN, SIZE, DURATION: Retrospective cohort study of 1 047 644 first births to low-risk women using routinely collected, national administrative data of deliveries in English maternity units between 1 April 2000 and 31 March 2012. PARTICIPANTS/MATERIALS, SETTING, METHODS: Primiparous women aged 15-40 years who had a singleton, term, live birth in the English National Health Service were included. Women with high-risk pregnancies involving placenta praevia, pre-eclampsia, eclampsia (gestational or pre-existing), hypertension or diabetes were excluded from the main analysis. Kaplan-Meier analyses and Cox proportional hazard models were used to assess the effect of mode of delivery on time to subsequent birth, adjusted for age, ethnicity, socio-economic deprivation and year of index delivery. MAIN RESULTS AND THE ROLE OF CHANCE: Among low-risk primiparous women, 224 024 (21.4%) were delivered by Caesarean section. The Kaplan-Meier estimate of the subsequent birth rate at 10 years for the cohort was 74.7%. Compared with vaginal delivery, subsequent birth rates were marginally lower after elective Caesarean for breech (adjusted hazard ratio, HR 0.96, 95% CI 0.94-0.98). Larger effects were observed after elective Caesarean for other indications (adjusted HR 0.81, 95% CI 0.78-0.83), and emergency Caesarean (adjusted HR 0.91, 95% CI 0.90-0.93). The effect was smallest for elective Caesarean for breech, and this was not statistically significant in women younger than 30 years of age (adjusted HR 0.98, 95% CI 0.96-1.01). LIMITATIONS, REASONS FOR CAUTION: We used birth cohorts from maternity units with good quality parity information. The data are likely to be nationally representative because the characteristics of the deliveries in included and omitted units were similar. There may be residual bias in our adjusted results due to unmeasured maternal factors such as obesity and voluntary absence of conception. Any residual bias would lead to an overestimate of the effect of Caesarean section on fertility, and the true effect is therefore likely to be smaller than the effect reported in our study. WIDER IMPLICATIONS OF THE FINDINGS: Our results provide strong evidence that there is no or only a slight effect of Caesarean section on future fertility. The clinical and social circumstances leading to the Caesarean section have a greater effect on future fertility than the Caesarean section itself. This finding is important in light of rising Caesarean section rates. STUDY FUNDING/COMPETING INTEREST(S): IG-U is supported by the Lindsay Stewart R&D Centre, Royal College of Obstetricians and Gynaecologists, UK. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: n/a.

Vaginal birth after caesarean section: a cohort study investigating factors associated with its uptake and success.

OBJECTIVES: To investigate the demographic and obstetric factors associated with the uptake and success rate of vaginal birth after caesarean section (VBAC). DESIGN: Cohort study using data from Hospital Episode Statistics. SETTING: English National Health Service. POPULATION: Women whose first birth resulted in a live singleton delivery by caesarean section between 1 April 2004 and 31 March 2011, and who had a second birth before 31 March 2012. METHODS: Logistic regression to estimate adjusted odds ratios (OR). MAIN OUTCOME MEASURES: Attempted and successful VBAC. RESULTS: Among the 143,970 women in the cohort, 75,086 (52.2%) attempted a VBAC for their second birth. Younger women, those of non-white ethnicity and those living in a more deprived area had higher rates of attempted VBAC. Overall, 47,602 women (63.4%) who attempted a VBAC had a successful vaginal birth. Younger women and women of white ethnicity had higher success rates. Black women had a particularly low success rate (OR, 0.54; 95% confidence interval [CI], 0.50-0.57). Women who had an emergency caesarean section in their first birth also had a lower VBAC success rate, particularly those with a history of failed induction of labour (OR, 0.59; 95% CI, 0.53-0.67). CONCLUSION: In this national cohort, just over one-half of women with a primary caesarean section who were eligible for a trial of labour attempted a VBAC for their second birth. Of these, almost two-thirds successfully achieved a vaginal delivery.

Impact of third- and fourth-degree perineal tears at first birth on subsequent pregnancy outcomes: a cohort study.

