Associations between duration of active second stage of labour and adverse maternal and neonatal outcomes: A cohort study of nulliparous women with spontaneous onset of labour.

OBJECTIVE: To investigate associations between the duration of the active second stage of labour and adverse maternal and neonatal outcomes. METHOD: This cohort study is based on data from a cluster randomised controlled trial (RCT) undertaken at 14 Norwegian birth clinics in Norway from 2014 to 2017. The final sample involved 6804 nulliparous women with a singleton fetus, cephalic presentation, spontaneous onset of labour at term, vaginal delivered and with an active second stage of labour. The women were grouped to active second stage of labour ≤ 60 min and active second stage of labour > 60 min. Binary logistic regression was used to estimate crude and adjusted odds ratios (ORs) of the maternal and neonatal outcomes with an associated 95% confidence intervals (CIs), comparing women in the two groups. RESULTS: There was an increased risk of postpartum haemorrhage > 1000 ml with an adjusted OR 1.31 (95% CI: 1.01-1.69) when the active second stage of labour exceeded 60 min. There was no significant difference in the risk of obstetric anal sphincter injuries (adjusted OR 0.93 [95% CI: 0.65-1.39]), Apgar scores < 7 at 5 min age (adjusted OR 1.13 [95% CI: 0.65-1.97]) or admission to the neonatal intensive care unit (adjusted OR 1.46 [95% CI: 0.61-3.51]) between the study groups. CONCLUSION: Women with an active second stage of labour that exceeds 60 min had an increased risk of postpartum haemorrhage > 1000 ml. We found no association between duration of active stage of labour and obstetric anal sphincter injuries or adverse neonatal outcomes.

Venous blood flow in maternal kidneys in third trimester of pregnancy.

Objectives: Maternal intra-abdominal pressure and hemodynamics change during pregnancy. The left renal vein may be compressed between the uterus and the spine and aorta, causing congestion and impaired venous return from the left kidney during late pregnancy. The aim of this study was to compare venous and arterial blood flow between the right and left kidney in the third trimester in women without known pregnancy complications.Methods: We conducted a prospective cohort study in 50 women with uncomplicated third-trimester pregnancies at Trondheim University Hospital, Norway, from January to April 2018. The arterial and venous blood flow were examined with pulsed wave Doppler in the hilum of the kidneys and the cross section of the area (CSA) of the vessels was measured from 3D acquisitions. Two diameters of the main vein and artery were measured after rotating the image of the vessels in the C-plane to be as circular as possible. CSA was calculated as π×(mean diameter/2)2. Blood flow volume (ml/minute) in the vessels were calculated as 0.5 × TAmax (cm/s)×CSA (cm2)×60. The main outcome was venous and arterial blood flow volumes, and secondary outcomes were maximum velocity (Vmax), minimum velocity (Vmin), pulsatile index (PI), time-averaged maximum flow (TAmax) and renal interolobar vein impedance index (RIVI). We also examined possible associations between blood flow and maternal age, BMI and blood pressure.Results: We observed differences in venous flow parameters between the two kidneys. The mean total flow volume in the renal veins was 274 ml/min in the left vein versus 358 ml/min in the right vein (p=.10). Vmax, TAmax, PI, and RIVI were all significantly lower in the left renal vein. No differences in arterial blood flow between the two kidneys were found. BMI was negatively correlated to flow in the left renal vein (r= -0.28; p<.05), but not associated to flow in the right renal vein.Conclusion: We found that venous flow pattern differs between left and right renal veins in uncomplicated late pregnancies, but the total flow was not significantly different. New studies should be done in women with preeclampsia.

Time to delivery based on sonographic assessment prior to forceps and vacuum.

INTRODUCTION: To compare the duration of vacuum and forceps delivery in relation to ultrasound assessment of fetal head position and station. METHODS: A prospective single-centre cohort study in nulliparous women at term with prolonged second stage of labour. Fetal head position was determined using transabdominal ultrasound and station as head-perineum distance (HPD) from transperineal ultrasound prior to an instrument. The primary outcome was duration of vacuum and forceps to vaginal delivery and was analysed as survival expressed by hazard ratio (HR). Secondary outcomes were delivery mode and immediate neonatal outcome. RESULTS: In the study population of 54 women, the primary instrument was vacuum for 36 and forceps for 18. Four women were delivered by Caesarean section. Estimated median duration for forceps deliveries was 5 min (95% CI 4.0-6.0) vs. 9 min (95% CI 7.3-10.6) for vacuum deliveries (P = 0.17; Log-rank test). The HR for vaginal delivery was 2.02 (95% CI 1.04-3.91, P = 0.038) after adjusting for HPD, maternal age and BMI. OP position had minor influence on the primary outcome (HR changed from 2.02 to 2.08). The first instrument failed in 11/31 (35.5%) where HPD > 35 mm vs. 2/21 (9.5%) where HPD ≤ 35 mm (P < 0.05). There were no cases of Apgar score <7 at 5 min or umbilical artery pH < 7.1. CONCLUSION: In prolonged second stage, delivery with forceps was achieved more quickly than by vacuum when matched for ultrasound determined head station. Irrespective of which was the primary instrument, the failure rate was greater at higher head stations.