A retrospective cohort study of the characteristics of unsuccessful operative vaginal deliveries

INTRODUCTION

Unsuccessful operative vaginal delivery (OVD) is associated with high rates of materno-fetal morbidity. We aimed to examine institutional rates of unsuccessful OVDs (uOVD) and compare them with successful OVD (sOVD) in order to identify factors to aid patient selection and education.

METHODS

A 6-month retrospective cohort study was performed on all unsuccessful and successful OVDs in a tertiary level maternity hospital in the Republic of Ireland. Maternal demographics and obstetric factors were assessed to evaluate potential underlying risk factors for unsuccessful operative vaginal delivery versus successful vaginal delivery.

RESULTS

There were 4,191 births during the study period with an OVD rate of 14.2% (n = 595) with 28 (4.7% of OVDs) being unsuccessful. Unsuccessful OVD were predominately nulliparous (25; 89.2%) with a mean maternal age of 30.1 years (range 20-42), with more than half (n = 15, 53.5%) being induced. The most common indication for induction was prolonged rupture of membranes (PROM) (n = 7, 25%) which was significantly different from the successful OVD group. A senior obstetrician was significantly more likely to be the primary operator in uOVD when compared to sOVD. (82.1 % V 54.1% p < 0.01). The majority of unsuccessful OVD were vacuum deliveries (n = 17; 60.7%), with a significantly higher mean birthweight when compared to successful OVD (3.695 kg V 3.483 kg; p < 0.01). Following an unsuccessful OVD, women were more likely to have a postpartum haemorrhage (64.2 % V 31.5% p < 0.01) and their infant was more likely to require admission to the neonatal intensive care unit (NICU) (32.1 % V 5.8% p < 0.01) when compared with successful OVD.

CONCLUSION

Risk factors for unsuccessful OVD were higher birth weight and induction of labour. There was a higher incidence of postpartum haemorrhage and NICU admission when compared with successful OVD.

Sonographic markers of fetal adiposity and risk of Cesarean delivery

OBJECTIVE

Increased fetal size is associated with shoulder dystocia during labor and subsequent need for assisted delivery. We sought to investigate if increased fetal adiposity diagnosed sonographically in late pregnancy is associated with increased risk of operative delivery.

METHODS

This secondary analysis of the Genesis Study recruited 2392 nulliparous women with singleton pregnancy in cephalic presentation, in a prospective, multicenter study, to examine prenatal and intrapartum predictors of Cesarean delivery. Participants underwent ultrasound and clinical evaluation between 39 + 0 and 40 + 6 weeks' gestation. Data on fetal biometry were not revealed to patients or to their managing clinicians. A fetal adiposity composite of fetal thigh adiposity and fetal abdominal wall thickness was compiled for each infant in order to determine whether fetal adiposity > 90^th centile was associated with an increased risk of Cesarean or operative vaginal delivery.

RESULTS

After exclusions, data were available for 2330 patients. Patients with a fetal adiposity composite > 90^th centile had a higher maternal body mass index (BMI) (25 ± 5 kg/m² vs 24 ± 4 kg/m² ; P = 0.005), birth weight (3872 ± 417 g vs 3585 ± 401 g; P < 0.0001) and rate of induction of labor (47% (108/232) vs 40% (834/2098); P = 0.048) than did those with an adiposity composite ≤ 90^th centile. Fetuses with adiposity composite > 90^th centile were more likely to require Cesarean delivery than were those with adiposity composite ≤ 90^th centile (P < 0.0001). After adjusting for birth weight, maternal BMI and need for induction of labor, fetal adiposity > 90^th centile remained a risk factor for Cesarean delivery (P < 0.0001). A fetal adiposity composite > 90^th centile was more predictive of the need for unplanned Cesarean delivery than was an estimated fetal weight > 90^th centile (odds ratio, 2.20 (95% CI, 1.65-2.94; P < 0.001) vs 1.74 (95% CI, 1.29-2.35; P < 0.001). Having an adiposity composite > 90^th centile was not associated with an increased likelihood of operative vaginal delivery when compared with having an adiposity composite ≤ 90^th centile (P = 0.37).

