Table 1 Description and classification of the variables

Sickle cell disease

Sickle cell disease (SCD)

Sickle cell trait

No sickle cell disease/trait

Pregnancy results

Spontaneous abortion

Induced abortion

Live birth

Stillbirth

Haemoglobin level of the mother

Severe anaemia (HB ≤7g/dl)

Anaemia (HB ≤11g/dl)

Gestational week

Pre-term (≤36 gestational week)

Full-term (37–42 weeks)

Post-term (>42 weeks)

Blood transfusion

0

1–2

3 and more

Caesarean section (for live/stillbirth)

Yes

No

Birth weight of the children (for live/stillbirth)

Severely low birth weight (<1.5 kg)

Low birth weight (<2.5 kg)

Normal birth weight (>2.5 kg)

Diagnose morbidities during pregnancy

• Sickle cell crises (only for sickle cell patient)

Yes, No

• Intrauterine growth retardation

Yes, No

• Pregnancy-induced hypertension

Yes, No

• Eclampsia

Yes, No

• Preterm labour pain

Yes, No