STUDY QUESTION: Do paternal and maternal lifestyle factors influence the risk of hypertensive pregnancy complications, gestational diabetes mellitus (GDM), spontaneous preterm birth and small-for-gestational-age (SGA)? SUMMARY ANSWER: Paternal lifestyle factors do not exert an independent effect on the investigated outcomes while maternal prepregnancy BMI and maternal smoking during pregnancy influence the risk of hypertensive pregnancy complications, GDM and SGA. WHAT IS KNOWN ALREADY: Maternal lifestyle factors are associated with perinatal complications, but the impact of paternal lifestyle factors is unclear. STUDY DESIGN, SIZE, DURATION: Data from the GECKO (Groningen Expert Center for Kids with Obesity) Drenthe cohort, a prospective population-based birth-cohort of children born between April 2006 and April 2007 in a northern province of The Netherlands, were analysed. The parents of 2958 children (62% of those approached) gave their consent to participate in the study and the data of 2264 (77%) couples were available for analysis. PARTICIPANTS/MATERIALS, SETTINGS, METHOD: All pregnant women in the Dutch province of Drenthe with an expected date of delivery between April 2006 and April 2007 were invited to participate and included during the third trimester of their pregnancy or within 6 months after delivery. All consenting couples received extensive questionnaires including lifestyle, biological and socio-demographic-related questions covering the period of 6 months prior to conception. Outcome data were obtained from midwives and hospital registries. Univariable and multivariable logistic regression analyses were used to determine the impact of the lifestyle factors on the primary outcome measures. MAIN RESULTS AND THE ROLE OF CHANCE: Of all 2264 women, 241 women (10.6%) developed a hypertensive pregnancy complication, 50 women (2.2%) developed GDM, 79 (3.5%) children were spontaneously delivered preterm and 155 children (6.8%) were SGA. All paternal and maternal lifestyle factors were positively correlated. Multivariable analysis showed that paternal lifestyle factors did not have an independent influence on the investigated outcomes. Of the maternal factors, prepregnancy BMI was independently associated with an increased risk of a hypertensive disorder during pregnancy (odds ratio (OR): 1.12, 95% CI 1.09-1.16), a higher risk of GDM (OR BMI >23 kg/m(2), per BMI unit: 1.13, 95% CI 1.08-1.18) and with a decreased risk of SGA (OR per BMI point 0.94, 95% CI 0.90-0.99). Maternal smoking during pregnancy was significantly associated with SGA (OR 3.00, 95% CI 1.80-4.99) in multivariable analysis. LIMITATIONS, REASONS FOR CAUTION: The retrospective nature of the questionnaire may have induced recall bias. Selection bias might have occurred, as ethnic minorities were less willing to co-operate in the GECKO Drenthe study. The possibility of misclassification bias regarding the primary outcome measures cannot be ruled out. Inclusion bias might have occurred as not all questionnaires of the parents of the children participating in the GECKO Drenthe cohort were completed. WIDER IMPLICATIONS OF THE FINDINGS: Paternal lifestyle factors do not have an independent effect on the investigated adverse pregnancy outcomes. However, as paternal and maternal lifestyles are positively correlated, both partners should be involved in preconception counselling regarding the investigated outcome measures.
STUDY QUESTION: Do paternal and maternal lifestyle factors influence the risk of hypertensive pregnancy complications, gestational diabetes mellitus (GDM), spontaneous preterm birth and small-for-gestational-age (SGA)? SUMMARY ANSWER: Paternal lifestyle factors do not exert an independent effect on the investigated outcomes while maternal prepregnancy BMI and maternal smoking during pregnancy influence the risk of hypertensive pregnancy complications, GDM and SGA. WHAT IS KNOWN ALREADY: Maternal lifestyle factors are associated with perinatal complications, but the impact of paternal lifestyle factors is unclear. STUDY DESIGN, SIZE, DURATION: Data from the GECKO (Groningen Expert Center for Kids with Obesity) Drenthe cohort, a prospective population-based birth-cohort of children born between April 2006 and April 2007 in a northern province of The Netherlands, were analysed. The parents of 2958 children (62% of those approached) gave their consent to participate in the study and the data of 2264 (77%) couples were available for analysis. PARTICIPANTS/MATERIALS, SETTINGS, METHOD: All pregnant women in the Dutch province of Drenthe with an expected date of delivery between April 2006 and April 2007 were invited to participate and included during the third trimester of their pregnancy or within 6 months after delivery. All consenting couples received extensive questionnaires including lifestyle, biological and socio-demographic-related questions covering the period of 6 months prior to conception. Outcome data were obtained from midwives and hospital registries. Univariable and multivariable logistic regression analyses were used to determine the impact of the lifestyle factors on the primary outcome measures. MAIN RESULTS AND THE ROLE OF CHANCE: Of all 2264 women, 241 women (10.6%) developed a hypertensive pregnancy complication, 50 women (2.2%) developed GDM, 79 (3.5%) children were spontaneously delivered preterm and 155 children (6.8%) were SGA. All paternal and maternal lifestyle factors were positively correlated. Multivariable analysis showed that paternal lifestyle factors did not have an independent influence on the investigated outcomes. Of the maternal factors, prepregnancy BMI was independently associated with an increased risk of a hypertensive disorder during pregnancy (odds ratio (OR): 1.12, 95% CI 1.09-1.16), a higher risk of GDM (OR BMI >23 kg/m(2), per BMI unit: 1.13, 95% CI 1.08-1.18) and with a decreased risk of SGA (OR per BMI point 0.94, 95% CI 0.90-0.99). Maternal smoking during pregnancy was significantly associated with SGA (OR 3.00, 95% CI 1.80-4.99) in multivariable analysis. LIMITATIONS, REASONS FOR CAUTION: The retrospective nature of the questionnaire may have induced recall bias. Selection bias might have occurred, as ethnic minorities were less willing to co-operate in the GECKO Drenthe study. The possibility of misclassification bias regarding the primary outcome measures cannot be ruled out. Inclusion bias might have occurred as not all questionnaires of the parents of the children participating in the GECKO Drenthe cohort were completed. WIDER IMPLICATIONS OF THE FINDINGS: Paternal lifestyle factors do not have an independent effect on the investigated adverse pregnancy outcomes. However, as paternal and maternal lifestyles are positively correlated, both partners should be involved in preconception counselling regarding the investigated outcome measures.