OBJECTIVE: To investigate, among women who have had a third- or fourth-degree perineal tear, the mode of delivery in subsequent pregnancies as well as the recurrence rate of third- or fourth-degree tears. DESIGN: A retrospective cohort study of deliveries using a national administrative database. SETTING: The English National Health Service between 1 April 2004 and 31 March 2012. POPULATION: A total of 639,402 primiparous women who had a singleton, term, vaginal live birth between April 2004 and March 2011, and a second birth before April 2012. METHODS: Multivariable logistic regression models were used to estimate odds ratios, adjusted for other risk factors. MAIN OUTCOME MEASURES: Mode of delivery and recurrence of tears at second birth. RESULTS: The rate of elective caesarean at second birth was 24.2% for women with a third- or fourth-degree tear at first birth, and 1.5% for women without (adjusted odds ratio, aOR 18.3, 95% confidence interval, 95% CI 16.4-20.4). Among women who had a vaginal delivery at second birth, the rate of third- or fourth-degree tears was 7.2% for women with a third- or fourth-degree tear at first birth, compared with 1.3% for women without (aOR 5.5, 95% CI 5.2-5.9). CONCLUSIONS: The risk of a severe perineal tear is increased five-fold in women who had a third- or fourth-degree tear in their first delivery. This increased risk should be taken into account when decisions about mode of delivery are made.

Impact of Caesarean section on subsequent fertility: a systematic review and meta-analysis.

STUDY QUESTION: Is there an association between a Caesarean section and subsequent fertility? SUMMARY ANSWER: Most studies report that fertility is reduced after Caesarean section compared with vaginal delivery. However, studies with a more robust design show smaller effects and it is uncertain whether the association is causal. WHAT IS KNOWN ALREADY: A previous systematic review published in 1996 summarizing six studies including 85 728 women suggested that Caesarean section reduces subsequent fertility. The included studies suffer from severe methodological limitations. STUDY DESIGN, SIZE, DURATION: Systematic review and meta-analysis of cohort studies comparing subsequent reproductive outcomes of women who had a Caesarean section with those who delivered vaginally. PARTICIPANTS/MATERIALS, SETTING, METHODS: Searches of Cochrane Library, Medline, Embase, CINAHL Plus and Maternity and Infant Care databases were conducted in December 2011 to identify randomized and non-randomized studies that compared the subsequent fertility outcomes after a Caesarean section and after a vaginal delivery. Eighteen cohort studies including 591 850 women matched the inclusion criteria. Risk of bias was assessed by the Newcastle-Ottawa scale (NOS). Data extraction was done independently by two reviewers. The meta-analysis was based on a random-effects model. Subgroup analyses were performed to assess whether the estimated effect was influenced by parity, risk adjustment, maternal choice, cohort period, and study quality and size. MAIN RESULTS AND THE ROLE OF CHANCE: The impact of Caesarean section on subsequent pregnancies could be analysed in 10 studies and on subsequent births in 16 studies. A meta-analysis suggests that patients who had undergone a Caesarean section had a 9% lower subsequent pregnancy rate [risk ratio (RR) 0.91, 95% confidence interval (CI) (0.87, 0.95)] and 11% lower birth rate [RR 0.89, 95% CI (0.87, 0.92)], compared with patients who had delivered vaginally. Studies that controlled for maternal age or specifically analysed primary elective Caesarean section for breech delivery, and those that were least prone to bias according to the NOS reported smaller effects. LIMITATIONS, REASONS FOR CAUTION: There is significant variation in the design and methods of included studies. Residual bias in the adjusted results is likely as no study was able to control for a number of important maternal characteristics, such as a history of infertility or maternal obesity. WIDER IMPLICATIONS OF THE FINDINGS: Further research is needed to reduce the impact of selection bias by indication through creating more comparable patient groups and applying risk adjustment.

Rates of subsequent surgery following endometrial ablation among English women with menorrhagia: population-based cohort study.

OBJECTIVE: To assess the risk of further surgery amongst women who had an initial endometrial ablation (EA) for the treatment of heavy menstrual bleeding (HMB). DESIGN: A retrospective cohort study using a national administrative database. SETTING: Population-based study of hospital care in the English National Health Service. POPULATION: A cohort of 114,910 women who had EA for HMB between January 2000 and December 2011. METHODS: Multiple Cox regressions were performed to identify the risks of a further procedure, adjusted for age, social deprivation, year and type of initial EA, and presence of fibroids/polyps. MAIN OUTCOME MEASURES: Time to repeat EA or hysterectomy after initial surgery. RESULTS: Of 114,910 women undergoing EA, 16.7% had at least one subsequent procedure within 5 years. Higher rates of subsequent surgery were associated with younger age at initial EA, with women aged under 35 years having an adjusted hazard ratio of 2.83 (95% CI 2.67-2.99), compared with women aged over 45 years. Women who had radiofrequency ablation were less likely to have subsequent surgery as compared with first-generation techniques (HR 0.69, 95% CI 0.63-0.76). The rate of a subsequent hysterectomy within 5 years was 13.5%. Younger women (OR 0.59, 95% CI 0.51-0.69) and those who had balloon, microwave, or radiofrequency ablation were less likely to have a second EA procedure, rather than a hysterectomy. CONCLUSIONS: One in six women have further surgery after EA for HMB, which is a higher rate than reported in clinical trials. This risk of further surgery decreases with age.

