Wave W1 W2 W3 W4 W5 W6
Time of collection Up to 12 weeks gest 13 to 24 weeks gest 25 weeks to birth Birth 18 mths 6 yrs
Year 2007-2009 2007-2009 2007-2009 2007-2009 2008-2011 2014-2016
Obstetric history P:SDVM C
Mode of conception  P:SDVM C
Parity P:SDVM C
Estimated due date  P:SDVM C
Pregnancy complications P:SDVM
S – self report
P – parent report
C – child report
T – teacher report
N – welfare nurse
O – observation
XM: Mother
XF/P: Father/partner
XC: Child
XS: Sibling
XG: Grandparent

SDV: Study Devised Variable