Explanation of variable:
    type of obstetrical problem
    
 
    Format of data:
     character: 
    - 1 = Preterm contractions 
- 2 = Shortened cervix 
- 3 = Preterm rupture of membranes 
- 4 = Antepartum bleeding 
- 5 = Intrauterine growth retardation (IUGR) 
- 6 = Preeclampsia/HELLP 
- 7 = Hypertension 
- 8 = Gestational diabetes (unspecified type) 
- 8.1 = Gestational diabetes (Diet) 
- 8.2 = Gestational diabetes (Insulin) 
- 9 = Placental abruption 
- 10 = Placenta praevia 
- 99 = Other, specify in PROB_S