Maternal complications in settings where two-thirds of extremely preterm births are delivered by cesarean section

Fetal station at caesarean section and risk of subsequent preterm birth - A cohort study

OBJECTIVES

An increased risk of preterm birth (PTB) following a caesarean section (CS) in the second stage of labor has been demonstrated. We aimed to investigate the relationship between the station of the presenting fetal part and the surgical technique at first CS, and the risk of subsequent PTB.

STUDY DESIGN

This was a cohort study of 11,850 women in Sweden, delivered by CS in 2001-2007 at any of 23 birth units, with a second delivery in 2001-2009. Clinical information was retrieved from electronic birth records linked to national health registers. The risk of subsequent PTB was analyzed by fetal station, defined as low (at or below the ischial spines) or high (above the ischial spines), and aspects of the surgical technique at index CS. Associations were explored with logistic regression and results are presented as odds ratios (ORs) with 95% confidence intervals (CIs), by type and severity (very early < 32 gestational weeks and moderate preterm 32-36 gestational weeks) of PTB. Multiple logistic regression included adjustments for maternal age, gestational age at first delivery, and inter-delivery interval.

RESULTS

Out of 11,850 women delivered by CS, 1,016 (8.6%) delivered preterm in their subsequent pregnancy. There was an increased likelihood of spontaneous PTB, but not with medically indicated PTB, after an index CS with the fetal presenting part at a low station (aOR 1.61, 95% CI 1.23-2.11). CS performed at a low station was associated with birth < 32 gestational weeks (aOR 1.73, 95% CI 1.05-2.84) and birth at 32-36 gestational weeks (aOR 1.29, 95% CI 1.00-1.65), compared with high fetal station. Thickness of the uterine wall, incision type, and closure of the uterus at index CS did not affect the risk.

CONCLUSION

A primary CS at a low station was associated with a subsequent spontaneous PTB, but not medically indicated PTB. Surgical technique at index CS did not alter the risk.

Severe maternal morbidity in preterm cesarean delivery: A systematic review and meta-analysis

OBJECTIVE

More than half of extremely preterm infants are delivered by cesarean section. Few data are available about severe maternal morbidity (SMM) of these extremely preterm cesarean. The objective was to determine whether gestational age under 26 weeks of gestation (weeks) was associated with an increased risk of SMM compared with gestational age between 26 and 34 weeks in women having a cesarean delivery.

MATERIAL AND METHODS

We searched MEDLINE, ISI Web of Science, the Cochrane Database, PROSPERO, and ClinicalTrials.gov on January 31, 2020. The search strategy clustered terms describing SMM and preterm cesarean delivery. No restrictions on language, publication status, and study design were applied. Abstracts were included if there was sufficient information to assess study quality. The authors of all identified studies were contacted to request for aggregated data. Relative risks (RR) were calculated using the inverse variance method. The primary outcome was SMM as defined in each study. We analyzed data on preterm cesarean deliveries between 22 and 34 weeks. The protocol was registered in PROSPERO (registration: CRD42019128644).

RESULTS

Six studies involving 45,572 women (3,440 delivering < 26 weeks; 42,132 delivering between 26 and 34 weeks) were included. SMM occurred in 607 women (17.6 %) < 26 weeks and 4,483 women (10.6 %) between 26 and 34 weeks. Gestational age < 26 weeks was associated with an increased risk of SMM (RR, 1.65; 95 % CI [Confidence Interval], 1.52-1.78; I² = 40 %). Gestational age < 26 weeks remained associated with SMM in the subgroup analyses depending on the type of the study (prospective or retrospective), country of the study (European or non-European), and high quality of the study. A sensitivity analysis showed that gestational age < 25 weeks was also associated with SMM in preterm cesarean delivery (RR, 1.66; 95 % CI, 1.50-1.83; I² = 3%).

CONCLUSIONS

Gestational age < 26 weeks was associated with an increased risk of SMM in women having a preterm cesarean delivery. Obstetricians and neonatologists should be aware of the increased risk of SMM in cesarean.

Maternal outcomes of cesarean delivery performed at early gestational ages: a systematic review and meta-analysis

OBJECTIVE

This study aimed to report maternal outcomes of preterm (<34 weeks of gestation) cesarean delivery.

DATA SOURCES

Medline, Embase, and ClinicalTrials.gov databases were searched electronically on September 1, 2020, utilizing combinations of the relevant medical subject heading terms, key words, and word variants for "cesarean delivery" and "outcome."

STUDY ELIGIBILITY CRITERIA

We included only studies reporting maternal outcomes of cesarean delivery performed at <34 weeks of gestation.

STUDY APPRAISAL AND SYNTHESIS METHODS

The primary outcome was a composite score of maternal surgical morbidity including maternal death, severe intrasurgical or postpartum hemorrhage, hysterectomy, need for blood transfusion, and damage to adjacent organs. Secondary outcomes were individual components of the primary outcome, need for reoperation, postsurgical infection, thromboembolism, and hysterectomy. We also performed 2 subgroup analyses considering cesarean delivery performed at <28 and <26 weeks of gestation. Meta-analyses of proportions using random effects model were used to combine data.

