B.OSS

A nationwide Obstetric Surveillance System to identify and analyze rare disorders/complications of pregnancy in Belgium

Definitions

Antenatal Pulmonary Embolism 

B.OSS will use the same definition as used by UKOSS, to enable comparison and participation in international studies.

  • EITHER

PE is confirmed using suitable imaging (angiography, computed tomography, echocardiography, magnetic resonance imaging or ventilation-perfusion scan showing a  high probability of PE)

  • OR      PE is confirmed at surgery or postmortem
  • OR      a clinician has made a diagnosis of PE with signs and symptoms consistent with PE present, and the patient has received a course of anticoagulation therapy (>1 week duration)

Eclampsia

defined according to UKOSS as

any woman with convulsion(s) during pregnancy or within the first 10 days after delivery, in combination with at least 2 of the following features within 24 hours of the convulsion(s) :

  • Hypertension : a maximum diastolic Blood Pressure of >= 90 mmHg and a diastolic increment of >= 25 mmHg (having had a diastolic Blood Pressure <90 mmHg at the first antenatal visit)

  • Proteinuria : at least + protein in a random urine sample or >= 0.3 g of proteins in a 24-hour collection

  • Thrombocytopenia : platelet count < 100000/ml

  • Raised transaminase levels : ALT of >= 42 IU/l or AST of >= 42 IU/l

Uterine rupture

Uterine rupture a larger definition is used including all uterine rupture cases as defined by UKOSS, but also to consider all other forms of uterine rupture as defined by the LEMMoN study in the Netherlands.

Uterine rupture as defined by UKOSS (a complete separation of the wall of the pregnant uterus, with or without expulsion of the fetus, involving rupture of the membranes at the site of the uterine rupture or extension into uterine muscle separate from any previous scar, and endangering the life of the mother or the fetus),

Uterine rupture as defined by the LEMMoN study in the Netherlands (the occurrence of clinical symptoms (abdominal pain, abnormal fetal heart rate pattern, acute loss of contractions, vaginal blood loss), leading to an emergency caesarean delivery, at which the presumed diagnosis of uterine rupture was confirmed; or peripartum hysterectomy of laparotomy for uterine rupture after vaginal birth

UKOSS and LEMMoN both excluded any asymptomatic palpable or visualized defect (for example dehiscence) noted incidentally at caesarean delivery.

Postpartum Hysterectomy and embolisation of the uterine arteries

Postpartum Hysterectomy and embolisation of the uterine arteries as defined by UKOSS: being any woman giving birth to a fetus or infant and undergoing a hysterectomy in the same clinical episode. Similarly “peripartum embolization of the uterine arteries” will be considered when occurring in the same clinical episode.  

Spontaneous hemoperitoneum in pregnancy (SHiP)

Key points:

  • SHiP is the occurence of sudden hemorrhage intraabdominally in pregnancy – unrelated to trauma or rupture of the uterus
  • SHiP has been associated with endometriosis, rupture of uterine artery or varicose veins and aneurysms of the splenic artery.
  • SHiP is rare but potentially fatal for the mother and the fetus.

Inclusion criteria: Any pregnancy after 22 weeks with sudden intraabdominal hemorrhage requiring surgery (CS, laparotomy, laparoscopy) - without preceding trauma.

Excluding: uterine rupture, trauma.

Anaphylaxis in Pregnancy

The cases will be all pregnant women (during pregnancy and up to 48 hours post delivery) identified as having anaphylaxis according to the following definition (Resuscitation Council, 2008).

Anaphylaxis is defined as a severe, life-threatening generalised or systemic hypersensitivity reaction. The following two criteria must be met for a diagnosis of anaphylaxis to be made:

1. A life-threatening airway problem and/or breathing problem and/or circulatory problem

2. Sudden onset and rapid progression of symptoms

1. A life-threatening airway problem is taken to include:

- Laryngeal or pharyngeal oedema

- Hoarse voice

- Stridor

2. A life-threatening breathing problem is taken to include:

- Shortness of breath and raised respiratory rate (or dyspnea)

- Wheeze (laryngospasm or bronchospasm)

- Decreased oxygen saturations

- Confusion secondary to hypoxia

- Cyanosis

- Respiratory exhaustion or respiratory arrest

3. A life-threatening circulatory problem is taken to include:

- Signs of shock such as faintness, pallor or clammy skin

- Tachycardia >100bpm

- Systolic BP <90mmHg or MBP<60mmHg or measured hypotension

- Decreasing level of consciousness

- Signs of ischaemia on ECG

- Cardiac arrest

Previous definitions have included skin and/or mucosal features as a core criteria. However, these may not be evident if treatment is rapidly implemented, so this study shall include all women in whom the final clinical diagnosis is anaphylaxis, irrespective of the presence or absence of skin/mucosal changes.