2.1 Study population and design
The present study was based on the
baseline study of the birth cohort in Jinan, the capital city of
Shandong Province in China, from December 2018 to December 2019. Data
were collected in 15 community vaccination clinics which were selected
from 116 community vaccination clinics in the study area. Women who met
the inclusion criteria were investigated when their newborns were filed
for outpatient vaccination.
Eligibility criteria included: (1) the infant was delivered without
congenital disease; (2) lived in Jinan during pregnancy; (3) does not
have mental diseases or other diseases that affect normal communication.
Only singleton live births were included.
A self-designed questionnaire for basic information of infants and
mothers was used for a one-to-one face-to-face questionnaire survey. The
information about infants includes birth outcomes, newborn birth weight,
and so on, the maternal information including her general demographic
characteristics, family economic conditions, last menstrual period and
gestational age, physical exercise during pregnancy (including the
frequency, time, and primary exercise patterns), and others included
maternal tobacco exposure, work, and nutrition during pregnancy.
The study was approved by the Ethics Committee of Preventive Medicine of
Shandong University (Approved number: 20170315), and all participants
gave their informed consent.