Antepartum, Intrapartum, and Maternal-Fetal Factors Affecting the Newborn
Risk factors are the anticipatory map
Antepartum factors: pregestational and gestational diabetes (macrosomia, birth trauma, hypoglycemia, respiratory distress, polycythemia), chronic and pregnancy-associated hypertension (growth restriction, abruption, preterm birth), tobacco and substance use, thyroid disease, cholestasis, alloimmunization, and multiple gestation. Intrapartum factors: group B streptococcus status, duration of membrane rupture, maternal fever or chorioamnionitis, meconium, fetal heart rate category, operative or instrumented delivery, and medications - magnesium sulfate (hypotonia, respiratory depression, poor feeding), opioids, and general anesthesia.
Timing and growth are the traps
Late preterm infants (34 0/7–36 6/7 weeks) look like small term newborns but carry multiplied risk: hypoglycemia, jaundice, feeding difficulty, temperature instability, apnea. Gestational age drives the plan more than weight does. Separate small for gestational age (a growth curve descriptor) from intrauterine growth restriction (a pathologic process); not every SGA infant is growth restricted, and not every growth-restricted infant is SGA.
Worked example
Rupture of membranes 20 hours, maternal temperature 38.3 °C, GBS status unknown, fetal tachycardia. This infant is at risk for early-onset sepsis. Correct action: notify the team, anticipate a complete blood count and blood culture with possible antibiotics, and observe closely. A well-appearing infant does not automatically escape evaluation when maternal chorioamnionitis is present. Meconium is similar: only a minority develop meconium aspiration syndrome, so not every meconium birth requires intubation.