Third- and fourth-degree perineal tears among primiparous women in England between 2000 and 2012: time trends and risk factors.

OBJECTIVE: To describe the trends of severe perineal tears in England and to investigate to what extent the changes in related risk factors could explain the observed trends. DESIGN: A retrospective cohort study of singleton deliveries from a national administrative database. SETTING: The English National Health Service between 1 April 2000 and 31 March 2012. POPULATION: A cohort of 1 035 253 primiparous women who had a singleton, term, cephalic, vaginal birth. METHODS: Multivariable logistic regression was used to estimate the impact of financial year of birth (labelled by starting year), adjusting for major risk factors. MAIN OUTCOME MEASURE: The rate of third-degree (anal sphincter is torn) or fourth-degree (anal sphincter as well as rectal mucosa are torn) perineal tears. RESULTS: The rate of reported third- or fourth-degree perineal tears tripled from 1.8 to 5.9% during the study period. The rate of episiotomy varied between 30 and 36%. An increasing proportion of ventouse deliveries (from 67.8 to 78.6%) and non-instrumental deliveries (from 15.1 to 19.1%) were assisted by an episiotomy. A higher risk of third- or fourth-degree perineal tears was associated with a maternal age above 25 years, instrumental delivery (forceps and ventouse), especially without episiotomy, Asian ethnicity, a more affluent socio-economic status, higher birthweight, and shoulder dystocia. CONCLUSIONS: Changes in major risk factors are unlikely explanations for the observed increase in the rate of third- or fourth-degree tears. The improved recognition of tears following the implementation of a standardised classification of perineal tears is the most likely explanation.

Surgery for menorrhagia within English regions: variation in rates of endometrial ablation and hysterectomy.

OBJECTIVE: To examine variation between English regions in the use of surgery (endometrial ablation or hysterectomy) for the treatment of menorrhagia. DESIGN: Analysis of Hospital Episodes Statistics (HES) data to produce rates of surgery for English Strategic Health Authorities (SHAs) and Primary Care Trusts (PCTs). POPULATION: Women aged between 25 and 59 years who had endometrial ablation or hysterectomy for menorrhagia between April 2003 and March 2006 in English NHS hospitals. METHODS: Multilevel Poisson regression was used to determine the level of systematic variation in the regional rates of surgery and their association with regional characteristics (deprivation, service provision and mix of surgical procedures). MAIN OUTCOME MEASURE: Age-standardised annual rates of surgery. RESULTS: The English rate of surgery for menorrhagia was 143 procedures per 100 000 women. Surgical rates within SHAs ranged from 52 to 230 procedures per 100 000 women, while rates within PCTs ranged from 20 to 420 procedures per 100 000 women. While, 60% of all procedures were endometrial ablations, the proportion across SHAs varied, ranging from 46% to 75%. Surgery rates were associated with the regional characteristics, but only weakly, and risk adjustment reduced the amount of unexplained variation by <15% at both SHA and PCT levels. CONCLUSION: Regional differences in surgical rates for menorrhagia have persisted despite changes in practice and improved evidence, suggesting there is scope for improving the management of menorrhagia within England.

A randomized trial of management of pre-labor rupture of membranes at term in multiparous women using vaginal prostaglandin gel.

OBJECTIVE: To compare conservative management of pre-labor spontaneous rupture of membranes (SROM) with the use of prostaglandin (PG) E2 in healthy parous women at term (gestational age at least 37 weeks). METHODS: An open randomized study was conducted with 100 parous women; 50 were treated conservatively for 24 hours, and 50 were managed actively using PGE2 gel (1 mg), administered at admission and repeated 6 hours later if labor was not established. Both groups received intravenous oxytocin if labor did not start within 24 hours after admission. RESULTS: The use of PGE2 gel led to a significant reduction in the mean interval (+/- standard error of the mean) from SROM to onset of labor: 17.26 +/- 1.51 hours in the conservative group versus 6.50 +/- 1.23 in the PGE2 group. A significantly smaller proportion of subjects required oxytocin in the PGE2 group (12 versus 38%, P < .02). The two groups were comparable with respect to analgesic requirements. Within 24 hours of SROM, 80% of the women in the PG group and 56% in the conservative group had delivered (P < .02). Most women delivered vaginally, 96% of those managed conservatively and 100% of those managed actively with PGE2. CONCLUSION: Active management using PGE2 gel in parous women with pre-labor SROM significantly improves the time to delivery without influencing the cesarean rate or fetal-maternal infective morbidity.