CONCLUSIONS

Fetuses with increased adipose deposition are more likely to require Cesarean delivery than are those without increased adiposity. Consideration should, therefore, be given to adding fetal thigh adiposity and abdominal wall thickness to fetal sonographic assessment in late pregnancy. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Platelet reactivity changes significantly throughout all trimesters of pregnancy compared with the nonpregnant state: a prospective study

OBJECTIVE

Platelets play an important role in the pathophysiology of uteroplacental disease and platelet reactivity may be an important marker of uteroplacental disease activity. However, platelet reactivity has not been evaluated comprehensively in normal pregnancy. We sought to evaluate platelet reactivity using a number of agonists at defined time points in pregnancy using a novel platelet assay and compare these with a nonpregnant cohort.

DESIGN

Prospective longitudinal study.

SETTING

Outpatient department of a large tertiary referral centre.

SAMPLE

Eighty participants with 30 nonpregnant women and 50 pregnant women assessed longitudinally.

METHODS

This was a prospective cohort study performed longitudinally throughout uncomplicated singleton pregnancies with participants recruited before 15 weeks of gestation. They were controlled for a number of factors known to affect platelet reactivity. Blood samples were obtained in each trimester. Thirty nonpregnant healthy female volunteers also had a platelet assay performed. A modification of standard light transmission aggregometry was used to assess platelet function, with light absorbance measured following the addition of five different agonists at submaximal concentrations. Dose-response curves were plotted for each agonist for the nonpregnant cohort and in each trimester for the pregnant cohort.

MAIN OUTCOME MEASURES

Dose-response curves and median effective concentration.

RESULTS

When compared with the nonpregnant controls a significant reduction was demonstrated in platelet reactivity to collagen during the first trimester of pregnancy (P < 0.0001). Platelet aggregation increased significantly from the first to third trimesters in response to collagen and arachidonic acid.

CONCLUSION

Platelet reactivity varies according to pregnancy state, gestational age and agonist. The finding that platelet reactivity is reduced in the first trimester of pregnancy may be useful for the interpretation of further studies examining the role of platelet reactivity in the first trimester of pregnancies that develop uteroplacental disease.

Ponderal index (PI) vs birth weight centiles in the low-risk primigravid population: which is the better predictor of fetal wellbeing?

Our objective was to compare Ponderal index (PI) with birth weight centiles as predictors of perinatal morbidity and to determine which best reflects the presence of placental disease. We prospectively recruited 1,011 low-risk primigravidas and calculated PI and birth weight centiles following delivery. Perinatal morbidity was defined as: pre-term birth (PTB); fetal acidosis; an Apgar score <7 at 5 min or neonatal resuscitation. Placental disease was defined as chronic uteroplacental insufficiency (CUPI); villous dysmaturity; infection or vascular pathology. Ponderal index was statistically reduced (25.33 vs 27.79 p =0.001) and the incidence of infant birth weight <9th centile was statistically higher (11.1% vs 5.1%; p =0.004) in cases with PTB and in CUPI (26.23 vs 27.84; p =0.001 and 28.2.1% vs 10.4%; p =0.002). Both PI and infant birth weight centile <9th centile for gestational age correlate with PTB, however overall, both are poor predictors of neonatal and placental disease.

Born before arrival births: impact of a changing obstetric population

This retrospective cohort study examined 143/39,895 (0.36%) consecutive born-before-arrival (BBA) births. The incidence of BBA births doubled from 0.26% in 2005 to 0.5% in 2009. This increase was mainly attributed to the increase of non-Irish nationals and patients from low socioeconomic groups attending for antenatal care. Poor social background was often coupled with current or past substance misuse and/or a diagnosis of an infectious disease. While there was no excess in maternal morbidity, the perinatal mortality rate among BBA births was three-fold increased (27.9/1,000) when compared with the overall rate for all inborn babies in our hospital (8.5/1,000) but significantly less than previously published (58.4/1,000). Results of our study call for continuing training of paramedic staff involved in these deliveries and neonatal resuscitation. Given the easy accessibility of antenatal services in Ireland, this study highlights the urgent need for optimising parental education and care in this vulnerable group of patients.

Screening for Chlamydia trachomatis in asymptomatic women attending outpatient clinics in a large maternity hospital in Dublin, Ireland

BACKGROUND

Chlamydia trachomatis can cause a sexually transmitted infection, which, untreated, may result in considerable morbidity.

