Pregnancy outcomes
Follow up the outcome of each pregnant woman’s delivery. Preterm birth refers to the gestational age <37 weeks. Low birth weight refers to the birth weight of newborns <2500g regardless of gestational age. PROM refers to the rupture of the membranes before delivery. Neonatal asphyxia refers to: 1) there are risk factors for neonatal asphyxia; 2) Apgar score ≤ 7 at 1 or 5 minutes after birth; 3) umbilical artery blood gas parameter pH <7.15; 4) exclude other causes of low Apgar score (11). Neonatal infection is defined as a laboratory-diagnosed bacterial infection (positive blood, cerebrospinal fluid, or urine culture) and/or the presence of clinical signs of infection (pneumonia, fever, hypothermia, or respiratory distress, etc.)(12). Stillbirth means that the fetus has no signs of life after birth at 28 weeks and later. Meconium-stained amniotic fluid (MSAF) means that amniotic fluid is contaminated with meconium and presents different colors, such as: lightly stained yellow, greenish color or dark green(13). Puerperal infection refers to infection of the genital tract during delivery and puerperium, causing local and systemic inflammatory, affecting postpartum recovery and even newborn feeding(14). Neonatal Intensive Care Unit (NICU) admission refers to the transfer of newborns to NICU after birth.