The Study
Material and Methods
In the first two years the project will focus on the following complications (roughly estimated total numbers in the Nordic countries per year are given in parenthesis):
· Uterine rupture (200 - 300)
· Placenta percreta (200-250)
· Peripartum hysterectomy (60 - 100)
· Severe peripartum haemorrhage (transfusion > 5 units of blood) (300 - 400)
Identification of cases and controls
The study will identify cases from two sources:
(1) The Nordic Birth Registers, and the Danish Transfusion Database
(2) Directly from obstetricians/midwifes at the obstetric units
The Transfusion Database will exclusively be used in Denmark to identify cases with peripartum haemorrhage receiving more than three units of blood.
The direct report is based on requested information on cases by a monthly mail from the national responsible member of the research group to obstetricians, one from each region in each of the Nordic countries.
The background population for the study will be described by common variables in the Nordic Medical Birth Registers.
Data entry
There are two methods to collect data for the database.
1. On identification of a case, the obstetrician will fill in an electronic form that is forwarded to the central team in Denmark and stored at Rigshospitalet.
2. For those who cannot or do not wish to use the electronic form - a paper form with identical questions forwarded to the national central team and entered in a local database or forwarded to the central team in Denmark.
The collaborators at the Medical Birth Registries will identify two matched controls for each case and ask the obstetrician to fill in and forward the forms.
On identification of a case, the Medical Birth Registry will provide the data for the two preceding women giving birth at the same hospital (unmatched control group). The matched control group is also identified using the Medical Birth Registry. The central team will update the Medical Birth Registry on the needed information. When specific questions arise that cannot be solved by register data – ”control questionnaires” will be sent out to the reporting clinicians.
The data collection forms will seek confirmation of the appropriate case definition and additional information on risk factors, management and outcomes. The additional information will exceed that, which is reported to the Medical Birth Register. Identical data collection forms will be used for the controls except for details of the specific condition.
Statistical analyses
Risk factor profiles will be compared with those of controls and those of the background population described in the Nordic Medical Birth Registries.
Incidence rates with 95% confidence intervals will be calculated and outcomes (maternal death, other major complication, perinatal death) explored in the above-mentioned pre-specified subgroups.
For comparision of dichotome data a chi2 test or Fischers exact test will be used.
Outcome variables will be analyzed by univariate or multivariate logistic regression and results will be presented with Odds ratios and 95% confidence limits.
Case description
Uterine rupture
Definition:
· Complete uterine rupture (including myometrium, peritoneum and fetal membranes)
· Incomplete uterine rupture (including myometrium but with intact peritoneum and fetal membranes
In cases with both uterine rupture and hysterectomy cases should be reported by the data collection form for uterine rupture.
Recorded variables:
Age, BMI, Parity, Smoker (yes/no), Previous caesarean section (yes/no), Type of previous caesarean (low transverse/other), Closure of the uterine wall (one or two layer), major pregnancy complications, maternal morbidity, induction of labour (yes/no), Induction with prostaglandins (yes/no), Augmentation of labour with oxytocin (yes/no), Duration of labour (<8hrs, ≥8hrs), Anatomy and treatment of the rupture, etc.
Placenta percreta
Definition:
Patients with vaginal delivery and difficult, incomplete manual removal of placenta and blood transfusion within 48 hours
Patients with caesarean section and with difficult removal of placenta assessed to be accrete or percrete
In cases with both placenta percreta and hysterectomy cases should be reported by the data collection form for placenta percreta.
Recorded variables:
Age, Parity, Smoker, BMI, Previous caesarean section (yes/no), Type of previous caesarean (low transverse/other), Closure of the uterine wall (one or two layer), major pregnancy complications, maternal morbidity, week and method of diagnosis of abnormal placenta, Surgical procedure, Medical treatment (Metrotexate), Number of blood transfusions, Transfusion of Factor VII, etc.
Peripartum hysterectomy
Definition:
Cases with hysterectomy within 7 days after delivery
Recorded variables:
Age, BMI, Parity, Smoker, Previous caesarean section (yes/no), type of previous caesarean (low transverse/other), Closure of the uterine wall (one or two layer), major pregnancy complications, maternal morbidity, induction of labour (yes/no), induction with prostaglandins (yes/no), augmentation of labour with oxytocin (yes/no), Duration of labour (<8hrs, ≥8hrs), Indication of hysterectomy Treatment of post partum haemorrhage prior to hysterectomy etc.
Severe peripartum haemorrhage
Definition:
Patients receiving 6 or more units of “whole blood” or “Packed red cells” within 7 days after delivery.
Cases with placenta percreta, uterine rupture or hysterectomy should be reported using the relevant data collection forms
Recorded variables
Age, BMI, parity, smoker, previous caesarean section, type of previous caesarean (low transverse/other), closure of the uterine wall (one or two layer), major pregnancy complications, maternal morbidity, induction of labour, induction with prostaglandins, augmentation of labour with oxytocin (yes/no), duration of labour, anatomy of the rupture, medical and surgical treatment of post partum haemorrhage, administration of i.v. replacement fluids etc.
Time schedule
Data collection for the pilot study is scheduled to start April 2009. The official study will start the 1. of September and continue for two whole years.