RESULTS

A total of 15 studies involving 8378 women undergoing cesarean delivery at <34 weeks of gestation were included in the systematic review. Composite adverse maternal outcome was reported in 16.2% of women (95% confidence interval, 15.4-17.0) undergoing a cesarean delivery before 34 weeks of gestation. Hemorrhage, either intra- or postoperative, was observed in 6.9% of cases (95% confidence interval, 6.4-7.5), whereas 6.3% (95% confidence interval, 4.2-8.7) required blood transfusion. Damage to adjacent organs complicated the primary surgery in 2.0% of women (95% confidence interval, 0.1-6.4), whereas 1.2% (95% confidence interval, 0.3-3.4) required a reoperation after cesarean delivery. Maternal death occurred in 0.1% (95% confidence interval, 0.0-1.4). In women undergoing cesarean delivery at <28 weeks of gestation, composite adverse maternal outcome complicated 22.9% of cases (95% confidence interval, 16.7-33.8) and 14.0% (95% confidence interval, 5.8-24.9) experienced hemorrhage whereas 7.7% (95% confidence interval, 4.4-11.8) required blood transfusion. Finally, when considering women undergoing cesarean delivery at <26 weeks of gestation, composite adverse maternal outcome was reported in 24.8% (95% confidence interval, 10.1-43.4), whereas the corresponding figures for hemorrhage and need for blood transfusion were 9.2% (95% confidence interval, 1.7-21.6) and 6.1% (95% confidence interval, 0.3-10.0), respectively.

CONCLUSION

Early cesarean delivery is affected by a high rate of maternal intra- and postoperative complications. The findings from systematic review can help clinicians in counseling parents when cesarean delivery is required in an early gestational age.

Lower gestational age is associated with severe maternal morbidity of preterm cesarean delivery

OBJECTIVE

To evaluate whether gestational age was associated with the severe maternal morbidity (SMM) of preterm cesarean delivery between 22 and 34 weeks of gestation (weeks).

MATERIAL AND METHODS

We performed an observational retrospective cohort study in two tertiary university hospitals in 2018. We included all mothers of preterm infants born by caesarean delivery between 22 and 34 weeks, excluding mothers with multiple births greater than two, with pregnancy terminations or stillbirths, and who died unrelated to obstetrical causes. The principal endpoint, SMM, was a composite outcome (classical uterine incision, postpartum hemorrhage defined by blood loss ≥ 500 mL, blood transfusion, any injury to adjacent organs, unplanned procedure/need for reintervention, Intensive Care Unit (ICU) stay longer than 24 h, postpartum fever, and/or death).

RESULTS

Among the 252 women, SMM occurred in 89 (35.3 %) cases. After multivariate analysis, gestational age was independently associated with SMM (adjusted Odds Ratio [aOR] 0.87; 95 % Confidence Interval [CI] 0.78-0.97). The other variables statistically associated with SMM were type of pregnancy with a negative association with twin pregnancy (aOR, 0.44; 95 % CI, 0.20-0.93) and a positive association with general anesthesia (aOR, 2.52; 95 % CI, 1.25-5.13). A sensitivity analysis was performed and found an association, at the limit of significance, between gestational age < 28 weeks and SMM (aOR, 1.80; 95 % CI, 0.99-3.27, p = 0.05).

CONCLUSION

Lower gestational age was associated with the risk of SMM for preterm caesarean delivery between 22 and 34 weeks. Obstetricians should integrate this knowledge into their shared decision-making processes with parents.

Intraoperative adverse events associated with extremely preterm cesarean deliveries

INTRODUCTION

At the same time as survival is increasing among premature babies born before 26 weeks of gestation, the rates of cesarean deliveries before 26 weeks is also rising. Our purpose was to compare the frequency of intraoperative adverse events during cesarean deliveries in two gestational age groups: 24-25 weeks and 26-27 weeks.

MATERIAL AND METHODS

This single-center retrospective cohort study included all women with cesarean deliveries performed before 28⁺⁰ weeks from 2007 through 2015. It compared the frequency of intraoperative adverse events between two groups: those at 24-25 weeks of gestation and at 26-27 weeks. Intraoperative adverse events were a classical incision, transplacental incision, difficulty in fetal extraction (explicitly mentioned in the surgical report), postpartum hemorrhage (≥500 mL of blood loss), and injury to internal organs. A composite outcome including at least one of these events enabled us to analyze the risk factors for intraoperative adverse events with univariate and multivariable analysis. Stratified analyses by the indication for the cesarean were performed.

RESULTS

We compared 74 cesarean deliveries at 24-25 weeks of gestation and 214 at 26-27 weeks. Intraoperative adverse events occurred at higher rates in the 24-25-week group (63.5 vs. 30.8%, p < 0.001). After adjustment for confounding factors, this group remained at significantly higher risk of intraoperative adverse events [adjusted odds ratio 5.04 (2.67-9.50)], even after stratification by indication for the cesarean.

CONCLUSION

These results should help obstetricians and women making decisions about cesarean deliveries at these extremely low gestational ages.