Royal officials have confirmed that Kate, the Duchess of Cambridge, has safely given birth to a healthy baby boy who is now third in line for the throne of the British monarchy. He was delivered at 4.24pm British summer time (8.24am PST) weighing 8 pounds and 6 ounces.
The Queen's gynecologist Marcus Setchell, who led the medical team to deliver the baby at St. Mary's Hospital in London, signed the news bulletin that is now displayed on an easel at the front of Buckingham Palace, a tradition for royal birth news.
The world's media has been camped outside St. Mary's Hospital since Kate arrived by car for labor at around 6am BST with her husband Will, the Duke of Cambridge, who was still at her side during the birth. A Kensington Palace statement on behalf of Will said: "We could not be happier."
How the news appeared on Twitter
Around 13.30pm PST: "The Queen and Prince Philip are delighted at the news of the birth of The Duke and Duchess of Cambridge's baby."
Around 12.55pm PST: "William and Kate have had a baby boy. 8lb 60z. Born at 4.24pm. William was present. #RoyalBaby"
Around 01.15am PST: "According to Kate's spokesman, 'things are progressing as normal'. #RoyalBaby"
Is "one week late" normal?
The royal family itself gave no official confirmation of Kate's due date, but media speculation is that today's birth was one week overdue. Doctors do not, however, consider one week past a due date to be a problem in healthy pregnant women.
The normal length of a pregnancy (or gestation - calculated from the last menstrual period to birth) is between 38 and 42 weeks, a four-week window in which the timing of a birth could be healthy.
Obstetricians describe infants born before 37 weeks as premature, while it is not until after 42 weeks that babies are considered "postmature."
Was Kate's labor induced?
Again, Kensington Palace on the day of the royal birth has so far given no response to widespread media speculation over whether or not Kate's labor was induced.
The American Congress of Obstetricians and Gynecologists (ACOG) says induction of childbirth in the US has more than doubled since 1990. In 2006, more than 1 in 5 of all pregnant women had their labor induced. There are similar concerns in the UK over increasing rates of induction and Cesarian section operations.
Following the rise in US inductions, ACOG recently revised its guidelines for maternity ward doctors on when and how to induce childbirths.
Induction is appropriate in some health conditions in the pregnant woman or the unborn baby, ACOG says, as long as the "gestational age of the fetus" has been "determined to be at least 39 weeks" or "fetal lung maturity" has been established.
ACOG outlines a number of options available to obstetricians when such induction is appropriate:
"Cervical ripening is the first component to labor induction. If the cervix is not sufficiently dilated, then drugs or mechanical cervical dilators should be used to ripen the cervix before labor is induced."
"Once the cervix is dilated, labor can be induced with oxytocin, membrane stripping, rupture of the amniotic membrane, or nipple stimulation."
"Misoprostol is a commonly used off-label drug that both ripens the cervix and induces labor."
"The ACOG guidelines indicate that inducing labor with misoprostol should be avoided in women who have had even one prior Cesarean delivery due to the possibility of uterine rupture (which can be catastrophic)."