The luteal phase after oocyte recovery in a spontaneous cycle.

There is disagreement as to whether follicular aspiration and oocyte recovery leads to a defective luteal phase. A group of 20 women with mild endometriosis was studied over two consecutive spontaneous cycles. Follicular aspiration and oocyte recovery was performed 32 hours after the onset of the endogenous luteinizing hormone surge during the second cycle. There was little disturbance of the luteal phase or in the pituitary gonadal relationship in the aspirated cycle. Although a significantly lower serum progesterone was noted on day 8 of post-oocyte recovery, all results were within the normal range seen in the control cycles.

A biodegradable composite scaffold for cell transplantation.

Cell transplantation is rapidly becoming a therapeutic option to treat disease and injury. However, standard techniques for cell seeding on non-woven polymer meshes or within gels may not be suitable for immediate implantation or surgical manipulations of freshly isolated cells. Therefore, a biodegradable composite system was developed as a way to rapidly entrap cells within a support of predefined shape to potentially facilitate cell delivery into a target site (e.g. meniscal tears in the avascular zone). The composite construct consisted of freshly isolated cells, in this case pig chondrocytes, entrapped in a fibrin gel phase and dispersed throughout the void volume of a polyglycolic acid (PGA) non-woven mesh. Composites were cultured for up to 4 weeks. In vitro degradation of fibrin gel was evaluated via gel-entrapped urokinase. At 28 days in culture, glycosaminoglycan (GAG) content per cell in the composite scaffolds was 2.6 times that of the PGA-only cell construct group and 88% that of native pig cartilage. Total collagen content per cell in the composite scaffolds was not significantly different from the PGA-only cell construct group (P > 0.02) and represented 40% of the value determined for native cartilage. Varying the concentration of entrapped urokinase could effect controlled degradation of fibrin gel.

A reappraisal of the maternal syndrome associated with hydrops fetalis.

A pregnancy complicated by severe rhesus isoimmunization can not only lead to fetal loss but may also be complicated by a rarely described maternal syndrome. The unusual clinical features of one such case and the probable underlying pathophysiology are described.

A prospective comparative study on the use of prostaglandin E2 gel (2 mg) and prostaglandin E2 tablet (3 mg) for the induction of labour in primigravid women with unfavorable cervices.

Eighty primigravid patients with singleton pregnancies, cephalic presentation and unfavourable cervices (score less than 5) between 37 and 43 weeks gestation were studied prospectively to compare the ripening effect of vaginal PGE2 (3 mg) tablet with that of PGE2 gel (2 mg). Following the use of gel, the final mean cervical score was considerably improved and half of the patients went into spontaneous labour. The requirement for oxytocin augmentation was also reduced. The priming-to-induction and induction-to-delivery intervals were also considerably shortened in gel-treated patients. The proportion of patients delivered by Caesarean section in the gel group was lower than that in the tablet group (30 vs. 15%).

The impact of previous danazol treatment on circulating hormone levels, follicular development and oocyte maturity in minimal-mild endometriosis.

The purpose of this study was to assess the impact of previous danazol treatment on peripheral endocrinology, folliculogenesis, oocyte maturity and follicular fluid endocrinology in women with minimal-mild endometriosis in a spontaneous menstrual cycle. A group of 10 women previously treated with danazol (Group A) and another group of 10 women whose endometriosis was left untreated (Group B) were studied. A group of 10 women with tubal infertility acted as a Control. Circulating hormone levels and characteristics of an endogenous luteinizing hormone (LH) surge were studied. A diagnostic laparoscopy was performed 32 h after the onset of an endogenous LH surge in all women to undertake follicular aspiration. There were no significant differences in oocyte maturity, fertilisation and cleavage rate among women studied in three study groups. The presence of peritoneal endometriosis did not affect the steroidogenic potential of the granulosa cells, and the endocrine milieu of the pre-ovulatory oocyte was comparable in all study groups.

The accuracy of measurements of ovarian follicular scanning by inexperienced observers using real-time sector scanning.

