Beyoncé and Jay Z's twins premature delivery has delayed the singers' from bringing home their newborn babies. But sources say the hospital is just taking standard precautions after children are delivered early.

TMZ reported that twins, a boy and a girl, are undergoing treatment for jaundice and that as of a few days ago they were still in the hospital. Sources told the website that Jay Z said the twins are “under the lights,” which is a term used when treating the condition. So how serious is it?

Jaundice is due to high bilirubin (a brownish yellow substance created when old red blood cells are replaced by new ones) levels and is often caused when a baby’s liver is immature and can properly process the substance. This causes the skin and whites of the eyes to turn yellow. To treat this, babies are put under lights that help reduce bilirubin in the blood, therefore getting rid of jaundice. Luckily, there are no long-term effects for babies who suffer from jaundice, and it’s common with premature births.

Beyonce's Twins Have Arrived Sources confirmed that Beyonce and Jay Z recently welcomed their twins. But the couple still has not revealed the babies' names.

Though the condition is common, the couple isn’t taking any chances and is keeping their newborns in the hospital until they stabilize, according to the report.

The news of the arrival of Beyonce and Jay-Z’s bundles of joy was confirmed when the “Lemonade” singer’s dad made an announcement on Twitter. “They're here! #beyonce #twins #jayz #happybirthday,” Mathew Knowles wrote on Twitter, posting a card saying, “Happy birthday to the twins! Love, Granddad.”

Then an unidentified woman was photographed Friday carrying a bouquet of pink, blue and purple flowers with a card that seemed to say “B + J” and pink and blue balloons in the shape of feet that read “Baby Girl” and “Baby Boy.” And a source close to the couple told People that “Bey and Jay are thrilled and have started sharing the news with their family and closest friends.”

Beyonce Blue Ivy Mothers Day Beyonce and Blue Ivy celebrated Mother's Day in adorable matching dresses.

Meanwhile, there’s still no comment from Beyonce or Jay Z. Fans were hoping to get an official announcement on Sunday during the BET Awards when Chloe x Halle delivered the “Formation” singer’s acceptance speech for the viewer’s choice award. But there was no mention of her new bundles of joy.

Jay-Z was also supposed to be doing promotional work this week for his new album called “4:44,” which comes out on June 30, but he canceled appearances and has stayed mum as well. There are reports he’s going to the delay the tour of his new album to make sure the new additions to his family are home safe and sound.

What do you think Beyoncé and Jay Z should name the twins? Let us know your take in the comments section below!