Caput succedaneum is swelling of the scalp in a newborn. It is most often brought on by pressure from the uterus or vaginal wall during a head-first (vertex) delivery.
A caput succedaneum is more likely to form during a prolonged or difficult delivery. This is especially true after the membranes have ruptured, because the amniotic sac is no longer providing a protective cushion for the baby's head. Vacuum extraction can also increase the chances of a caput succedaneum.
A caput succedaneum is sometimes identified by prenatal ultrasound even before labor or delivery begins. It has been found as early as 31 weeks of pregnancy. More often than not, this is associated with either premature rupture of the membranes or too little amniotic fluid (oligohydramnios). All other things being equal, the longer the membranes are intact, the less likely it is that a caput will form.
A physical examination will confirm that the swelling is a caput succedaneum. No testing is necessary.
No treatment is necessary, and it usually heals spontaneously within a few days.
Complete recovery can be expected, with the scalp regaining its normal contour.
This condition is usually noticed immediately after delivery of the child, so no call is necessary -- unless you have additional questions.
Mangurten HH. Birth Injuries. In: Fanaroff AA, Martin RJ, eds. Neonatal-Perinatal Medicine: Diseases of the Fetus and Infant. 9th ed. Philadelphia, Pa: Mosby Elsevier; 2010.