Results
We hope to present the results at the NFOG Congress in June 2012, Bergen
In the first two years the project will focus on the following complications (roughly estimated total numbers in the Nordic countries per year are given in parenthesis):
· Uterine rupture (200 - 300)
· Placenta percreta (200-250)
· Peripartum hysterectomy (60 - 100)
· Severe peripartum haemorrhage (transfusion > 5 units of blood) (300 - 400)
Identification of cases and controls
The study will identify cases from two sources:
(1) The Nordic Birth Registers, and the Danish Transfusion Database
(2) Directly from obstetricians/midwifes at the obstetric units
The Transfusion Database will exclusively be used in Denmark to identify cases with peripartum haemorrhage receiving more than three units of blood.
The direct report is based on requested information on cases by a monthly mail from the national responsible member of the research group to obstetricians, one from each region in each of the Nordic countries.
The background population for the study will be described by common variables in the Nordic Medical Birth Registers.
Data entry
There are two methods to collect data for the database.
1. On identification of a case, the obstetrician will fill in an electronic form that is forwarded to the central team in Denmark and stored at Rigshospitalet.
2. For those who cannot or do not wish to use the electronic form - a paper form with identical questions forwarded to the national central team and entered in a local database or forwarded to the central team in Denmark.
The collaborators at the Medical Birth Registries will identify two matched controls for each case and ask the obstetrician to fill in and forward the forms.
On identification of a case, the Medical Birth Registry will provide the data for the two preceding women giving birth at the same hospital (unmatched control group). The matched control group is also identified using the Medical Birth Registry. The central team will update the Medical Birth Registry on the needed information. When specific questions arise that cannot be solved by register data – ”control questionnaires” will be sent out to the reporting clinicians.
The data collection forms will seek confirmation of the appropriate case definition and additional information on risk factors, management and outcomes. The additional information will exceed that, which is reported to the Medical Birth Register. Identical data collection forms will be used for the controls except for details of the specific condition.
Statistical analyses
Risk factor profiles will be compared with those of controls and those of the background population described in the Nordic Medical Birth Registries.
Incidence rates with 95% confidence intervals will be calculated and outcomes (maternal death, other major complication, perinatal death) explored in the above-mentioned pre-specified subgroups.
For comparision of dichotome data a chi2 test or Fischers exact test will be used.
Outcome variables will be analyzed by univariate or multivariate logistic regression and results will be presented with Odds ratios and 95% confidence limits.
Case description
Uterine rupture
Definition:
· Complete uterine rupture (including myometrium, peritoneum and fetal membranes)
· Incomplete uterine rupture (including myometrium but with intact peritoneum and fetal membranes
In cases with both uterine rupture and hysterectomy cases should be reported by the data collection form for uterine rupture.
Recorded variables:
Age, BMI, Parity, Smoker (yes/no), Previous caesarean section (yes/no), Type of previous caesarean (low transverse/other), Closure of the uterine wall (one or two layer), major pregnancy complications, maternal morbidity, induction of labour (yes/no), Induction with prostaglandins (yes/no), Augmentation of labour with oxytocin (yes/no), Duration of labour (<8hrs, ≥8hrs), Anatomy and treatment of the rupture, etc.
Placenta percreta
Definition:
Patients with vaginal delivery and difficult, incomplete manual removal of placenta and blood transfusion within 48 hours
Patients with caesarean section and with difficult removal of placenta assessed to be accrete or percrete
In cases with both placenta percreta and hysterectomy cases should be reported by the data collection form for placenta percreta.
Recorded variables:
Age, Parity, Smoker, BMI, Previous caesarean section (yes/no), Type of previous caesarean (low transverse/other), Closure of the uterine wall (one or two layer), major pregnancy complications, maternal morbidity, week and method of diagnosis of abnormal placenta, Surgical procedure, Medical treatment (Metrotexate), Number of blood transfusions, Transfusion of Factor VII, etc.
Peripartum hysterectomy
Definition:
Cases with hysterectomy within 7 days after delivery
Recorded variables:
Age, BMI, Parity, Smoker, Previous caesarean section (yes/no), type of previous caesarean (low transverse/other), Closure of the uterine wall (one or two layer), major pregnancy complications, maternal morbidity, induction of labour (yes/no), induction with prostaglandins (yes/no), augmentation of labour with oxytocin (yes/no), Duration of labour (<8hrs, ≥8hrs), Indication of hysterectomy Treatment of post partum haemorrhage prior to hysterectomy etc.
Severe peripartum haemorrhage
Definition:
Patients receiving 6 or more units of “whole blood” or “Packed red cells” within 7 days after delivery.
Cases with placenta percreta, uterine rupture or hysterectomy should be reported using the relevant data collection forms
Recorded variables
Age, BMI, parity, smoker, previous caesarean section, type of previous caesarean (low transverse/other), closure of the uterine wall (one or two layer), major pregnancy complications, maternal morbidity, induction of labour, induction with prostaglandins, augmentation of labour with oxytocin (yes/no), duration of labour, anatomy of the rupture, medical and surgical treatment of post partum haemorrhage, administration of i.v. replacement fluids etc.
Time schedule
Data collection for the pilot study is scheduled to start April 2009. The official study will start the 1. of September and continue for two whole years.
Results
We hope to present the results at the NFOG Congress in June 2012, Bergen
