= Notes on the Pregnancy-Related Tables = 

[[PageOutline]]

The correct and accurate modelling of a pregnancy and its outcomes is rather involved, and some assumptions had to be made. This page illustrates the model used in the pregnancy tables to which these assumptions lead.

== Example ==

Consider the following example: 

 1. A female patient (123) gets pregnant at time `(a)`. 
 1. At time `(b)` she has an abortion which causes the dead fetus of `CHILD 701`. 
 1. At time `(c)`, she gets pregnant again. 
 1. The delivery of this pregnancy is at time `(d)`, when the twins (`CHILD 702` and `CHILD 703`) are born.

{{{
              (a)     (b)             (c)          (d)
MUM 123   -----|-------|---------------|------------|--------------------

CHILD 701              |-|
CHILD 702                                           |--------------------
CHILD 703                                           |--------------------
}}}

This story is described in the different pregnancy tables as follows:

**There are two records in [[TablePreg|tblPREG]], one for each pregnancy:**

||= **MOTHER_ID** =||= **PREG_SEQ** =||= MENS_D =||= ... =||
|| 123 || 1 || (a) || ... ||
|| 123 || 2 || (c) || ... ||

**There are three records in [[TablePregOut|tblPREG_OUT]] describing the pregnancy outcome for each fetus**:

||= **MOTHER_ID** =||= **PREG_SEQ** =||= **CHILD_ID** =||= OUTCOM =||= ... =||
|| 123 || 1 || 701 || 21 || ... ||
|| 123 || 2 || 702 ||  1 || ... ||
|| 123 || 2 || 703 ||  1 || ... ||

**There is one record in [[TableDeliveryMum|tblDELIVERY_MUM]]:**

||= **MOTHER_ID** =||= **PREG_SEQ** =||= **MEMRUP_D** =||= ... =||
|| 123 || 2 || (d) || ... ||

**There are two records in [[TableDeliveryChild|tblDELIVERY_CHILD]]:**

||= **MOTHER_ID** =||= **MEMRUP_D** =||= **CHILD_ID** =||= ... =||
|| 123 || (d) || 702 || ... ||
|| 123 || (d) || 703 || ... ||

**There are two records in [[TableNewborn|tblNEWBORN]]**:

||= **CHILD_ID** =||= ... =||
|| 702 || ... ||
|| 703 || ... ||

== Important relations ==

The following statements are true for a well-encoded data set:

 1. Every record in [[TablePregOut|tblPREG_OUT]] refers to some existing record in [[TablePreg|tblPREG]].
 2. For every record in [[TablePregOut|tblPREG_OUT]] that describes a delivery, there is exactly one record in [[TableDeliveryChild|tblDELIVERY_CHILD]] referring to it.
 3. For every record in [[TableDeliveryMum|tblDELIVERY_MUM]], there are 1 or more records in [[TableDeliveryChild|tblDELIVERY_CHILD]] referring to it.
 4. For every record in [[TableNewborn|tblNEWBORN]] there is exactly one record in [[TableDeliveryChild|tblDELIVERY_CHILD]] referring to the same child.
 5. For every record in [[TableDeliveryMum|tblDELIVERY_MUM]], there is some record in [[TablePreg|tblPREG]] to which it refers.