METHODS

A prevalence study was conducted for C trachomatis using nucleic acid amplification technology in asymptomatic women, and certain risk factors that may be used to direct future screening strategies were assessed.

RESULTS

The study population comprised 945 asymptomatic women, of whom 783 were attending antenatal clinics, 91 were attending infertility clinics and 71 were attending family planning clinics. An overall C trachomatis prevalence of 3.7% (35/945) was found, with the highest prevalence of 11.2% (22/196) in Irish single women aged <25 years. Logistic regression analysis showed that single status and age <25 years were independent, statistically significant predictors of C trachomatis infection.

CONCLUSION

These results support routine screening of asymptomatic women who are sexually active and aged <25 years. An opportunist active screening of all sexually active women independent of age should be additionally considered if resources permit.

The role of investigations for term stillbirths

The aim of the study was to document the role of laboratory investigations for unexpected stillbirths at term. It was a retrospective casenote review of 75 unexpected stillbirths at term from 1995 to 1999, at the National Maternity Hospital, Dublin, Republic of Ireland. Investigations performed included blood tests, chromosomal analysis, autopsy and placental histology. Perinatal autopsy was the most informative investigation with positive findings in 49% of cases. There were positive placental findings in 37% of cases. Six of the 26 cases showed abnormal karyotyping. Of the blood tests performed, the Kleihauer-Betke test was most informative, revealing a feto-maternal haemorrhage in 8% of cases and anticardiolipin antibodies were positive in 4% of cases. FBC, TORCH and glycosylated Hb were negative in all 75 patients. Despite thorough investigations 32 of cases (43%) remained unexplained.

Active management of labour revisited: the first 1000 primiparous labours in 2000

This was a prospective observational study in a tertiary referral obstetric unit in Dublin to ascertain the delivery outcome in the first 1000 nulliparous women in 2000. The initial diagnosis of labour was confirmed in the first 1000 consecutive nulliparous women in spontaneous labour with cephalic presentation at term. All patients underwent active management of labour. Active management included strict criteria for the diagnosis of labour, early amniotomy, 2-hourly vaginal examinations, oxytocin augmentation where progress of labour was slow and the presence of a companion (personal nurse) in labour. Epidural analgesia was freely available. Mode of delivery, duration of labour, analgesia usage and maternal and perinatal complications were the main outcome measures. All patients presented with painful uterine contractions, 75% with show in addition, and 36% had spontaneous rupture of membranes on admission. Eighty per cent presented with a cervical dilatation of <or= 2 cm; 72.2% had epidural for pain relief. In 81.8% of cases electronic fetal monitoring was used to monitor the baby. Oxytocin was used in 51.8% to augment labour and a further 6.4% required its use for the first time in the second stage of labour. Fetal blood sampling was performed in 20.8%. The spontaneous vaginal delivery rate was 71.8%, 4.2% were delivered by caesarean section and the operative vaginal delivery rate was 24%. The incidence of prolonged labour (labour duration >12 hours) was 4.3%. Postpartum haemorrhage occurred in 3.8% of mothers and 1.6% of babies were admitted to the special care baby unit. Our study suggests that active management of labour is associated with a low incidence of prolonged labour and a low caesarean section rate.

Effect of early maternal iron stores on placental weight and structure

BACKGROUND

Large placental size and low birthweight have been implicated as factors predicting high blood pressure in adulthood. Maternal anaemia has been suggested as a link. We investigated the interaction between maternal iron status and other factors known to influence birthweight and placental size.

METHODS

In a prospective study of 1650 low-risk, singleton, caucasian pregnancies, we related placental size and birthweight to maternal iron status, socioeconomic status, and parity. Placental morphology was assessed in 17 randomly chosen primigravid pregnancies.

