Table 1.

Database schema

Main forms (minimal dataset)
Data form	Data level 1	Data level 2	Data level 3	Comments
Registration	Initials; date of birth; postcode; hospital number; NHS number; number of fetuses; consent to database; consent to storage of baby identifier			Initials, date of birth, hospital number and NHS number are transferred to separate “Patient Details Database”.
Clinic Record	Demographics	Expected date of delivery (EDD)
		Gravida		Number of pregnancies, including current
		Parity		Number of live births or pregnancies ending at 24+ 0 or more weeks’ gestation
		Height (cm)
		Weight (kg)
		BMI (kg/m2)		Calculated from height and weight
		Age (at EDD)		Calculated from date of birth and EDD.
		Ethnicity		Drop down list
		Smoking status		Drop down list
		Lower super output area		Postcode converted to lower super output area.
	Risk factors/ reasons for referral	Previous preterm birth	Number of previous preterm births and earliest gestation
		Previous premature ruptured membranes (PPROM)	Number of previous PPROMs and earliest gestation
		Previous late miscarriage	Number of previous late miscarriages and latest gestation
		Previous cervical surgery	Number of previous cervical surgeries and most significant procedure
		Uterine abnormality		Drop down list
		Multiple pregnancy		Enter number
		Other risk factors		Drop down list and free text
	Preterm clinic visits	Date		Enter date
		Gestation		Calculated from date of visit and EDD
		Shortest cervical length
		Fetal fibronectin results
		Infection screen results
		Other test results
		Symptoms	None; abdominal/ back pain; tightenings; tightenings and pain; vaginal pressure; PV loss; other
	Preterm birth interventions	Type	E.g. cerclage; progesterone; pessary; bedrest; admission
		Sub-type	E.g. low vaginal cerclage; high vaginal cerclage; abdominal cerclage
		Indication for intervention	History indicated; ultrasound indicated; emergency/rescue
		Intervention date
		Gestation		Calculated from EDD and date of intervention
		Date of delivery
	Pregnancy outcome	Onset of labour	Spontaneous; induced; pre-labour caesarean
		Gestation at delivery		Calculated from EDD and date of delivery
		Birthweight
		Maternal outcomes	No significant morbidities; maternal infection or inflammation; pre-labour rupture of membranes; harm to mother from intervention; ITU admission Maternal death
		Neonatal outcomes	Livebirth; stillbirth; miscarriage; NNU admission; infection (proven, ≤ 72 h); early neuro-developmental morbidity; late neuro-developmental morbidity; gastro-intestinal morbidity; respiratory morbidity; harm to infant from intervention; neonatal death
Additional data forms	Comments (for additional details if required)
Medical History	Tick and text boxes for recording of medical conditions and current medications.
Obstetric History	Space for recording previous pregnancies: year; gestation, outcome; onset of labour; mode of delivery; preterm birth interventions; gestation at intervention.
Cervical Surgery	Space for recording cervical surgery: year; type; anaesthetic; depth
Antenatal details	Details of preterm interventions; day assessment episodes and antenatal inpatient nights, e.g. tocolysis; steroid administration; antibiotics; progesterone; cerclage; pessary.
Delivery Details	Onset of labour; reason if not spontaneous; magnesium sulphate and antibiotics in labour; markers of maternal infection (e.g. pyrexia, test results); blood loss; date of discharge; number of postnatal nights.
Neonatal Details	Date and time of delivery; gestation at delivery; date and time of rupture of membranes; mode of delivery; gender; birthweight; Apgar scores; congenital abnormalities; NNU admission; neonatal morbidities and death; discharge from hospital; number of inpatient nights (one form created per fetus).
Research Participation Record	Record of patient’s participation in preterm birth research: study name; study ID; date of enrolment; study design; treatment allocation.