Three inexperienced operators (2 midwives and one obstetric registrar) were given ten sessions of training in ovarian follicular scanning. During each session, five patients were examined jointly. Once the inexperienced observers had received sufficient training the prospective study was started. Twenty measurements by each inexperienced observer were compared to measurements made by an experienced observer. In 17% of measurements the error was greater than 3 mm, the errors being evenly distributed among the three observers. After a further five sessions of instructions, another set of sixty measurements was generated: 93% of these measurements correlated exactly among the inexperienced operators and between the inexperienced and the experienced operator. This study suggests that after a supervised training of 15 sessions, obstetricians and midwives with prior obstetric scanning experience can produce reliable ovarian follicular measurements.

A randomized prospective trial comparing single dose prostaglandin E2 vaginal gel with forewater amniotomy for induction of labour.

A prospective randomized parallel-group study was carried out to compare the efficacy of a single dose vaginal prostaglandin E2 gel with forewater amniotomy for induction of labour at term in 260 parturients (110 primigravid and 150 parous women) with low risk pregnancy and favourable cervix. In the prostaglandin E2 (PGE2) managed group, the primigravidae were treated with 2 mg PGE2 gel and parous patients with 1 mg PGE2 gel. Forewater amniotomy was performed 4 h later, or sooner if women requested analgesia. In the amniotomy group, artificial forewater amniotomy was carried out and a repeat cervical assessment done 4 h later, or sooner if women requested analgesia. In both groups, intravenous oxytocin was established if there was evidence of disordered uterine activity, 6 h after the start of initial intervention. An assessment of consumers' views was carried out by using a standardized questionnaire completed 48 h after delivery. There was a significant reduction in the requirement for oxytocin augmentation in women treated with PGE2: primigravidae, odds ratio (OR), 0.27 and 95% confidence interval (CI), 0.12-0.61; multiparae, OR, 0.19 and 95% CI, 0.08-0.45. Fewer primigravidae managed with PGE2 gel required epidural analgesia (OR, 0.16; 95% CI, 0.06-1.00). Fewer parous women managed with PGE2 gel required parenteral opiates (OR, 0.44; 95% CI, 0.23-0.85) and more women required inhalation analgesia or no analgesia (OR, 2.22; 95% CI, 1.76-2.79). The intervention to delivery intervals were shortened in PGE2 groups independent of parity but the differences were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Maternal height, shoe size, and outcome of labour in white primigravidas: a prospective anthropometric study.

A total of 563 white primigravid patients at Raigmore Hospital, Inverness, were recruited in a prospective study to examine the association between maternal height, shoe size, and the outcome of labour. There was a significantly increased caesarean section rate in women of short stature but no association between mode of delivery and shoe size. Babies born vaginally had heavier birth weights with increasing height and shoe size. Babies born by caesarean section were heavier than those born vaginally, but their birthweight showed no relation with either height or shoe size. Shoe size is not a useful clinical predictor for the probability of cephalopelvic disproportion, and, although maternal height is a better clinical guide to pelvic adequacy in labour, 80% of mothers less than 160 cm tall delivered vaginally. A well conducted trial of labour should be considered in all primigravid patients with cephalic presentation irrespective of maternal height or shoe size if no obstetric complication exists.

Simultaneous presentation of ectopic pregnancy and hyperthyroidism.

Hyperthyroidism is known to occur uncommonly in pregnancy (about 0.5 per 1000). The incidence of ectopic pregnancy is approximately 9.6 per 1000 pregnancies. Both conditions, if unrecognised and untreated can have potentially fatal consequences. We describe a case of hyperthyroidism and ectopic pregnancy presenting concurrently, and highlight the difficulties encountered in diagnosis when two clinical conditions present with indistinguishable clinical signs.

Maternal height, birthweight, obstetric conjugate and their influence on the management of parturients with a previous cesarean scar.

A retrospective analysis was made of the second deliveries of 492 women who had previously undergone emergency cesarean section with a clinical indication of cephalopelvic disproportion and had undergone X-ray pelvimetry. In their index (second) pregnancy, 234 (47%) had an elective cesarean section; 122 (25%) gave birth vaginally and 136 (28%) had undergone an emergency cesarean section. Maternal height had a moderate value as a surrogate measure of pelvic capacity. A trial labor was more often allowed in women with larger obstetrical conjugate (inlet) measurements but likelihood of a successful outcome of labor was not influenced by the above pelvic measurements. A baby weighing more than 4000 g was associated with a greatly reduced chance of a vaginal delivery. The study confirms the limitations of X-ray pelvimetry measurements and proposes that antenatal estimation of fetal size may be of benefit in determining the likelihood of success in a trial labor.