FINDINGS

Parity was an important determinant of birthweight (mean standard deviation score -0.13 [SD 0.90] para 0; -0.24 [0.90] para 1; 0.32 [1.1] para 2; 0.21 [1.1] para > or = 3; p<0.0001) and placental weight (mean 655 g [SD 130]; 679 g [122]; 675 g [139]; 694 g [157], respectively; p=0.01). Cigarette smoking influenced birthweight only. Socioeconomic status had little effect after correction for parity. In addition to parity, the factors influencing placental weight were maternal height, weight, and serum ferritin concentration at booking, but not haemoglobin concentration. Serum ferritin concentrations were associated with folate intake and parity. In the placental morphology subset, serum ferritin concentration was inversely related to overall measures of peripheral villous capillarization. Haemoglobin concentration showed no such association.

INTERPRETATION

These findings show a relation between maternal anaemia and placental size and birthweight across the normal range for these measures. Low ferritin concentrations in early pregnancy were associated with increased placental vascularisation at term. The association between ferritin concentration and folate supplementation emphasises the importance of preconceptional health, particularly in women at high risk of iron deficiency.

Intra-amniotic inflammation in human gastroschisis: possible aetiology of postnatal bowel dysfunction

OBJECTIVE

To assess amniotic fluid for evidence of an inflammatory exudate in association with fetal gastroschisis.

SETTING

University College Hospital, London and Institute of Child Health, London.

SAMPLE

Samples of amniotic fluid in the third trimester from pregnant women with a diagnosis of fetal gastroschisis (n = 10) and from a control group (n = 10) with a normal fetus.

METHODS

Cytological analysis of the fluid was performed. Flow cytometry was performed on the amniotic fluid using antibodies for the myeloid cell antigen CD15, the leucocyte beta integrin CD11b/CD18 and CD3, CD19, CD56 and CD25. Tumour necrosis factor alpha and interleukin-8 levels were assayed in the amniotic fluid.

RESULTS

An acute inflammatory exudate, composed predominantly of neutrophil polymorphs and mononuclear cells, was found in the amniotic fluid in fetal gastroschisis but not in control cases. When amniotic fluid samples from cases of fetal gastroschisis were stained with CD15, analysis by flow cytometry showed a clear positive population. This CD15 population showed markedly elevated levels of CD11b. No distinct population of CD15 positive cells was seen in amniotic fluid samples examined from the control group. No staining was seen with antibodies to CD3, CD19, CD56 or CD25 in amniotic fluid obtained from either group. There was no significant difference between tumour necrosis factor alpha levels measured in the amniotic fluid of cases of fetal gastroschisis (median 102 pg/mL; range 20-340) and those of the control group (140 pg/mL; range 20-548) (P = 0.1). The levels of interleukin-8 were markedly elevated in the amniotic fluid of cases of fetal gastroschisis (median 6320 pg/mL; range 4732-13,800) compared with the control group (median 1738 pg/mL; range 623 2861;) (P < 0.01).

CONCLUSION

Human fetal gastroschisis is associated with an inflammatory exudate in the amniotic fluid which may have implications for postnatal bowel function.

Perinatal outcome and prognostic factors in prenatally diagnosed congenital diaphragmatic hernia

OBJECTIVE

The purpose of this study was to assess perinatal outcome in cases of prenatally diagnosed congenital diaphragmatic hernia and identify the prognostic value of various prenatal factors.

DESIGN

Retrospective review of fetal medicine, obstetric and histopathology records in all 34 cases of congenital diaphragmatic hernia identified prenatally between 1992 and 1996 at a tertiary referral fetal medicine unit.

RESULTS

Overall survival was 18%. None of those with bilateral (0/1) or right-sided (0/5) congenital diaphragmatic hernia survived, whereas 21% (6/28) of those with left-sided hernias survived. Prenatal karyotyping was performed in 71% (n = 24) and five chromosomal abnormalities were identified. The pregnancy was terminated in 15 cases (44%). In the 19 continuing pregnancies, the survival rate was 32% (6/19). In those with an isolated congenital diaphragmatic hernia, the survival rate was 38% (5/13), and in those in which the hernia was isolated and left-sided, the survival rate was 56% (5/9). In ongoing pregnancies diagnosed after 24 weeks, the survival rate was 33% (2/6) compared with 31% (4/13) in pregnancies diagnosed at < or = 24 weeks. Of those infants who had surgical repair, six out of seven (86%) survived.

CONCLUSIONS

These data clearly demonstrate an improved prognosis in fetuses with an isolated left-sided congenital diaphragmatic hernia.