This is referred to as "delivery en caul". Complete expulsion of the baby signals the successful completion of the second stage of labour. Some babies, especially preterm infants, are born covered with a waxy or cheese-like white substance called vernix. It is thought to have some protective roles during fetal development and for a few hours after birth. The second stage varies from one woman to another. In first labours, birth is usually completed within three hours whereas in subsequent
labours, birth is usually completed within two hours. Second-stage labours longer than three hours are associated with declining rates of spontaneous vaginal delivery and increasing rates of infection, perineal tears, and obstetric haemorrhage, as well as the need for intensive care of the neonate. Third stage: placenta delivery
The period from just after the fetus is expelled until just after the placenta is expelled is called the third stage of labour or the involution stage. Placental expulsion begins as a physiological separation from the wall of the uterus. The average time from delivery of the baby until complete expulsion of the placenta is estimated to be 10–12 minutes dependent on whether active or expectant management is employed. In as many as 3% of all vaginal deliveries, the duration of the third stage is longer than 30 minutes and raises concern for retained placenta.Placental expulsion can be managed actively or it can be managed expectantly, allowing the placenta to be expelled without medical assistance.
This illustrates how hypervirulent strains can arise from non-pathgenic strains due to the high propensity of gene transfers and DNA uptake by N. meningitidis. Diagnosis
A small amount of cerebrospinal fluid (CSF) is sent to the laboratory as soon as possible for analysis. The diagnosis is suspected, when Gram-negative diplococci are seen on Gram stain of a centrifuged sample of CSF; sometimes they are located inside white blood cells. The microscopic identification takes around 1–2 hours after specimen arrival in the laboratory.The gold standard of diagnosis is microbiological isolation of N. meningitidis by growth from a sterile body fluid, which could be CSF or blood. Diagnosis is confirmed when the organism has grown, most often on a chocolate agar plate, but also on Thayer-Martin agar. To differentiate any bacterial growth from other species a small amount of a bacterial colony is tested for oxidase, catalase for which all clinically relevant Neisseria show a positive reaction, and the carbohydrates maltose, sucrose, and glucose, in which N. meningitidis will ferment that is, utilize the glucose and maltose. Finally, serology determines the subgroup of the N. meningitidis, which is important for epidemiological surveillance purposes; this may often only be done in specialized laboratories. The above tests take a minimum of 48–72 hours turnaround time for growing the organism, and up to a week more for serotyping.