Call the Midwife’s Nonnatus House takes “extreme step” in first-look clip

"Both twins are showing signs of infection," Dr Patrick Turner (Stephen McGann) says. "Lets send these samples off to the lab but this is gastroenteritis."

Shelagh (Laura Main) comments on the fact that a number of mothers in the ward already have the stomach flu, with their babies likely contracting it next. "We're going to have to close the maternity home and probably the surgery," Dr Turner states.

"That's such an extreme step," Shelagh sighs. "But any newborns who catch this could become severely dehydrated in a matter of hours," Dr Turner says.

Soon, Shelagh draws up a plan of round-the-clock nursing care with limited staff rotation to reduce the risk of it spreading further. "Which means us – we'll have to stay for the duration," Trixie (Helen George) says.

The dramatic clip ends with Vinita Khatri cradling her baby and in distress, calling for a nurse. And in the final moments, it looks like her baby has gastroenteritis as well.

Watch the preview below:

As well as the expected chaos in episode 4, the team will be joined by Sister Monica Joan (Judy Parfitt), who must dig deep to ensure all mothers and newborn babies recover from the worrying outbreak.

Unfortunately, their actions have not gone unnoticed by the Board of Health, who are less than happy with the way things have been handled.

The synopsis for the episode also reveals: "When Nurse Crane attends a ventouse training course at St Cuthbert’s, her age is called into question by the consultant running the course, and she is summoned to a meeting with the Board of Health.

"She starts to question her own abilities and suffers a crisis of confidence whilst overseeing the care of Simone and Larry Lucas, who are expecting their second child.

"They are a young couple living in a council flat, and when the seemingly straightforward delivery runs into problems, Nurse Crane faces the challenges of a traumatic delivery alone."

The episode will also focus on Reggie (Daniel Laurie), who is home from the Glasshouse Village, but is not his usual self. He is drained of energy and suffering some hair loss.

Concerned, Violet (Annabelle Apsion) and Fred (Cliff Parisi) try to work out what’s wrong, but it's not until Cyril (Zephryn Taitte) encourages Reggie to seek help that they finally get some answers.

Call the Midwife airs on BBC One on Sundays at 8pm and is also available to stream on BBC iPlayer.

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