Effect of mode of delivery on perinatal outcome in severe preterm birth: systematic review and meta-analysis

OBJECTIVE

To review the evidence on the effect of mode of delivery on perinatal outcome of fetuses born before 32 weeks' gestation.

METHODS

MEDLINE, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), the ClinicalTrials.gov registry and gray literature sources were searched, starting from the year 2000 to reflect contemporary practice in perinatal care. Non-randomized or randomized studies that included singleton fetuses without chromosomal abnormality or major congenital defect delivered vaginally or via Cesarean section were eligible for inclusion in the analysis. Primary outcomes were neonatal death, defined as death in the first 28 days of age, and survival to discharge. Secondary outcomes were other adverse perinatal events. The ROBINS-I tool was used to assess the risk of bias. The overall quality of evidence for the outcomes was assessed according to GRADE. Summary odds ratios (ORs) with 95% CIs were calculated, and random-effects models were used for data synthesis. Subgroup analysis was performed for delivery before 28 weeks, delivery between 28 and 32 weeks and according to fetal presentation at delivery.

RESULTS

A total of 27 retrospective studies (22 887 neonates) were included in the systematic review and meta-analysis, all of which reported on singleton pregnancies. Among cases born before 28 weeks, vaginal delivery significantly increased the risk of neonatal death of fetuses with any type of presentation (n = 1496) (OR 1.87 (95% CI, 1.05-3.35); I2  = 65%, very low quality of evidence) and of fetuses with breech presentation (n = 733) (OR 3.55 (95% CI, 2.42-5.21); I2  = 21%, moderate quality of evidence). The odds of survival to discharge were significantly decreased among fetuses with breech presentation delivered before 28 weeks (n = 646) (OR 0.36 (95% CI, 0.24-0.54); I2  = 21%, low quality of evidence). Among breech fetuses born between 28 and 32 weeks, vaginal delivery increased the odds of perinatal death (intrapartum and neonatal) (n = 1581) (OR 3.06 (95% CI, 1.47-6.35); I2  = 0%, high quality of evidence). In non-cephalic fetuses born between 24 and 32 weeks, vaginal delivery decreased the odds of survival to discharge (n = 1030) (OR 0.28 (95% CI, 0.19-0.40); I2  = 0%, moderate quality of evidence). No significant effect on mortality of mode of delivery was observed in cephalic fetuses at any gestational age.

CONCLUSIONS

This systematic review and meta-analysis suggests that vaginal delivery in severe preterm birth is associated with an increased risk of neonatal and perinatal death in breech fetuses, while no significant association was observed for cephalic fetuses. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

[Puerperal inhibition of lactation with metergoline or bromocriptine]

In a controlled, randomised, prospective, clinical study, the effect of prolactin suppression and clinical course of the lactation suppressors Bromocriptine and Metergoline were investigated. During 7 months 150 patients were studied. 81 of those patients, who did not nurse, were treated by Bromocriptine (primary lactation suppression: n = 62, secondary suppression: n = 19) and 69 of the patients were treated by Metergoline (primary suppression: n = 54, secondary suppression: n = 15). The drugs were administrated orally to all subjects, dosed 2 x 2.5 mg/d of Bromocriptine for 14 days and 3 x 4 mg/d of Metergoline for 10 days, starting in average after 13 hours. Puerperal suppression of prolactine were compared with randomised breast feeding subjects (n = 30). In Bromocriptine treated women the average plasma prolactin level decreased from 78.4 +/- 22 ng/ml to 17.0 +/- 3.3 ng/ml during five days of treatment. In Metergoline treated women the plasma prolactin level decreased from 129.7 +/- 15.1 ng/ml to 56.9 +/- 10.0 ng/ml during the first days of treatment. Prolactin level of breast feeding subjects decreased from 233.6 +/- 21.4 ng/ml to 185.8 +/- 23.7 ng/ml during the same period (p < 0.05). There is no statistical significancy of clinical difference of both drugs, but a statistical trend was seen. With Bromocriptine treated women were suppressed efficiently in 71 of 81 cases, 10 refused. Refusals were divided in two quality levels, level I with subjects with moderate complaints and little puerperal lactation, level II with subjects with considerable complaints including strong puerperal lactation. With Metergoline suppressed women, treatment was efficiently in 51 of 69 cases, but refusals of level I were observed in 11 cases and refusals of level II were observed in 7 cases. The results show that Bromocriptine and Metergoline are effective on suppression of lactation. Under the current drug dose of Metergoline an advantage of Bromocriptine were observed. Only further studies could investigate, whether an adaptation of drug dose would improve the clinical efficiency of Metergoline.

[Vaginal delivery in breech presentation does not increase early newborn morbidity. Results of 423 infants with breech presentation 1988-1992]

423 deliveries by breech presentation (1988-1992), delivered by vaginally or abdominally management, were analysed. 72 preterm (32nd to 36th gestational week) and 351 term labours were studied. In 239/423 (56.5%) cases neonates were delivered vaginally, in 54/423 (12.8%) and 130/423 (30.7%) cases primary or secondary cesarean section was necessary. In 120/423 (51.9%) cases of all primaparous spontaneously delivery were realized. There was no difference in early morbidity of vaginal und abdominal delivered neonates (pHNA, APGAR-Score, intracranially bleeding). Three intracranially bleedings (I degrees, II degrees, III degrees) observed in the vaginally delivery group (n = 239), were not the result of breech presentation or vaginally management. No correlation between vaginally management, acidosis and intracranially bleeding were observed. In patients presented with preterm labour (32nd to 36th gestational week) and/or fetal intrauterin growth retardation, cesarean section could be indicated. In postnatal sonographic screening of all neonates hip joint disorders were twice more frequently in female neonates (n = 51 vs. n = 26) without correlation to delivery mode. In conclusion, if certain personally and equipmently conditions are considered, vaginally delivery mode does not correlate to an increase of early neonatal morbidity.