Just before the fourth season of the period medical drama "Call the Midwife" runs its fourth episode this coming weekend, the fifth season of the series got the green light from BBC and the producers. 

Season 5 will reportedly include a Christmas special slated in December this year. This will be followed by eight hour-long episodes in 2016. Currently, there is no official release date for the fifth season. BBC has not revealed a specific U.K. release date either. 

One of the protagonists of the show's Christmas special is Jennifer Worth, the nurse who wrote the memoir on which the show is based. 

Meanwhile, the fourth episode of the series' fourth season will stray away from the usual childbirth and trauma that were featured in previous episodes. Instead, it may set up some storyline, including a gaping crack in Trix and Tom's relationship after they have become engaged. 

The synopsis of the episode 4 reads: 

"The midwives face one of their busiest nights to date, whilst Sister Winifred concentrates her efforts on the prostitutes of Poplar. Elsewhere, cracks start to appear in Trixie and Tom Hereward's relationship." 

"Call the Midwife" is a new type of medical drama featuring nurse midwives in the East End of London in the 1950s. The show first aired in January 2012, and was an instant hit with viewers. It is one of the most-watched dramas in Britain with the episodes averaging 10 million viewers each. 

The show stars Miranda Hart (winner of the Best Actress prize at the National Television Awards last year) as Camilla "Chummy" Noakes. Other stars are Jenny Agutter as Sister Julienne and Pam Ferris as Sister Evangelina. 

As of now, audience can sit back and enjoy the fourth season until it completes its series of eight episodes, then look forward to the arrival of the fifth season of the show.