We did not have information on infant sex, alcohol, tobacco or other drug exposure, prenatal care, maternal disease status, paternal demographic characteristics, or marital status.
This pattern of increasingly underreporting of paternal demographic data led us to speculate that pregnancies for which paternal characteristics are partially or completely missing may be associated with increased risk for uteroplacental bleeding disorders.
Tan et al.[ 27] reported that the association between missing paternal demographic and placental abruption among twin births to be significantly higher in pregnancies with paternal information totally missing (RR 1.44, 95% CI 1.27, 1.61), compared with paternal information partially missing (RR 1.03, 95% CI 0.67, 1.39).
Data on paternal demographics, notably race and age, from birth certificate data are becoming increasingly incomplete in recent years.
"Parental demographic factors" included maternal and paternal age (categorized as 19 24 years, 25 29 years, 30 34 years, and ≥ 35 years), immigration status (foreign-born or not, as inferred from country of birth), and marital status (married or not).
In addition, maternal demographic details are obtained; maternal and paternal height are measured and maternal weight is serially measured during the pregnancy; maternal, paternal and offspring DNA are collected; and, samples of placenta and membranes are collected at birth.
The questionnaire included parental demographic and socioeconomic information, a detailed residential history, maternal and paternal occupational history, family history of ASD, smoking history, maternal reproductive and pregnancy history, and child's medical history.
In contrast, paternal educational level was significantly associated with the risk of LBW, after adjustment for maternal educational level, parental demographics, and health services factors.
A previous study using the same birth registry reported that paternal socio-demographic factors seemed to be more important predictors of perinatal mortality than maternal socio-demographic factors in this area [ 11].
Such variables are paternal socio-demographic characteristics, paternal mental health and paternal employment history.
Data were collected in a cross-sectional prospective survey on maternal and paternal geo-demographic factors, maternal health and pregnancy history (MHPH) and neonatal outcome from all public hospitals (Hayatabad Medical Complex, Khyber Teaching Hospital, Lady Reading Hospital, and Government Maternity Hospital) in Peshawar during August to November 2003 through clinicians on duty.
