Pregnancy

That occurred at four maternity units in the prefecture of Heraklion during 1 year starting in February 2007 by trained nurses and midwives. 1,610 women of gestational age less than 15 weeks agreed to participate, from a total of 1,765 women first approached (response rate 91%). Almost 1,300 mothers were followed up until delivery.

During planned visits to their obstetrician in early, mid and late-pregnancy and through phone interviews, women were invited to complete questionnaires, participate in physical examinations and provide biological samples. Medical records were also available due to the continuous collaboration with midwives and obstetric clinics. Data collection in the prenatal phase included:

Questionnaires

Τhere were 3 questionnaires covering the period of pregnancy. They contained a broad range of questions about maternal socio-demographic background, reproductive and medical histories, family history, pregnancy related events and complications, mood and personality characteristics, lifestyle and diet during pregnancy, environmental exposures as well as information for the father. Read more on the questionnaires and on the food frequency questionnaire.

a) Maternal social capital: was assessed by the Social Capital Questionnaire (SCQ) (Onyx and Bullen, 2000). SCQ has been validated in Greece (SCQ-G) comprising a general social capital factor, as well as six factors in 36 questions (Kritsotakis et al., 2008, 2010): Participation in the Local Community, Feelings of Safety, Family/Friends Connections, Value of Life and Social Agency, Tolerance of Diversity, and Work Connections.

b) Maternal mood and psychopathology: Anxiety (State-Trait Anxiety Inventory STATI), depressive symptoms (Edinburg Postnatal Depression Scale, EPDS), and personality characteristics (Eysenck personality Questionnaire-Revised EPQ-R) were evaluated.

c) Environmental and occupational exposures:

- Lifestyle, housing conditions:

  • Smoking and other nicotine products
  • The mother's exercise habits
  • Concerns, sleep and relationships with family and friends
  • Working status and working exposures
  • Medical history and family history

- Food frequency questionnaire

It was completed in early and mid-pregnancy in order to assess dietary habits over pregnancy. Frequency of consumption and average portion size of 250 food items were asked along with information on cooking methods, supplements consumption, alcohol use, organic food consumption, different types of vegetarianism, dietary changes due to pregnancy, as well as conditions of pregnancy that could affect diet and food intake (nausea, vomiting, etc.). The questions were hierarchical, from general to more specific. The exact frequency of consumption was given per day, per week and/or per month, depending on the food item. Photographs were used to visualise small, medium and large portion sizes for each food item.

Physical examination and medical records

They were planned at the first major ultrasound and at mid-pregnancy including height, weight and blood pressure measurements. We also collected data on fetal ultrasound examinations performed at each prenatal visit. These ultrasound examinations were used for both establishing gestational age and assessing fetal growth patterns.

Biological samples

Blood samples in a fasting state were collected at the time of the first major ultrasound as well as urine samples. Biomarkers measured in those samples included, nutrition-related markers (e.g. vitamins, lipid profile, glucose,insulin), inflammatory markers, thyroid hormones, persistent organic pollutants, pthalates, cotinine and others.

Birth

Type of delivery, the anesthesia required as well as the health state and anthropometric measurements of the newborn (weight, length and head circumference) were recorded at birth or otherwise subtracted from the medical records. A sample of cord blood was taken, if mothers agreed on that.